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Cases Studies in Public Health Available Online

First study of mers animal host in saudi arabia.

Case studies aren’t just for business schools anymore. Columbia University’s Mailman School of Public Health has been using the case method to teach MPH students as part of the new Columbia Public Health Curriculum. Now, six of the School’s public health cases have been published online, making them available to classrooms anywhere.

“The case method can be a powerful tool for learning public health. It gives students the opportunity to gain experience making decisions in the face of uncertainty, much as they will have to do every day when they graduate and leave us to work in their chosen field,” says Melissa Begg, ScD , Vice Dean for Education at the Mailman School, who is leading the implementation of the new MPH curriculum.

Each case study tells a detailed story which stops mid-action, asking students to imagine themselves into the shoes of a decision-maker facing a tough call. One case developed with the help of David Abramson, PhD , assistant professor of Sociomedical Sciences, looks at the decision of whether to evacuate two hospitals during Superstorm Sandy. Another looks at how to win a community’s trust, as told through the experience of Mailman scientists conducting a federally-funded study of arsenic-tainted water in Bangladesh.

Classroom discussions are lively, and most important, there isn’t a single right answer. “Students practice taking positions and defending them based on the available evidence, while developing communication and critical thinking skills,” explains Dr. Begg. “They learn to argue persuasively for their points of view.

The Mailman School case studies are available through Columbia University’s Case Consortium website, which also features cases by Columbia’s Journalism School and the School for International and Public Affairs (SIPA). They are available free (after registration) to educators and at a nominal cost to students, professionals, and other interested parties. 

“While most existing case curriculum remains paper-based, the Mailman School cases are online and multimedia, meeting students where they live in the digital media world,” says Kirsten Lundberg, MPA, director of the Case Consortium @ Columbia.

The “discussion-based” case study approach has historic roots reaching back to Socrates, and was popularized in the 20th century by business schools. To see the cases, please visit  Case Consortium  and click on Cases.

Public Health Case Studies

Voluntary or Regulated? The Trans Fat Campaign in New York City

This case takes students behind the scenes in the world of public health policymaking.  Students follow the New York City Department of Health and Mental Hygiene, and the process it went through to craft a policy to reduce public consumption of trans fats in restaurants. In 2005, after considerable internal negotiations, the department’s Bureau of Chronic Disease Prevention and Control elected to launch a public awareness campaign aimed equally at consumers, restaurants and their suppliers. But after a year, the awareness campaign had not budged the rate of trans fat use in restaurants. In 2006, the department decided to resort to regulation, despite the risks of triggering protests of a “nanny state,” not to mention pushback from industry.

When BEST Intentions Go Awry: Arsenic Mitigation in Bangladesh

This case is about a public health response to the widespread arsenic contamination of groundwater in Bangladesh. It examines the lead-up to a 2008 media crisis that confronted a Columbia University clinical trial of a potential treatment for arsenic poisoning. The case raises for discussion the challenges of conducting research in rural, less developed and culturally insular communities. It also asks how to help communities while studying them—complicated by funding restrictions and a possible skewing of results. 

Community Savings, or Community Threat? California Policy for Ill and Elderly Inmates

This case looks at the challenges that confront public health professionals who work in a corrections environment. By 2011, a court-appointed Receiver had made progress in fixing a broken system of medical care for prisoners in California. But costs spiraled ever higher for elderly and ailing inmates. Public health officials had to balance competing public priorities: save taxpayer dollars while treating patients. A new law allowed the sickest prisoners to move to community-based care—but now public health doctors had to decide: who qualified for medical parole?

Credible Voice: WHO-Beijing and the SARS Crisis

This case study takes students into the Beijing office of the World Health Organization as it dealt with the SARS crisis in early 2003. The WHO serves as the world’s monitor of disease outbreak and control. It is able to mobilize legions of the world’s best scientists to analyze, diagnose, prescribe treatments for and contain diseases. However, it depends on the cooperation of the countries experiencing an epidemic. What happens when that cooperation is limited or nonexistent?

The Elusive Tuberculosis Case: The CDC and Andrew Speaker

This case explores the ethical and logistical challenges that doctors face when an infectious disease patient does not cooperate with advice to stay out of public spaces in order to protect the general welfare. In April 2007, a young Atlanta lawyer, Andrew Speaker, was diagnosed with active tuberculosis. Initially cooperative, Speaker departs without notice for Greece and his scheduled wedding even though it is clear that his strain of TB is more lethal and difficult-to-treat than anticipated. 

Evacuate or Stay? Northshore LIJ and Hurricane Sandy

This case examines the pros and cons of evacuating medical facilities in the face of a looming natural disaster. In October 2012, the North Shore-Long Island Jewish Hospitals (North Shore-LIJ) network braced—together with rest of the East coast—for the advent of Hurricane Sandy. Weather forecasters painted a grim picture, and North Shore-LIJ had three hospitals in low-lying areas. Vice President of Protective Services James Romagnoli and COO Mark Solazzo had seen this scenario only a year earlier, when in August 2011 they evacuated hospitals in advance of Hurricane Irene. But Irene had, at the last moment, spared New York City. With that unnecessary evacuation fresh in their minds, the two officials had to decide what to do as Sandy approached.

• Open access
• Published: 10 November 2020

Case study research for better evaluations of complex interventions: rationale and challenges

• Sara Paparini   ORCID: orcid.org/0000-0002-1909-2481 1 ,
• Judith Green 2 ,
• Chrysanthi Papoutsi 1 ,
• Jamie Murdoch 3 ,
• Mark Petticrew 4 ,
• Trish Greenhalgh 1 ,
• Benjamin Hanckel 5 &
• Sara Shaw 1  

BMC Medicine volume  18 , Article number:  301 ( 2020 ) Cite this article

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The need for better methods for evaluation in health research has been widely recognised. The ‘complexity turn’ has drawn attention to the limitations of relying on causal inference from randomised controlled trials alone for understanding whether, and under which conditions, interventions in complex systems improve health services or the public health, and what mechanisms might link interventions and outcomes. We argue that case study research—currently denigrated as poor evidence—is an under-utilised resource for not only providing evidence about context and transferability, but also for helping strengthen causal inferences when pathways between intervention and effects are likely to be non-linear.

Case study research, as an overall approach, is based on in-depth explorations of complex phenomena in their natural, or real-life, settings. Empirical case studies typically enable dynamic understanding of complex challenges and provide evidence about causal mechanisms and the necessary and sufficient conditions (contexts) for intervention implementation and effects. This is essential evidence not just for researchers concerned about internal and external validity, but also research users in policy and practice who need to know what the likely effects of complex programmes or interventions will be in their settings. The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence. Second, there is little consensus about what a case study is, and considerable diversity in how empirical case studies are conducted and reported. Finally, as case study researchers typically (and appropriately) focus on thick description (that captures contextual detail), it can be challenging to identify the key messages related to intervention evaluation from case study reports.

Whilst the diversity of published case studies in health services and public health research is rich and productive, we recommend further clarity and specific methodological guidance for those reporting case study research for evaluation audiences.

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The need for methodological development to address the most urgent challenges in health research has been well-documented. Many of the most pressing questions for public health research, where the focus is on system-level determinants [ 1 , 2 ], and for health services research, where provisions typically vary across sites and are provided through interlocking networks of services [ 3 ], require methodological approaches that can attend to complexity. The need for methodological advance has arisen, in part, as a result of the diminishing returns from randomised controlled trials (RCTs) where they have been used to answer questions about the effects of interventions in complex systems [ 4 , 5 , 6 ]. In conditions of complexity, there is limited value in maintaining the current orientation to experimental trial designs in the health sciences as providing ‘gold standard’ evidence of effect.

There are increasing calls for methodological pluralism [ 7 , 8 ], with the recognition that complex intervention and context are not easily or usefully separated (as is often the situation when using trial design), and that system interruptions may have effects that are not reducible to linear causal pathways between intervention and outcome. These calls are reflected in a shifting and contested discourse of trial design, seen with the emergence of realist [ 9 ], adaptive and hybrid (types 1, 2 and 3) [ 10 , 11 ] trials that blend studies of effectiveness with a close consideration of the contexts of implementation. Similarly, process evaluation has now become a core component of complex healthcare intervention trials, reflected in MRC guidance on how to explore implementation, causal mechanisms and context [ 12 ].

Evidence about the context of an intervention is crucial for questions of external validity. As Woolcock [ 4 ] notes, even if RCT designs are accepted as robust for maximising internal validity, questions of transferability (how well the intervention works in different contexts) and generalisability (how well the intervention can be scaled up) remain unanswered [ 5 , 13 ]. For research evidence to have impact on policy and systems organisation, and thus to improve population and patient health, there is an urgent need for better methods for strengthening external validity, including a better understanding of the relationship between intervention and context [ 14 ].

Policymakers, healthcare commissioners and other research users require credible evidence of relevance to their settings and populations [ 15 ], to perform what Rosengarten and Savransky [ 16 ] call ‘careful abstraction’ to the locales that matter for them. They also require robust evidence for understanding complex causal pathways. Case study research, currently under-utilised in public health and health services evaluation, can offer considerable potential for strengthening faith in both external and internal validity. For example, in an empirical case study of how the policy of free bus travel had specific health effects in London, UK, a quasi-experimental evaluation (led by JG) identified how important aspects of context (a good public transport system) and intervention (that it was universal) were necessary conditions for the observed effects, thus providing useful, actionable evidence for decision-makers in other contexts [ 17 ].

The overall approach of case study research is based on the in-depth exploration of complex phenomena in their natural, or ‘real-life’, settings. Empirical case studies typically enable dynamic understanding of complex challenges rather than restricting the focus on narrow problem delineations and simple fixes. Case study research is a diverse and somewhat contested field, with multiple definitions and perspectives grounded in different ways of viewing the world, and involving different combinations of methods. In this paper, we raise awareness of such plurality and highlight the contribution that case study research can make to the evaluation of complex system-level interventions. We review some of the challenges in exploiting the current evidence base from empirical case studies and conclude by recommending that further guidance and minimum reporting criteria for evaluation using case studies, appropriate for audiences in the health sciences, can enhance the take-up of evidence from case study research.

Case study research offers evidence about context, causal inference in complex systems and implementation

Well-conducted and described empirical case studies provide evidence on context, complexity and mechanisms for understanding how, where and why interventions have their observed effects. Recognition of the importance of context for understanding the relationships between interventions and outcomes is hardly new. In 1943, Canguilhem berated an over-reliance on experimental designs for determining universal physiological laws: ‘As if one could determine a phenomenon’s essence apart from its conditions! As if conditions were a mask or frame which changed neither the face nor the picture!’ ([ 18 ] p126). More recently, a concern with context has been expressed in health systems and public health research as part of what has been called the ‘complexity turn’ [ 1 ]: a recognition that many of the most enduring challenges for developing an evidence base require a consideration of system-level effects [ 1 ] and the conceptualisation of interventions as interruptions in systems [ 19 ].

The case study approach is widely recognised as offering an invaluable resource for understanding the dynamic and evolving influence of context on complex, system-level interventions [ 20 , 21 , 22 , 23 ]. Empirically, case studies can directly inform assessments of where, when, how and for whom interventions might be successfully implemented, by helping to specify the necessary and sufficient conditions under which interventions might have effects and to consolidate learning on how interdependencies, emergence and unpredictability can be managed to achieve and sustain desired effects. Case study research has the potential to address four objectives for improving research and reporting of context recently set out by guidance on taking account of context in population health research [ 24 ], that is to (1) improve the appropriateness of intervention development for specific contexts, (2) improve understanding of ‘how’ interventions work, (3) better understand how and why impacts vary across contexts and (4) ensure reports of intervention studies are most useful for decision-makers and researchers.

However, evaluations of complex healthcare interventions have arguably not exploited the full potential of case study research and can learn much from other disciplines. For evaluative research, exploratory case studies have had a traditional role of providing data on ‘process’, or initial ‘hypothesis-generating’ scoping, but might also have an increasing salience for explanatory aims. Across the social and political sciences, different kinds of case studies are undertaken to meet diverse aims (description, exploration or explanation) and across different scales (from small N qualitative studies that aim to elucidate processes, or provide thick description, to more systematic techniques designed for medium-to-large N cases).

Case studies with explanatory aims vary in terms of their positioning within mixed-methods projects, with designs including (but not restricted to) (1) single N of 1 studies of interventions in specific contexts, where the overall design is a case study that may incorporate one or more (randomised or not) comparisons over time and between variables within the case; (2) a series of cases conducted or synthesised to provide explanation from variations between cases; and (3) case studies of particular settings within RCT or quasi-experimental designs to explore variation in effects or implementation.

Detailed qualitative research (typically done as ‘case studies’ within process evaluations) provides evidence for the plausibility of mechanisms [ 25 ], offering theoretical generalisations for how interventions may function under different conditions. Although RCT designs reduce many threats to internal validity, the mechanisms of effect remain opaque, particularly when the causal pathways between ‘intervention’ and ‘effect’ are long and potentially non-linear: case study research has a more fundamental role here, in providing detailed observational evidence for causal claims [ 26 ] as well as producing a rich, nuanced picture of tensions and multiple perspectives [ 8 ].

Longitudinal or cross-case analysis may be best suited for evidence generation in system-level evaluative research. Turner [ 27 ], for instance, reflecting on the complex processes in major system change, has argued for the need for methods that integrate learning across cases, to develop theoretical knowledge that would enable inferences beyond the single case, and to develop generalisable theory about organisational and structural change in health systems. Qualitative Comparative Analysis (QCA) [ 28 ] is one such formal method for deriving causal claims, using set theory mathematics to integrate data from empirical case studies to answer questions about the configurations of causal pathways linking conditions to outcomes [ 29 , 30 ].

Nonetheless, the single N case study, too, provides opportunities for theoretical development [ 31 ], and theoretical generalisation or analytical refinement [ 32 ]. How ‘the case’ and ‘context’ are conceptualised is crucial here. Findings from the single case may seem to be confined to its intrinsic particularities in a specific and distinct context [ 33 ]. However, if such context is viewed as exemplifying wider social and political forces, the single case can be ‘telling’, rather than ‘typical’, and offer insight into a wider issue [ 34 ]. Internal comparisons within the case can offer rich possibilities for logical inferences about causation [ 17 ]. Further, case studies of any size can be used for theory testing through refutation [ 22 ]. The potential lies, then, in utilising the strengths and plurality of case study to support theory-driven research within different methodological paradigms.

Evaluation research in health has much to learn from a range of social sciences where case study methodology has been used to develop various kinds of causal inference. For instance, Gerring [ 35 ] expands on the within-case variations utilised to make causal claims. For Gerring [ 35 ], case studies come into their own with regard to invariant or strong causal claims (such as X is a necessary and/or sufficient condition for Y) rather than for probabilistic causal claims. For the latter (where experimental methods might have an advantage in estimating effect sizes), case studies offer evidence on mechanisms: from observations of X affecting Y, from process tracing or from pattern matching. Case studies also support the study of emergent causation, that is, the multiple interacting properties that account for particular and unexpected outcomes in complex systems, such as in healthcare [ 8 ].

Finally, efficacy (or beliefs about efficacy) is not the only contributor to intervention uptake, with a range of organisational and policy contingencies affecting whether an intervention is likely to be rolled out in practice. Case study research is, therefore, invaluable for learning about contextual contingencies and identifying the conditions necessary for interventions to become normalised (i.e. implemented routinely) in practice [ 36 ].

The challenges in exploiting evidence from case study research

At present, there are significant challenges in exploiting the benefits of case study research in evaluative health research, which relate to status, definition and reporting. Case study research has been marginalised at the bottom of an evidence hierarchy, seen to offer little by way of explanatory power, if nonetheless useful for adding descriptive data on process or providing useful illustrations for policymakers [ 37 ]. This is an opportune moment to revisit this low status. As health researchers are increasingly charged with evaluating ‘natural experiments’—the use of face masks in the response to the COVID-19 pandemic being a recent example [ 38 ]—rather than interventions that take place in settings that can be controlled, research approaches using methods to strengthen causal inference that does not require randomisation become more relevant.

A second challenge for improving the use of case study evidence in evaluative health research is that, as we have seen, what is meant by ‘case study’ varies widely, not only across but also within disciplines. There is indeed little consensus amongst methodologists as to how to define ‘a case study’. Definitions focus, variously, on small sample size or lack of control over the intervention (e.g. [ 39 ] p194), on in-depth study and context [ 40 , 41 ], on the logic of inference used [ 35 ] or on distinct research strategies which incorporate a number of methods to address questions of ‘how’ and ‘why’ [ 42 ]. Moreover, definitions developed for specific disciplines do not capture the range of ways in which case study research is carried out across disciplines. Multiple definitions of case study reflect the richness and diversity of the approach. However, evidence suggests that a lack of consensus across methodologists results in some of the limitations of published reports of empirical case studies [ 43 , 44 ]. Hyett and colleagues [ 43 ], for instance, reviewing reports in qualitative journals, found little match between methodological definitions of case study research and how authors used the term.

This raises the third challenge we identify that case study reports are typically not written in ways that are accessible or useful for the evaluation research community and policymakers. Case studies may not appear in journals widely read by those in the health sciences, either because space constraints preclude the reporting of rich, thick descriptions, or because of the reported lack of willingness of some biomedical journals to publish research that uses qualitative methods [ 45 ], signalling the persistence of the aforementioned evidence hierarchy. Where they do, however, the term ‘case study’ is used to indicate, interchangeably, a qualitative study, an N of 1 sample, or a multi-method, in-depth analysis of one example from a population of phenomena. Definitions of what constitutes the ‘case’ are frequently lacking and appear to be used as a synonym for the settings in which the research is conducted. Despite offering insights for evaluation, the primary aims may not have been evaluative, so the implications may not be explicitly drawn out. Indeed, some case study reports might properly be aiming for thick description without necessarily seeking to inform about context or causality.

Acknowledging plurality and developing guidance

We recognise that definitional and methodological plurality is not only inevitable, but also a necessary and creative reflection of the very different epistemological and disciplinary origins of health researchers, and the aims they have in doing and reporting case study research. Indeed, to provide some clarity, Thomas [ 46 ] has suggested a typology of subject/purpose/approach/process for classifying aims (e.g. evaluative or exploratory), sample rationale and selection and methods for data generation of case studies. We also recognise that the diversity of methods used in case study research, and the necessary focus on narrative reporting, does not lend itself to straightforward development of formal quality or reporting criteria.

Existing checklists for reporting case study research from the social sciences—for example Lincoln and Guba’s [ 47 ] and Stake’s [ 33 ]—are primarily orientated to the quality of narrative produced, and the extent to which they encapsulate thick description, rather than the more pragmatic issues of implications for intervention effects. Those designed for clinical settings, such as the CARE (CAse REports) guidelines, provide specific reporting guidelines for medical case reports about single, or small groups of patients [ 48 ], not for case study research.

The Design of Case Study Research in Health Care (DESCARTE) model [ 44 ] suggests a series of questions to be asked of a case study researcher (including clarity about the philosophy underpinning their research), study design (with a focus on case definition) and analysis (to improve process). The model resembles toolkits for enhancing the quality and robustness of qualitative and mixed-methods research reporting, and it is usefully open-ended and non-prescriptive. However, even if it does include some reflections on context, the model does not fully address aspects of context, logic and causal inference that are perhaps most relevant for evaluative research in health.

Hence, for evaluative research where the aim is to report empirical findings in ways that are intended to be pragmatically useful for health policy and practice, this may be an opportune time to consider how to best navigate plurality around what is (minimally) important to report when publishing empirical case studies, especially with regards to the complex relationships between context and interventions, information that case study research is well placed to provide.

The conventional scientific quest for certainty, predictability and linear causality (maximised in RCT designs) has to be augmented by the study of uncertainty, unpredictability and emergent causality [ 8 ] in complex systems. This will require methodological pluralism, and openness to broadening the evidence base to better understand both causality in and the transferability of system change intervention [ 14 , 20 , 23 , 25 ]. Case study research evidence is essential, yet is currently under exploited in the health sciences. If evaluative health research is to move beyond the current impasse on methods for understanding interventions as interruptions in complex systems, we need to consider in more detail how researchers can conduct and report empirical case studies which do aim to elucidate the contextual factors which interact with interventions to produce particular effects. To this end, supported by the UK’s Medical Research Council, we are embracing the challenge to develop guidance for case study researchers studying complex interventions. Following a meta-narrative review of the literature, we are planning a Delphi study to inform guidance that will, at minimum, cover the value of case study research for evaluating the interrelationship between context and complex system-level interventions; for situating and defining ‘the case’, and generalising from case studies; as well as provide specific guidance on conducting, analysing and reporting case study research. Our hope is that such guidance can support researchers evaluating interventions in complex systems to better exploit the diversity and richness of case study research.

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Abbreviations

Qualitative comparative analysis

Quasi-experimental design

Randomised controlled trial

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This work was funded by the Medical Research Council - MRC Award MR/S014632/1 HCS: Case study, Context and Complex interventions (TRIPLE C). SP was additionally funded by the University of Oxford's Higher Education Innovation Fund (HEIF).

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Sara Paparini, Chrysanthi Papoutsi, Trish Greenhalgh & Sara Shaw

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Judith Green

School of Health Sciences, University of East Anglia, Norwich, UK

Jamie Murdoch

Public Health, Environments and Society, London School of Hygiene & Tropical Medicin, London, UK

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Institute for Culture and Society, Western Sydney University, Penrith, Australia

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JG, MP, SP, JM, TG, CP and SS drafted the initial paper; all authors contributed to the drafting of the final version, and read and approved the final manuscript.

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Paparini, S., Green, J., Papoutsi, C. et al. Case study research for better evaluations of complex interventions: rationale and challenges. BMC Med 18 , 301 (2020). https://doi.org/10.1186/s12916-020-01777-6

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• Roberta Heale 1 ,
• Alison Twycross 2
• 1 School of Nursing , Laurentian University , Sudbury , Ontario , Canada
• 2 School of Health and Social Care , London South Bank University , London , UK
• Correspondence to Dr Roberta Heale, School of Nursing, Laurentian University, Sudbury, ON P3E2C6, Canada; rheale{at}laurentian.ca

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What is it?

Case study is a research methodology, typically seen in social and life sciences. There is no one definition of case study research. 1 However, very simply… ‘a case study can be defined as an intensive study about a person, a group of people or a unit, which is aimed to generalize over several units’. 1 A case study has also been described as an intensive, systematic investigation of a single individual, group, community or some other unit in which the researcher examines in-depth data relating to several variables. 2

Often there are several similar cases to consider such as educational or social service programmes that are delivered from a number of locations. Although similar, they are complex and have unique features. In these circumstances, the evaluation of several, similar cases will provide a better answer to a research question than if only one case is examined, hence the multiple-case study. Stake asserts that the cases are grouped and viewed as one entity, called the quintain . 6  ‘We study what is similar and different about the cases to understand the quintain better’. 6

The steps when using case study methodology are the same as for other types of research. 6 The first step is defining the single case or identifying a group of similar cases that can then be incorporated into a multiple-case study. A search to determine what is known about the case(s) is typically conducted. This may include a review of the literature, grey literature, media, reports and more, which serves to establish a basic understanding of the cases and informs the development of research questions. Data in case studies are often, but not exclusively, qualitative in nature. In multiple-case studies, analysis within cases and across cases is conducted. Themes arise from the analyses and assertions about the cases as a whole, or the quintain, emerge. 6

Benefits and limitations of case studies

If a researcher wants to study a specific phenomenon arising from a particular entity, then a single-case study is warranted and will allow for a in-depth understanding of the single phenomenon and, as discussed above, would involve collecting several different types of data. This is illustrated in example 1 below.

Using a multiple-case research study allows for a more in-depth understanding of the cases as a unit, through comparison of similarities and differences of the individual cases embedded within the quintain. Evidence arising from multiple-case studies is often stronger and more reliable than from single-case research. Multiple-case studies allow for more comprehensive exploration of research questions and theory development. 6

Despite the advantages of case studies, there are limitations. The sheer volume of data is difficult to organise and data analysis and integration strategies need to be carefully thought through. There is also sometimes a temptation to veer away from the research focus. 2 Reporting of findings from multiple-case research studies is also challenging at times, 1 particularly in relation to the word limits for some journal papers.

Examples of case studies

Example 1: nurses’ paediatric pain management practices.

One of the authors of this paper (AT) has used a case study approach to explore nurses’ paediatric pain management practices. This involved collecting several datasets:

Observational data to gain a picture about actual pain management practices.

Questionnaire data about nurses’ knowledge about paediatric pain management practices and how well they felt they managed pain in children.

Questionnaire data about how critical nurses perceived pain management tasks to be.

These datasets were analysed separately and then compared 7–9 and demonstrated that nurses’ level of theoretical did not impact on the quality of their pain management practices. 7 Nor did individual nurse’s perceptions of how critical a task was effect the likelihood of them carrying out this task in practice. 8 There was also a difference in self-reported and observed practices 9 ; actual (observed) practices did not confirm to best practice guidelines, whereas self-reported practices tended to.

Example 2: quality of care for complex patients at Nurse Practitioner-Led Clinics (NPLCs)

The other author of this paper (RH) has conducted a multiple-case study to determine the quality of care for patients with complex clinical presentations in NPLCs in Ontario, Canada. 10 Five NPLCs served as individual cases that, together, represented the quatrain. Three types of data were collected including:

Review of documentation related to the NPLC model (media, annual reports, research articles, grey literature and regulatory legislation).

Interviews with nurse practitioners (NPs) practising at the five NPLCs to determine their perceptions of the impact of the NPLC model on the quality of care provided to patients with multimorbidity.

Chart audits conducted at the five NPLCs to determine the extent to which evidence-based guidelines were followed for patients with diabetes and at least one other chronic condition.

The three sources of data collected from the five NPLCs were analysed and themes arose related to the quality of care for complex patients at NPLCs. The multiple-case study confirmed that nurse practitioners are the primary care providers at the NPLCs, and this positively impacts the quality of care for patients with multimorbidity. Healthcare policy, such as lack of an increase in salary for NPs for 10 years, has resulted in issues in recruitment and retention of NPs at NPLCs. This, along with insufficient resources in the communities where NPLCs are located and high patient vulnerability at NPLCs, have a negative impact on the quality of care. 10

These examples illustrate how collecting data about a single case or multiple cases helps us to better understand the phenomenon in question. Case study methodology serves to provide a framework for evaluation and analysis of complex issues. It shines a light on the holistic nature of nursing practice and offers a perspective that informs improved patient care.

• Gustafsson J
• Calanzaro M
• Sandelowski M

Competing interests None declared.

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The case study approach

• Sarah Crowe 1 ,
• Kathrin Cresswell 2 ,
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• Guro Huby 3 ,
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The case study approach allows in-depth, multi-faceted explorations of complex issues in their real-life settings. The value of the case study approach is well recognised in the fields of business, law and policy, but somewhat less so in health services research. Based on our experiences of conducting several health-related case studies, we reflect on the different types of case study design, the specific research questions this approach can help answer, the data sources that tend to be used, and the particular advantages and disadvantages of employing this methodological approach. The paper concludes with key pointers to aid those designing and appraising proposals for conducting case study research, and a checklist to help readers assess the quality of case study reports.

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Introduction

The case study approach is particularly useful to employ when there is a need to obtain an in-depth appreciation of an issue, event or phenomenon of interest, in its natural real-life context. Our aim in writing this piece is to provide insights into when to consider employing this approach and an overview of key methodological considerations in relation to the design, planning, analysis, interpretation and reporting of case studies.

The illustrative 'grand round', 'case report' and 'case series' have a long tradition in clinical practice and research. Presenting detailed critiques, typically of one or more patients, aims to provide insights into aspects of the clinical case and, in doing so, illustrate broader lessons that may be learnt. In research, the conceptually-related case study approach can be used, for example, to describe in detail a patient's episode of care, explore professional attitudes to and experiences of a new policy initiative or service development or more generally to 'investigate contemporary phenomena within its real-life context' [ 1 ]. Based on our experiences of conducting a range of case studies, we reflect on when to consider using this approach, discuss the key steps involved and illustrate, with examples, some of the practical challenges of attaining an in-depth understanding of a 'case' as an integrated whole. In keeping with previously published work, we acknowledge the importance of theory to underpin the design, selection, conduct and interpretation of case studies[ 2 ]. In so doing, we make passing reference to the different epistemological approaches used in case study research by key theoreticians and methodologists in this field of enquiry.

This paper is structured around the following main questions: What is a case study? What are case studies used for? How are case studies conducted? What are the potential pitfalls and how can these be avoided? We draw in particular on four of our own recently published examples of case studies (see Tables 1 , 2 , 3 and 4 ) and those of others to illustrate our discussion[ 3 – 7 ].

What is a case study?

A case study is a research approach that is used to generate an in-depth, multi-faceted understanding of a complex issue in its real-life context. It is an established research design that is used extensively in a wide variety of disciplines, particularly in the social sciences. A case study can be defined in a variety of ways (Table 5 ), the central tenet being the need to explore an event or phenomenon in depth and in its natural context. It is for this reason sometimes referred to as a "naturalistic" design; this is in contrast to an "experimental" design (such as a randomised controlled trial) in which the investigator seeks to exert control over and manipulate the variable(s) of interest.

Stake's work has been particularly influential in defining the case study approach to scientific enquiry. He has helpfully characterised three main types of case study: intrinsic , instrumental and collective [ 8 ]. An intrinsic case study is typically undertaken to learn about a unique phenomenon. The researcher should define the uniqueness of the phenomenon, which distinguishes it from all others. In contrast, the instrumental case study uses a particular case (some of which may be better than others) to gain a broader appreciation of an issue or phenomenon. The collective case study involves studying multiple cases simultaneously or sequentially in an attempt to generate a still broader appreciation of a particular issue.

These are however not necessarily mutually exclusive categories. In the first of our examples (Table 1 ), we undertook an intrinsic case study to investigate the issue of recruitment of minority ethnic people into the specific context of asthma research studies, but it developed into a instrumental case study through seeking to understand the issue of recruitment of these marginalised populations more generally, generating a number of the findings that are potentially transferable to other disease contexts[ 3 ]. In contrast, the other three examples (see Tables 2 , 3 and 4 ) employed collective case study designs to study the introduction of workforce reconfiguration in primary care, the implementation of electronic health records into hospitals, and to understand the ways in which healthcare students learn about patient safety considerations[ 4 – 6 ]. Although our study focusing on the introduction of General Practitioners with Specialist Interests (Table 2 ) was explicitly collective in design (four contrasting primary care organisations were studied), is was also instrumental in that this particular professional group was studied as an exemplar of the more general phenomenon of workforce redesign[ 4 ].

What are case studies used for?

According to Yin, case studies can be used to explain, describe or explore events or phenomena in the everyday contexts in which they occur[ 1 ]. These can, for example, help to understand and explain causal links and pathways resulting from a new policy initiative or service development (see Tables 2 and 3 , for example)[ 1 ]. In contrast to experimental designs, which seek to test a specific hypothesis through deliberately manipulating the environment (like, for example, in a randomised controlled trial giving a new drug to randomly selected individuals and then comparing outcomes with controls),[ 9 ] the case study approach lends itself well to capturing information on more explanatory ' how ', 'what' and ' why ' questions, such as ' how is the intervention being implemented and received on the ground?'. The case study approach can offer additional insights into what gaps exist in its delivery or why one implementation strategy might be chosen over another. This in turn can help develop or refine theory, as shown in our study of the teaching of patient safety in undergraduate curricula (Table 4 )[ 6 , 10 ]. Key questions to consider when selecting the most appropriate study design are whether it is desirable or indeed possible to undertake a formal experimental investigation in which individuals and/or organisations are allocated to an intervention or control arm? Or whether the wish is to obtain a more naturalistic understanding of an issue? The former is ideally studied using a controlled experimental design, whereas the latter is more appropriately studied using a case study design.

Case studies may be approached in different ways depending on the epistemological standpoint of the researcher, that is, whether they take a critical (questioning one's own and others' assumptions), interpretivist (trying to understand individual and shared social meanings) or positivist approach (orientating towards the criteria of natural sciences, such as focusing on generalisability considerations) (Table 6 ). Whilst such a schema can be conceptually helpful, it may be appropriate to draw on more than one approach in any case study, particularly in the context of conducting health services research. Doolin has, for example, noted that in the context of undertaking interpretative case studies, researchers can usefully draw on a critical, reflective perspective which seeks to take into account the wider social and political environment that has shaped the case[ 11 ].

How are case studies conducted?

Here, we focus on the main stages of research activity when planning and undertaking a case study; the crucial stages are: defining the case; selecting the case(s); collecting and analysing the data; interpreting data; and reporting the findings.

Defining the case

Carefully formulated research question(s), informed by the existing literature and a prior appreciation of the theoretical issues and setting(s), are all important in appropriately and succinctly defining the case[ 8 , 12 ]. Crucially, each case should have a pre-defined boundary which clarifies the nature and time period covered by the case study (i.e. its scope, beginning and end), the relevant social group, organisation or geographical area of interest to the investigator, the types of evidence to be collected, and the priorities for data collection and analysis (see Table 7 )[ 1 ]. A theory driven approach to defining the case may help generate knowledge that is potentially transferable to a range of clinical contexts and behaviours; using theory is also likely to result in a more informed appreciation of, for example, how and why interventions have succeeded or failed[ 13 ].

For example, in our evaluation of the introduction of electronic health records in English hospitals (Table 3 ), we defined our cases as the NHS Trusts that were receiving the new technology[ 5 ]. Our focus was on how the technology was being implemented. However, if the primary research interest had been on the social and organisational dimensions of implementation, we might have defined our case differently as a grouping of healthcare professionals (e.g. doctors and/or nurses). The precise beginning and end of the case may however prove difficult to define. Pursuing this same example, when does the process of implementation and adoption of an electronic health record system really begin or end? Such judgements will inevitably be influenced by a range of factors, including the research question, theory of interest, the scope and richness of the gathered data and the resources available to the research team.

Selecting the case(s)

The decision on how to select the case(s) to study is a very important one that merits some reflection. In an intrinsic case study, the case is selected on its own merits[ 8 ]. The case is selected not because it is representative of other cases, but because of its uniqueness, which is of genuine interest to the researchers. This was, for example, the case in our study of the recruitment of minority ethnic participants into asthma research (Table 1 ) as our earlier work had demonstrated the marginalisation of minority ethnic people with asthma, despite evidence of disproportionate asthma morbidity[ 14 , 15 ]. In another example of an intrinsic case study, Hellstrom et al.[ 16 ] studied an elderly married couple living with dementia to explore how dementia had impacted on their understanding of home, their everyday life and their relationships.

For an instrumental case study, selecting a "typical" case can work well[ 8 ]. In contrast to the intrinsic case study, the particular case which is chosen is of less importance than selecting a case that allows the researcher to investigate an issue or phenomenon. For example, in order to gain an understanding of doctors' responses to health policy initiatives, Som undertook an instrumental case study interviewing clinicians who had a range of responsibilities for clinical governance in one NHS acute hospital trust[ 17 ]. Sampling a "deviant" or "atypical" case may however prove even more informative, potentially enabling the researcher to identify causal processes, generate hypotheses and develop theory.

In collective or multiple case studies, a number of cases are carefully selected. This offers the advantage of allowing comparisons to be made across several cases and/or replication. Choosing a "typical" case may enable the findings to be generalised to theory (i.e. analytical generalisation) or to test theory by replicating the findings in a second or even a third case (i.e. replication logic)[ 1 ]. Yin suggests two or three literal replications (i.e. predicting similar results) if the theory is straightforward and five or more if the theory is more subtle. However, critics might argue that selecting 'cases' in this way is insufficiently reflexive and ill-suited to the complexities of contemporary healthcare organisations.

The selected case study site(s) should allow the research team access to the group of individuals, the organisation, the processes or whatever else constitutes the chosen unit of analysis for the study. Access is therefore a central consideration; the researcher needs to come to know the case study site(s) well and to work cooperatively with them. Selected cases need to be not only interesting but also hospitable to the inquiry [ 8 ] if they are to be informative and answer the research question(s). Case study sites may also be pre-selected for the researcher, with decisions being influenced by key stakeholders. For example, our selection of case study sites in the evaluation of the implementation and adoption of electronic health record systems (see Table 3 ) was heavily influenced by NHS Connecting for Health, the government agency that was responsible for overseeing the National Programme for Information Technology (NPfIT)[ 5 ]. This prominent stakeholder had already selected the NHS sites (through a competitive bidding process) to be early adopters of the electronic health record systems and had negotiated contracts that detailed the deployment timelines.

It is also important to consider in advance the likely burden and risks associated with participation for those who (or the site(s) which) comprise the case study. Of particular importance is the obligation for the researcher to think through the ethical implications of the study (e.g. the risk of inadvertently breaching anonymity or confidentiality) and to ensure that potential participants/participating sites are provided with sufficient information to make an informed choice about joining the study. The outcome of providing this information might be that the emotive burden associated with participation, or the organisational disruption associated with supporting the fieldwork, is considered so high that the individuals or sites decide against participation.

In our example of evaluating implementations of electronic health record systems, given the restricted number of early adopter sites available to us, we sought purposively to select a diverse range of implementation cases among those that were available[ 5 ]. We chose a mixture of teaching, non-teaching and Foundation Trust hospitals, and examples of each of the three electronic health record systems procured centrally by the NPfIT. At one recruited site, it quickly became apparent that access was problematic because of competing demands on that organisation. Recognising the importance of full access and co-operative working for generating rich data, the research team decided not to pursue work at that site and instead to focus on other recruited sites.

Collecting the data

In order to develop a thorough understanding of the case, the case study approach usually involves the collection of multiple sources of evidence, using a range of quantitative (e.g. questionnaires, audits and analysis of routinely collected healthcare data) and more commonly qualitative techniques (e.g. interviews, focus groups and observations). The use of multiple sources of data (data triangulation) has been advocated as a way of increasing the internal validity of a study (i.e. the extent to which the method is appropriate to answer the research question)[ 8 , 18 – 21 ]. An underlying assumption is that data collected in different ways should lead to similar conclusions, and approaching the same issue from different angles can help develop a holistic picture of the phenomenon (Table 2 )[ 4 ].

Brazier and colleagues used a mixed-methods case study approach to investigate the impact of a cancer care programme[ 22 ]. Here, quantitative measures were collected with questionnaires before, and five months after, the start of the intervention which did not yield any statistically significant results. Qualitative interviews with patients however helped provide an insight into potentially beneficial process-related aspects of the programme, such as greater, perceived patient involvement in care. The authors reported how this case study approach provided a number of contextual factors likely to influence the effectiveness of the intervention and which were not likely to have been obtained from quantitative methods alone.

In collective or multiple case studies, data collection needs to be flexible enough to allow a detailed description of each individual case to be developed (e.g. the nature of different cancer care programmes), before considering the emerging similarities and differences in cross-case comparisons (e.g. to explore why one programme is more effective than another). It is important that data sources from different cases are, where possible, broadly comparable for this purpose even though they may vary in nature and depth.

Analysing, interpreting and reporting case studies

Making sense and offering a coherent interpretation of the typically disparate sources of data (whether qualitative alone or together with quantitative) is far from straightforward. Repeated reviewing and sorting of the voluminous and detail-rich data are integral to the process of analysis. In collective case studies, it is helpful to analyse data relating to the individual component cases first, before making comparisons across cases. Attention needs to be paid to variations within each case and, where relevant, the relationship between different causes, effects and outcomes[ 23 ]. Data will need to be organised and coded to allow the key issues, both derived from the literature and emerging from the dataset, to be easily retrieved at a later stage. An initial coding frame can help capture these issues and can be applied systematically to the whole dataset with the aid of a qualitative data analysis software package.

The Framework approach is a practical approach, comprising of five stages (familiarisation; identifying a thematic framework; indexing; charting; mapping and interpretation) , to managing and analysing large datasets particularly if time is limited, as was the case in our study of recruitment of South Asians into asthma research (Table 1 )[ 3 , 24 ]. Theoretical frameworks may also play an important role in integrating different sources of data and examining emerging themes. For example, we drew on a socio-technical framework to help explain the connections between different elements - technology; people; and the organisational settings within which they worked - in our study of the introduction of electronic health record systems (Table 3 )[ 5 ]. Our study of patient safety in undergraduate curricula drew on an evaluation-based approach to design and analysis, which emphasised the importance of the academic, organisational and practice contexts through which students learn (Table 4 )[ 6 ].

Case study findings can have implications both for theory development and theory testing. They may establish, strengthen or weaken historical explanations of a case and, in certain circumstances, allow theoretical (as opposed to statistical) generalisation beyond the particular cases studied[ 12 ]. These theoretical lenses should not, however, constitute a strait-jacket and the cases should not be "forced to fit" the particular theoretical framework that is being employed.

When reporting findings, it is important to provide the reader with enough contextual information to understand the processes that were followed and how the conclusions were reached. In a collective case study, researchers may choose to present the findings from individual cases separately before amalgamating across cases. Care must be taken to ensure the anonymity of both case sites and individual participants (if agreed in advance) by allocating appropriate codes or withholding descriptors. In the example given in Table 3 , we decided against providing detailed information on the NHS sites and individual participants in order to avoid the risk of inadvertent disclosure of identities[ 5 , 25 ].

What are the potential pitfalls and how can these be avoided?

The case study approach is, as with all research, not without its limitations. When investigating the formal and informal ways undergraduate students learn about patient safety (Table 4 ), for example, we rapidly accumulated a large quantity of data. The volume of data, together with the time restrictions in place, impacted on the depth of analysis that was possible within the available resources. This highlights a more general point of the importance of avoiding the temptation to collect as much data as possible; adequate time also needs to be set aside for data analysis and interpretation of what are often highly complex datasets.

Case study research has sometimes been criticised for lacking scientific rigour and providing little basis for generalisation (i.e. producing findings that may be transferable to other settings)[ 1 ]. There are several ways to address these concerns, including: the use of theoretical sampling (i.e. drawing on a particular conceptual framework); respondent validation (i.e. participants checking emerging findings and the researcher's interpretation, and providing an opinion as to whether they feel these are accurate); and transparency throughout the research process (see Table 8 )[ 8 , 18 – 21 , 23 , 26 ]. Transparency can be achieved by describing in detail the steps involved in case selection, data collection, the reasons for the particular methods chosen, and the researcher's background and level of involvement (i.e. being explicit about how the researcher has influenced data collection and interpretation). Seeking potential, alternative explanations, and being explicit about how interpretations and conclusions were reached, help readers to judge the trustworthiness of the case study report. Stake provides a critique checklist for a case study report (Table 9 )[ 8 ].

Conclusions

The case study approach allows, amongst other things, critical events, interventions, policy developments and programme-based service reforms to be studied in detail in a real-life context. It should therefore be considered when an experimental design is either inappropriate to answer the research questions posed or impossible to undertake. Considering the frequency with which implementations of innovations are now taking place in healthcare settings and how well the case study approach lends itself to in-depth, complex health service research, we believe this approach should be more widely considered by researchers. Though inherently challenging, the research case study can, if carefully conceptualised and thoughtfully undertaken and reported, yield powerful insights into many important aspects of health and healthcare delivery.

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Acknowledgements

We are grateful to the participants and colleagues who contributed to the individual case studies that we have drawn on. This work received no direct funding, but it has been informed by projects funded by Asthma UK, the NHS Service Delivery Organisation, NHS Connecting for Health Evaluation Programme, and Patient Safety Research Portfolio. We would also like to thank the expert reviewers for their insightful and constructive feedback. Our thanks are also due to Dr. Allison Worth who commented on an earlier draft of this manuscript.

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AS conceived this article. SC, KC and AR wrote this paper with GH, AA and AS all commenting on various drafts. SC and AS are guarantors.

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Crowe, S., Cresswell, K., Robertson, A. et al. The case study approach. BMC Med Res Methodol 11 , 100 (2011). https://doi.org/10.1186/1471-2288-11-100

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What is a case study?

A case study is a qualitative research approach where multiple methods of data collection are used for a detailed examination of a single 'case'. A case is a single unit in a study. It can be a person or an organisation, like a clinic, police force, factory or a hospital. A case can also be a community or groups of people. Television series have also been used as case studies of how television programmes are produced. Sometimes researchers undertake more than one case study for purposes of comparison, e.g. private versus public hospitals. In medicine, there has been a tradition of using a singular person to give a detailed medical history or description of an unusual health condition. In social sciences, sometimes a life history is considered a case study as it is a detailed analysis of a single case.

Case studies focus on the complexity, dynamics and circumstances of a single case (sometimes called a phenomenon). Multiple research methods are used. Cases are intensively explored in-depth, retrospectively, currently and sometimes over time. By focusing on small numbers, greater depth and more details can be obtained. This is in contrast to quantitative methods which gathers specific concise information on a large number of cases.

The aim is to understand the case/phenomenon selected for study. The researcher gives detailed descriptions, develops possible explanations and evaluates the phenomenon. Case studies are designed to provide detailed information about a specific area but there is often a view to place the case in the context of the wider society. For example, a case study of migrants' health in Yorkshire can be used as a basis for understanding their needs and relationships with the wider society. However, it should be noted that the material case studies produce is not generalisable. Quantitative research can be done later on to assess how typical the situation and/or organisation is. Case studies are sometimes used to develop a theory.

Case study seeks to answer the question "what are the characteristics of the phenomenon?"

Researchers spend an extended period of time on-site with their participants and collect a substantial amount of data from a wide variety of sources. Data collection typically consists of unstructured interviews, observation and document analysis (such as information from records, analysis of official statistics). In other words, formal and informal interviews, interactive fieldwork and some use of quantitative measures. It is advisable to carry out a pilot study first using a sub-group within the organisation to test that what you intend to do will work. It is good to iron out the design faults before jumping in to do the study. While large-scale case studies can be costly and time-consuming, a small-scale case study has little financial cost. Perhaps, this is why it is a popular research method used by graduate students!

Analysis will depend upon the methods used. For example, you would use qualitative analysis for unstructured interviews and observations and a content analysis for documents. Usually, this will consist of interpretational (i.e. search for themes), structural (search for patterns in discourse) and reflective (portrayal of participants' views). Like other qualitative approaches, the case study is reliant on the skills of the investigator to interpret the data in a rigorous manner rather than just reporting selective perceptions.

The case study is not suited to the traditional presentation of results (i.e. statement of problem, literature review, methods, analysis and conclusions). Instead, a case study consists of (1)a chronological or biographical description of the case; (2) the investigator's approach to understanding and investigating the case and (3) description of each of the main components of the case. It is good to use illustrations of particular episodes to back up your findings.

• Good for the study of complex social settings.
• Useful in the exploratory, early stages of research and for generating hypotheses.
• Becoming more common in evaluative studies where case studies can be used to evaluate a health programme.
• Can be used as a biographical research method (unstructured interviews to obtain a narrative of a respondent's life).
• Can be used by investigators using a phenomenological perspective.
• It has long been used by clinicians in relation to the understanding of disease.

Further reading

Bowling, A. Research Methods in Health, 2nd Edition. Open University Press, 2002.

Leedy, P. Practical Research: Planning and Design. 6th Edition. Merril, New Jersey, 1997.

• Research article
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Reliability of case definitions for public health surveillance assessed by Round-Robin test methodology

• Gérard Krause 1 ,
• Bonita Brodhun 1 ,
• Doris Altmann 1 ,
• Hermann Claus 1 &
• Justus Benzler 1  

BMC Public Health volume  6 , Article number:  129 ( 2006 ) Cite this article

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Case definitions have been recognized to be important elements of public health surveillance systems. They are to assure comparability and consistency of surveillance data and have crucial impact on the sensitivity and the positive predictive value of a surveillance system. The reliability of case definitions has rarely been investigated systematically.

We conducted a Round-Robin test by asking all 425 local health departments (LHD) and the 16 state health departments (SHD) in Germany to classify a selection of 68 case examples using case definitions. By multivariate analysis we investigated factors linked to classification agreement with a gold standard, which was defined by an expert panel.

A total of 7870 classifications were done by 396 LHD (93%) and all SHD. Reporting sensitivity was 90.0%, positive predictive value 76.6%. Polio case examples had the lowest reporting precision, salmonellosis case examples the highest (OR = 0.008; CI: 0.005–0.013). Case definitions with a check-list format of clinical criteria resulted in higher reporting precision than case definitions with a narrative description (OR = 3.08; CI: 2.47–3.83). Reporting precision was higher among SHD compared to LHD (OR = 1.52; CI: 1.14–2.02).

Our findings led to a systematic revision of the German case definitions and build the basis for general recommendations for the creation of case definitions. These include, among others, that testable yes/no criteria in a check-list format is likely to improve reliability, and that software used for data transmission should be designed in strict accordance with the case definitions. The findings of this study are largely applicable to case definitions in many other countries or international networks as they share the same structural and editorial characteristics of the case definitions evaluated in this study before their revision.

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Case definitions have been recognized to be important elements of public health surveillance systems [ 1 ]. They are to assure comparability and consistency of surveillance data and have crucial impact on the sensitivity and the positive predictive value of a surveillance system. The World Health Organization has been encouraging the use of case definitions to make surveillance data comparable between countries. One of the first case definitions used for national disease reporting was the case definition for AIDS published by the Centers for Disease Control and Prevention (CDC) in 1982 [ 2 ]. In 1985 Sacks published a survey among all 50 US states, Puerto Rico, and Washington, DC, that revealed important variations in the case definitions between the different states, and concluded the necessity to unify case definitions if surveillance data between states are to be compared [ 3 ]. In 1990 the CDC in collaboration with the Council of State and Territorial Epidemiologists published an edition of case definitions for public health surveillance [ 4 , 5 ].

Since then case definitions have become an important tool of other national surveillance systems and international surveillance networks. Koo and colleagues have analyzed surveillance data for Cholera in Latin America and have described the importance of uniform case definitions to make data comparable between countries [ 6 ]. In 2003 the European Union (EU) case definitions for the European networks have reached obligatory status for the member states reporting to the EU [ 7 ]. During the SARS epidemic the case definition had a major impact on whether and how countries were considered affected or not, resulting in severe political and economic consequences for a number of countries [ 8 ].

Coggon and colleagues have demonstrated the difficulties of determining optimal case definitions if a satisfactory diagnostic gold standard is lacking [ 9 ]. In sharp contrast to the importance of case definitions hardly any research has been published on the performance of surveillance case definitions. Studies are rare on how local health departments and other health professionals are able to understand case definitions and to what extent case definitions are unambiguous enough to really assure reliability. To our knowledge, the only publication investigating this issue was focused on case definitions for nosocomial infections: Gastmeier and colleagues had investigated how uniform the case definitions of the nosocomial infections surveillance system in Germany had been applied by different investigators using a set of 60 case studies [ 10 ]. Due to the general importance of case definition for public health surveillance and the current need for harmonization in international surveillance systems we conducted a systematic evaluation of the national case definitions with the objective to identify general as well as specific criteria and recommendations for improvement of case definitions.

Notification and reporting procedure

Germany is a federal republic with 16 states subdivided into 440 counties. As in many countries the local (county) health departments (total number: 425) are the primary recipients of infectious disease notifications made by physicians and laboratories. Local health departments verify the incoming notifications and assess the need for public health action. Local health departments use one of five software products on the market to classify the case reports according to the national edition of case definitions and to report these cases electronically to the state health department. From there the report is being forwarded to the Robert Koch Institute (RKI), the federal institution in charge of national infectious disease surveillance in Germany [ 11 ].

Introduction of case definitions

The edition of national case definitions for all notifiable infectious diseases was introduced in Germany in 2001, following the implementation of a new law to control infectious diseases (Infektionsschutzgesetz, IfSG) [ 12 – 14 ]. The IfSG determines the set of diseases and pathogens to be notified by physicians and laboratories throughout the Federal Republic of Germany. The five eastern states, which formerly belonged to the Democratic Republic of Germany (East Germany) and the State of Berlin have enacted complementary rules that make certain diseases additionally notifiable within the state jurisdiction, that are not notifiable in all of Germany.

The case definitions were developed by the RKI, using the delphi method including the expertise of state epidemiologists, national reference laboratories and medical and scientific associations for the specific diseases. The case definitions for infectious conditions under public health surveillance published by the CDC were also taken into account [ 5 , 15 ]. After having published the IfSG case definitions in the fall of 2000 to be implemented with the beginning of 2001 the RKI also published additional case definitions in January 2002 for some of the diseases exclusively notifiable in the eastern states jurisdictions [ 11 , 16 ]. From June 2002 to September 2003 we had conducted a systematic evaluation of the case definitions with the purpose to revise them by the end of 2003.

Structure and classification of case definitions

The German case definitions are divided into three types of evidence: Clinical picture, laboratory detection, and epidemiological confirmation. The types of evidence are specifically defined for each disease (see table 1 ). Based on whether or not requirements for these three types of evidence are fulfilled a case is classified into five categories. In the revised 2004 edition of case definitions these categories are named: A) clinically diagnosed illness (neither epidemiologically nor laboratory-confirmed), B) clinically and epidemiologically confirmed illness (not laboratory-confirmed), C) clinically and laboratory-confirmed illness, D) laboratory-detected infection not fulfilling clinical criteria, E) laboratory-detected infection with unknown clinical picture. (In the 2001 edition of case definitions these five categories were named slightly differently)

For most notifiable diseases only categories B, C, D and E are reportable from the local health department to the next level, requiring at least laboratory detection of the pathogen or epidemiological confirmation. For some exceptions (e.g. tuberculosis, polio, measles, Creutzfeldt-Jakob disease), cases are also reported from the local health department to the next level if category A – the clinical picture alone – is fulfilled.

Round-Robin test

In June 2002 we conducted a Round-Robin test in analogy to the established quality control procedure of laboratories and other testing units [ 17 ]. Round-Robin tests are mainly used in proficiency tests in order to determine laboratory performance by means of comparing tests on identical items by two or more laboratories in accordance with predetermined conditions [ 18 ].

We asked each local and state health department to classify a selection of 68 written case examples on the basis of the case definitions that were implemented in 2001 (2002 respectively for disease only notifiable in East German States). While proficiency tests generally intent to assess the ability of laboratories in finding identical results, we applied this method to assess to which extend the case definitions were unambiguous enough to assure identical classification by the health departments.

Definitions of outcome variables

We applied four different outcome variables in our analysis:

Disease identification: A disease was defined as being correctly identified if the participant of the Round-Robin test was able to identify the correct disease of the case example.

Case categorization: A case example was considered correctly categorized if the participant classified the case example with the correct disease and the correct case definition category as defined in the gold standard.

Reporting: The decision on reportability was considered correct if a case that should have been reported to the next level would have been forwarded according to the case definition category, given that the correct disease was identified. Inversely decision on reporting was also seen to be correct if a case that should not have been reported to the next level was in fact classified in a way that the case would have been held back. However, cases forwarded with wrong disease identification (see above) were a priori considered incorrect. Thus reporting was based on the question whether the case needed to be forwarded to the state level or not, which is a direct result of the disease identification and the case definition category. Sensitivity of reporting was defined as the number of cases that would have been correctly forwarded divided by the number of cases that should have been forwarded according to the gold standard. The positive predictive value of reporting was defined as the number of cases that should have been forwarded among those that would have been forwarded. Precision of reporting is defined as the number of cases that would have been either correctly forwarded to the state level, or would have been correctly held back at the local health department level, divided by the total number of case examples. Unless stated otherwise, reporting precision was the outcome parameter used in the following analysis.

Clinical classification: To specifically assess the effect of different styles in formulating case definitions, a fourth outcome variable was used. The clinical classification was considered correct if the part regarding the clinical picture was classified according to the gold standard, regardless whether other parts of the case definition were correctly classified or not. This analysis was done to compare case definitions with narrative description of the clinical picture (as in all former IfSG case definitions) to case definitions with a more explicit check-list format of clinical criteria, that was implemented for diseases additionally notifiable in specific states and for the new IfSG case definitions.

Case examples

The case examples consisted in facsimile excerpts of one or more of the following sources: laboratory report form, physician form, and protocol of the patient interview [see additional file 1]. The case examples were created based on real cases that have come to the attention of the RKI in the quality control process and in the information service hotline that the RKI is offering to the health departments. The case examples were pre-tested among epidemiologists within the RKI and among epidemiologists and public health nurses in the state and local health departments.

Selection and distribution of case examples

A total of 68 case examples for 17 different diseases were created. In order to limit the time needed to classify the case examples, each local health department in West Germany (including Berlin) received four different case examples each for four different notifiable diseases resulting in 16 case examples to be classified. Local health departments in East Germany (excluding Berlin) received an additional set of four case examples for one of four diseases additionally notifiable in East German states, resulting in a total of 20 case examples.

In order to stratify the case examples of the 17 diseases among the local health departments, we created eight sets of case examples, as shown in table 2 . Sets A to D were randomly distributed among local health departments in each West German state; sets E to H were randomly distributed among local health departments of each East German state. As shown in table 3 , the Salmonella case examples appeared in all eight sets, in order to have the possibility to compare between local health departments and other determinants based on identical case examples.

Epidemiologists in state health departments participating in the study received set A (West Germany) or set E (East Germany). Epidemiologists at the RKI, not involved in designing the case examples, were asked to fill out all 68 case examples. For the analysis the variable "group" was defined as indicated in table 2 in order to control for a possible allocation bias of participants.

Gold standard definition

After the data of the respondents had been analyzed, the classification originally intended while creating the case definition, was challenged with the results of the respondents. Three epidemiologists then reassessed each individual case example and re-examined whether the classification originally intended was still justified. Based on this process the gold standard was defined for each case example.

Quantitative analysis

We compared the responses to the established gold standard and stratified by the following variables: health department being in an East German versus a West German state, disease of the case example, whether or not physicians participate in routine quality control of case reports (versus this being done exclusively by public health nurses), institutional level (local health department, state health department, RKI), acceptance and style of case definitions (check-list vs. text) and software used at local health department. Because of the selection and distribution of case examples described above, we conducted the individual analyses for each group. After univariate analysis we conducted a multivariate analysis using SPSS 13.0 for Windows (Version 13.0.1).

Qualitative analysis

The distribution of the classifications was compared to the gold standard, in order to identify common discrepancies. Based on these discrepancies we identified which part of the case definition was affected and identified specific aspects of the case definitions that had repeatedly been interpreted differently by the participants, indicating failure of the case definition to be unambiguous and reliable. These aspects were then summarized in order to deduct commonalities which could then lead to specific recommendations on how to improve this particular case definition and also on how to improve formulation of case definitions in general.

In May 2002 – simultaneously with the Round-Robin test – we conducted a written survey addressed to all 425 local health departments in Germany. Among various questions on the structure and equipment of the local health departments, and their experiences with the new IfSG, we also asked about the profession of the person who had actually filled the questionnaire and about his or her attitudes and experiences towards the case definitions.

Study population

We received completed forms from 396 (93%) of 425 local health departments. Additionally, 30 epidemiologists from all 16 states and 18 epidemiologists within the RKI had completed the forms. This resulted in a total of 7870 classifications of case examples.

The survey was completed by 400 (94%) of the 425 health departments.

Quantitative analysis of Round-Robin test

The overall result of the Round-Robin test shows that in 7003 case examples (89.0% of all 7870 classified case examples) the correct disease was identified (disease identification). In 4073 case examples (51.8%) the participants classified the case in the expected case definition category (case categorization). In 5042 case examples (64.1%) the correct disease was classified such that the case would have been reported and in 4847 case examples (61.6%) the clinical categorization was correct. Of 4291 case examples that were reportable, 3860 (90.0%) were classified such that they would have been reported (reporting sensitivity); of 5042 case examples that would have been reported to the state health department, 3860 (76.6%) were actually reportable (positive predictive value of reporting), while 1182 (23.4%) should have been excluded from reporting. Of all 7870 case examples the precision of reporting was 79.5%.

Group-wise multivariate analysis

The multivariate analysis was limited to data from the local health departments and without additional case examples for the East German states (n = 5995). Only statistically significant associations are mentioned in the following.

The disease of the case examples was for all groups significantly associated with reporting (p < 0.001 in group 1, 2 and 4, p = 0.022 in group 3).

Software used at local health department

Local health departments using the RKI-software showed a higher chance to identify the disease (disease identification) of the case example according to the gold standard compared to health departments using any of the commercially available software programs (group 2: OR = 1.85, CI: 1.20 – 2.84 and group 3: OR = 1.76, CI: 1.17 – 2.66). Additionally health departments in group 3 using the RKI software had a higher chance of classifying case examples (clinical classification) according to the gold standard (OR = 1.32, CI: 1.01 – 1.70).

East Germany versus West Germany

Analysis of case examples used in both East and West Germany showed that local health departments in East Germany had a lower chance of identifying the disease correctly compared to West German local health departments in group 1 (OR = 0.40, CI: 0.27 – 0.58), of identifying the case definition category correctly in group 2 (OR = 0.76, CI: 0.58 – 1.00) and of correctly reporting in group1 (OR = 0.73, CI: 0.54 – 0.99).

Participating professions

Local health departments where the physician was involved in applying the case definition in the daily routine, showed a lower chance of agreement in disease identification in group 1 (OR = 0.61, CI: 0.41 – 0.89) and a higher chance of agreement in reporting in group 4 (OR = 1.36, CI: 1.02 – 1.81).

Attitudes towards case definitions

Local health departments that stated that case definitions were a valuable tool had higher rates of agreement with the gold standard for disease identification (OR = 2.09, CI: 1.16 – 3.75) and case categorization (OR = 1.71, CI: 1.10 – 2.65) in group 1.

Summarized multivariate analysis

In order to assess whether there might have been a bias in allocating participating health departments to specific groups of case examples we made a separate analysis exclusively with the 4 Salmonella -like case examples which all groups had in common. The analysis among the 1508 classified case examples showed no significant association between group and reporting, suggesting no evidence for allocation bias.

In the summarized model, in which the responses of all groups were analyzed, the disease of the case examples was significantly associated with reporting (p < 0.001). Local health departments where a physician was involved in applying the case definition in the daily routine, showed a lower chance to identify the disease correctly (OR = 0.82, CI: 0.68 – 0.99). Local health departments in East Germany had a lower chance to identify the disease correctly (OR = 0.74, CI: 0.62 – 0.88) and of reporting correctly to the next level compared to West German local health departments (OR = 0.84, CI: 0.73 – 0.96).

Comparing the diseases

For the outcome variable 'reporting' the case examples of Salmonella had higher rates of agreement with the gold standard compared to case examples of all other diseases. For this reason separate analyses were done comparing the different diseases by using Salmonella cases examples as the reference variable adjusted for East/West. Based on the magnitude of the odds ratios, we found that the examples for CJD (OR = 0.012, CI: 0.008 – 0.017) and Polio (OR = 0.008, CI: 0.005 – 0.013) had the lowest chance of reporting precision compared to Salmonella case examples. Details are shown in table 1 .

Narrative format versus check-list format

The classification of the clinical picture, one element of the case definition, was separately analyzed in a model including exclusively data from East German health departments (n = 2019) and RKI (n = 1016). These were the only participants exposed to case examples of disease nationally reportable (with narrative description of the clinical picture) and to case examples of diseases only notifiable in East German states (check-list format). The results of the univariate analysis show, that agreement in case classification with the gold standard was more than three times as high when the respective case definitions had listed the clinical criteria in a check-list format instead of a narrative description (OR = 3.08, CI: 2.47 – 3.83).

Administrative level

The administrative level at which the respondents worked, was significantly associated with the outcome reporting. For the analysis we used all cases of set A and set E (without the additionally diseases for the East German States, n = 2213). Adjusted for the diseases the chance of correct reporting to the next level was 1.5 times higher in cases done by state level staff compared to those done by local health department staff (OR = 1.52, CI: 1.14 – 2.02).

Qualitative results

The following observations have been made in the qualitative analysis of the responses:

The concept of epidemiological confirmation was not well understood. For example travel in endemic countries was equivocally seen as an epidemiological confirmation (e.g. haemorrhagic fever and travel to Egypt). Re-evaluation of the case definitions showed that in fact there was only a vague definition of the epidemiological confirmation.

Participants appeared to have difficulties in deciding whether all clinical signs and symptoms mentioned in the case definition had to be existent in a case, or whether they were only listed as descriptive examples.

Case examples of diarrheal disease without any evidence of a specific pathogen, were frequently classified as salmonellosis.

Laboratory findings with only one elevated antibody value in serum were repeatedly classified as laboratory detection although the case definition required a rise in antibody level.

In some case definitions detection of the pathogen is only accepted if the detection was done in specific materials (normally sterile material such as blood for detecting N. meningitidis ). This limitation was frequently neglected.

Some of the information in the case definition intended to serve as additional background information was mistakenly used as selection criteria (e.g. statement that clinician described rash as "very typical" for measles, but fever was missing).

Survey results

When asked about the availability of the case definitions, 395 (99%) of 398 local health departments responded that the case definition were accessible at the work place. The case definitions were seen as useful by 377 (95%) of 397 health departments who answered this question and not useful by 20 (5%). The clarity of the individual sections of the case definitions was rated differently: The section on the clinical picture of the case definitions was seen as unambiguous in all case definitions by 72 respondents (18%), in the majority of case definitions by 305 (76%), in the minority by 20 (5%), and in none of the case definitions by one (0.3%) of the respondents (n = 398 respondents). The section on the laboratory confirmation of the case definitions was seen as unambiguous in all case definitions by 137 respondents (34%), in the majority of case definitions by 248 (62%), and in the minority by 11 (3%) (n = 396).

Three-hundred and three (87%) of 347 health departments stated that case classifications were done exclusively or primarily by public health nurses. With respect to the case examples presented to the participants, 220 (55%) of 396 respondents (from the local health departments) stated that the case examples were realistic.

The results of our evaluation have shown that although case definitions may appear to be clearly defined, they may be interpreted quite differently by their users, which may result in severe misclassifications and reduced sensitivity and positive predictive value. This study is believed to be the first to systematically assess these effects quantitatively on a large scale, covering 396 (93%) of 425 local health departments in Germany providing at the same time clear evidence on how case definitions can be improved.

The sensitivity and the positive predictive value calculated from this Round-Robin test does not have the intention to represent the respective values of the real surveillance data, these values serve as comparative measurements within the study. It must be kept in mind that we created the case examples specifically to identify need for improvement of the case definitions. Therefore the majority of case examples were intentionally characterized by borderline constellations, meant to represent realistic challenges to the case definition and its user. We also intentionally included rare diseases with high public health importance. The fact that 56% of the participants perceived the case examples to be realistic, indicates that daily routine might generally confront health departments with case reports that might be easier to classify. This explains why case examples of polio (no reported cases since 1998) and CJD (approx. 80 cases per year) had extremely lower rates of agreement compared to Salmonella case examples (approx. 57.000 cases per year) [ 19 , 20 ].

Also the complexity of the case definition itself is likely to affect reporting precision. Unfortunately much of the complexity of the case definition is a result of methodological limitations of available laboratory tests and cannot be influenced. The case definition system with its three different types of evidence leading to five different categories may appear very complex and less intuitive that the classical categories of "suspect", "probable" and "confirmed". The detailed differentiation of the German case definitions however enables us to apply computer algorithms in order to translate these to the EU case definitions and thus make the data compatible to the standards of various European surveillance networks and to WHO reports.

Reassessment of the gold standard after receipt of the responses resulted in modifications of 5 of the 68 case examples. This procedure took place in an initial review process of gold standard before the actual analysis was done. We believe it was legitimate and necessary in order to correct for biases caused by unforeseen ambiguity of the case examples.

The software used at the local health department was significantly associated with the quality of the data in only some subgroups and outcomes. Apparently the software is not a very strong determinant in the given study design, although our experience in implementing the electronic surveillance system in Germany showed that commercially available software products often do not fully implement the standards published by the RKI for data transmission software or they do so with a delay of several years [ 21 ].

The other interesting finding is that the administrative level of the participants was significantly associated with the outcome: Participants from state health departments had a significantly higher rate of agreement with the reporting gold standard than the participants from local health departments. This might be explained by the fact that staff at the state level is generally higher trained in epidemiology and infectious diseases than local health department staff and they are routinely involved in quality control of incoming case reports and also training and supervision of local health departments' staff.

Classification of the clinical picture resulted in significantly better results in the univariate analysis if the relevant case definition had a check-list format of the clinical picture (for diseases notifiable only in eastern states) as opposed to case examples of diseases for which the relevant case definition had a narrative description of the clinical picture (as in the old version of the national case definitions which participants had used as a reference). The dominant effect of the disease-variable, however, made this association disappear in the multivariate model. The most convincing explanation for this effect is, that after initial experience with the national case definitions, RKI had already changed the way of defining the clinical picture when creating case definitions for the diseases only notifiable in Eastern German states: The clinical picture was now defined in a clear check-list of signs and symptoms, instead of an unspecific mentioning of various possible signs and symptoms, such as in the first edition of the IfSG case definitions. Based on the findings of this study we have in the meanwhile applied this principle of a clear check-list in the second edition of the IfSG case definitions.

The results of the study were integrated in a case example book, which contains each of the 68 case examples followed by the required gold standard classification, descriptive statistics of the responses and a commentary interpreting these results and explaining the required gold standard. This case example book was mailed to all participants after termination of the study and is also available on the RKI website [ 22 ].

All the observed quantitative effects and their propagated explanations merge into the one main conclusion: Case definitions must be very carefully formulated in order to assure their unambiguous interpretation by local health department personnel. The detailed evaluation of our study has resulted in a substantially revised edition of the German case definitions [ 23 , 24 ]:

We rephrased the case definitions in a check-list format indicating clearly how many of the symptoms and signs had to be fulfilled in which combination.

Some diseases previously jointly described in one case definition were defined separately (Dengue was separated from other haemorrhagic fever; hemolytic uraemic syndrome was created new, separately from EHEC and Shigella .)

We rephrased the definitions in a way that for serologic confirmation the necessity for two samples is clearly apparent at the beginning of the phrase.

The material in which the pathogen has to be detected is now highlighted and is only listed if it is relevant for the case definition.

A glossary now defines the expressions that are being used repeatedly in the case definitions

The case definitions are now limited to criteria relevant for the decision process. All additional explanatory information is clearly indicated as such in a separate section of the case definition

The evidence type "epidemiological confirmation" was completely redesigned and replaces the previously used term "epidemiological link". The accepted types of epidemiological links are now specified individually for each case definition.

One practical implication, that is supported by this analysis is, that software used at the local health department must be designed with strict accordance to the case definitions using identical terminology and structuring which would have been more easily archived if all local health departments had been equipped with one identical software system developed within or under supervision of one institution. Possibly other countries in the process of developing or implementing new electronic surveillance systems might want to learn form this experience [ 21 , 25 ].

The case example book, which resulted from this study, constitutes a detailed feed back for the participants of the study and is now being used as training material for public health nurses.

We have demonstrated that rigorous reduction of case definitions to testable yes/no-criteria in a check-list format is likely to improve their reliability. Reducing the differential diagnostic complexity of a disease to a limited number of yes/no-criteria, is a major challenge, but it also carries the benefit of facilitating computerized testing algorithms for quality control and for case classifications.

As the reliability of epidemiologic surveillance largely depends on the reliability of its case definitions, it is essential to create and revise case definitions based on systematic evaluations [ 9 ]. Most of the basic principles for the revision of the German case definition edition deducted from this analysis may also be applicable for case definitions in other countries (such as the United States, Ireland, Sweden, Mexico) or international networks (EU, WHO) as they share the same structural and editorial characteristics that we identified to be problematic in the first edition of the German case definitions [ 4 , 7 , 8 , 26 , 27 ]. We therefore believe that our findings are highly relevant for many national and international surveillance systems.

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Acknowledgements

We would like to thank all participating colleagues at the local and state health departments and at the RKI. Miriam Friedemann and Gerlinde Gloeckner made valuable contributions to this study, and Inge Mücke in preparation of this manuscript. Thank you to all of them.

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Gérard Krause, Bonita Brodhun, Doris Altmann, Hermann Claus & Justus Benzler

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Authors' contributions

GK conceived of the study and is responsible for the design of the study, the creation of case examples and the gold standard definition. He supervised the study and is responsible for the analysis and interpretation of the data and the literature research.

BB is responsible for the pilot testing of case examples and survey, the study management, data entry and data management, and participated in the data analysis.

DA participated in the statistical analysis.

HC participated in the management of the data, the design of the study and the data analysis.

JB participated in the definition of the gold standard, the analysis and the interpretation of data and is responsible for the revision of new case definitions.

All authors read and approved the final manuscript.

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Krause, G., Brodhun, B., Altmann, D. et al. Reliability of case definitions for public health surveillance assessed by Round-Robin test methodology. BMC Public Health 6 , 129 (2006). https://doi.org/10.1186/1471-2458-6-129

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Call for Case Studies: Strategic Action for Urban Health

The WHO Urban Health team is seeking examples that illustrate a strategic approach to urban health. Collectively, these case studies are intended to show that such an approach can originate and flourish from a wide range of entry points across a diversity of sectors and scales, while leveraging many different combinations of partners. The case studies will inform a major global WHO report on strategic action for urban health, expected in fall 2024. Selected cases will be developed for inclusion in the report; the urban health team will work with submitters of these cases to produce concise summaries. All submitted cases that meet eligibility criteria will be promoted and made available on the WHO website and, as appropriate, in subsequent publications.

Background to this call

The health of urban populations emerges from the interactions of urban environments with the behaviour of individual actors and human institutions. Urban health is both a measure of the levels and patterns of health and wellbeing in cities and the art and science of safeguarding and continually improving them.

Because every aspect of urban life can affect human wellbeing, urban health relies on action across all sectors—not only within health, but across planning, housing, transportation, water, sanitation, energy, and many others. This breadth of influences is widely recognized, yet urban health action has often focused on improving health impacts within a single sector or system, or alternatively, on addressing a narrowly defined set of health outcomes, modifying certain key behaviours, or improving health for a particular population group.

Such efforts have widely succeeded in improving urban health outcomes, and cities are healthier, on average, than rural areas. Yet, much remains to be done. Urban areas feature large—and often growing—health inequities, especially in slums and informal settlements. In virtually all cities, there remain unrealized opportunities to improve health and health equity.

Moreover, the actions needed to improve health in cities often positively impact other goals of sustainable development. There is thus tremendous potential for achieving co-benefits through an approach that accounts for dynamic interactions across sectors.

Achieving the highest levels of urban health—and realizing its wide-ranging potential co-benefits—requires coordinating action across all urban sectors and systems while anticipating future challenges. That is, it depends on a strategy to sustainably mainstream health across urban policy and practice. This ‘strategic’ approach to urban health depends, among other things, on sophisticated arrangements for governance and finance, generating and working with evidence, fostering innovation, and generating and sustaining effective partnerships while promoting broad participation.

WHO’s urban health team has been working to develop guidance on strategic action for urban health, including through a recent series of policy briefs focusing on these issues. This case study call will add to this effort, helping to make visible the relevance, potential, and possibilities of strategic action.

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Case studies may represent action at national or subnational (e.g., province, state, municipality, or city) scales and should describe specific interventions, policies, institutions, partnerships, or other pertinent efforts. They need not involve the health sector (though many will) but should be relevant to the health and wellbeing of urban residents. Cases need not represent unqualified successes—indeed, cases that illustrate barriers to success or failed attempts at strategic action will be considered. We are seeking illustrative cases representing all regions, cultures, and levels of development, and a diverse range of urban contexts (including different city sizes, demographic profiles, informal communities, governance structures, and other factors).

This call is for cases that illustrate strategic action, as described in the WHO Strategic Guide to Urban Health Policy briefs. Cases that highlight potential or intended actions that have yet to be formalized or initiated will not be accepted. Likewise, cases that describe narrowly focused interventions or research related to health determinants, risk factors, or outcomes will not be considered unless linked to broader strategic action. We are particularly interested in cases that can demonstrate evidence of health impacts.

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H. Barrett D, W. Ortmann L, Dawson A, et al., editors. Public Health Ethics: Cases Spanning the Globe [Internet]. Cham (CH): Springer; 2016. doi: 10.1007/978-3-319-23847-0_1

Public Health Ethics: Cases Spanning the Globe [Internet].

Chapter 1 public health ethics: global cases, practice, and context.

Leonard W. Ortmann , Ph.D., Drue H. Barrett , Ph.D., Carla Saenz , Ph.D., Ruth Gaare Bernheim , J.D., M.P.H., Angus Dawson , Ph.D., Jo A. Valentine , M.S.W., and Andreas Reis , M.D., M.Sc.

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Published online: April 13, 2016.

Introducing public health ethics poses two special challenges. First, it is a relatively new field that combines public health and practical ethics. Its unfamiliarity requires considerable explanation, yet its scope and emergent qualities make delineation difficult. Moreover, while the early development of public health ethics occurred in a western context, its reach, like public health itself, has become global. A second challenge, then, is to articulate an approach specific enough to provide clear guidance yet sufficiently flexible and encompassing to adapt to global contexts. Broadly speaking, public health ethics helps guide practical decisions affecting population or community health based on scientific evidence and in accordance with accepted values and standards of right and wrong. In these ways, public health ethics builds on its parent disciplines of public health and ethics. This dual inheritance plays out in the definition the U.S. Centers for Disease Control and Prevention (CDC) offers of public health ethics: “A systematic process to clarify, prioritize, and justify possible courses of public health action based on ethical principles, values and beliefs of stakeholders, and scientific and other information” (CDC 2011). Public health ethics shares with other fields of practical and professional ethics both the general theories of ethics and a common store of ethical principles, values, and beliefs. It differs from these other fields largely in the nature of challenges that public health officials typically encounter and in the ethical frameworks it employs to address these challenges. Frameworks provide methodical approaches or procedures that tailor general ethical theories, principles, values, and beliefs to the specific ethical challenges that arise in a particular field. Although no framework is definitive, many are useful, and some are especially effective in particular contexts. This chapter will conclude by setting forth a straightforward, stepwise ethics framework that provides a tool for analyzing the cases in this volume and, more importantly, one that public health practitioners have found useful in a range of contexts. For a public health practitioner, knowing how to employ an ethics framework to address a range of ethical challenges in public health—a know-how that depends on practice—is the ultimate take-home message.

1.1. Introduction

Introducing public health ethics poses two special challenges. First, it is a relatively new field that combines public health and practical ethics. Its unfamiliarity requires considerable explanation, yet its scope and emergent qualities make delineation difficult. Moreover, while the early development of public health ethics occurred in a Western context, its reach, like public health itself, has become global. A second challenge, then, is to articulate an approach specific enough to provide clear guidance yet sufficiently flexible and encompassing to adapt to global contexts. Broadly speaking, public health ethics helps guide practical decisions affecting population or community health based on scientific evidence and in accordance with accepted values and standards of right and wrong. In these ways, public health ethics builds on its parent disciplines of public health and ethics. This dual inheritance plays out in the definition the U.S. Centers for Disease Control and Prevention (CDC) offers of public health ethics: “A systematic process to clarify, prioritize, and justify possible courses of public health action based on ethical principles, values and beliefs of stakeholders, and scientific and other information” (CDC 2011 ). Public health ethics shares with other fields of practical and professional ethics both the general theories of ethics and a common store of ethical principles, values, and beliefs. It differs from these other fields largely in the nature of challenges that public health officials typically encounter and in the ethical frameworks it employs to address these challenges. Frameworks provide methodical approaches or procedures that tailor general ethical theories, principles, values, and beliefs to the specific ethical challenges that arise in a particular field. Although no framework is definitive, many are useful, and some are especially effective in particular contexts. This chapter will conclude by setting forth a straightforward, stepwise ethics framework that provides a tool for analyzing the cases in this volume and, more importantly, one that public health practitioners have found useful in a range of contexts. For a public health practitioner, knowing how to employ an ethics framework to address a range of ethical challenges in public health—a know-how that depends on practice—is the ultimate take-home message.

We learn new things more readily when we can relate them to familiar things, and we understand complex things by breaking them into their components. Accordingly, throughout this introductory chapter, we will relate public health ethics to more familiar concepts and better-known related fields, while the immediately following section will explore the components of public health ethics that derive from its parent disciplines of public health and ethics. After describing public health’s core activities, goals, and values, we will explain why ethical concepts like the right to health, social justice, and health equity directly follow as central concerns of public health. After defining ethics broadly in everyday terms, we will examine the complementary roles facts and values play in public health. This examination is important because the respective bases of the two parent disciplines differ considerably; public health science rests on the logic of scientific discovery, whereas ethics rests on the logic of right action and good decision making. We will then contrast the more familiar, everyday understanding of morality with the formal discipline of ethics as a prelude to considering three well-known ethical theories relevant to public health. Because both laws and ethical rules establish parameters for public health practice, their similarity and difference need to be clarified. This extended account, first of parent disciplines, then of kindred concepts, and finally of family resemblances between the related fields of clinical ethics, bioethics, and research ethics, will culminate in an effort to characterize what is distinctive about public health ethics.

1.2. Public Health

There are many definitions of public health. They often begin as descriptions of current practice but once established become prescriptions for subsequent practice. It is important, then, to consider definitions, because they shape not only public health practice, but also how we conceive of public health ethics (Dawson and Verweij 2007 ). The same logic applies to how we think about the individual concepts of health and the public. Defining health as the absence of disease or symptoms, for example, more readily fits allopathic medicine, which focuses on negating symptoms to treat disease. But it hardly fits public health’s emphasis on preventive measures that address root causes rather than symptoms. Nor does it cover public health’s promotion of health and well-being across a range of interventions. In this regard, the World Health Organization (WHO) offers a definition of health more suitable to public health: “A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity” (WHO 2006 ). But even this more holistic definition does not sufficiently clarify the meaning of “public” in public health. Dawson and Verweij ( 2007 ) identify two primary meanings of “public” in public health, each of which they break down into three senses. Public can mean population-wide and refer to (1) the epidemiologically measured health of a population or group, (2) the distribution of health in a population, or (3) the underlying social and environmental conditions impacting everyone’s health. Public also can mean collectively accomplished and requiring (1) the concerted actions of many people and institutions whether governmental or nongovernmental; (2) the cooperation or involvement of the public, or (3) the public’s joint participation to realize the health improvement.

In a practical field like public health, definition often takes the form of enumerating key activities, such as surveillance, sanitation, maintaining food and workplace safety, disease prevention and control, and promoting healthy behavior. The identification of the ten essential services of public health illustrates this enumerative approach (Fig. 1.1 ) (Public Health Functions Steering Committee 1994 ). These services fall under three overarching functions of assessment, policy development, and assurance that constitute an integrated cyclic process. The delivery of these services in local, regional, or national public health agencies accordingly defines public health practice. In this schema, research is a distinct practical service but also integral to all public health activities, providing insights and innovative solutions at every point. Public health ethics addresses the entire spectrum of ethical issues that arise in any area of public health practice but especially in those areas where no specific guidelines govern practice.

Essential Public Health Services. (1) Monitor health status to identify community health problems. (2) Diagnose and investigate health problems and health hazards in the community. (3) Inform, educate, and empower people about health issues. (4) Mobilize (more...)

Public health is the science and the art of preventing disease, prolonging life, and promoting physical health and efficiency through organized community efforts … and the development of the social machinery which will ensure to every individual in the community a standard of living adequate for the maintenance of health (Winslow 1920 ).

These two definitions highlight the importance of collective action to address the health needs of populations. Public health’s population focus distinguishes it from clinical medicine’s focus on individual patients, though examples like vaccination indicate that the two fields can overlap. Epidemiologists statistically aggregate the health data of individuals to provide a picture of population health, but populations ultimately originate from communities of individuals who constitute social wholes. Individuals in society stand in complex relations of interdependence, competition, and solidarity that can impact health in ways that transcend the individual. Thus, in addition to aggregating individual medical data, epidemiologists need to measure the impact of various social factors on health. To tackle the complex, often competing health needs of social groups, public health practitioners need to dialogue and partner with their communities. At a higher administrative level, public health officials need to manage intersectoral collaborations, navigate political processes, and formulate public health law. Four distinguishing features of public health practice—the pursuit of the collective good, a focus on prevention, the use of government or collective action, and an emphasis on an outcome-based (utilitarian) approach—generate most of the ethical challenges public health practitioners typically face (Faden and Shebaya 2010 ).

1.2.1. Core Values

People value many things such as friends and family, material goods and resources, knowledge, and art. Some things people value are ethical virtues like courage or honesty, whereas others are ethical principles like justice and equality. People generally value what they consider important, what matters to them, and what gives their lives meaning. Public health’s primary goals and commitments reflect its core values, which are rooted in health, science, and the community (Public Health Leadership Society 2002 ). Everyone recognizes the value of health, but public health approaches health in relation to science and the community in its endeavor to prevent disease and injury, protect the public from harm, and promote health and well-being. But seeing how science and community represent values requires a word of explanation.

The commitment to science as a value stance often becomes apparent only in relation to people who distrust science or prioritize other value commitments such as economic interests or religion. Public health values science by endeavoring to base interventions and policies on the best available data and evidence-based practices. That endeavor entails a commitment to conduct surveillance and research, because only by understanding the social burden of disease and its underlying or structural causes can public health impact the health of the entire population. The qualifier “best available” is a reminder of the need to continuously improve practice and not rely on tradition or current practices. It also reminds us that during emergencies, time and resource constraints limit the ability to gather evidence.

Public health values community in two obvious senses. First, it recognizes that the success of most health interventions depends on a community’s acceptance, cooperation, or participation. Second, it recognizes that to be successful, public health must respect the community’s values and gain the trust of its members. Yet there is a third, deeper sense in which community represents a value. A community is, to emphasize again, neither a statistical abstraction nor a mere aggregate of individuals but rather a network of relationships and emotional bonds between people sharing a life in common organized through a political and moral order (Jennings 2007 ). The value that best reflects this fundamental, relational character of social life is solidarity . Solidarity can remain unspoken yet operative because it forms the basis of social life and collective action. Just as communities are not mere aggregates of individuals, neither are the agencies or organizations that make the collective decisions that affect the community. Personal interests, to be sure, can motivate individuals, but the felt recognition of a common plight, that we are all in it together, underlies the collective decisions society and public health must make to solve collective problems. To say that public health values community means that it values solidarity, even when solidarity remains unacknowledged as is often the case (Dawson and Jennings 2012 ).

1.2.2. Health Equity, Social Justice, and Social Determinants of Health

As the foregoing goals, definitions, core values, and commitments of public health clearly suggest, the right to health and health equity are central, not peripheral, to public health’s mission. Chapter 8 on international collaboration will examine some practical challenges in addressing the right to health and social determinants of health, so the emphasis here will be on the rationale for achieving health equity as a matter of social justice.

Despite greater individual access to health care and advances in public health, high burdens of disease remain across much of the globe. Some differences in disease burden result from genetics and some from variable risks of exposure to infectious agents and other threats, but most of the differential burden arises from social, economic, and political conditions. These conditions include poverty, lack of education, and discrimination against particular social groups and often reflect historical injustices or long-standing systemic, structural deficiencies. Collectively, these conditions have come to be known as social determinants of health (Blane 1999 ). Greater access to individual health care can mitigate their effect, but an adequate response to them requires concerted public action to address their underlying causes.

Whether comparing countries or groups within countries, social stratification by social determinants correlates with differences in health status (Marmot 2007 ). These health differences have aroused widespread concern, but how one defines them significantly affects public health practice (Braveman 2006 ). In particular, distinguishing health disparity from health inequity is critical. As a comparative indicator of health status, health disparity is a neutral, epidemiologic term that need not imply an ethical obligation to remedy. Health disparities, however, can and frequently do reflect underlying inequities. WHO defines health inequities as health differences that are “socially produced; systematic in their distribution across the population; and unfair” (WHO 2007 ). Terms like “inequity” and “unfair” are ethical terms that imply an obligation to redress an injustice. Justice has a range of meanings that include giving people what they deserve or are owed and distributing goods and services fairly. Justice in a medical context often involves the individual’s access to health services. In public health, discussions of health equity usually involve questions of how to distribute health benefits fairly or how to achieve better health outcomes among communities or groups that suffer health inequities. Attaining greater equity might involve the politically controversial strategy of disproportionally distributing resources within a population, by, for example, distributing more to those most in need. A less-controversial strategy is to improve health outcomes for all, even while devoting special efforts to those most in need. WHO defines health equity as “the absence of unfair and avoidable or remediable differences in health among population groups defined socially, economically, demographically, or geographically” (WHO 2007 ).

Achieving health equity is most urgent for groups who have experienced histories of marginalization and discrimination and who continue to experience higher rates of illness and premature deaths than members of the mainstream population. Especially for these groups, “social injustice is killing people on a grand scale” (WHO 2008 ). Realizing the goal of social justice with respect to health means achieving health equity. Doing so requires not only a fair distribution of health outcomes, it also means that “ideally everyone should have a fair opportunity to attain their full health potential” and that “no one should be disadvantaged from achieving this potential, if it can be avoided” (Whitehead 1992 ). For many, these goals imply that social justice obligates public health to improve any social condition that prevents people from maintaining a standard of life adequate to maintain health (Powers and Faden 2006 ). Although some believe that improving social conditions that affect health overextends public health’s mandate, such a broad mandate is arguably consistent with both Winslow’s and IOM’s definitions of public health. Moreover, such a broad mandate has both nineteenth century precursors in the social medicine movement and more recent precedents in the “Health for All” strategy that emphasizes health promotion and the “Health in All Policies” strategy (Kickbusch 2003 ; Freiler et al. 2013 ). But a major milestone was reached with the 2008 report of the WHO Commission on Social Determinants of Health that sought to “marshal the evidence on what can be done to promote health equity, and to foster a global movement to achieve it” (WHO 2008 ). and essential services, establish policies that provide an equitable basis for health improvement, and gather and monitor data on health equity, achieving equity ultimately will depend on the cooperation of government and civil society (Blas et al. 2008 ).

1.3. Ethics

People strive to be “good,” to do the “right” thing and to lead a “good life,” but where do such basic, familiar moral values as good and right originate? Throughout history, religious people have explained these ideas as revelations of divine command. Anthropologists, however, view morals as customs that govern social interactions, and because all cultures display such customs, interpret moral practices in terms of a survival function rooted in human nature. By contrast, many social and political thinkers emphasize that moral concepts result from social conventions or agreements that are subject to deliberation and change. Governments today often consult social scientists and health experts who empirically investigate what fosters or improves human life, health, and happiness. Where science informs law and policy, it helps define in a conventional sense what we mean by good and right. In particular, public health science helps establish what is considered good for the health of populations and communities. Further below we will examine three ethical theories prominent in public health ethics that offer contrasting perspectives on the nature and basis of morality. In the meantime, we will address three general questions that a public health practitioner first approaching the study of ethics might well ask: how does science relate to ethics, what is the difference between ethics and morality, and what sort of things count as principles or basic concepts in ethics?

1.3.1. Scientific Facts and Ethical Values

Public health practice increasingly requires appreciation of the complementary roles facts and values play in making and justifying decisions. Observation reveals facts, while scientific research controls and manipulates the experimental context to discover causation or correlation. Data on disease burden, research on intervention effectiveness, and estimates of the resultant health benefits for the population generally inform public health interventions. Health messaging can often inform the public about the scientific rationale underlying public health interventions. Nevertheless, in the mind of the public, scientific evidence does not always invalidate or outweigh other sources of evidence or appeals to emotions, interests, and values. While public health practitioners give more weight to community health and scientific evidence, they also need to consider how the public will respond to an intervention. Successfully implementing public health actions, then, will often entail weighing the public’s attitudes, interests, and values in relation to public health’s core values.

Two mundane features of public health practice often serve to conceal value assumptions: shared core values and standard practice. First, sharing values can render them invisible as assumptions, until they unexpectedly become contested. Unwelcome surprises occur when interventions that presuppose core values affect stakeholders who do not share those values, as when parents refuse to have children vaccinated based on media hearsay or individuals reject a highly effective program as governmental intrusion. Avoiding such surprises begins with becoming aware of one’s own value presuppositions in relation to those of other stakeholders and community members. Second, routine use of evidence-based standards can conceal underlying value assumptions. If developed and tested to address a known health problem, as is common, an intervention’s purpose and effectiveness is taken for granted. Standard interventions, then, generally require no more justification than noting their standard status or seeing that “the facts dictated” their use. “Dictating” facts are indicators that trigger use of a standard intervention (e.g., meeting the criteria of a case definition or documenting exposure to a dangerous level of a contaminant). Such “dictating facts,” more properly speaking, only indicate the appropriate intervention but cannot literally dictate that anything be done. What in the end dictate actions are the values, goals, and obligations that the standard intervention presupposes and that practitioners tacitly ratify each time they apply the standard. In other words, values, goals, and obligations, even when tacit, form a necessary bridge between knowledge and action.

Though standard practices tacitly incorporate ethical principles, they seldom raise ethical challenges. Challenges more typically arise in unusual or extreme situations where standards are not yet in place, are changing, or are competing. These situations include emergency operations, foreign cultural settings, emergent fields with innovative interventions, or periods of severe budget constraints that force prioritization of programs. In such challenging situations where no value consensus exists or where evidence does not point to a single course of action, public health ethics provides a process to determine and justify a course of action. That justification can incorporate a number of factors: evidence base for the intervention, cost effectiveness, analysis of relevant ethical rules and stakeholder values, a creative design of options or alternatives that embody these values, and a fair and transparent decision-making process that incorporates stakeholder contributions.

Recognizing one’s own value assumptions in relation to those of the public will be critical for implementing new interventions wherever success depends on public acceptance. The public will not embrace interventions that embody or presuppose values that clash with community values or whose relative importance is low compared to other community values. Members of the public generally are more committed to their political views, ethical and religious values, and an intervention’s impact on them personally than to scientific evidence or community impact. Public health practitioners need to recognize that no matter how compelling to them, community impact and scientific rationale seldom resonate as deeply with the public. Consequently, in communicating, public health practitioners need to supplement scientific messaging with dialogue, an appeal to common values, or enlistment of spokespersons who share the value orientation of the relevant stakeholders or community. Regarding some controversial matters, ultimate success in implementing an intervention may require building a social consensus (Ortmann and Iskander 2013 ).

In certain situations, untangling factual claims based on science from value judgments is critical for success. For example, suppose independent investigators have scientifically verified the level of worker exposure to a toxic chemical used in industry. Determining what level of exposure would be safe, however, remains a value judgment that depends on the degree of concern that people have about safety. Placing a higher value on safety might result in stricter controls that decrease risk for workers, but the financial costs of decreasing risks could cut industry profits or jobs, even as health costs fall. Stakeholders representing industry, workers, or public health practitioners might have different positions regarding a safe level of exposure. To make a good decision about a safe exposure level, the value of safety might have to be discussed and weighed in relation to business, employment, and health considerations. However, these varying positions regarding safety need not imply disregard for safety or disagreement on the underlying facts. Rather, they illustrate that conflicting value judgments can coexist despite a consensus on both the underlying facts and the importance of a particular value such as safety.

Directly addressing the value conflicts in such situations through ethical deliberation makes more sense than calling into question the underlying facts and can lead to better, fairer, and more transparent decisions. It is also important to recognize that doubting the science often represents an underlying value dispute masquerading as a scientific dispute (Brunk et al. 1991 ). Sowing doubt on scientific assessments merely as a tactic to oppose an evidence-based policy or recommendation undermines science. This doubt can exert pressure to test and retest results, raising the bar for scientific validity ever higher (Michaels 2008 ). The solution is not to litigate, as it were, the science, but to recognize that communicating risk is a social process that goes beyond science messaging and must take cultural attitudes, perceptions, and symbolic meanings into account (Krimsky and Plough 1988 ). Where profound value disagreements prevail, public health legitimately prioritizes its core values but cannot speak for everyone. Stakeholder views require a fair hearing, whether through media research, stakeholder analysis, or direct solicitation of input from individuals, focus groups, or public meetings. By design, a fair, transparent ethical decision-making procedure can help determine what value tradeoffs are feasible and what values may be nonnegotiable. Such a deliberative procedure can help to gain public acceptance and become part of the justification for a course of action.

To those accustomed to rigorous research methods and evidence-based standards of practice, navigating the world of ethical values and rules can be perplexing. Values, as the term itself implies, manifest valences, that is, variable degrees of commitment or estimations of importance along a continuum. Individuals rank values differently, change their rankings, and will alter their relative ranking of values in different contexts. The range of options for ethical rules are far more limited, namely, to obey or not obey. Nevertheless, the ethical rules governing particular situations also vary from country to country or even from jurisdiction to jurisdiction within a country. Despite this variability in values and ethical rules, reducing ethical judgment to mere opinion or to a consensus of opinion relative only to personal or cultural preferences would be a mistake. Ethical values and rules enjoy the approval of history, custom, law, and religious tradition, but they also find anchor biologically, psychologically, and socially in human life. Value judgments and ethical determinations, then, are not relative as much as correlative; that is, they correlate and resonate with these deeper roots of human life that we share. If humans indeed share a set of fundamental values, then ethical conflicts primarily reflect differences in prioritizing values in a particular context, rather than a fundamental disagreement about values. This point of view provides grounds for optimism about the possibility of finding a deeper basis for understanding and mutual respect, if not agreement, when ethical tensions surface.

1.3.2. Ethics and Morality

• Recognizing ethical issues and distinguishing them from factual issues;
• Providing a vocabulary to systematically discuss ethics;
• Identifying appropriate ethical principles to guide action in a particular context;
• Using these principles to analyze actions in regard to their ethical acceptability;
• Understanding the competing moral claims and values of stakeholders;
• Designing alternative courses of action that incorporate these claims and values;
• Evaluating which alternative best fits a given context, all things considered
• Establishing a procedurally just, transparent process for decision making; and
• Justifying decisions regarding recommendations, policies, or interventions.

1.3.3. Ethical Principles

Principles are general categories, rules, or guidelines that form the basis of a discipline. In ethics, there are various kinds of principles and many examples of each kind. The kinds include basic ethical categories (e.g., virtues, values, or rights), ethical commands or rules of conduct (e.g., not stealing, not harming, or treating others with respect), and guidelines for weighing outcomes (e.g., achieving the greatest good for the greatest number, distributing burdens and benefits fairly, or properly proportioning benefit to harm). Ethical principles like justice or respect for autonomy are simultaneously values, ideals, and the basis for deriving rules of conduct. Such rules serve as ethical standards to evaluate past and pending actions, programs, and policy recommendations. When addressing complex or controversial issues or issues involving numerous stakeholders, many different principles can come into play. But because ethical decision making depends on context (e.g., on local circumstances, community stakeholders, and decision makers), no formula can determine the most relevant ethical principles. Nevertheless, most ethicists and practitioners working in a field would agree that certain principles, theories, or frameworks provide more helpful guidance for that field. Given the need for flexibility, some prefer to speak not of ethical principles but of “general moral considerations” that can provide guidance in public health practice (Childress et al. 2002 ). At any rate, a complex ethical challenge involving stakeholders with competing moral claims frequently demands consideration of a variety of ethical principles and theories to address the situation and justify a proposed intervention. For these reasons, it will be useful both to examine below several ethical theories used in public health ethics and to provide at the end of the chapter a framework that is generally applicable to ethical issues that arise in public health.

1.3.4. Ethical Theories

As used here, an ethical framework refers to a tool or approach for practically addressing ethical challenges that often includes a stepwise procedure. An ethical framework may rely heavily on just one ethical theory, but frameworks generally take a pragmatic approach that procedurally allows for using a variety of theories or principles as the issue or context demands. Whereas an ethical framework has a practical orientation, an ethical theory also addresses more fundamental questions, so-called “metaethical” questions. Does morality originate in divine command, human nature, or human convention? Is it essentially a habit, intuition, form of reasoning, or a quality or purpose of an action? An ethical theory will offer a distinct, coherent understanding of the source and nature of morality that will shape how one reasons about moral issues and determine which principles are most important. Two persons employing the same theory, however, will not necessarily reach the same conclusion about an ethical issue; much will depend on which aspects of the issue they deem most important and on how they weigh different factors. Nevertheless, because a particular ethical theory tends to favor certain principles or types of principles, using the same theoretical approach will lead to similar lines of reasoning and selection of principles.

The diversity of ethical theories does not imply their mutual opposition so much as points to the extensive range of the moral landscape and the need to illuminate its various contours. A helpful way of illuminating this landscape is to distinguish theories depending on whether they focus on the actor, the action, or the results of action. To illustrate this particular way of carving up the moral landscape, Table 1.1 describes some well-known ethical theories.

Ethical theories

Aristotle’s virtue ethics is an ethical theory that focuses on the moral character of the actor or agent (Bartlett and Collins 2011 ). Classic virtues are dispositions or stable patterns of behavior that lie between extremes of vice; courage, for example, lies between the extremes of cowardice and foolhardiness in taking risks. Habit and practice are necessary to develop virtues whose possession we equate with good character and that equip a person to be effective in society or an organization. Because good character translates into virtuous action that others aspire to emulate, we tacitly invoke virtue ethics whenever we ask how an outstanding public figure or health leader would handle a situation. In a modern professional context, virtues also include the skills the profession has identified that lead to success in that profession and which professional education and training instill in practitioners. Once established, virtues readily become the standards of obligation and accountability to evaluate professional performance and function similarly to the rules and principles of duty discussed below. Holding public health institutions accountable for the professional competence of their employees illustrates virtue ethics (Public Health leadership Society 2002 ). More recently, the capabilities approach has exploited the potential of virtue ethics to guide decisions about policy or interventions in a way that goes beyond matters of professional training and responsibilities. This approach takes a broader developmental view of human agency and capacity building. It conceives health as a fundamental capability necessary for individuals to succeed in society, one on which many further capabilities depend (Sen 2009 ; Ruger 2010 ).

An ethical theory that focuses on action or, more properly, the rules governing action, is deontology. The word deontology comes from the ancient Greek word, deontos , which means duty. Because duties oblige us to obey rules that govern actions or conduct, they bind or constrain the will ahead of action. In judging whether an action is right or wrong, deontology ignores consideration of harmful or beneficial consequences and relies on these rules of duty to serve as the standard of judgment. People usually have rules of duty or obligation in mind when they speak of ethical standards or worry that standards are breaking down. Examples of these rules include religious commandments to honor parents, not lie, or not steal and rules of social interaction such as treating people fairly, doing them no harm, or respecting their rights. Rights often are said to stand in reciprocal relation to duties. Thus, the right to free speech presupposes a duty to respect the right of others to speak or the public health obligation to ensure conditions for maintaining health presupposes a right to health.

Deontology as a theory owes most to Immanuel Kant’s view of the “good will” and his closely linked account of autonomy. A person of morally good will does the right thing for its own sake, which means acting purely for the sake of duty. Duties are moral rules or laws that bind the will and limit the scope of action. For Kant, basing decision for one’s action solely on duty without regard to the potential good or bad consequences of the action is the only legitimate basis for moral action. Kant even goes so far as to say that “a free will and a will under moral laws are one and the same” (Gregor et al. 2012 ).

Kant conceives duty as the quintessential expression of autonomy, which may come as a surprise to those who equate autonomy with rational free choice or even just following one’s preferences without interference. However, the meaning of autonomy for Kant derives from its literal meaning in Greek, autos (self) and nomos (law); namely, self-legislating. Autonomy enacts from within the moral rules and principles that bind the will and guide action. However, not every self-originating impulse should be obeyed; only actions conceivable as universal laws morally bind the will. Morally laying down the law for oneself entails legislating for everyone, but universally legislating does not mean asserting one’s will over others. Nor does it mean that the ethical content of a moral law or duty is valid eternally and everywhere. Rather, it refers to the “categorical imperative” an unconditional requirement for an action to be moral. To qualify as a duty, a rule that commands action must apply to every rational person. Stealing, for example, could never qualify as a duty, because a situation where everyone steals from everyone else would undercut the one-sided advantage of stealing that the thief hopes to exploit. Although self-directed, autonomous action is necessarily other-regarding.

Kant maintains that the categorical imperative can be expressed in two other ways equivalent to universality, namely, “respect for humanity” and a “kingdom of ends” (Gregor et al. 2012 ). In each, this other-regarding dimension of autonomy is evident. Respecting humanity means never treating persons as mere means or objects but always treating them as ends, that is, regarding them as fellow autonomous agents. Autonomously agreeing on actions, interventions, or policies requires that decision makers mutually consider and understand their reasons for action and be willing to abide by the rules derived from these reasons as laws they collectively impose upon themselves (O’Neill 2002 ).

The idea of a fellowship of mutual consideration comes out most clearly in Kant’s concept of a kingdom of ends. This concept is really the ideal of a systematic union or commonwealth of autonomous individuals making laws that apply to everyone. This ideal presupposes that ethical deliberation places respect for others as ends, as autonomous agents, above self-interest. The core idea is that we only consider actions that could gain acceptance by a community in which all see themselves as sovereigns who lay down universal laws binding on themselves and others. The hope is that the body of law governing society progressively embodies this ideal. Such mutual regard in laying down the moral laws that will bind one’s actions differs significantly from insistence on noninterference with individual free choice, let alone with personal preferences. Conversely, the aspiration behind Kant’s view of autonomy harmonizes well with the public health obligation to address collective problems through collective action.

For utilitarianism, judging the rightness of an action depends on an estimation of its subsequent practical outcome or result rather than on its conformity to principles of duty. Utilitarianism considers ethically best that course of action that will result in the greatest net benefits over harms. A utilitarian approach underlies cost-benefit analyses that weigh an intervention’s costs (risks, harms, burdens, or disadvantages) against its benefits (advantages, utility, improvements, cost savings). In addition to its focus on consequences, utilitarianism is egalitarian, communitarian, and scientific in outlook. It is egalitarian in considering everyone’s benefit and equally weighting each person’s good, as opposed to privileging certain people. It is communitarian in attempting to increase benefits to society rather than individuals, seeking the “greatest good for the greatest number.” It endeavors to be scientific by quantifying harms and benefits, accounting for probability, and calculating net benefit. Calculating net benefits over harms is less problematic when relevant factors employ a common scale of measurement, for example, weighing the financial costs of treating a disease with the cost savings from preventing that disease. Comparing different outcomes (e.g., financial costs versus quality-adjusted life years) sometimes involves difficult judgments about the relative value of each outcome. Because the utilitarian approach seeks to determine and promote the collective good based on aggregate measures, it readily lends itself to justifying public health interventions.

1.3.5. Law Versus Ethics

Laws share certain deontological features with ethical principles of action (and with religious commandments). They all define one’s obligations or duties and typically take the form of rules or commands regarding what one should or should not do. They can lay down positive requirements to fulfill but more commonly establish parameters that prohibit certain actions or constrain liberty in some way. Laws do not differ from ethical rules primarily based on content, because an ethical rule can become a law without changing the rule’s content. For Kant, at least, the crucial difference between ethics and law concerns one’s reason for obeying; namely, whether one acts purely voluntarily out of a sense of duty or merely in external conformity with duty, either to appear to be moral or out of fear of penalty or punishment. Laws are rules enforced by penalty or punishment, which many people might otherwise break. Society can tolerate the flouting of some rules, but disobedience of more important rules can disrupt society or create danger. For these reasons, society establishes and enforces laws regarding socially important matters, not leaving their compliance up to individual prerogative. An ethical rule’s enactment as law, therefore, implies agreement by society or the law’s enactors on the importance of strictly regulating the behavior the law governs. Law can be a blunt instrument that effectively compels compliance, which suffices to satisfy the reasons for its enactment, even if it cannot coax voluntary obedience from an inward sense of duty.

In theory, deontologically evaluating a past or proposed action is a straightforward binary determination of compliance or noncompliance with a legal or ethical rule. In practice, however, defining a rule’s scope or determining exactly which actions fall under it can prove difficult. Moreover, when different rules apply, determining which should take precedence often becomes problematic, especially when they conflict. Lying to protect a relative, for example, can put the duty to speak truthfully into conflict with familial obligations. Determining which rule takes precedence can involve reasoning clearly from ethical principles, weighing the underlying values embodied in the law, or considering the practical impact of the intervention in context. Because laws demand compliance, they are more rigid. Additional legal stipulations can prioritize or specify how to apply laws in certain situations, but doing so increases their complexity. Ethical guidelines operate more flexibly than rigid, compulsory laws and more readily accommodate compromise. With ethical guidelines, decision makers can consider and rank the underlying values the ethical rules serve to promote. Doing so allows for trade-offs between competing ethical considerations and for deciding which values it makes sense to prioritize in the given context. Conversely, law’s comparative rigidity can be a virtue where only stricter oversight and enforcement will ensure compliance and establish order.

Across cultures, legal, ethical, and religious rules prohibiting basic offenses such as lying, theft and murder show considerable overlap. However, cultures vary in exactly which rules are matters of individual choice and which are matters of legal enforcement and punishment. This variability also applies to the status of rules and standards governing research on human subjects. Even within a country, significant variability can prevail in whether human subjects’ research rules and standards are legal regulations or ethical guidelines (U.S. Department of Health and Human Services 2015 ). Some see the lack of legal regulation as a breach in protections, but others prefer guidelines, arguing that regulations tie reviewer hands, making it more difficult to make trade-offs or nuanced judgments based on moral discernment of the particulars of each case (Verweij and Dawson 2009 ). Because each approach offers advantages and disadvantages, political culture and local context must ultimately decide whether human subjects’ research rules exist as enforceable regulations or ethical guidelines.

Regardless of whether it takes the form of guidelines or law, research ethics will govern only a fraction of the ethical issues that the field of public health must address. In many areas of public health practice, there are no specific ethical guidelines or regulations. To address ethical challenges in these areas or to address emergent challenges, the ethical practice of public health therefore requires the ability to use general ethical frameworks. Such frameworks can employ checklists of questions and stepwise procedures. However, because novel challenges continually emerge and changing contexts introduce nuances no set of rules can anticipate, public health professionals ultimately need to practice ethical decision making over time in order to cultivate moral judgment and discernment.

By laying down and enforcing what may, must, or cannot be done, legal rules function as boundaries of acceptable behavior. Ethics, science, budgets or politics, each in its own way, also can restrict the scope of action. Public health practitioners and officials therefore first need to conduct a feasibility analysis to determine the relevant limits on possible interventions or policies. Determining these limits seldom will restrict the scope of action to a single possible course. Given multiple possibilities, most people will aspire to the best course of action beyond the legal floor of minimally acceptable behavior yet within the other relevant limits. As a result, the ethical challenges public health practitioners face seldom involve stark choices between right or wrong, good or evil. A good feasibility analysis will have ruled out any unethical or illegal options or alternative courses of action in advance. Rather, the tough choices more frequently involve selecting the best alternative from among competing goods, each of which to a greater or lesser degree realizes the public health goal and embodies relevant stakeholder values.

Whereas determining and complying with the various limits on action is largely an analytic process, designing alternatives is a synthetic, creative process. Alternatives should all realize the public health goal and incorporate the perspectives and values of subject matter experts and relevant stakeholders. Deciding upon the best alternative must take into account how it will realize the public health goal in a particular context and with respect to the stakeholders. For example, advocating contraceptives to reduce unwanted teen pregnancy might seem to promise success based on efficacy studies, but ethical controversy could render such a program less than optimal in some contexts. Political culture or social norms can confer partisan advantage or disadvantage to some alternatives, while other alternatives may enjoy an advantage because of the experience and expertise of a health department. Whatever alternative practitioners finally choose, their choice will presuppose a prioritizing of values. The foregoing account highlights why public health practitioners need to see ethics as something more than a compliance matter. It transcends compliance because public health ethics also involves practical decision making, which should include stakeholder analysis, the incorporation of stakeholder values in the design of alternatives, and a fair, transparent deliberative process to evaluate alternatives.

1.4. Public Health Ethics

Compared with more established fields of practical ethics such as clinical ethics, research ethics, and bioethics, the field of public health ethics is relatively new. Consequently, many public health practitioners may be better acquainted with these more established fields than with public health ethics. In particular, practitioners may already be acquainted with the four principles these fields rely on for ethical evaluation: beneficence, nonmaleficence, respect for persons (autonomy), and justice (U.S. Department of Health, Education, and Welfare 1979 ; Beauchamp and Childress 2012 ). Being applicable to health and research, these four principles also are relevant to public health, but having arisen to address issues in other fields, they need to be adapted to a public health context. Even then, they still fall short in addressing the ethical challenges that arise in public health. Examining these related ethics fields and showing how the four principles fit into a public health context can serve by way of contrast to indicate what is distinctive about public health ethics.

1.4.1. Research Ethics, Clinical Ethics, and Bioethics: Principlism and the Four Principles

Research ethics entails the wider notion of scientific integrity but is best known and most developed in relation to medical research involving human subjects. The development of human subjects’ research ethics guidelines can neither be divorced from breaches of ethical conduct in human subjects’ research nor wholly reduced to a reaction to these events. But beginning with the Nuremberg Code ( 1947 ), balancing risks and benefits to research subjects and getting their informed consent have been cornerstones of international research ethics guidelines. Far more influential than the Nuremberg Code , the Declaration of Helsinki from the World Medical Association (WMA) is a fundamental document in international human subjects’ research ethics guidelines. Its initial 1964 version included provisions for proxy consent for those with diminished autonomy. Its 1975 revision called for review of research by an independent committee, now known as an ethics review committee (WMA 1964 , 1975, 2013). The use of such committees began spreading under the aegis of WHO and then in response to the HIV/AIDS pandemic, as the number of large-scale vaccine and drug trials grew in developing countries. In the United States, research regulations set forth in the Common Rule govern ethics review committees as well as all human subjects’ research that receives U.S. government funding (U.S. Department of Health and Human Services 2009 ). In the United States, a standing ethics review committee generally functions within a specific governmental or university institution and therefore is referred to as an institutional review board (IRB). Beginning in 1982, the Council for International Organizations of Medical Sciences (CIOMS), in collaboration with WHO, proposed international ethical guidelines for biomedical research involving human subjects (CIOMS 2002 ).

Our discussion of these documents has only highlighted key provisions of what is required to ensure the safety of human subjects. CIOMS’s most recent research guidelines ( 2002 ), for example, contain more than 60 pages of text, explanation, and commentary. But ensuring ethical conduct and scientific integrity in research requires more than the oversight function of ethical review committees. It also requires extensive training not only in research ethics but also in a number of related areas. Training and guidelines should cover, among other things, mentoring of junior researchers, authorship and publications policy, conflicts of interest that arise in partnerships and collaborative science, and data acquisition, management, sharing and ownership. Ethics training can help develop moral judgment. The hope is that training and application will enable practitioners to reason about new, difficult, or ambiguous cases in morally discerning ways.

Clinical ethics address the ethical issues that arise in clinical practice. Until the advent of bioethics, medical professionalism emphasized the health care provider’s obligation to prioritize the patient’s welfare, the health care provider’s professional judgment about what would most benefit the patient, and the importance of establishing patient trust. The traditional model of clinical ethics was frankly paternalistic. Under the influence of bioethics, many health care providers began embracing a more patient-centered model of care that emphasized patient autonomy and informed consent. This patient-centered model conceives care as a contract between patient and provider. The emphasis on contracts strikes some as an inappropriate consumerist model that undervalues professional judgment and undermines patient trust in the medical profession. Tensions between these two models have led to a compromise that reasserts the importance of medical professionalism and clinical judgment, while acknowledging the importance of respecting patient autonomy (ABIM Foundation et al. 2002 ).

Bioethics has a range of meanings, the first of which applies to ethical issues brought about by advances in biomedicine and biotechnology. Ethical issues that arise from using life-sustaining technologies in end-of-life and beginning-of-life care epitomize this sense of bioethics. But bioethics also arose in response to medical paternalism and to the abuse of human subjects in medical research. Bioethics has championed informed consent, patient autonomy in doctor-patient relationships and the safety of human subjects in research. However, many bioethicists think the focus on clinical ethics and on personal autonomy unduly restricts bioethics’ purview. They advocate a more holistic, social justice approach in bioethics, which has been referred to as “population-based bioethics” or “integrative bioethics” (Sodeke 2012 ). It can be argued that this expansion of bioethics beyond clinical ethics into population issues moves bioethics into the arena of public health ethics (Callahan and Jennings 2002 ).

Principlism came into being in a 1979 document called the Belmont Report (U.S. Department of Health, Education, and Welfare 1979 ). The report was the work of the U.S. National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research, which convened in 1974 partly in response to the exposé of the U.S. Public Health Service Tuskegee Syphilis Study. The Belmont Report became the basis for revising 45 CFR 46, the so-called Common Rule, part of the legally binding U.S. Code of Federal Regulations, governing the protection of human subjects (U.S. Department of Health and Human Services 2009 ). The Belmont Report clearly explained the underlying ethical principles that informed existing regulations and provided an ethical framework for thinking about subsequent regulations. Principlism has remained the predominant ethical framework in biomedical ethics (Beauchamp and Childress 2012 ). Its explanatory groundwork accounts for much of its success, but its relevance to medicine and research, the prestige that attaches to these fields, and its compatibility with liberal individualism also have played a role.

Beneficence (doing good) and nonmaleficence (doing no harm) date back to the Hippocratic Oath as medical principles. Collapsing them both into beneficence, as the Belmont Report does, underscores the practical consideration that biomedical decisions generally aim to optimize net benefit over harm, rather than to maximize only benefits or minimize only harms or risks. However, these principles are distinct, not mere opposites. Not doing harm has a certain priority (first, do no harm), because not benefitting someone seems a less serious offense than doing that person harm. That priority partly reflects the human tendency more readily to forgive overlooked benefits (errors of omission) than deliberate actions resulting in harm (errors of commission).

Justice has several meanings that include due process and fair deliberative procedure, properly assessing what people are owed or due, and equitable distribution of burdens and benefits. According to philosophic tradition, justice has always functioned dually, applying to individuals but more importantly serving as an overarching principle for adjudicating competing claims in relation to the group or to other members of society. The phrase, “social justice,” then, is redundant but in political contexts marked by individualism serves as a reminder of justice’s social dimension. In fact, this phrase came into vogue in public health circles to counter the ideology of “market justice,” which views the equal access of individuals to the free market as a valid, reliable, and preferred means for sorting out issues of economic and social justice (Beauchamp 1976 ). The notion of health equity, which compares different groups, primarily refers to this social dimension of justice, although denial of access to health care, a contributing factor to health inequity, violates what the individual is owed.

Respect for persons emphasizes that individuals, as agents in charge of their own lives and bodies, have the right to make decisions and choices free from undue interference. Respect for persons forms the basis of informed consent, namely, the right of patients and human research subjects to be informed of, and to assent to, medical or research procedures they might undergo, especially procedures that pose potential harm or risk. Conducting research on human subjects or performing medical procedures on patients without their prior knowledge or consent in most cases violates their personal autonomy. However, health professionals have a special (i.e., paternal) obligation to look out for the welfare of people with diminished decisional capacity—such as those in a coma or the very young—and to protect them from harm.

These four principles were originally conceived as prima facie principles, that is, each expressed a self-evident though not absolutely binding obligation and none had an inherent priority over another. However, in many Western countries and in the United States in particular, respect for persons has dominated discussion in bioethics, clinical ethics, and research ethics where it often takes precedence as a moral consideration over the other principles. This ascendancy most likely reflects the high value that these countries place on liberty and freedom. At any rate, in public discourse generally and in public debate about public health interventions, respect for persons often amounts to an insistence on noninterference with individual free choice or with personal preferences. Although Kant’s other-regarding idea of moral autonomy, harmonizes well with collective decision making, the insistence on noninterference with personal choice often creates impediments to the implementation of public health interventions. In part for this reason, the social justice movement has had to challenge the emphasis on respect for persons in order to promote the public good and health equity.

1.4.2. Contrast between Clinical Ethics and Public Health Ethics

Table 1.2 contrasts the individual focus of clinical ethics with the community/population focus of public health ethics. Because public health and clinical practice can overlap, the items in the respective columns represent tendencies along a continuum rather than stark opposites. Where separate agencies carry out public health services and medical care, these contrasts may be more pronounced. The overlap between public health and clinical practice makes it even more important to highlight their differences to bring out distinctive features of public health ethics.

Comparison of areas of focus/tendency in clinical ethics and public health ethics

The table makes clear that the Belmont principles of beneficence (seeking benefits), nonmaleficence (avoiding harm), respect for persons, and justice remain important in public health, but must be extended to accommodate the broader scope of public health interventions. This broader scope entails many types of professionals, interventions and policies that display a political and social dimension, and a wider range of activities such as community engagement, intersectoral collaboration, collective decision making, and governmental administration. As a result, prevailing political philosophies and culture will necessarily shape the way public health functions. The crucial point is that differences of scale that produce a higher order of complexity also produce qualitative differences that introduce different patterns of causation. Among other things, this means that social factors do not merely represent aggregated individual factors and so cannot always be addressed in the same way as individual factors.

1.4.3. Individual Versus Relational Autonomy

For understanding what is qualitatively distinct about public health, the contrast between respect for individual persons and the relational autonomy of community members is key. Respect for persons upholds an individual’s right to make independent decisions free from undue pressure, but relational autonomy emphasizes that individual actions occur in the context of other people whom these actions will affect. The potential harmful impact of individual action on the welfare of others sets a limit to individual action. Relational autonomy draws attention, then, to the interdependence of people living in communities and to the solidarity that arises from the emotional bonds that shared lives create. Anthropology teaches that people always find themselves in a network of social relations, while evolutionary biology has shown how profoundly people are built from the physiological ground up as sociopolitical beings. Because it presupposes the social context of language and reasoning ability, individual autonomy also depends developmentally on relational autonomy. That is, people only become autonomous through relations and interactions with others. As African humanism (ubuntu philosophy) epitomizes it, umuntu ngumuntu ngabantu , “a person is a person through other persons” (Louw 2008 ). Familial and communal deliberate processes are foundational for the development of individual autonomy and provide an even deeper basis for collective decisions than the type of solidarity that comes to the fore in crises or in the face of common predicaments. Kant would reject any suggestion that developmental context, emotional bonds or feelings of solidarity underpin moral autonomy. Nevertheless, moral autonomy and relational autonomy both display an inner-directed, but other-oriented feature that readily aligns with collective decision making.

These points about the foundational character of social relatedness, solidarity, interdependence, and communal decision making do not readily align with certain features of social contract theory, on whose principles liberal democracy is based. Whereas virtually every other political tradition conceives the sociopolitical realm as a natural feature of human life, social contract theory posits humankind’s original state, the state of nature, as one of solitary individualism. In this view, society or at least civil society come into existence voluntarily through a contract that creates government through the consent of the governed (Riley 1982 ). Although never seriously advanced as a scientific account of society’s origins, social contract theory nevertheless has exerted a powerful influence as a political founding myth. As such, it has made personal liberty, free choice, and consent of the governed presumptive values of societies whose governing political philosophy rests on social contract theory. By “presumptive,” we mean that the value, norm, or claim is assumed to be valid or have priority, so that the onus is on the person who objects to the presumption to justify a different value, norm, or claim.

1.4.4. Personal Autonomy as a Presumptive Value of Liberal Democracy

Personal autonomy in a clinical and research context generally means respect for the patient’s right to receive an explanation of a medical procedure or research intervention, to be informed of any potential benefits or harms, and to freely choose whether to accept the procedure or participate in the research. More generally and in other contexts, personal autonomy has come to mean an insistence on liberty, free choice, and noninterference with personal preferences. Personal autonomy in this more general sense owes more to John Stuart Mill’s nineteenth-century views on liberty than to Kant’s eighteenth-century idea of autonomy (O’Neil 2002 ; Dawson 2011 ). An important aspect of Mill’s view of liberty is the “harm principle,” which holds that “the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others” (Mill 1989 ). What people choose to do regarding themselves is no business of government. Interfering with this private sphere of self-determination constitutes governmental paternalism. This interference diminishes the sphere of liberty that affords individuals the chance to direct their own lives and develop their talents and character to the highest degree. A chief advantage of democratic society, one that benefits the entire society, is the creative social dynamism that emerges from the synergism between individuals who are developing their talents and abilities.

Arguably, the primary aim of the harm principle is to promote the kind of individual self-development that benefits society rather than to champion every exercise of free choice. At any rate, some have sought to distinguish this edifying version of personal autonomy from an all-encompassing version that demands undue deference to any and all personal choices and preferences merely because they are personal (O’Neill 2002 ; Dawson 2011 ; Powers et al. 2012 ). Presuming, or insisting on, the validity of personal autonomy makes more sense in the delimited context of medicine and biomedical research on human subjects where an individual’s body is the focus of activity. It makes less sense in the far wider sphere of public health activity where social interactions and the interdependence of people come into play. Absolutizing personal autonomy in the sphere of public health would give effective veto power over every collective decision aimed at the public good to any individual who felt constrained by that decision. A more moderate version might distinguish levels of importance of personal choices and exercises of liberty. A collective decision concerning the public good could override some personal choices and limit liberty, even when they did not involve direct harm to others. Such decisions, when made in the context of a fair, transparent process of ethical deliberation involving stakeholders, are more likely to get buy-in from a community and less likely to be labeled paternalistic.

Because public health considers the relation between individuals and the collective good, it necessarily has a political dimension. How a country’s political culture balances this relation will drive and constrain public health practice and so shape the nature of the ethical frameworks that are appropriate to a country’s politics (Hyder et al. 2008 ). In the brief history of public health ethics, the most important ethics frameworks have emerged in the political context of liberal democracy. Many of these frameworks reflect the tensions between public health’s obligation to act collectively for the common good and the presumptive value of personal autonomy. The principle of least infringement and Kass’s code of restraint illustrate the effort to mediate such tensions (Kass 2001 ). The code of restraint strives to balance autonomy claims against the obligation to safeguard community health by determining what intervention most effectively protects health while minimally infringing on liberty. In a liberal political context that recognizes Mill’s harm principle, this strategy justifies the trumping of personal autonomy as long as imminent harm threatens the populace, for example, in a deadly outbreak of contagious disease. But where the threat of harm to others is indirect or not immediate, as with the obesity epidemic, the harm principle less readily justifies a liberty-limiting intervention such as banning or taxing certain foods. Utilitarian approaches that weigh the health advantages of intervention and the disadvantages of obesity clearly support obesity intervention, but limiting interventions to those that do not restrict personal choices also have limited effectiveness. In Chap. 6 , Jennings considers the relative merits of these approaches in his overview of the ethical issues in environmental and occupational public health. His discussion raises the question of the extent to which an ethical framework should adapt itself to the presumptive values of the political context or should reflect the nature of the practical field under investigation. To some extent, it must do both.

The three-step framework offered in the next section is designed to guide decision makers, through questions, to assess the ethical dimensions of a case, including which moral considerations (e.g., population utility or liberty) may have more weight than others, given the issue or context. This contextual approach provides the flexibility and starting point for deliberation to accommodate the issues globally and to uncover the varying perspectives of stakeholders with potentially different presumptive moral norms (e.g., solidarity versus individual rights).

1.5. Ethical Frameworks

What at first glance demarcates public health ethics from related fields of health ethics are the ethical problems that public health professionals typically encounter in their practice and the ethical frameworks used in practice to address these problems. Regarding these ethical problems, this casebook offers a representative, but not exhaustive, sample. Regarding ethical frameworks, this chapter has suggested two competing criteria for choosing. On the one hand, ethical frameworks should be grounded in their topics. Dawson ( 2011 ) expresses the point succinctly by arguing that public health should be the foundation of public health ethics. Accordingly, we have presented a view of public health ethics that builds on the definitions of public, health, and public health, and on the goals of public health practice. But we have also defined ethics and indicated how public health ethics draws on numerous ethical theories and can provide a moral guide grounded in the norms of benefiting others, preventing harms, and providing utility. We have pointed out its distinguishing principles based on the facts of community and interdependence. Lastly, we have situated public health ethics within the process of ethical decision making about which options are the most justifiable means to achieve public health goals in a particular context. In the end, grounding public health ethics in public health may require public health leaders to have the courage to advocate public health values and goals, even when that position is unpopular. Such a stance may be justified, for example, where the feasibility of a much-needed public health intervention requires a long-range strategy to change social norms or build social consensus.

On the other hand, precisely because public health itself is practical, pragmatic, and community oriented, an ethical framework designed for it must accommodate itself to a country’s presumptive values and political culture. This consideration illustrates that the feasibility of public health interventions usually depends on their alignment with the political culture, while their success usually implies public acceptance. Many established frameworks, like that of Kass, seem designed with a liberal political context in mind that gives presumptive weight to individual liberty, which may limit the range of interventions that can be justified. Newer approaches to ethical analysis in public health place more emphasis on social values like equity and solidarity, although these newer approaches often are difficult to put into practice (Lee 2012 ). In addition, while newer approaches may offer clear reasons to justify a broader range of interventions, the reasons may be less persuasive if they do not consider the presumptive values in context. For example, in Chap. 3 , Daniels discusses the ethical conflicts that arise during pandemics between the standard goal of improving population health and emergency contexts that demand allocating scarce resources in a way that treats people fairly. He asks, if in the pandemic context we believe that saving the most lives trumps giving priority to those who are sickest, can we justify revising the usual priority given to the sickest in health care?

Arguably, what would be most useful is not a set of frameworks designed for specific presumptive values, but, rather, a framework that can accommodate any presumptive values and consider them in relation to values rooted in public health or in context. The three-step framework that follows is a straightforward tool to help practitioners analyze the ethical tensions in a particular context. It addresses Daniels’ tough question directly by considering health care’s presumptive prioritization of the sickest in relation to the public health value of saving the most lives in a pandemic.

1.6. A Three-Step Approach to Public Health Decision Making

In the case of an epidemic, it is important to control the spread of the disease, but as much attention should be paid to the rights of the noninfected patients who need urgent medical care. There may be as many people who died from other illnesses and could not get into hospital as there were who died from SARS. Equity is required in the amount of attention given to a wide array of people, including patients with and without SARS. Accountability for making reasonable decisions, transparency and fairness are expected …. (Singer et al. 2003 )

The questions clarify the relevant factors, such as stakeholder claims, alternative actions, and possible justifications for deciding on one course of action.

1.6.1. An Approach to Ethical Analysis and Justification in Context

• What are the risks, harms, or concerns?
• What are the appropriate public health goals in this context?
• What is the scope and legitimacy of legal authority, and which laws and regulations apply?
• What are the moral norms and claims of stakeholders, and how strong are they?
• Are precedent legal or ethical cases relevant for identifying the presumptive moral norms?
• Which features of the social-cultural-historical context apply?
• Do professional codes of ethics provide guidance?
• What are the short- and long-term options, given the assessment of the public health issue and context in Step I?

Utility: Does the public health action produce the best balance of benefits over harms and other costs?

Equity and Justice: Is health equity advanced? Are the benefits and burdens distributed fairly (distributive justice)? Is there appropriate public participation, including the participation of affected parties (procedural justice)?

Respect for Individual and Community Interests: Does the public health action respect self-determination and human rights, as well as civic roles and community values (e.g., trustworthiness, solidarity) (Dawson and Jennings 2012 )?

• Other Moral Considerations in Public Health: Are there other moral considerations in public health that are important to consider? (For example, reciprocity, solidarity, protecting privacy and confidentiality; keeping promises and commitments; or disclosing information and speaking honestly, sometimes grouped as transparency.)
• Effectiveness: Is the public health action likely to be effective?
• Proportionality: Will the probable benefits of the action outweigh the infringed moral considerations?
• Necessity: Is the action necessary (i.e., will overriding a conflicting ethical norm achieve an important public health goal)?
• Least Infringement: Is the public health action the least restrictive means available?
• Public Justification: Can decision makers offer public justification in the political and cultural context that stakeholders, the public, and those most affected find acceptable?

There are several stakeholders: the child, the child’s family (including parents but also several siblings), and the public, which expects the health department to protect the community from TB. Regarding moral claims, the child has some expectations of freedom of movement, and privacy; the family has similar expectations regarding privacy, respect for parental rights, and the freedom to administer medications to their child at a convenient time and place. However, these claims are not absolute, and competing moral claims can outweigh them. The child has a moral claim that could compete with her parent’s claim, specifically, that receiving DOT will reduce the risk of inappropriate treatment and relapse compared to having her parents administer the medications. In addition, the public has a moral claim based on two expectations: ( 1 ) that the health department will protect the community from TB, and ( 2 ) that people contagious for TB and other infectious diseases will protect others by behaving in an appropriate manner, including staying home when contagious and cooperating with treatment recommendations. This is especially concerning in this case because the immigration health officials had discussed the risks with the parents, warning them to seek treatment as soon as the child developed symptoms, yet the parents waited several months before taking the child to a pediatrician (Melnick 2015a , 175).

Consider another short scenario that illustrates the value of exploring options under Step II. A new policy is being considered that would require parental consent for newborn screening. Parental consent currently is not required, although newborn testing is not conducted if there are parental objections. The health department has been asked to take a position on the pending policy. What position should the health department take? What are the options?

Options include mandatory screening without consent, routine screening with advance notification (Opt In), routine screening without advance notification (Opt Out) (i.e., screening and testing done unless the parents object), voluntary screening (i.e., screening requires full consent and might also include a pre- and post-counseling session with each new mother). Some arguments that might be offered against requiring parental consent focus on the fact that (1) the benefits of screening are obvious and substantial, relative to potential harms; (2) parents have few good reasons to justify parental refusal and place their child at risk for harm; (3) obtaining consent from each parent is difficult, costly, and an unwarranted expenditure of time and money; and (4) the history of newborn screening has become acceptable and routine. Some arguments that may be raised for requiring parental consent include (1) parental consent is necessary because refusal of newborn screening is reasonable given the increasing list of diseases included in the battery of newborn tests and the low probability of many of these diseases; (2) newborn screening can have adverse consequences such as psychological harms associated with false positive tests; (3) long-term parental caretaking is enhanced when parents are included in all clinical decisions about their children; and (4) the process of obtaining consent need not be time-consuming or burdensome but rather can help enhance the health professional-patient relationship (CDC 2012 ). Which arguments are stronger, and which of the options are the most ethically justifiable? The answer may depend on the social and political context in which the issue is considered, and which ethical values carry weight in that context. Whether there were presumptive values in place would be explored through the questions in Step I, which examines previous cases, the applicable laws and policies, and stakeholder claims in context. So, for example, in a society that has a strong moral norm or presumption for solidarity, there could be a presumption for continuing population newborn screening without parental consent. On the other hand, for a society that has a liberal political context that has a presumption for individual liberty, there may be a presumption for an option that seeks more explicit consent from parents. In either context, the presumptive moral norms are not determinative but are rebuttable, so the arguments or reasons to override those norms must be stronger.

Consider a third case from public health practice in which a person (the index case) infected with primary syphilis and HIV refuses to provide contact information for his wife, insisting that he and his wife had not had sexual relations for several years. Contact tracing and partner notification have been important tools historically for public health officials, although these interventions can involve thorny ethical tensions, requiring health officials to justify their decisions. In this type of situation, health officers will consider several options, starting with those that infringe least on the index case’s choices. For example, they might first provide to the index case additional information and assurance about confidentiality while allowing him to notify his wife voluntarily, either alone or with the help of public health workers. If this proves unsuccessful, other interventions might be considered, such as incentives, the threat of restrictions such as isolation, or attempts to notify the wife without his knowledge or consent. Each of these options would be determined in context, using the questions in Step III. Questions considered may include (1) Would the options likely accomplish the goal of warning and testing the wife without risking greater harm or possible adverse outcomes for the wife (e.g., domestic violence, loss of income, or loss of housing)? (2) Is there significant concern about a risk of harm to others, such as family members or children, so that the burdens and benefits of the action would not be distributed fairly? (3) Is the action the least restrictive of the important moral claims of the stakeholders? (4) Is it necessary now to override conflicting claims to achieve the public health goal? Answering the questions in Step III helps decision makers consider whether actions are justifiable. As one health officer explains, “Public health officials should justify their decisions with deliberations that build not only community support and trust, but also build support and trust from the individuals and families directly affected” (Melnick 2015b ).

As the scenarios illustrate, public health is a social and political undertaking. Thus, making difficult choices in public health implicates important social, cultural, and political norms embedded in a particular context and community of stakeholders (Childress and Bernheim 2008 ). Regardless of whether decision makers work in a government public health agency, community nonprofit, nongovernmental organization (NGO) from another country, or a global organization, decision makers must rigorously assess the public health issue in context , to minimally be able to act “in ways that preserve the moral foundations of social collaboration” at the core of collective health activity (Calabresi and Bobbitt 1978 ).

The context specifically includes attention to stakeholders and relationships among public health stakeholders and community members, including the common understanding of their roles, obligations, and collaborations. Especially in global public health, it is important to note that even the decision makers are stakeholders, in some sense, and often, when they are health professionals, they have their own social-cultural norms and their own professional codes that can provide guidance. Appeals to the codes of particular professions, however, do not provide a sufficient justification for a public health decision, since justifications should be grounded in a society’s widely shared ethical values and norms.

Engaging stakeholders and addressing claims, especially those of the people most affected by a public health issue, in ethical analysis, is especially important and can sometimes support and strengthen the collaboration and cohesion needed for public acceptance of a decision. The ways to engage and reason with stakeholders in an ethical analysis will vary in different settings and communities, depending on community values, cohesion, and expectations, and can range from establishing an ethics board for deliberation, to gathering information from focus groups or social media, to including stakeholder representatives on the decision-making team. Stakeholder norms and claims are a critical feature for an ethical analysis in order to achieve a primary goal in public health—the development and maintenance of relationships of trust, defined in a report from IOM as “the belief that those with whom one interacts will take one’s interests into account, even in situations in which one is not in a position to recognize, evaluate, or thwart a potentially negative course of action by those trusted” (IOM 1996 ).

Ethical analysis is a dynamic process and, particularly for the practice of public health, is best accomplished through group deliberations that involve understanding others’ perspectives and thinking independently and imaginatively. Public health professionals often have to decide how best to realize numerous important societal norms and values when pursuing public health goals. Ethical tensions do occur in public health and at times require overriding an important principle, value, or moral consideration to undertake a justifiable public health action. However, a structured ethical analysis can often lead to imaginative alternatives that transcend or minimize ethical tensions and to decisions that most or many stakeholders find acceptable.

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• Cite this Page Ortmann LW, Barrett DH, Saenz C, et al. Public Health Ethics: Global Cases, Practice, and Context. 2016 Apr 13. In: H. Barrett D, W. Ortmann L, Dawson A, et al., editors. Public Health Ethics: Cases Spanning the Globe [Internet]. Cham (CH): Springer; 2016. Chapter 1. doi: 10.1007/978-3-319-23847-0_1
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. Type 508 Accommodation and the title of the report in the subject line of e-mail. State and local public health officials rely on health-care providers, laboratories, and other public health personnel to report the occurrence of notifiable diseases to state and local health departments. Without such data, trends cannot be accurately monitored, unusual occurrences of diseases might not be detected, and the effectiveness of intervention activities cannot be easily evaluated. In the United States, requirements for reporting diseases are mandated by state laws or regulations, and the list of reportable diseases in each state differs. In October 1990, in collaboration with the Council of State and Territorial Epidemiologists, CDC published Case Definitions for Public Health Surveillance (MMWR 1990;39{No. RR-13}), which, for the first time, provided uniform criteria for reporting cases. This report provides updated uniform criteria * for state health department personnel to use when reporting the nationally notifiable infectious diseases listed in Part 1 of this report. A revision date is listed for each case definition that has been revised. Newly generated case definitions that have not been published previously are designated as "adopted" on the specified date. Case definitions for some infectious conditions not designated as nationally notifiable are included in Part 2 of this report. Some of these conditions may have been nationally notifiable or may become so; definitions are included here to facilitate interpretation of data for these diseases. These conditions may be reportable in some states. INTRODUCTION State and local public health officials rely on health-care providers, laboratories, and other public health personnel to report the occurrence of notifiable diseases to state and local health departments. Without such data, trends cannot be accurately monitored, unusual occurrences of diseases might not be detected, and the effectiveness of intervention activities cannot be easily evaluated. In the United States, requirements for reporting diseases are mandated by state laws or regulations, and the list of reportable diseases in each state differs. CDC and the Council of State and Territorial Epidemiologists (CSTE) have established a policy that requires state health departments to report cases of selected diseases ( ) to CDC's National Notifiable Diseases Surveillance System (NNDSS) (1,2). However, before 1990, the usefulness of such data was limited by the lack of uniform case definitions for public health surveillance. Without explicit criteria for identifying cases for public health surveillance purposes, state health departments and individual practitioners often applied different criteria for reporting similar cases (3). In October 1990, in collaboration with CSTE, CDC published Case Definitions for Public Health Surveillance (4), which, for the first time, provided uniform criteria for reporting cases to increase the specificity of reporting and improve the comparability of diseases reported from different geographic areas. This report supersedes the 1990 report, which included infectious diseases and one noninfectious condition (i.e., spinal cord injury). The CDC Surveillance Coordination Group has established a steering committee that is charged with the development of a broad range of case definitions for noninfectious conditions (e.g., environmental or occupational conditions, chronic diseases, adverse reproductive health events, and injuries). This report provides updated uniform criteria for public health professionals to use when reporting the nationally notifiable infectious diseases listed in Part 1. A revision date is included for each case definition that has been revised. Newly generated case definitions that have not been previously published are designated as "adopted" on the specified date. Data for nationally notifiable diseases reported by the 50 states, New York City, the District of Columbia, and the U.S. territories are collated and published weekly in the Morbidity and Mortality Weekly Report (MMWR). Cases reported by state health departments to the NNDSS for weekly publication are provisional because of ongoing revision of information and delayed reporting; thus, these numbers may change. Updated final reports are published annually in CDC's Summary of Notifiable Diseases, United States (1). The CDC/CSTE surveillance case definitions included in this report differ in their use of clinical, laboratory, and epidemiologic criteria to define cases. Some clinical syndromes do not have confirmatory laboratory tests; however, laboratory evidence may be one component of a clinical definition (e.g., toxic-shock syndrome). Most case definitions include a brief clinical description; however, unless this description is explicitly cited in the case classification section, it is included only as background information. Some diseases require laboratory confirmation for diagnosis regardless of clinical symptoms, whereas others are diagnosed based on epidemiologic data. Many case definitions for the childhood vaccine-preventable diseases and foodborne diseases include epidemiologic criteria (e.g., exposure to probable or confirmed cases of disease or to a point source of infection {i.e., a single source of infection, such as an event resulting in a foodborne-disease outbreak, to which all confirmed case-patients were exposed}). In some instances, the anatomic site of infection may be important; for example, respiratory diphtheria is notifiable, whereas cutaneous diphtheria is not. Substantial amounts of information, including results of laboratory tests, must be collected for many diseases before a final case classification is possible. State health departments should continue prompt reporting of provisional cases to CDC, and records should be updated with the appropriate classification status when additional surveillance information becomes available. Cases should be categorized as laboratory-confirmed (a subset of all confirmed cases) only if they meet the laboratory criteria specified. For additional information about procedures for reporting diseases to CDC, see the Manual of Procedures for the Reporting of Nationally Notifiable Diseases to CDC (5). Case definitions for some infectious conditions not considered nationally notifiable also are included in this report. Some of these conditions may have been nationally reportable or may become so; definitions are included here to facilitate interpretation of data for these diseases ( ). State health departments also provide CDC with information regarding certain conditions of public health interest, whether nationally reportable, through supplementary surveillance systems that collect more detailed, condition-specific information (5). The usefulness of public health surveillance data depends on its uniformity, simplicity, and timeliness. The case definitions contained in this report establish uniform criteria for disease reporting and should not be used as the sole criteria for establishing clinical diagnoses, determining the standard of care necessary for a particular patient, setting guidelines for quality assurance, or providing standards for reimbursement. Use of additional clinical, epidemiologic, and laboratory data may enable a physician to diagnose a disease even though the formal surveillance case definition may not be met. The list of nationally reportable infectious diseases changes periodically. Diseases may be added to the list as new pathogens emerge or deleted as their incidence declines. Public health officials at state health departments and CDC collaborate in determining which diseases should be nationally notifiable; CSTE, in conjunction with CDC, makes recommendations annually for additions and deletions to the list of nationally notifiable diseases (1,2). As knowledge increases and diagnostic technology improves, some definitions will change to reflect those trends. Thus, future revisions can be expected. This report also is available in AdobeTM AcrobatTM portable document format (.pdf) through the World-Wide Web at http://www.cdc.gov/epo/mmwr/other/case_def/about.html. Future changes to the case definitions for nationally notifiable infectious diseases will be announced in the MMWR and made available in the electronic version. How to Use Information in This Report Terms that are used in case classifications for both Parts 1 and 2 are defined (see Definition of Terms Used in Case Classification). Because each case definition in Parts 1 and 2 is intended to stand alone, abbreviations are defined the first time they appear in each case definition section and abbreviated throughout the rest of that section. A publications list is included only for the section on acquired immunodeficiency syndrome (AIDS); this list provides further sources regarding AIDS. These case definitions are to be used for identifying and classifying cases, both of which are often done retrospectively, for national reporting purposes. They should not be used as criteria for public health action. For many conditions of public health importance, action to contain disease should be initiated as soon as a problem is identified; in many circumstances, appropriate public health action should be undertaken even though insufficient information is available to determine whether cases meet the case definition. Definition of Terms Used in Case Classification Clinically compatible case: a clinical syndrome generally compatible with the disease, as described in the clinical description. Confirmed case: a case that is classified as confirmed for reporting purposes. Epidemiologically linked case: a case in which a) the patient has had contact with one or more persons who either have/had the disease or have been exposed to a point source of infection (i.e., a single source of infection, such as an event leading to a foodborne-disease outbreak, to which all confirmed case-patients were exposed) and b) transmission of the agent by the usual modes of transmission is plausible. A case may be considered epidemiologically linked to a laboratory-confirmed case if at least one case in the chain of transmission is laboratory confirmed. Laboratory-confirmed case: a case that is confirmed by one or more of the laboratory methods listed in the case definition under Laboratory Criteria for Diagnosis. Although other laboratory methods can be used in clinical diagnosis, only those listed are accepted as laboratory confirmation for national reporting purposes. Probable case: a case that is classified as probable for reporting purposes. Supportive or presumptive laboratory results: specified laboratory results that are consistent with the diagnosis, yet do not meet the criteria for laboratory confirmation. Suspected case: a case that is classified as suspected for reporting purposes. PART 1. CASE DEFINITIONS FOR NATIONALLY NOTIFIABLE INFECTIOUS DISEASES Acquired Immunodeficiency Syndrome (AIDS) (Effective 1/1/93) Case definition CDC has expanded the acquired immunodeficiency syndrome (AIDS) surveillance case definition to include all human immunodeficiency virus (HIV)-infected adolescents and adults aged greater than or equal to 13 years who have either a) less than 200 CD4+ T-lymphocytes/uL; b) a CD4+ T-lymphocyte percentage of total lymphocytes of less than 14%; or c) any of the following three clinical conditions: pulmonary tuberculosis, recurrent pneumonia, or invasive cervical cancer. The expanded definition retains the 23 clinical conditions in the AIDS surveillance case definition published in 1987. (See publication {1} in Publications List in this section for complete information referring to this case definition.) The AIDS surveillance case definition for children aged less than 13 years has not changed and retains the clinical conditions listed in the AIDS surveillance case definition published in 1987. However, definitions for HIV encephalopathy, HIV wasting syndrome, and HIV infection in children have been revised and the 1987 definition has been updated. (See Publication {2} in Publications List for complete information pertaining to this case definition.) Laboratory criteria for diagnosis See Publication (1) in Publications List. Case classification CDC has revised the classification system for HIV infection to emphasize the clinical importance of the CD4+ T-lymphocyte count in the categorization of HIV-related clinical conditions. This classification system replaces the system published by CDC in 1986. (See Publication {1} in Publications List for complete information pertaining to this case definition.) Publications list (1) CDC. 1993 Revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. MMWR 1992;41(No. RR-17). (2) CDC. 1994 Revised classification system for human immunodeficiency virus infection in children less than 13 years of age. MMWR 1994;43(No. RR-12). (3) CDC. Interpretation and use of the Western blot assay for serodiagnosis of human immunodeficiency virus type-1 infection. MMWR 1989;38(No. S-7). (4) Revision of the CDC surveillance case definition for acquired immunodeficiency syndrome. MMWR 1987;36(suppl:)1-15s. Anthrax (Revised 9/96) Clinical Description An illness with acute onset characterized by several distinct clinical forms, including the following: Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Botulism, Foodborne (Revised 9/96) Clinical description Ingestion of botulinum toxin results in an illness of variable severity. Common symptoms are diplopia, blurred vision, and bulbar weakness. Symmetric paralysis may progress rapidly. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with an epidemiologic link (e.g., ingestion of a home-canned food within the previous 48 hours) Confirmed: a clinically compatible case that is laboratory confirmed or that occurs among persons who ate the same food as persons who have laboratory-confirmed botulism Botulism, Infant (Revised 9/96) Clinical description An illness of infants, characterized by constipation, poor feeding, and "failure to thrive" that may be followed by progressive weakness, impaired respiration, and death Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory-confirmed, occurring in a child aged less than 1 year Botulism, Wound Clinical description An illness resulting from toxin produced by Clostridium botulinum that has infected a wound. Common symptoms are diplopia, blurred vision, and bulbar weakness. Symmetric paralysis may progress rapidly. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed in a patient who has no suspected exposure to contaminated food and who has a history of a fresh, contaminated wound during the 2 weeks before onset of symptoms Botulism, Other Clinical description See Botulism, Foodborne. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed in a patient aged greater than or equal to 1 year who has no history of ingestion of suspect food and has no wounds Brucellosis Clinical description An illness characterized by acute or insidious onset of fever, night sweats, undue fatigue, anorexia, weight loss, headache, and arthralgia Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case or that has supportive serology (i.e., Brucella agglutination titer of greater than or equal to 160 in one or more serum specimens obtained after onset of symptoms) Confirmed: a clinically compatible case that is laboratory confirmed Chancroid (Revised 9/96) Clinical description A sexually transmitted disease characterized by painful genital ulceration and inflammatory inguinal adenopathy. The disease is caused by infection with Haemophilus ducreyi. Laboratory criteria for diagnosis --Isolation of H. ducreyi from a clinical specimen Case classification Probable: a clinically compatible case with both a) no evidence of Treponema pallidum infection by darkfield microscopic examination of ulcer exudate or by a serologic test for syphilis performed greater than or equal to 7 days after onset of ulcers and b) either a clinical presentation of the ulcer(s) not typical of disease caused by herpes simplex virus (HSV) or a culture negative for HSV. Confirmed: a clinically compatible case that is laboratory confirmed Chlamydia trachomatis, Genital Infections (Revised 9/96) Clinical description Infection with Chlamydia trachomatis may result in urethritis, epididymitis, cervicitis, acute salpingitis, or other syndromes when sexually transmitted; however, the infection is often asymptomatic in women. Perinatal infections may result in inclusion conjunctivitis and pneumonia in newborns. Other syndromes caused by C. trachomatis include lymphogranuloma venereum (see Lymphogranuloma Venereum) and trachoma. Laboratory criteria for diagnosis Case classification Confirmed: a case that is laboratory confirmed Cholera (Revised 9/96) Clinical description An illness characterized by diarrhea and/or vomiting; severity is variable. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Comment Illnesses caused by strains of V. cholerae other than toxigenic V. cholerae O1 or O139 should not be reported as cases of cholera. The etiologic agent of a case of cholera should be reported as either V. cholerae O1 or V. cholerae O139. Only confirmed cases should be reported to NNDSS by state health departments. Coccidioidomycosis (Revised 9/96) Clinical description Infection may be asymptomatic or may produce an acute or chronic disease. Although the disease initially resembles an influenza-like febrile illness primarily involving the bronchopulmonary system, dissemination can occur to multiple organ systems. Clinical case definition An illness characterized by one or more of the following: Laboratory criteria for diagnosis Case classification Confirmed: a case that meets the clinical case definition and is laboratory confirmed Cryptosporidiosis (Adopted 3/95) Clinical description An illness caused by the protozoan Cryptosporidium parvum and characterized by diarrhea, abdominal cramps, loss of appetite, low-grade fever, nausea, and vomiting. Infected persons may be asymptomatic. The disease can be prolonged and life-threatening in severely immunocompromised persons. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Diphtheria (Revised 3/95) Clinical description An upper-respiratory tract illness characterized by sore throat, low-grade fever, and an adherent membrane of the tonsil(s), pharynx, and/or nose Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is not laboratory confirmed and is not epidemiologically linked to a laboratory-confirmed case Confirmed: a clinically compatible case that is either laboratory confirmed or epidemiologically linked to a laboratory-confirmed case Comment Cutaneous diphtheria should not be reported. Respiratory disease caused by nontoxigenic C. diphtheriae should be reported as diphtheria. All diphtheria isolates, regardless of association with disease, should be sent to the Diphtheria Laboratory, National Center for Infectious Diseases, CDC. Encephalitis, Arboviral (Revised 9/96) Clinical description Arboviral infection may result in a febrile illness of variable severity associated with neurologic symptoms ranging from headache to aseptic meningitis or encephalitis. Arboviral encephalitis cannot be distinguished clinically from other central nervous system (CNS) infections. Symptoms can include headache, confusion or other alteration in sensorium, nausea, and vomiting. Signs may include fever, meningismus, cranial nerve palsies, paresis or paralysis, sensory deficits, altered reflexes, convulsions, abnormal movements, and coma of varying degree. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case occurring during a period when arboviral transmission is likely, and with the following supportive serology: a stable (less than or equal to twofold change) elevated antibody titer to an arbovirus (e.g., greater than or equal to 320 by hemagglutination inhibition, greater than or equal to 128 by complement fixation, greater than or equal to 256 by immunofluorescence, and greater than or equal to 160 by neutralization, or greater than or equal to 400 by enzyme immunoassay IgM). Confirmed: a clinically compatible case that is laboratory confirmed Comment The seasonality of arboviral transmission is variable and depends on the geographic location of exposure, the specific cycles of viral transmission, and local climatic conditions. Reporting should be etiology-specific (see below; the four encephalitides printed in bold are nationally reportable to CDC): Escherichia coli O157:H7 (Revised 9/96) Clinical description An infection of variable severity characterized by diarrhea (often bloody) and abdominal cramps. Illness may be complicated by hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP); asymptomatic infections also may occur. Laboratory criteria for diagnosis Case classification Suspected: a case of postdiarrheal HUS or TTP (see HUS case definition) Probable: Confirmed: a case that is laboratory confirmed Comment Laboratory-confirmed isolates are reported via the Public Health Laboratory Information System (PHLIS), which is managed by the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC. Both probable and confirmed cases are reported to the National Notifiable Diseases Surveillance System (NNDSS), but only confirmed cases are reported to PHLIS. Confirmation is based on laboratory findings, and clinical illness is not required. Gonorrhea (Revised 9/96) Clinical description A sexually transmitted infection commonly manifested by urethritis, cervicitis, or salpingitis. Infection may be asymptomatic. Laboratory criteria for diagnosis Case classification Probable: a) demonstration of gram-negative intracellular diplococci in an endocervical smear obtained from a female or b) a written morbidity report of gonorrhea submitted by a physician Confirmed: a case that is laboratory confirmed Haemophilus influenzae (Invasive Disease) Clinical description Invasive disease caused by Haemophilus influenzae may produce any of several clinical syndromes, including meningitis, bacteremia, epiglottitis, or pneumonia. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with detection of H. influenzae type b antigen in CSF Confirmed: a clinically compatible case that is laboratory confirmed Comment Positive antigen test results from urine or serum samples are unreliable for diagnosis of H. influenzae disease. Hansen Disease (Leprosy) Clinical description A chronic bacterial disease characterized by the involvement primarily of skin as well as peripheral nerves and the mucosa of the upper airway. Clinical forms of Hansen disease represent a spectrum reflecting the cellular immune response to Mycobacterium leprae. The following characteristics are typical of the major forms of the disease: Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Hantavirus Pulmonary Syndrome (Revised 9/96) Clinical description Hantavirus pulmonary syndrome (HPS), commonly referred to as hantavirus disease, is a febrile illness characterized by bilateral interstitial pulmonary infiltrates and respiratory compromise usually requiring supplemental oxygen and clinically resembling acute respiratory disease syndrome (ARDS). The typical prodrome consists of fever, chills, myalgia, headache, and gastrointestinal symptoms. Typical clinical laboratory findings include hemoconcentration, left shift in the white blood cell count, neutrophilic leukocytosis, thrombocytopenia, and circulating immunoblasts. Clinical case definition An illness characterized by one or more of the following clinical features: Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Comment Laboratory testing should be performed or confirmed at a reference laboratory. Because the clinical illness is nonspecific and ARDS is common, a screening case definition can be used to determine which patients to test. In general, a predisposing medical condition (e.g., chronic pulmonary disease, malignancy, trauma, burn, and surgery) is a more likely cause of ARDS than HPS, and patients who have these underlying conditions and ARDS need not be tested for hantavirus. Hemolytic Uremic Syndrome, Postdiarrheal (Revised 9/96) Clinical description Hemolytic uremic syndrome (HUS) is characterized by the acute onset of microangiopathic hemolytic anemia, renal injury, and low platelet count. Thrombotic thrombocytopenic purpura (TTP) also is characterized by these features but can include central nervous system (CNS) involvement and fever and may have a more gradual onset. Most cases of HUS (but few cases of TTP) occur after an acute gastrointestinal illness (usually diarrheal). Laboratory criteria for diagnosis The following are both present at some time during the illness: Note: A low platelet count can usually, but not always, be detected early in the illness, but it may then become normal or even high. If a platelet count obtained within 7 days after onset of the acute gastrointestinal illness is not less than 150,000/mm3, other diagnoses should be considered. Case classification Probable: Confirmed: an acute illness diagnosed as HUS or TTP that both meets the laboratory criteria and began within 3 weeks after onset of an episode of acute or bloody diarrhea Comment Some investigators consider HUS and TTP to be part of a continuum of disease. Therefore, criteria for diagnosing TTP on the basis of CNS involvement and fever are not provided because cases diagnosed clinically as postdiarrheal TTP also should meet the criteria for HUS. These cases are reported as postdiarrheal HUS. Hepatitis, Viral, Acute (Revised 9/96) Clinical case definition An acute illness with a) discrete onset of symptoms and b) jaundice or elevated serum aminotransferase levels Laboratory criteria for diagnosis Case classification Confirmed: a case that meets the clinical case definition and is laboratory confirmed or, for hepatitis A, a case that meets the clinical case definition and occurs in a person who has an epidemiologic link with a person who has laboratory-confirmed hepatitis A (i.e., household or sexual contact with an infected person during the 15-50 days before the onset of symptoms) Comment Clinical description Perinatal hepatitis B in the newborn may range from asymptomatic to fulminant hepatitis. Laboratory criteria for diagnosis Case classification HBsAg positivity in any infant aged greater than 1-24 months who was born in the United States or in U.S. territories to an HBsAg-positive mother Comment Infants born to HBsAg-positive mothers should receive hepatitis B immune globulin (HBIG) and the first dose of hepatitis B vaccine within 24 hours of birth, followed by the second and third doses of vaccine at 1 and 6 months of age, respectively. Postvaccination testing for antibody to HBsAg and HBsAg is recommended from 3 to 6 months following completion of the vaccine series. If HBIG and the initial dose of vaccine are delayed for greater than 1 month after birth, testing for HBsAg may determine if the infant is already infected. HIV Infection, Pediatric Case definition Refer to 1994 Revised Classification System for Human Immunodeficiency Virus Infection in Children less than 13 Years of Age (MMWR 1994;43{No. RR-12}:1-10). Legionellosis (Revised 9/96) Clinical description Legionellosis is associated with two clinically and epidemiologically distinct illnesses: Legionnaires disease, which is characterized by fever, myalgia, cough, pneumonia, and Pontiac fever, a milder illness without pneumonia. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Comment The previously used category of "probable case," which was based on a single IFA titer, lacks specificity for surveillance and is no longer used. Lyme Disease (Revised 9/96) Clinical description A systemic, tickborne disease with protean manifestations, including dermatologic, rheumatologic, neurologic, and cardiac abnormalities. The best clinical marker for the disease is the initial skin lesion (i.e., erythema migrans {EM}) that occurs in 60%-80% of patients. Laboratory criteria for diagnosis Case classification Confirmed: a) a case with EM or b) a case with at least one late manifestation (as defined below) that is laboratory confirmed. Comment This surveillance case definition was developed for national reporting of Lyme disease; it is not intended to be used in clinical diagnosis. Definition of terms used in the clinical description and case definition: Malaria (Revised 3/95) Clinical description Signs and symptoms are variable; however, most patients experience fever. In addition to fever, common associated symptoms include headache, back pain, chills, sweats, myalgia, nausea, vomiting, diarrhea, and cough. Untreated Plasmodium falciparum infection can lead to coma, renal failure, pulmonary edema, and death. The diagnosis of malaria should be considered for any person who has these symptoms and who has traveled to an area in which malaria is endemic. Asymptomatic parasitemia can occur among persons who have been long-term residents of areas in which malaria is endemic. Laboratory criteria for diagnosis Case classification Confirmed: an episode of microscopically confirmed malaria parasitemia in any person (symptomatic or asymptomatic) diagnosed in the United States, regardless of whether the person experienced previous episodes of malaria while outside the country Comment A subsequent attack experienced by the same person but caused by a different Plasmodium species is counted as an additional case. A subsequent attack experienced by the same person and caused by the same species in the United States may indicate a relapsing infection or treatment failure caused by drug resistance. Blood smears from questionable cases should be referred to the National Malaria Repository, CDC, for confirmation of the diagnosis. Cases also are classified according to the following World Health Organization categories: Indigenous: malaria acquired by mosquito transmission in an area where malaria is a regular occurrence Introduced: malaria acquired by mosquito transmission from an imported case in an area where malaria is not a regular occurrence Measles (Revised 9/96) Clinical case definition An illness characterized by all the following: Laboratory criteria for diagnosis Case classification Suspected: any febrile illness accompanied by rash Probable: a case that meets the clinical case definition, has noncontributory or no serologic or virologic testing, and is not epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed case. A laboratory-confirmed case does not need to meet the clinical case definition. Comment Confirmed cases should be reported to NNDSS. An imported case has its source outside the country or state. Rash onset occurs within 18 days after entering the jurisdiction, and illness cannot be linked to local transmission. Imported cases should be classified as: An indigenous case is defined as a case of measles that is not imported. Cases that are linked to imported cases should be classified as indigenous if the exposure to the imported case occurred in the reporting state. Any case that cannot be proved to be imported should be classified as indigenous. Meningococcal Disease Clinical description Meningococcal disease manifests most commonly as meningitis and/or meningococcemia that may progress rapidly to purpura fulminans, shock, and death. However, other manifestations might be observed. Laboratory criteria for diagnosis Case classification Probable: a case with a positive antigen test in CSF or clinical purpura fulminans in the absence of a positive blood culture Confirmed: a clinically compatible case that is laboratory confirmed Comment Positive antigen test results from urine or serum samples are unreliable for diagnosing meningococcal disease. Mumps (Revised 9/96) Clinical case definition An illness with acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting greater than or equal to 2 days, and without other apparent cause Laboratory criteria for diagnosis Case classification Probable: a case that meets the clinical case definition, has noncontributory or no serologic or virologic testing, and is not epidemiologically linked to a confirmed or probable case Confirmed: a case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed or probable case. A laboratory-confirmed case does not need to meet the clinical case definition. Comment Two probable cases that are epidemiologically linked would be considered confirmed, even in the absence of laboratory confirmation. False-positive IgM results by immunofluorescent antibody assays have been reported (8). Pertussis (Revised 9/96) Clinical case definition A cough illness lasting greater than or equal to 2 weeks with one of the following: paroxysms of coughing, inspiratory "whoop," or post-tussive vomiting, without other apparent cause Laboratory criteria for diagnosis Case classification Probable: a case that meets the clinical case definition, is not laboratory confirmed, and is not epidemiologically linked to a laboratory-confirmed case Confirmed: a case that is laboratory confirmed or one that meets the clinical case definition and is either laboratory confirmed or epidemiologically linked to a laboratory-confirmed case Comment The clinical case definition is appropriate for endemic or sporadic cases. In outbreak settings, a case may be defined as a cough illness lasting greater than or equal to 2 weeks. Because some studies have documented that direct fluorescent antibody testing of nasopharyngeal secretions has low sensitivity and variable specificity, it should not be relied on as a criterion for laboratory confirmation (9,10). Serologic testing for pertussis is available in some areas but is not standardized and, therefore, should not be relied on as a criterion for laboratory confirmation for national reporting purposes. Both probable and confirmed cases should be reported to NNDSS. Plague (Revised 9/96) Clinical description Plague is transmitted to humans by fleas or by direct exposure to infected tissues or respiratory droplets; the disease is characterized by fever, chills, headache, malaise, prostration, and leukocytosis that manifests in one or more of the following principal clinical forms: Laboratory criteria for diagnosis Presumptive Confirmatory Case classification Suspected: a clinically compatible case without presumptive or confirmatory laboratory results Probable: a clinically compatible case with presumptive laboratory results Confirmed: a clinically compatible case with confirmatory laboratory results Poliomyelitis, Paralytic Clinical case definition Acute onset of a flaccid paralysis of one or more limbs with decreased or absent tendon reflexes in the affected limbs, without other apparent cause, and without sensory or cognitive loss Case classification Probable: a case that meets the clinical case definition Confirmed: a case that meets the clinical case definition and in which the patient has a neurologic deficit 60 days after onset of initial symptoms, has died, or has unknown follow-up status Comment All suspected cases of paralytic poliomyelitis are reviewed by a panel of expert consultants before final classification occurs. Confirmed cases are then further classified based on epidemiologic and laboratory criteria (11). Only confirmed cases are included in Table I in the MMWR. Suspected cases are enumerated in a footnote to the MMWR table. Psittacosis (Revised 9/96) Clinical description An illness characterized by fever, chills, headache, photophobia, cough, and myalgia Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case or that has supportive serology (e.g., C. psittaci titer of greater than or equal to 32 in one or more serum specimens obtained after onset of symptoms) Confirmed: a clinically compatible case that is laboratory confirmed Comment The serologic findings by CF also may occur as a result of infection with Chlamydia pneumoniae or Chlamydia trachomatis. The MIF might be more specific for infection with C. psittaci, but experience with and availability of this newer test are more limited. Rabies, Animal Laboratory criteria for diagnosis Case classification Confirmed: a case that is laboratory confirmed Rabies, Human Clinical description Rabies is an acute encephalomyelitis that almost always progresses to coma or death within 10 days after the first symptom. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Comment Laboratory confirmation by all of the above methods is strongly recommended. Rocky Mountain Spotted Fever (Revised 9/96) Clinical description A tickborne febrile illness most commonly characterized by acute onset and usually accompanied by myalgia, headache, and petechial rash (on the palms and soles in two thirds of the cases) Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with a single IFA serologic titer of greater than or equal to 64 or a single CF titer of greater than or equal to 16 or other supportive serology (fourfold rise in titer or a single titer greater than or equal to 320 by Proteus OX-19 or OX-2, or a single titer greater than or equal to 128 by an LA, IHA, or MA test) Confirmed: a clinically compatible case that is laboratory confirmed Rubella (Revised 9/96) Clinical case definition An illness that has all the following characteristics: Case classification Suspected: any generalized rash illness of acute onset Probable: a case that meets the clinical case definition, has no or noncontributory serologic or virologic testing, and is not epidemiologically linked to a laboratory-confirmed case Confirmed: a case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a laboratory-confirmed case Comments Serum rubella IgM test results that are false positives have been reported in persons with other viral infections (e.g., acute infection with Epstein-Barr virus {infectious mononucleosis}, recent cytomegalovirus infection, and parvovirus infection) or in the presence of rheumatoid factor. Patients who have laboratory evidence of recent measles infection are excluded. Rubella, Congenital Syndrome (Revised 9/96) Clinical description An illness usually manifesting in infancy resulting from rubella infection in utero and characterized by signs or symptoms from the following categories: Clinical case definition Presence of any defects or laboratory data consistent with congenital rubella infection Laboratory criteria for diagnosis Case classification Suspected: a case with some compatible clinical findings but not meeting the criteria for a probable case Probable: a case that is not laboratory confirmed and that has any two complications listed in paragraph a) of the clinical description or one complication from paragraph a) and one from paragraph b), and lacks evidence of any other etiology Confirmed: a clinically compatible case that is laboratory confirmed Infection only: a case that demonstrates laboratory evidence of infection, but without any clinical symptoms or signs Comment In probable cases, either or both of the eye-related findings (i.e., cataracts and congenital glaucoma) are interpreted as a single complication. In cases classified as infection only, if any compatible signs or symptoms (e.g., hearing loss) are identified later, the case is reclassified as confirmed. Salmonellosis Clinical description An illness of variable severity commonly manifested by diarrhea, abdominal pain, nausea, and sometimes vomiting. Asymptomatic infections may occur and the organism may cause extraintestinal infections. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Comment Laboratory-confirmed isolates are reported to CDC via the Public Health Laboratory Information System (PHLIS), which is managed by the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC. Both probable and confirmed cases are reported to the National Notifiable Diseases Surveillance System, but only confirmed cases are reported to PHLIS. Both asymptomatic infections and infections at sites other than the gastrointestinal tract, if laboratory confirmed, are considered confirmed cases that should be reported to PHLIS. Shigellosis Clinical description An illness of variable severity characterized by diarrhea, fever, nausea, cramps, and tenesmus. Asymptomatic infections may occur. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Comment Laboratory-confirmed isolates are reported to CDC via the Public Health Laboratory Information System (PHLIS), which is managed by the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC. Both probable and confirmed cases are reported to the National Notifiable Diseases Surveillance System, but only confirmed cases are reported to PHLIS. Confirmation is based on laboratory findings, and clinical illness is not required. Streptococcal Disease, Invasive, Group A (Adopted 3/95) Clinical description Invasive group A streptococcal infections may manifest as any of several clinical syndromes, including pneumonia, bacteremia in association with cutaneous infection (e.g., cellulitis, erysipelas, or infection of a surgical or nonsurgical wound), deep soft-tissue infection (e.g., myositis or necrotizing fasciitis), meningitis, peritonitis, osteomyelitis, septic arthritis, postpartum sepsis (i.e., puerperal fever), neonatal sepsis, and nonfocal bacteremia. Laboratory criteria for diagnosis Case classification Confirmed: a case that is laboratory confirmed Comment See also Streptococcal Toxic-Shock Syndrome. Streptococcus pneumoniae, Drug-Resistant Invasive Disease (Revised 9/96) Clinical description Streptococcus pneumoniae causes many clinical syndromes, depending on the site of infection (e.g., acute otitis media, pneumonia, bacteremia, or meningitis). Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case caused by laboratory-confirmed culture of S. pneumoniae identified as "nonsusceptible" (i.e., an oxacillin zone size of less than 20 mm) when oxacillin screening is the only method of antimicrobial susceptibility testing performed Confirmed: a clinically compatible case that is laboratory confirmed Streptococcal Toxic-Shock Syndrome (Revised 9/96) Clinical description Streptococcal toxic-shock syndrome (STSS) is a severe illness associated with invasive or noninvasive group A streptococcal (Streptococcus pyogenes) infection. STSS may occur with infection at any site but most often occurs in association with infection of a cutaneous lesion. Signs of toxicity and a rapidly progressive clinical course are characteristic, and the case-fatality rate may exceed 50%. Clinical case definition An illness with the following clinical manifestations occurring within the first 48 hours of hospitalization or, for a nosocomial case, within the first 48 hours of illness: Laboratory criteria for diagnosis Case classification Probable: a case that meets the clinical case definition in the absence of another identified etiology for the illness and with isolation of group A Streptococcus from a nonsterile site Confirmed: a case that meets the clinical case definition and with isolation of group A Streptococcus from a normally sterile site (e.g., blood or cerebrospinal fluid or, less commonly, joint, pleural, or pericardial fluid) Comment See also Streptococcal Disease, Invasive, Group A and Toxic-Shock Syndrome. Syphilis (All Definitions Revised 9/96) Syphilis is a complex sexually transmitted disease that has a highly variable clinical course. Classification by a clinician with expertise in syphilis may take precedence over the following case definitions developed for surveillance purposes. Syphilis, primary Clinical description A stage of infection with Treponema pallidum characterized by one or more chancres (ulcers); chancres might differ considerably in clinical appearance. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with one or more ulcers (chancres) consistent with primary syphilis and a reactive serologic test (nontreponemal: Venereal Disease Research Laboratory {VDRL} or rapid plasma reagin {RPR}; treponemal: fluorescent treponemal antibody absorbed {FTA-ABS} or microhemagglutination assay for antibody to T. pallidum {MHA-TP}) Confirmed: a clinically compatible case that is laboratory confirmed Syphilis, secondary Clinical description A stage of infection caused by T. pallidum and characterized by localized or diffuse mucocutaneous lesions, often with generalized lymphadenopathy. The primary chancre may still be present. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with a nontreponemal (VDRL or RPR) titer greater than or equal to 4 Confirmed: a clinically compatible case that is laboratory confirmed Syphilis, latent Clinical description A stage of infection caused by T. pallidum in which organisms persist in the body of the infected person without causing symptoms or signs. Latent syphilis is subdivided into early, late, and unknown categories based on the duration of infection. Case classification Probable: no clinical signs or symptoms of syphilis and the presence of one of the following: Syphilis, early latent Clinical description A subcategory of latent syphilis. When initial infection has occurred within the previous 12 months, latent syphilis is classified as early latent. Case classification Probable: latent syphilis (see Syphilis, latent) in a person who has evidence of having acquired the infection within the previous 12 months based on one or more of the following criteria: Syphilis, late latent Clinical description A subcategory of latent syphilis. When initial infection has occurred greater than 1 year previously, latent syphilis is classified as late latent. Case classification Probable: latent syphilis (see Syphilis, latent) in a patient who has no evidence of having acquired the disease within the preceding 12 months (see Syphilis, early latent) and whose age and titer do not meet the criteria specified for latent syphilis of unknown duration. Syphilis, latent, of unknown duration Clinical description A subcategory of latent syphilis. When the date of initial infection cannot be established as having occurred within the previous year and the patient's age and titer meet criteria described below, latent syphilis is classified as latent syphilis of unknown duration. Case classification Probable: latent syphilis (see Syphilis, latent) that does not meet the criteria for early latent syphilis, and the patient is aged 13-35 years and has a nontreponemal titer greater than or equal to 32 Neurosyphilis Clinical description Evidence of central nervous system infection with T. pallidum Laboratory criteria for diagnosis Case classification Probable: syphilis of any stage, a negative VDRL in CSF, and both the following: Confirmed: syphilis of any stage that meets the laboratory criteria for neurosyphilis Syphilis, late, with clinical manifestations other than neurosyphilis (late benign syphilis and cardiovascular syphilis) Clinical description Clinical manifestations of late syphilis other than neurosyphilis may include inflammatory lesions of the cardiovascular system, skin, and bone. Rarely, other structures (e.g., the upper and lower respiratory tracts, mouth, eye, abdominal organs, reproductive organs, lymph nodes, and skeletal muscle) may be involved. Late syphilis usually becomes clinically manifest only after a period of 15-30 years of untreated infection. Laboratory criteria for diagnosis Demonstration of T. pallidum in late lesions by fluorescent antibody or special stains (although organisms are rarely visualized in late lesions) Case classification Probable: characteristic abnormalities or lesions of the cardiovascular system, skin, bone, or other structures with a reactive treponemal test, in the absence of other known causes of these abnormalities, and without CSF abnormalities and clinical symptoms or signs consistent with neurosyphilis Confirmed: a clinically compatible case that is laboratory confirmed Comment Analysis of CSF for evidence of neurosyphilis is necessary in the evaluation of late syphilis with clinical manifestations. Syphilitic Stillbirth Clinical description A fetal death that occurs after a 20-week gestation or in which the fetus weighs greater than 500 g and the mother had untreated or inadequately treated@ syphilis at delivery Comment For reporting purposes, syphilitic stillbirths should be reported as cases of congenital syphilis. Syphilis, Congenital (Revised 9/96) Clinical description A condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints). Laboratory criteria for diagnosis Case classification Probable: a condition affecting an infant whose mother had untreated or inadequately treated@@ syphilis at delivery, regardless of signs in the infant, or an infant or child who has a reactive treponemal test for syphilis and any one of the following: Confirmed: a case that is laboratory confirmed Comment Congenital and acquired syphilis may be difficult to distinguish when a child is seropositive after infancy. Signs of congenital syphilis may not be obvious, and stigmata may not yet have developed. Abnormal values for CSF VDRL, cell count, and protein, as well as IgM antibodies, may be found in either congenital or acquired syphilis. Findings on radiographs of long bones may help because radiographic changes in the metaphysis and epiphysis are considered classic signs of congenitally acquired syphilis. The decision may ultimately be based on maternal history and clinical judgment. In a young child, the possibility of sexual abuse should be considered as a cause of acquired rather than congenital syphilis, depending on the clinical picture. For reporting purposes, congenital syphilis includes cases of congenitally acquired syphilis among infants and children as well as syphilitic stillbirths. Tetanus (Revised 9/96) Clinical case definition Acute onset of hypertonia and/or painful muscular contractions (usually of the muscles of the jaw and neck) and generalized muscle spasms without other apparent medical cause Case classification Confirmed: a clinically compatible case, as reported by a health-care professional Toxic-Shock Syndrome Clinical case definition An illness with the following clinical manifestations: Laboratory criteria Negative results on the following tests, if obtained: Case classification Probable: a case in which five of the six clinical findings described above are present Confirmed: a case in which all six of the clinical findings described above are present, including desquamation, unless the patient dies before desquamation occurs Comment See also Streptococcal Toxic-Shock Syndrome. Trichinosis (Revised 9/96) Clinical description A disease caused by ingestion of Trichinella larvae. The disease has variable clinical manifestations. Common signs and symptoms among symptomatic persons include eosinophilia, fever, myalgia, and periorbital edema. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Comment In an outbreak setting, at least one case must be laboratory confirmed. Associated cases should be reported as confirmed if the patient shared an epidemiologically implicated meal or ate an epidemiologically implicated meat product and has either a positive serologic test for trichinosis or a clinically compatible illness. Tuberculosis (Revised 9/96) Clinical description A chronic bacterial infection caused by Mycobacterium tuberculosis, characterized pathologically by the formation of granulomas. The most common site of infection is the lung, but other organs may be involved. Clinical case definition A case that meets the following criteria: Laboratory criteria for diagnosis Case classification Confirmed: a case that meets the clinical case definition or is laboratory confirmed Comment A case should not be counted twice within any consecutive 12-month period. However, cases in which the patients had previously had verified disease should be reported again if the patients were discharged from treatment. Cases also should be reported again if patients were lost to supervision for greater than 12 months and disease can be verified again. Mycobacterial diseases other than those caused by M. tuberculosis complex should not be counted in tuberculosis morbidity statistics unless there is concurrent tuberculosis. Typhoid Fever Clinical description An illness caused by Salmonella typhi that is often characterized by insidious onset of sustained fever, headache, malaise, anorexia, relative bradycardia, constipation or diarrhea, and nonproductive cough. However, many mild and atypical infections occur. Carriage of S. typhi may be prolonged. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case in an outbreak Confirmed: a clinically compatible case that is laboratory confirmed Comment Isolation of the organism is required for confirmation. Serologic evidence alone is not sufficient for diagnosis. Asymptomatic carriage should not be reported as typhoid fever. Isolates of S. typhi are reported to the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC, through the Public Health Laboratory Information System. (See Salmonella.) Yellow Fever Clinical description A mosquito-borne viral illness characterized by acute onset and constitutional symptoms followed by a brief remission and a recurrence of fever, hepatitis, albuminuria, and symptoms and, in some instances, renal failure, shock, and generalized hemorrhages Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with supportive serology (stable elevated antibody titer to yellow fever virus {e.g., greater than or equal to 32 by complement fixation, greater than or equal to 256 by immunofluorescence assay, greater than or equal to 320 by hemagglutination inhibition, greater than or equal to 160 by neutralization, or a positive serologic result by immunoglobulin M-capture enzyme immunoassay}. Cross-reactive serologic reactions to other flaviviruses must be excluded, and the patient must not have a history of yellow fever vaccination.) Confirmed: a clinically compatible case that is laboratory confirmed PART 2. CASE DEFINITIONS FOR NON-NOTIFIABLE INFECTIOUS DISEASES Amebiasis Clinical description Infection of the large intestine by Entamoeba histolytica may result in an illness of variable severity ranging from mild, chronic diarrhea to fulminant dysentery. Infection also may be asymptomatic. Extraintestinal infection also can occur (e.g., hepatic abscess). Laboratory criteria for diagnosis Intestinal amebiasis Extraintestinal amebiasis Case classification Confirmed, intestinal amebiasis: a clinically compatible illness that is laboratory confirmed Confirmed, extraintestinal amebiasis: a parasitologically confirmed infection of extraintestinal tissue, or among symptomatic persons (with clinical or radiographic findings consistent with extraintestinal infection), demonstration of specific antibody against E. histolytica as measured by indirect hemagglutination or other reliable immunodiagnostic test (e.g., enzyme-linked immunosorbent assay) Comment Asymptomatic intestinal carriage of E. histolytica should not be reported. Among asymptomatic persons, a positive serologic test does not necessarily indicate extraintestinal amebiasis. Aseptic Meningitis Clinical description A syndrome characterized by acute onset of meningeal symptoms, fever, and cerebrospinal fluid pleocytosis, with bacteriologically sterile cultures Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case diagnosed by a physician as aseptic meningitis, with no laboratory evidence of bacterial or fungal meningitis. Comment Aseptic meningitis is a syndrome of multiple etiologies, but many cases are caused by a viral agent. Bacterial Meningitis, Other (Adopted 9/96) Clinical description Bacterial meningitis manifests most commonly with fever, headache, and a stiff neck; the disease may progress rapidly to shock and death. However, other manifestations may be observed. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is either laboratory confirmed or is accompanied by a positive blood culture Comment Cases of bacterial meningitis caused by Haemophilus influenzae, Neisseria meningitidis, group A Streptococcus, and Listeria monocytogenes should be reported to CDC's National Notifiable Diseases Surveillance System under the disease codes specific for these organisms. Only cases of bacterial meningitis caused by organisms other than those specified should be reported as cases of "bacterial meningitis, other." Campylobacter Infection Clinical description An infection that may result in diarrheal illness of variable severity Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Comment Only confirmed cases are reported to the laboratory-based surveillance system managed by the Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC. Cyclospora Infection (Adopted 9/96) Clinical description An illness of variable severity caused by the protozoan Cyclospora cayetanensis and commonly characterized by watery diarrhea, loss of appetite, weight loss, abdominal bloating and cramping, increased flatus, nausea, fatigue, and low-grade fever. Vomiting also may be noted. Relapses and asymptomatic infections can occur. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Comment Direct person-to-person transmission is unlikely because Cyclospora oocysts are not infectious at the time of excretion. Dengue Fever (Revised 9/96) Clinical description An acute febrile illness characterized by frontal headache, retro-ocular pain, muscle and joint pain, and rash. The principal vector is the Aedes aegypti mosquito and transmission usually occurs in tropical or subtropical areas. Severe manifestations (e.g., dengue hemorrhagic fever and dengue shock syndrome) are rare but may be fatal. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with supportive serologic findings (a reciprocal IgG antibody titer of greater than or equal to 1280 or a positive IgM antibody test on a single acute (late)- or convalescent-phase serum specimen to one or more dengue virus antigens) Confirmed: a clinically compatible case that is laboratory confirmed Comment Dengue hemorrhagic fever is defined as an acute febrile illness with minor or major bleeding phenomena, thrombocytopenia (less than or equal to 100,000/mm3), and evidence of plasma leakage documented by hemoconcentration (hematocrit increased by greater than or equal to 20%) or other objective evidence of increased capillary permeability. The definition of dengue shock syndrome follows all of the above criteria for dengue hemorrhagic fever and also includes hypotension or narrow pulse pressure (less than or equal to 20 mm Hg). Ehrlichiosis (Adopted 9/96) Clinical description A tickborne febrile illness most commonly characterized by acute onset, accompanied by headache, myalgia, rigors and/or malaise. Clinical laboratory findings may include intracytoplasmic microcolonies (morulae) in leukocytes of peripheral smear, cerebrospinal fluid (CSF), or bone marrow aspirate or biopsy, cytopenias (especially thrombocytopenia and leukopenia), and elevated liver enzymes (especially alanine aminotransferase or aspartate aminotransferase). There are two clinically similar yet serologically distinct forms of ehrlichiosis: a) human granulocytic ehrlichosis (HGE), caused by infection with an Ehrlichia equi-like agent and found primarily in the upper midwest and northeast, and b) human monocytic ehrlichiosis (HME) caused by Ehrlichia chaffeensis infection and found primarily in the southeastern quadrant of the United States. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with either a single IFA serologic titer greater than or equal to 64 or intracytoplasmic morulae identified in blood, bone marrow, or CSF leukocytes Confirmed: a clinically compatible case that is laboratory confirmed Comment All laboratory testing should be conducted by experienced personnel with appropriate training and should include appropriate controls and reagents necessary for accurate etiologic diagnosis. States in which cases of HGE and/or HME have occurred may submit reports to CDC. Genital Herpes (Herpes Simplex Virus) (Revised 9/96) Clinical description A condition characterized by visible, painful genital or anal lesions Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case (in which primary and secondary syphilis have been excluded by appropriate serologic tests and darkfield microscopy, when available) with either a diagnosis of genital herpes based on clinical presentation (without laboratory confirmation) or a history of one or more previous episodes of similar genital lesions Confirmed: a clinically compatible case that is laboratory confirmed Comment Genital herpes should be reported only once per patient. The first diagnosis for a patient with no previous diagnosis should be reported. Genital Warts (Revised 9/96) Clinical description An infection characterized by the presence of visible, exophytic (raised) growths on the internal or external genitalia, perineum, or perianal region Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case without histopathologic diagnosis and without microscopic or serologic evidence that the growth is the result of secondary syphilis Confirmed: a clinically compatible case that is laboratory confirmed Comment Genital warts should be reported only once per patient. The first diagnosis for a patient with no previous diagnosis should be reported. Giardiasis Clinical description An illness caused by the protozoan Giardia lamblia and characterized by diarrhea, abdominal cramps, bloating, weight loss, or malabsorption. Infected persons may be asymptomatic. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case that is epidemiologically linked to a confirmed case Confirmed: a case that is laboratory confirmed Granuloma Inguinale Clinical description A slowly progressive ulcerative disease of the skin and lymphatics of the genital and perianal area caused by infection with Calymmatobacterium granulomatis. A clinically compatible case would have one or more painless or minimally painful granulomatous lesions in the anogenital area. Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Leptospirosis Clinical description An illness characterized by fever, headache, chills, myalgia, conjunctival suffusion, and less frequently by meningitis, rash, jaundice, or renal insufficiency. Symptoms may be biphasic. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with supportive serologic findings (i.e., a Leptospira agglutination titer of greater than or equal to 200 in one or more serum specimens) Confirmed: a clinically compatible case that is laboratory confirmed Listeriosis Clinical description Infection caused by Listeria monocytogenes, which may produce any of several clinical syndromes, including stillbirth, listeriosis of the newborn, meningitis, bacteremia, or localized infections Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case that is laboratory confirmed Lymphogranuloma Venereum Clinical description Infection with L1, L2, or, L3 serovars of Chlamydia trachomatis may result in a disease characterized by genital lesions, suppurative regional lymphadenopathy, or hemorrhagic proctitis. The infection is usually sexually transmitted. Laboratory criteria for diagnosis Case classification Probable: a clinically compatible case with one or more tender fluctuant inguinal lymph nodes or characteristic proctogenital lesions with supportive laboratory findings of a single C. trachomatis complement fixation titer of greater than 64 Confirmed: a clinically compatible case that is laboratory confirmed Mucopurulent Cervicitis (Revised 9/96) Clinical description Cervical inflammation that is not the result of infection with Neisseria gonorrhoeae or Trichomonas vaginalis. Cervical inflammation is defined by the presence of one of the following criteria: Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case in a female who does not have either gonorrhea or trichomoniasis Comment Mucopurulent cervicitis (MPC) is a clinical diagnosis of exclusion. The syndrome may result from infection with any of several agents (see Chlamydia trachomatis, Genital Infections). If gonorrhea, trichomoniasis, and chlamydia are excluded, a clinically compatible illness should be classified as MPC. An illness in a female that meets the case definition of MPC and C. trachomatis infection should be classified as chlamydia. Nongonococcal Urethritis (Revised 9/96) Clinical description Urethral inflammation that is not the result of infection with Neisseria gonorrhoeae. Urethral inflammation may be diagnosed by the presence of one of the following criteria: Laboratory criteria for diagnosis Case classification Confirmed: a clinically compatible case in a male in whom gonorrhea is not found, either by culture, Gram stain, or antigen or nucleic acid detection Comment Nongonococcal urethritis (NGU) is a clinical diagnosis of exclusion. The syndrome may result from infection with any of several agents (see Chlamydia trachomatis, Genital Infection). If gonorrhea and chlamydia are excluded, a clinically compatible illness should be classified as NGU. An illness in a male that meets the case definition of NGU and C. trachomatis infection should be classified as chlamydia. Pelvic Inflammatory Disease (Revised 9/96) Clinical case definition A clinical syndrome resulting from the ascending spread of microorganisms from the vagina and endocervix to the endometrium, fallopian tubes, and/or contiguous structures. In a female who has lower abdominal pain and who has not been diagnosed as having an established cause other than pelvic inflammatory disease (PID) (e.g., ectopic pregnancy, acute appendicitis, and functional pain), all the following clinical criteria must be present: In addition to the preceding criteria, at least one of the following findings must also be present: Case classification Confirmed: a case that meets the clinical case definition Comment For reporting purposes, a clinician's report of PID should be counted as a case. Rheumatic Fever Clinical description An inflammatory illness that occurs as a delayed sequela of group A streptococcal infection Major criteria: carditis, polyarthritis, chorea, subcutaneous nodules, and erythema marginatum Minor criteria: a) previous rheumatic fever or rheumatic heart disease; b) arthralgia; c) fever; d) elevated erythrocyte sedimentation rate, positive C-reactive protein, or leukocytosis; and e) prolonged PR interval on an electrocardiogram Laboratory criteria for diagnosis Case classification Confirmed: an illness characterized by a) two major criteria or one major and two minor criteria (as described in Clinical Description) and b) supporting evidence of preceding group A streptococcal infection (14). Comment Supporting evidence to confirm streptococcal infection includes increased antistreptolysin-O or other streptococcal antibodies, throat culture positive for group A streptococcus, or recent scarlet fever. The absence of supporting evidence of preceding streptococcal infection should make the diagnosis doubtful, except in Sydenham chorea or low-grade carditis when rheumatic fever is first discovered after a long latent period from the antecedent infection. Tularemia (Revised 9/96) Clinical description An illness characterized by several distinct forms, including the following: Clinical diagnosis is supported by evidence or history of a tick or deerfly bite, exposure to tissues of a mammalian host of Francisella tularensis, or exposure to potentially contaminated water. Laboratory criteria for diagnosis Presumptive Confirmatory Case classification Probable: a clinically compatible case with laboratory results indicative of presumptive infection Confirmed: a clinically compatible case with confirmatory laboratory results Varicella (Chickenpox) (Revised 9/96) Clinical case definition An illness with acute onset of diffuse (generalized) papulovesicular rash without other apparent cause Laboratory criteria for diagnosis Case classification Probable: a case that meets the clinical case definition, is not laboratory confirmed, and is not epidemiologically linked to another probable or confirmed case Confirmed: a case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed or probable case Comment Two probable cases that are epidemiologically linked would be considered confirmed, even in the absence of laboratory confirmation. * These case definitions were developed in collaboration with epidemiologists at CDC and the Council of State and Territorial Epidemiologists (CSTE). They were approved by a full vote of the CSTE membership and also endorsed for use by the Association of State and Territorial Public Health Laboratory Directors (ASTPHLD).  ** Strains of E. coli O157:H7 that have lost the flagellar "H" antigen become nonmotile and are designated "NM."  *** Delta hepatitis is not a nationally notifiable disease.  **** Resistance defined by National Committee for Clinical Laboratory Standards (NCCLS)-approved methods and NCCLS-approved interpretive minimum inhibitory concentration (MIC) standards (ug/mL) for S. pneumoniae. NCCLS recommends that all invasive S. pneumoniae isolates found to be "possibly resistant" to beta-lactams (i.e., an oxacillin zone size of less than 20 mm) by oxacillin screening should undergo further susceptibility testing by using a quantitative MIC method acceptable for penicillin, extended-spectrum cephalosporins, and other drugs as clinically indicated (11,12).  @ Inadequate treatment consists of any nonpenicillin therapy or penicillin administered less than 30 days before delivery.  @@ Inadequate treatment consists of any nonpenicillin therapy or penicillin administered less than 30 days before delivery.  @@@ Use of rapid identification techniques for M. tuberculosis (e.g., DNA probes and mycolic acids high-pressure liquid chromatography performed on a culture from a clinical specimen) are acceptable under this criterion.  @@@@ Nucleic acid amplification (NAA) tests must be accompanied by culture for mycobacteria species. However, for surveillance purposes, CDC will accept results obtained from NAA tests approved by the Food and Drug Administration (FDA) and used according to the approved product labeling on the package insert. Current FDA-approved NAA tests are only approved for smear-positive respiratory specimens.   HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices. **Questions or messages regarding errors in formatting should be addressed to .   |    |  SEARCH  |    |  |    |    |  Centers for Disease Control and Prevention 1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A An official website of the United States government Here’s how you know Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. HHS Announces Cost Savings for 64 Prescription Drugs Thanks to the Medicare Rebate Program Established by the Biden-Harris Administration’s Lower Cost Prescription Drug Law Under President Biden’s Inflation Reduction Act, some people with Medicare will pay less for some Part B drugs if the drug’s price increased faster than the rate of inflation. The U.S. Department of Health and Human Services (HHS), through the Centers for Medicare & Medicaid Services (CMS), today announced that some Medicare enrollees will pay less for 64 drugs available through Medicare Part B. The drugs will have a lowered Part B coinsurance rate from July 1, 2024 – September 30, 2024, since each drug company raised prices faster than the rate of inflation.  Over 750,000 people with Medicare use these drugs annually, which treat conditions such as osteoporosis, cancer, and infections. White House Domestic Policy Advisor Neera Tanden will announce the cost savings on these life-saving drugs in a keynote address on the Biden-Harris Administration’s focus on lowering costs today at the Center for American Progress. “Without the Inflation Reduction Act, seniors were completely exposed to Big Pharma’s price hikes. Not anymore. Thanks to President Biden and the new Medicare inflation rebate program, seniors are protected and benefitting from lower Part B drug costs,” said White House Domestic Policy Advisor Neera Tanden. “The Biden-Harris Administration will continue fighting to bring down the cost of health care and prescription drugs for all Americans.” “President Biden’s Medicare prescription drug rebate program is putting money back in the pockets of seniors and people with disabilities, said HHS Secretary Xavier Becerra. “President Biden made lowering prescription drug costs for Americans a top priority, and he is delivering on that promise. Our work is not complete, and we will continue to fight for lower health care costs for all Americans.” Please find soundbites from HHS’ Chief Competition Officer, Stacy Sanders, here . Because of President Biden’s lower cost prescription drug law, the Inflation Reduction Act, which established the Medicare Prescription Drug Inflation Rebate Program, some people with Medicare who use these drugs during this time period may save between $1 and $4,593 per day. “Everyone should be able to afford their medication, and the Inflation Reduction Act continues to deliver on this goal to improve affordability,” said CMS Administrator Chiquita Brooks-LaSure. “Discouraging drug companies from price increases above the rate of inflation is a key part of this effort, and CMS continues to implement the law to bring savings to people with Medicare.” Padcev, a medication used to treat advanced bladder cancer, is an example of a prescription drug with a price that has increased faster than the rate of inflation every quarter since the Medicare Part B inflation rebate program went into effect, resulting in lowered Part B coinsurances for seniors and others with Medicare. A beneficiary taking Padcev as part of their cancer treatment may have saved as much as $1,181 from April 1, 2023 through March 31, 2024, depending on their coverage and course of treatment. Another example, Crysvita, treats a rare genetic disorder that causes impaired growth, muscle weakness, and bone pain. A beneficiary taking Crysvita may have saved as much as $765 from July 1, 2023 through March 31, 2024 depending on their coverage and course of treatment. The Medicare Prescription Drug Inflation Rebate Program is just one of the Inflation Reduction Act’s prescription drug provisions aimed at lowering drug costs. In addition to this program, the law expanded eligibility for full benefits under the Low-Income Subsidy program (LIS or “Extra Help”) under Medicare Part D at the beginning of this year. Nearly 300,000 people with low and modest incomes are now benefiting from the program’s expansion. A comprehensive public education campaign is underway to reach the more than three million people who are likely eligible for the program but not yet enrolled. In addition, as of January 1, 2024, some people enrolled in Medicare Part D who have high drug costs have their annual out-of-pocket costs capped at about $3,500. In 2025, all people with Medicare Part D will benefit from a $2,000 cap on annual out-of-pocket prescription drug costs. The Inflation Reduction Act requires drug companies to pay rebates to Medicare when prices increase faster than the rate of inflation for certain drugs. CMS intends to begin invoicing prescription drug companies for rebates owed to Medicare no later than fall 2025. The rebate amounts paid by drug companies will be deposited in the Federal Supplementary Medical Insurance Trust Fund, which will help ensure the long-term sustainability of the Medicare program for future generations. For more information on the Medicare Prescription Drug Inflation Rebate Program visit, https://www.cms.gov/inflation-reduction-act-and-medicare/inflation-rebates-medicare To view the fact sheet on the 64 Part B drugs with a coinsurance reduction for the quarter July 1, 2024 – September 30, 2024, visit, https://www.cms.gov/files/document/reduced-coinsurance-certain-part-b-rebatable-drugs-july-1-september-30-2024.pdf More information and helpful resources about the Inflation Reduction Act and how it is helping to lower costs for people with Medicare can be found at LowerDrugCosts.gov . Sign Up for Email Updates Receive the latest updates from the Secretary, Blogs, and News Releases Subscribe to RSS Receive latest updates Related News Releases Hhs publishes first round of inflation reduction act case studies on health sector climate investments, hhs releases new data showing over 10 million people with medicare received a free vaccine because of the president’s inflation reduction act; releases draft guidance for the second cycle of medicare drug price negotiation program, biden-harris administration furthers medicare drug price negotiations, releases new data on how the president’s historic law lowers health care costs for women, media inquiries. For general media inquiries, please contact  [email protected] . 471 COMMENTS Continuing to enhance the quality of case study methodology in health Introduction. The popularity of case study research methodology in Health Services Research (HSR) has grown over the past 40 years. 1 This may be attributed to a shift towards the use of implementation research and a newfound appreciation of contextual factors affecting the uptake of evidence-based interventions within diverse settings. 2 Incorporating context-specific information on the ... The case study approach A case study is a research approach that is used to generate an in-depth, multi-faceted understanding of a complex issue in its real-life context. It is an established research design that is used extensively in a wide variety of disciplines, particularly in the social sciences. A case study can be defined in a variety of ways (Table. Case Library The Harvard Chan Case Library is a collection of teaching cases with a public health focus, written by Harvard Chan faculty, case writers, and students, or in collaboration with other institutions and initiatives. Use the filters at right to search the case library by subject, geography, health condition, and representation of diversity and identity to find cases to fit your teaching needs. Case Study Methodology of Qualitative Research: Key Attributes and A case study is one of the most commonly used methodologies of social research. This article attempts to look into the various dimensions of a case study research strategy, the different epistemological strands which determine the particular case study type and approach adopted in the field, discusses the factors which can enhance the effectiveness of a case study research, and the debate ... Cases Studies in Public Health Available Online Case studies aren't just for business schools anymore. Columbia University's Mailman School of Public Health has been using the case method to teach MPH students as part of the new Columbia Public Health Curriculum. Now, six of the School's public health cases have been published online, making them available to classrooms anywhere."The case method can be a powerful tool for learning ... Case study research for better evaluations of complex interventions The Design of Case Study Research in Health Care (DESCARTE) model suggests a series of questions to be asked of a case study researcher (including clarity about the philosophy underpinning their research), study design (with a focus on case definition) and analysis (to improve process). The model resembles toolkits for enhancing the quality and ... PDF Case Definitions for Public Health Surveillance Clinical case definition. Acute onset of a flaccid paralysis of one or more limbs with decreased or absent tendon reflexes in the affected limbs, without other apparent cause, and without sensory or cognitive loss (as reported by a physician) Case classification Probable:a case that meets the clinical case definition. What is a case study? Case study is a research methodology, typically seen in social and life sciences. There is no one definition of case study research.1 However, very simply… 'a case study can be defined as an intensive study about a person, a group of people or a unit, which is aimed to generalize over several units'.1 A case study has also been described as an intensive, systematic investigation of a ... PDF Pubhlth 2: Case Studies in Public Health (89030) 1. Apply the process of analysis for public health cases. Understand the roleof public health by: • analyzing topics or cases in public health and society from current media or research, • describing the solution, if it exists, and • developing a unique approach or management for solving the problem. 2. Analyze the concepts of public ... PDF Essential Case Studies in Public Health: Putting Public Health into 10 essential public health services and the three IOM core public health functions. Each case addresses one or more of these essential services. Together, the cases engage students and practitioners in the process of thinking through problems inherent in implementing the 10 essential services and the three core functions. Epidemiologic Case Study Resources Case Studies in Public Health by Theodore H. Tulchinsky The cases chosen for this collection include those on traditional public health, such as sanitation, hygiene and infectious disease control, and also the organization, financing and quality of health care services. Each case study is presented in a systematic fashion to facilitate learning, with the case, background, current relevance ... Writing a case Writing a case. Farooqui, S., 2021. A Short Guide to Writing and Teaching Inclusive Cases, Harvard T.H. Chan School of Public Health. Developed by 2020-2021 Harvard Chan Equity, Diversity, and Inclusion Fellow Sana Farooqui (MPH 2021), this guide provides suggestions for case writers and course instructors on writing and selecting cases ... PDF How to write a case study This case study describes a public health program. CDC Epidemiologic Case Studies This page contains links to five classroom- style case studies on foodborne diseases. ATSDR E nvironmental Health and Medicine. This page contains links to approximately 20 classroom-style case studies focused on exposures to environmental hazards. Before you get ... How do we define the policy impact of public health research? A The review used mental health research and policy as a case study. ... including public and mental health. A definition specific to mental health is given: Research impact is a direct or indirect contribution of research processes or outputs that have informed (or resulted in) the development of new (mental) health policy/practices, or ... The case study approach The case study approach allows in-depth, multi-faceted explorations of complex issues in their real-life settings. The value of the case study approach is well recognised in the fields of business, law and policy, but somewhat less so in health services research. Based on our experiences of conducting several health-related case studies, we reflect on the different types of case study design ... 1.2: Essential Cases in the Development of Public Health Ethics 2.2 Case Study: Jacobson v. Massachusetts. The earliest activities associated with modern public health are sanitation and infectious disease control. From the first public health surveillance system in colonial America that required tavern keepers in Rhode Island to report contagious disease, to John Snow removing the Broad Street pump handle in London to end the 1854 cholera epidemic ... Case Study A case study is a qualitative research approach where multiple methods of data collection are used for a detailed examination of a single 'case'. A case is a single unit in a study. It can be a person or an organisation, like a clinic, police force, factory or a hospital. A case can also be a community or groups of people. Case Definitions for Public Health Surveillance A systemic, tick-borne disease with protean manifestations, including dermatologic, rheumatologic, neurologic, and cardiac abnormalities. The best clinical marker for the disease is the initial skin lesion, erythema migrans, that occurs among 60%-80% of patients. Clinical case definition. Erythema migrans, or. Case Studies in Public Health Practice, PUBHLTH 2 Presents case studies in various themes of public health practice to demonstrate how the principles of public health were established and continue to evolve. Course Requirements: • Lectures, Links and Videos each week • Discussion Forum assigned topic each week • Presentation a 5-minute audio narrative PowerPoint presentation with 6-10 Reliability of case definitions for public health surveillance assessed The case example book, which resulted from this study, constitutes a detailed feed back for the participants of the study and is now being used as training material for public health nurses. We have demonstrated that rigorous reduction of case definitions to testable yes/no-criteria in a check-list format is likely to improve their reliability. Reliability of case definitions for public health surveillance assessed Background Case definitions have been recognized to be important elements of public health surveillance systems. They are to assure comparability and consistency of surveillance data and have crucial impact on the sensitivity and the positive predictive value of a surveillance system. The reliability of case definitions has rarely been investigated systematically. Methods We conducted a Round ... Call for Case Studies: Strategic Action for Urban Health The WHO Urban Health team is seeking examples that illustrate a strategic approach to urban health. Collectively, these case studies are intended to show that such an approach can originate and flourish from a wide range of entry points across a diversity of sectors and scales, while leveraging many different combinations of partners. The case studies will inform a major global WHO report on ... Elsevier Education Portal Skip to main content Public Health Ethics: Global Cases, Practice, and Context Introducing public health ethics poses two special challenges. First, it is a relatively new field that combines public health and practical ethics. Its unfamiliarity requires considerable explanation, yet its scope and emergent qualities make delineation difficult. Moreover, while the early development of public health ethics occurred in a western context, its reach, like public health itself ... Case Definitions for Infectious Conditions Under Public Health Surveillance Confirmed: a clinically compatible case with confirmatory laboratory results. Poliomyelitis, Paralytic Clinical case definition. Acute onset of a flaccid paralysis of one or more limbs with decreased or absent tendon reflexes in the affected limbs, without other apparent cause, and without sensory or cognitive loss. HHS Announces Cost Savings for 64 Prescription Drugs Thanks to the Not anymore. Thanks to President Biden and the new Medicare inflation rebate program, seniors are protected and benefitting from lower Part B drug costs," said White House Domestic Policy Advisor Neera Tanden. "The Biden-Harris Administration will continue fighting to bring down the cost of health care and prescription drugs for all ... Cloud About Cloud. Cloud computing is the delivery of on-demand computing resources, everything from applications to data centers, over the internet. The various types of cloud computing deployment models include public cloud, private cloud, hybrid cloud, and multicloud. assignment essay homework paper phd report resume review speech