1. SEARO –CSR Early Warning and Surveillance System Module EWAR: a component of national surveillance systems National Surveillance System

2. SEARO –CSR Early Warning and Surveillance System Module Surveillance system Routine weekly, monthly and quarterly reporting EWAR Event basedCase based Report signal Report signal Outbreak investigation Evaluation Introduction to surveillance Role of IHR EWAR Structure, Prioritization of diseases, Case definitions Signal generation and verification GIS System evaluation Outbreak investigation Alert

3. SEARO –CSR Early Warning and Surveillance System Module Objectives of this lecture To define an early warning system (EWAR) To provide some examples of early warning indicators and thresholds To illustrate syndromic surveillance for EWAR using the example of SARS surveillance in the post-outbreak periods

4. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Strengthening Country EWARNS Part of a structured approach to strengthening the surveillance process of a country. Tools do not make EWARS, but EWARS need appropriate tools

5. SEARO –CSR Early Warning and Surveillance System Module EWAR One Component of Surveillance Systems Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance EWARS –Rumour verification, –Detect clusters in time, place or person, and –Change in trend. Programme monitoring –Programme indicators. Surveillance system monitoring –Operation indicators, –Support indicators, and –Output indicators. Requiring immediate investigation Requiring programme adjustment Requiring system improvement Requiring verification

6. SEARO –CSR Early Warning and Surveillance System Module EWAR and Programme monitoring Diverging Constraints? EWAR Attributes –Sensitivity –Timeliness –Flexibility –Simplicity Notification of cases –Suspect and probable –Immediate or weekly EWAR Attributes –Sensitivity –Timeliness –Flexibility –Simplicity Notification of cases –Suspect and probable –Immediate or weekly PROGRAMME MONITORING Attributes –Representativity –Completeness –Predictive positive value Notification of cases –Probable and confirmed –Monthly or yearly Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

7. SEARO –CSR Early Warning and Surveillance System Module Steps in EWAR implementation Communicable disease threat assessment Targeting threats through a prioritization exercise –The severity of the disease –Its potential for spread –Availability of control measures –Its link to travel and trade –International requirements (e.g. IHR) –Its potential for intentional release –The public perception Defining health events with EWARNS objective Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

8. SEARO –CSR Early Warning and Surveillance System Module Steps in EWAR implementation For each health event define: –Data sources –Case definition(s) –Type of surveillance –Frequency of reporting –Data to be collected –Indicators –Thresholds for action Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

9. SEARO –CSR Early Warning and Surveillance System Module Setting objectives The objectives depend on –epidemiological characteristics of the disease (morbidity, mortality) –mode of transmission of the disease in the event of an outbreak (person to person or point sources of outbreak) –nature of the public health interventions to control its spread Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

10. SEARO –CSR Early Warning and Surveillance System Module Clustered cases of gastroenteritis – in order to investigate, identify and control the source of infection Change in ILI trends –in order to trigger laboratory confirmation Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance HF cases –in order to implement infection control measures, expedite laboratory confirmation and institute appropriate control measures PH threats by capturing unstructured reports from the media, and informal sources –in order to verify and investigate them, and implement appropriate control measures

11. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Data sources –Rumours e.g: cluster of unknown severe event –Health centres e.g. suspect cases of cholera –Hospitals e.g. diphteria –Laboratories e.g. MRSA (Staphilococcus Aureus methicillin resistant) –Emergency rooms e.g. heat related deaths –Death registers

12. SEARO –CSR Early Warning and Surveillance System Module Case definitions –Syndromic e.g. acute watery diarrhoea –Disease specific e.g. botulism –Laboratory based e.g. listeria Type of surveillance –Comprehensive e.g haemorrhagic fever –Sentinel e.g. seasonal flu –Active e.g. AFP Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Case Definitions/ Type of Surveillance

13. SEARO –CSR Early Warning and Surveillance System Module Early Detection Relies on alert network –National and international –Addressing expected and unexpected risks –Functional link between Sensitised primary care providers Laboratories Epidemiologists Health managers Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

14. SEARO –CSR Early Warning and Surveillance System Module Nature of health event to detect Nature of the « event » depends on the source, the vehicle and the mode of transmission : –Massive and sudden Common point source (Salmonellosis…) Diffuse and progressive –Person to person (shigellosis, Hepatitis…) –Or sporadic and widespread Persistent common source (salmonella, listeria in food chain, legionella…) Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

15. SEARO –CSR Early Warning and Surveillance System Module Integrate indicators from various sources –Veterinary services Avian Flu Ebola –Food agency Foodborne outbreaks –Water supply companies Faecal contamination –Sanitation agency Legionella –International networks WHO Promed Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Integration

16. SEARO –CSR Early Warning and Surveillance System Module 810121416182022 Week of Report 0 5 10 15 20 25 30 Number of Reports Invasive Meningococcal Disease by Week of Report, Germany, 1998 Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

17. SEARO –CSR Early Warning and Surveillance System Module Distribution of bloody diarrhoea by Week of onset Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

18. SEARO –CSR Early Warning and Surveillance System Module Diffuse and progressive Difficult to detect early When to launch an investigation and response? Requires –Sensitisation of primary care providers –Early warning systems with built-in alert thresholds Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

19. SEARO –CSR Early Warning and Surveillance System Module Weekly Notification of Food Borne Illness, National EWAR System, France,1994-1998 95 96 97 98 37501124375011243750112437501124 0- 5- 10- 15- 20- 25- Week Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

20. SEARO –CSR Early Warning and Surveillance System Module Sporadic and Wide Spread Difficult to identify Requires –Sensitisation of primary care providers –Advanced laboratory techniques –International alert networks Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

21. SEARO –CSR Early Warning and Surveillance System Module Distribution of Legionellosis Cases by date of onset and Origin, World Soccer Cup, France, June-July 1998 Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

22. SEARO –CSR Early Warning and Surveillance System Module Gaps in EWARNS Function EWARS often lack –Integration with other routine surveillance and Health Management Information System (HMIS) –Appropriate indicators –Action-oriented thresholds –Tools for information synthesis Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

23. SEARO –CSR Early Warning and Surveillance System Module Surveillance Indicators Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Early warning indicators Programme monitoring indicators System operation indicators System support indicators System output indicators

24. SEARO –CSR Early Warning and Surveillance System Module EWAR Indicators Early warning indicators can be expressed as: –Absolute numbers, counts –Rates # of events/population at risk –Proportional morbidity % of reports for 1 event –Percentage of specific cases case fatality ratio % of cases under 5 years of age % of cases with certain strain Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

25. SEARO –CSR Early Warning and Surveillance System Module Thresholds for EWAR Choice of threshold affected by; –Objective of surveillance, –Mode of disease transmission, and –Nature of interventions. Absolute value –Count: 1 case of AFP –Rate: > 15 meningo. meningitis/100,000/week Relative increase –2 fold increase over 3 weeks Statistical cut-off –> 90 th percentile of historical data –> 1.64 standard deviations from historical mean –Time series analysis Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

26. SEARO –CSR Early Warning and Surveillance System Module Thresholds Based on Median Diarrhoea in Madaba district, Jordan, 2000-2001 Historical period = 5 weeks centered around current week for past 5 years = 25 weeks Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

27. SEARO –CSR Early Warning and Surveillance System Module Thresholds Based on Periodic Regression Diarrhoea in Madaba district, Jordan, 2000-2001 Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

28. SEARO –CSR Early Warning and Surveillance System Module Information Synthesis for EWAR Systems "Verification" bulletin –Potential alerts Epidemiological summary bulletin –Synthesis "Executive" information system –Interactive tables, maps and charts –Drill-down approach Key indicators for Health Information System Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

29. SEARO –CSR Early Warning and Surveillance System Module Verification Bulletin Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

30. SEARO –CSR Early Warning and Surveillance System Module "Executive" Information Systems Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

31. SEARO –CSR Early Warning and Surveillance System Module Syndromic Surveillance Syndromic surveillance is an approach where health staff, assisted by automated data acquisition and thresholds, monitor disease indicators in real-time to timely detect outbreaks Source: adapted from Dan Sosin, CDC, Framework for Evaluating Surveillance Systems For Early Detection of Outbreaks Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

32. SEARO –CSR Early Warning and Surveillance System Module Why Using Syndromic Surveillance To increase surveillance effectiveness –By increasing sensitivity and timeliness of detection (bio terrorism) –By allowing detection of emerging “unknown” infections (“new bugs”) When confirmation is not desirable on all cases –E.g. influenza and cholera epidemics When confirmation is limited –Health facilities at peripheral level –Laboratory resources cannot cope with all cases (SARS) Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

33. SEARO –CSR Early Warning and Surveillance System Module Objectives of SARS Syndromic Surveillance in the post-outbreak phase To increase sensitivity and timeliness of detection of outbreaks of respiratory illnesses and rule out re-emergence of SARS In the increased risk areas Outbreak Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

34. SEARO –CSR Early Warning and Surveillance System Module SARS Syndromic Surveillance, 2003 Underlying assumptions Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance The first cases or clusters of SARS may be missed Diffuse-progressive nature of the health event. SARS has aspecific clinical features and no rapid diagnostic test is available –Clinical features of the disease –Diagnostic capacity Seasonal occurrence of other respiratory diseases (influenza, other CoV) Epidemiological pattern of diseases with similar clinical characteristics in the region.

35. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance SARS Re-emergence Risk assessment Potential zone of re- emergence of SARS-CoV Nodal areas Low risk areas

36. SEARO –CSR Early Warning and Surveillance System Module Staged approach to surveillance Potential zone of re-emergence of SARS –SARS EWARN –Enhanced surveillance for SARS –Special studies for infections in animals and humans Nodal areas –SARS EWARN –Enhanced surveillance for SARS Low risk areas –SARS Alert Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

37. SEARO –CSR Early Warning and Surveillance System Module Definition of a SARS “Alert” for EWAR 2 or > HCW –in same HCU –fulfilling clinical case definition of SARS –with onset of illness in the same 10-day period OR Hospital acquired illness in 3 or > persons –in same HCU –fulfilling clinical case definition of SARS –with onset of illness in the same 10-day period Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

38. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Post-outbreak Case definition Post-Outbreak Case-Definitions Outbreak case definition Clinical SARS Atypical pneumonia Suspect Probable

39. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance SARS Clinical case definition Fever (  38°C) AND –One or more symptoms of lower respiratory tract illness (cough, difficulty of breathing, shortness of breath) AND –Radiographic evidence of lung infiltrates consistent with pneumonia or RDS –OR autopsy findings consistent with the pathology of pneumonia or RDS without an identifiable cause AND –No alternative diagnosis can fully explain the illness

40. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance SARS Laboratory case definition PCR positive for SARS-CoV (  2 different clinical specimens OR sequential sampling from the same site OR  2 assays or repeat PCR using a new RNA extract from the original clinical sample on each occasion of testing) OR Seroconversion or 4-fold or greater rise in titre between acute and convalescent phase sera by ELISA or IFA OR Virus isolation with PCR validation

41. SEARO –CSR Early Warning and Surveillance System Module Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance Aggregated notification Syndromic Surveillance Link with SARS Surveillance CRF notification Fever + Respiratory + chest X-ray Clinical SARS Atypical pneumonia Suspect Probable

42. SEARO –CSR Early Warning and Surveillance System Module Alert Thresholds for Syndromic Surveillance Strengthen EWAR Implement EWAR Early Detection Indicators Information Synthesis Syndromic Surveillance

43. SEARO –CSR Early Warning and Surveillance System Module Question Time 1.How do you think EWAR complements a Surveillance system?