Outbreak investigation report Agnes Hajdu EpiTrain III, Jurmala, Latvia Based on EPIET material

Steps of an outbreak investigation Confirm outbreak diagnosis Define a case Identify cases and obtain information Descriptive data collection and analysis Develop hypothesis Analytical studies to test hypothesis Communication – Outbreak report Control measures

Outbreak reports First: What are they? Why write them? Who writes them? Who reads them? Then: Structure Frequent problems Confidentiality Legal issues

What are outbreak reports? Formal outbreak reports –Preliminary, interim, final report Reports to colleagues –national bulletin, Eurosurveillance, conference/ seminars (Inter)national outbreak reporting systems Journal publications

Why write them? To document the outbreak –Present investigation methods, control measures –Potential legal issue To verify recommendations To enhance quality of investigations In order to prevent future outbreaks and assist in investigation&control of similar incidents

Who writes them? The outbreak control team (OCT) Named authors Each participating agency must agree with what is said Who owns the report?

Who reads them? All agencies represented on the OCT Policy making bodies Professional colleagues The public The lawyers

Structure of the report 1.Summary 2.Introduction and Background 3.Outbreak description 4.Methods 5.Results 6.Discussion 7.Lessons learned 8.Recommendations 9.References 10.Appendices

1. Summary Key –Features, setting of the outbreak: Who – What – Where – When? –Lessons learned –Recommendations Ongoing action Further action required

2. Introduction and Background Population demographics Surveillance data Previous similar outbreaks Description of the are/site/facility –e.g. Healthcare system –e.g. Industries involved –Any unusal point

3. Outbreak description The initial story –How was the outbreak reported? –Steps taken to confirm it? –What was known to date? Why was an investigation undertaken? Management of the outbreak –OCT members, objectives, assistance, control measures Media relations

4. Methods Epidemiological –Case definition, case finding, study design (descriptive-analytical) Laboratory –Clinical and environmental specimens (types, how they were collected) Environmental studies –Site visit and risk assessment, traceback Other studies

5. Results Epidemiological –Number of responses and participation rate –Number of cases –Overall attack rates and by age, sex, exposure –Symptoms, duration and outcomes of illness –Description (time, place, person) –Epidemic curve (incubation period) Laboratory findings Environmental study findings –Inspection report Other studies

6. Discussion Main hypotheses (likely causative agent and mode of transmission) Justify conclusions and actions –Clear interpretation of results –Explain how results confirmed/disproved hypothesis Limitations, possible biases Explain action to protect public health Highlight any problems

7. Lessons learned Lessons for participating agencies –Problems encountered –Mistakes made –Suggestions for improvement Lessons that may be useful for others Key points from internal/external audit

8. Recommendations What should be done –To control this outbreak –To prevent future outbreaks –To improve management of future outbreaks Be specific: to whom? Be realistic: feasible actions

9. References Vancouver referencing system vancouver.html

10. Appendices Chronology of events General background OCT (members, terms of reference) Detailed results Maps Epidemiological questionnaire Letters to patients/physicians Press releases Costs of the outbreak Acknowledgements

Problems Confidentiality –What should not be included? Legal issues Delay in writing the report Not writing the report at all..

Confidentiality To individual patients To commercial businesses Details may remain in meeting minutes Media disclosure Legal disclosure

Legal issues Who owns the report / the data? Prosecuting agencies may deem the information to be confidential but… … health authorities have a duty to provide the public with information

Report published Jan. 1997: outbreak report on MMWR: –Legionaires disease (LD) associated with whirlpool spa on display, USA Febr. 1999: major outbreak LD, Holland –Source: whirlpool spa on display –Lawsuit against government: failure to act on available knowledge (MMWR)

Conclusion Duty to –document the outbreak –inform the colleagues –prevent and control future outbreaks Good report = half publication –Write article, case study

Some reports stay alive John Snow, 1843, Broad Street Pump Outbreak - Cholera