Case and Contact Investigation Training

1. Case and Contact Investigation Training Public Health Seattle and King County

3. Objectives - Learner will know: • What a case investigation is • What a contact investigation is • What the steps in an investigation are • The purpose of a contact investigation interview • How to prioritize contacts • How to decide when to expand and investigation • How to evaluate a contact investigation

4. What is a contact investigation? • It is a procedure for identifying people exposed to someone with an infectious disease, determining their risk for becoming infected, evaluating them for disease and providing them with appropriate treatment.

5. What is a case investigation? • It is the process for identifying and confirming, through symptoms, laboratory test results and epidemiological evidence, who has a communicable, serious disease then treating this person and educating them on how to reduce the spread of their particular disease.

6. Why are case and contact investigations done? • To establish diagnosis • To do lab testing • To perform clinical evaluations • To treat infected people • To provide counseling to exposed people concerning disease control recommendations • To prevent transmission to other people • To prevent future outbreaks of disease

7. When is a case and contact investigation done? • It is done when someone with a serious and communicable infectious disease is reported to the health department. This report can come from a private health care provider, a laboratory, hospital, correctional facility or other institution where the patient is diagnosed.

8. Definitions • Contacts - people exposed to someone with an infectious disease, generally including household members, roommates or housemates, close friends, coworkers, classmates and others • Types of contacts: • household or family • social • school • work • other

9. Definitions continued • Close contact - a person who has had prolonged, frequent or intense contact with a sick person while they were infectious resulting in increased risk for transmission of the infection • Other than close contacts - contacts with less intense, less frequent or shorter durations of contact with the infected person corresponding to a lower risk for disease transmission

10. Definitions continued • High priority contacts - the contacts who are at most risk for serious disease and for the spread of disease to vulnerable populations • Index patient - a person with suspected or confirmed disease who is the initial case identified by the health department

11. Definitions continued • Source case - a person with an infectious disease who is responsible for transmitting the disease to someone else • Primary case - the person who introduces the disease into the population

12. Definitions continued • High risk contacts - contacts at particularly high risk of developing disease, young children, the elderly or immune compromised individuals or contacts that if they became infected would pose a significant risk to other vulnerable populations, (health care workers, teachers etc.)

13. Definitions continued • Infection rate - the percentage of persons who become ill out of all exposed people • Period of infectiousness - the time period during which an ill person is capable of transmitting disease • Transmission - The spread of an infectious agent from one person to another

14. Definitions continued • Field investigation - visiting the person’s home, workplace and other places a case spent time. The purpose is to identify contacts and evaluate the environmental characteristics of the place in which exposure occurred. • Exposure - The condition of being exposed to something that could have a harmful effect, such as an infectious agent.

15. Steps in a case investigation • Identify missing data pieces • Conduct interviews with primary care providers and laboratories • Track laboratory results • Identify if the case needs to be isolated or quarantined • Document the information you are gathering

16. Steps in a case investigation continued • Report and coordinate efforts with the state department of health • Seek consultation from other health department employees, CDC, WHO etc.

17. Steps in a contact investigation • Establish the data collection tools that are going to be used • Clarify rationale for contact investigation • Set contact investigation priorities • Conduct the patient interview: Field investigation Risk assessment for transmission • Decision about priority of contacts • Evaluation of contacts

18. Steps in a contact investigation continued • Treatment and follow up for contacts • Decision about whether or not to expand testing • Evaluation of contact investigation activities

19. Ensure prompt and accurate data intake and assessment • Establish forms and process as to how data is collected • Ensure that all staff are aware of what information to gather and what to do with this data • Arrange for any immediate care or isolation needed for identified patients and their contacts

20. Ensure prompt and accurate data intake and assessment continued • Develop a system to follow up on missing or incomplete data • Process data • entry • analysis

21. Index patient info. Name Address Phone (wk, home, cell) Date of Birth Employment or school Sex Race/ethnicity/language Disease onset, communicable period Symptoms Contact info. Name Address Date of birth Phone Relationship to patient Setting of exposure Days of exposure Hours of exposure Close/casual contact Symptoms Examples of Elements for Data Collection Forms for Contact Investigations

22. Purpose of Contact Investigation Interview • To find out more about the case’s symptoms to help determine period of infectiousness • To find out the places where the case spent time while they were infectious

23. Purpose of Contact Investigation Interview continued • To identify the case’s contacts, get locating information for them and find out how long the contacts were exposed to the patient while they were infectious • To describe the nature of the contact including the date of exposure and the type of contact

24. Symptoms • Does the contact have symptoms • How long have they had symptoms for • Contacts may be able to relate these symptoms to dates such as holidays or birthdays • With the patient’s approval family members or friends can also be interviewed to determine when symptoms began, (approval is not required but is nice to get if possible)

25. Potential barriers to performing good contact investigations • Nearly everyone has contact with someone but it can be difficult to identify who these people are • Patients may be reluctant to identify their contacts. For example they may be hesitant to identify people with whom they use illegal drugs, people who are here illegally or they simply may not want friends or family to know they are sick.

26. Barriers continued • The interviewer should be sensitive to their fears, explain the importance of evaluating the contacts and assure the patient that confidentiality will be maintained to the fullest extent of the law, (i.e. if child abuse is occurring this must be reported to authorities etc.) • A good contact investigation form can help in obtaining consistent, accurate information.

27. Places • Have case or contact go over their daily routine • People spend most of their time: at home, work or school or in leisure or recreational environments • Case should also be asked the characteristics of each place, including the size of the place, the amount of time spent there and what kind of ventilation was present and how much crowding there was in the area

28. Environmental assessment • For airborne diseases assess for: • circulation of air • length of time in the environment • size of the airspace • location of the index case and each contact in the air space • proximity and duration of contact • did the contact have physical contact with the case’s saliva

29. Environmental assessment continued • For food borne illnesses: • food history • food storage and handling • types of foods

30. Environmental assessment continued • For water borne illnesses: • water sources • amount of water consumed • type of exposure to water

31. How to prioritize contacts • To use time and resources well the investigation should be focused on the high priority contacts or the people most at risk for developing and/or transmitting severe disease.

32. How to prioritize contacts continued • Whether transmission occurs or not depends on how infectious the case is, how susceptible the contact is, the nature of the exposure between the case and the contact and what kind of environment the interaction between case and contact occurs in.

33. People with lower immunity: elderly children under the age of four HIV positive people other immunosuppressed individuals People who have had: close regular prolonged contact Contacts most likely to be infected

34. Concentric circle testing • This is a method of testing contacts in order of risk for infection based on exposure time and circumstances. First the closest circle to the patient is evaluated then if they are positive the next circle is tested and so on until evaluation is deemed no longer necessary.

35. How to decide whether or not to expand testing • Evaluate the highest risk priority group for infection • Look at the infection rate amongst these individuals • If significant infection has occurred amongst the first group of close contacts then the investigation should be expanded

36. Contact Investigation Evaluation • Were the appropriate of contacts identified? • Were the highest priority contacts identified and tested? • Was the investigation performed in all applicable settings? • Was the investigation expanded appropriately?

37. Contact Investigation Evaluation continued • Were contacts completely evaluated and where appropriate, given treatment? • Did identified contacts complete, where appropriate, treatment regime? • Did identified cases, where appropriate, treatment regime?

38. Contact Investigation Evaluation continued • Program evaluation is a critical component of every program. Evaluation of performance is important to ensure that resources and priorities are being used effectively on the highest priority activities.

39. Review • Today we learned….

40. Sources of information for this presentation: • Dr. Jeff Duchin, Chief of Communicable Disease and Epidemiology, Public Health Seattle and King County • Janice Boase, Assistant Chief of Communicable Disease and Epidemiology, Public Health Seattle and King County • CDC Self Study Modules on Tuberculosis, Case and Contact Investigations