Introduction to Surveillance

2. Introduction to Surveillance Session 4, Part 1

3. Learning ObjectivesSession 4, Part 1 • Explain the surveillance “feedback loop” of data and information flow through local, state, and federal channels • Describe characteristics of three different methods of surveillance: active, passive, and syndromic • List 5 applications of public health surveillance

4. OverviewSession 4, Part 1 • How surveillance works • Passive, active, and syndromic surveillance • Applications of surveillance data • Surveillance limitations and challenges

5. How Surveillance Works

6. What is Surveillance? The ongoing systematic collection, analysis, and interpretation of health data, essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination to those who need to know. - Centers for Disease Control and Prevention (CDC)

7. Surveillance Flow Standardized data collection • Physicians • Laboratories • STD clinics • Community health clinics • Emergency departments (EDs) County and state health departments, CDC analyze data using statistical methods

8. Surveillance Flow Standardized data collection • Physicians • Laboratories • STD clinics • Community health clinics • EDs County and state health departments, CDC analyze data using statistical methods Dissemination to those who need to know Dissemination to those who need to know • Public health officials • Health directors • Health policy officials

9. Surveillance Flow Standardized data collection • Physicians • Laboratories • STD clinics • Community health clinics • EDs County and state health departments, CDC analyze data using statistical methods Dissemination to those who need to know Dissemination to those who need to know Change in public health practice (vaccination, reduction of risk factors, medical intervention, etc.) Public health planning and intervention • Public health officials • Health directors • Health policy officials

10. Surveillance Flow Standardized data collection • Physicians • Laboratories • STD clinics • Community health clinics • EDs County and state health departments, CDC analyze data using statistical methods Dissemination to those who need to know Public health evaluation Dissemination to those who need to know Change in public health practice (vaccination, reduction of risk factors, medical intervention, etc.) Public health planning and intervention • Public health officials • Health directors • Health policy officials

11. National Notifiable Diseases Surveillance System (NNDSS) • National list • ~60 nationally infectious diseases • ~6 non-infectious diseases / conditions • Produced by CSTE each year • State list • Each state modifies as needed • State law mandates reporting requirements

12. Sources of Surveillance Data • Mortality reporting • Legally required as part of vital statistics programs in most countries • Morbidity reporting • Notifiable disease reporting (legally required) or specially created systems

13. Sources of Surveillance Data • Surveys, e.g. BRFSS • Epidemic reporting / cluster investigation • Laboratory investigations and reporting • Individual investigations

14. Management of Surveillance Data • Timeliness • Completeness • Accuracy Analysis of Surveillance Data • Trends • Clusters • Patterns

15. Methods of Surveillance Passive Active Syndromic

16. Passive Surveillance Laboratories, physicians, or other health care providers regularly report cases of disease to the local or state health department based on a standard case definition of that particular disease.

17. Communicable Disease Reporting:Passive Surveillance Lab Physician Hospital Public CDC Local Health Department State

18. Anthrax Arboviralneuroinvasive and non-neuroinvasive diseases California serogroup virus disease Eastern equine encephalitis virus disease Powassan virus disease St. Louis encephalitis virus disease West Nile virus disease Western equine encephalitis virus disease Babesiosis Botulism Botulism, foodborne Botulism, infant Botulism, other (wound & unspecified) Brucellosis Chancroid Chlamydia trachomatis infection Cholera Excerpt: 2011 Recommended Reportable Diseases Specific reportable diseases and conditions are mandated by state law, and can differ for every state.

19. Active Surveillance Local or state health departments initiate the collection of specific cases of disease from laboratories, physicians, or other health care providers.

20. Communicable Disease Reporting:Active Surveillance Lab Physician Hospital CDC Local Heath Department State

21. Active Surveillance Applications • Outbreak investigations • Other times when complete case ascertainment is desired • Research study • Incomplete information reported

22. Advantages and Limitations Passive Surveillance Active Surveillance Advantages Complete data Flexible Limitations Costly • Advantages • Inexpensive • Low data collection burden for health department • Limitations • Under-reporting • Missing information • Can be slow

23. Syndromic Surveillance The ongoing, systematic collection, analysis, interpretation, and application of real-time indicators for disease that allow for detection before public health authorities would otherwise identify them.

24. What are “Indicators of Disease?” • Clinical signs that we can categorize into syndromes • Not a specific diagnosis Example: Cough + Sore throat + Fatigue + Fever =Influenza-like illness

25. Syndromic Surveillance Example Daily temperatures and GP visits for heat syndrome, Bordeaux, 1 June – 31 Aug, 2006 Source: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=18905

26. Common SyndromesUnder Surveillance • Gastroenteritis • Influenza-like illness (ILI) • Meningitis / Encephalitis • Rash / Fever sydromes • Botulinic syndrome • Hemorrhagic syndromes

27. Why Do Syndromic Surveillance? • Early detection • Ideally automated • Outbreak characterization • Magnitude, rate of spread, effectiveness of control measures • Detection of unexplained deaths

28. Limitations of Syndromic Surveillance (1) • Limited by available data • False alarms • Inconsistent reporting sources • IT failure

29. Limitations of Syndromic Surveillance (2) • Inadequate sensitivity: failure to detect outbreaks or emergencies • Outbreak is too small • Population disperses after exposure, cluster not evident

30. Limitations of Syndromic Surveillance (3) • Costly • Infrastructure and staff • Complicated data use agreements

31. Surveillance Applications

32. Applications • Establish public health priorities • Aid in determining resource allocation • Assess public health programs • Facilitate research • Determine baseline level of disease • Detect epidemics • Estimate magnitude of the problem • Determine geographical distribution

33. Establish Public Health Priorities • Frequency • Incidence, prevalence, mortality, years of life lost • Severity • Case fatality rate, hospitalization, disability • Cost • Direct, indirect

34. Resource Allocation TUBERCULOSIS: Reported cases per 100,000 population, United States, 2010 Source: National TB Surveillance System MMWR March 25, 2011 / 60(11);333-337

35. Assess Public Health Programs Laboratory Confirmed Cases of Meningitis C, England and Wales, 1998 - 2010 Source: Health Protection Agency, Infectious Diseases, Meningitis, Epidemiologic Data http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1234859709051?p=1201094595391

36. Determine Baseline Rates TB Case Rates in U.S.-born vs. Foreign-born Persons United States, 1993–2009* Cases per 100,000 *Updated as of July 1, 2010.

37. Early Detection of Epidemics Boston, MA

38. Surveillance Limitations and Challenges

39. Surveillance Limitations (1) • Uneven application of information technology • Paper-based versus electronic • Timeliness • Reporting time requirement • Reporting burden

40. Surveillance Limitations (2) • Completeness • Unreported cases • Incomplete reports • Consistency of reporting

41. Limitations: Multiple Categorical Systems Current Situation Program Specific Reports and Summaries MMWR Annual Summaries MMWR Weekly Tables Statistical Surveys for Chronic Diseases, Injuries and Other Public Health Problems CDC STD*MIS TIMS NNDSS EIP Systems PHLIS HARS Varied communications methods and security - specific to each system - including diskettes, e-mail, direct modem lines, etc. State Health Dept Reporting by Paper Form, Telephone & Fax Data Sources EIP Systems HARS STD*MIS TIMS NETSS PHLIS Physicians Varied communications methods and security - specific to each system- including paper forms, diskettes, e-mail, direct modem lines, etc. Chart Review Lab Reports HARS STD*MIS TIMS NETSS EIP Systems* PHLIS City/County Health Department * EIP Systems (ABC, UD, Foodnet) STD*MIS (Optional at the Clinic) TIMS (Optional at the Clinic)

42. National Electronic Disease Surveillance System (NEDSS) • Not a traditional surveillance system • Electronically integrates existing surveillance systems for easy data collection, storage and access • Includes security measures to ensure confidentiality • Allows data queries

43. Surveillance Challenges • Assessing quality of the data • Using case definitions • Translating data into information

44. Quality of the Data • Completeness of case ascertainment • Assessment of completeness, accuracy, and timeliness of reports ‘Tip of the iceberg’

45. Surveillance Challenges by Definition • Clinical vs. surveillance case definitions • Cases ‘worked’ vs. cases ‘counted’ • Place of exposure, residence, or diagnosis • Re-infection or duplicate report • Frequencies by date of onset, date of diagnosis, or date of report

46. Translating Data into Information • Provides the basis for public health action • Requires sound analysis and interpretation • Extracts meaningful, actionable findings • Requires clear presentation of complex issues

47. Summary • Public health surveillance is the ongoing collection, analysis, interpretation of health data and dissemination of information • Surveillance data are used for planning, implementation, and evaluation of public health practice • Surveillance data collection can be passive, active, or syndromic; each type presents unique advantages and limitations

48. References and Resources • Bonetti M, et al. Syndromic Surveillance. Harvard Center for Public Health Preparedness; August 2003. • Public Health Surveillance Program Office [Web page]. Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/osels/ph_surveillance/. Accessed March 1, 2012. • State Electronic Disease Surveillance Systems --- United States, 2007 and 2010. MMWR Morb Mortal Wkly Rep. 2011;60(41):1421-1423. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6041a3.htm?s_cid=mm6041a3_w. Accessed March 1, 2012. • Nationally Notifiable Conditions [Web page]. Division of Notifiable Diseases and Healthcare Information, Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/osels/ph_surveillance/nndss/phs/infdis.htm. Accessed March 1, 2012.

49. References and Resources • Notifiable Diseases/Deaths in Selected Cities Weekly Information. MMWR Morb Mortal Wkly Rep. 2004;53(21):460-468. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5321md.htm. Accessed March 1, 2012. • Flamand C, Larrieu S, Couvy F, Jouves B, Josseran L, Filleul L. Validation of a Syndromic Surveillance System using General Practioner House Calls Network, Bordeaux, France. Eurosurveillance. 2008;13(25). Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=18905. Accessed March 1, 2012.