HomeThe interview of an infectious TB patient for contact tracing is one of the most important parts of the investigation. It takes considerable skill and is most successful when done by staff with training/experience in public health interview techniques, including motivational interviewing, and who are familiar with local social patterns.43–46 The initial interview can also lay the foundation for long-term adherence to TB treatment, and should be approached as an integral component of TB care for the patient. Most TB patients in Canada were born in countries with high TB incidence or in First Nations/Inuit communities (see Chapter 1: Epidemiology of Tuberculosis in Canada), so language and cultural perceptions about TB, TB stigma and health are very important to support the trust and rapport essential for full disclosure.44,47 Interviews are best carried out in the language the patient is most comfortable with, if necessary through a professional interpreter or an objective third party (not a family member). Face-to-face interviewing, in privacy, is ideal.
Confidentiality of contact investigations should be stressed, but note that legislation may permit or require release of information about the case’s diagnosis to specific individuals (including public health authorities). For example, some information may have to be shared in confidence with selected individuals (eg, a school principal) in order to identify or reach contacts and ensure that they, too, get the medical follow-up they need.
Interviewing is usually best extended over two or more sessions, a week or more apart, as the patient becomes more familiar with public health staff, and the initial stress and anxiety over the diagnosis are resolving. Patients may find it helpful to look at contact lists on their phone, social media, or calendars as a memory aide. Proxy or supplemental interviews with family, close friends, work supervisors, etc. (ideally with patient permission) may be helpful if patients are unable or unwilling to participate. All patients should routinely be asked about the locations where they spend time regularly, as well as names of specific close contacts. Location-based investigation is the basis for social-network approaches discussed below; it is especially critical when highly infectious patients are unable (or unwilling) to name specific contacts in the settings where they spend time.48–51 Location-based screening will inevitably include some nonexposed individuals, but may be the only way to reach contacts at risk in those settings.
All interviews to identify contacts should include the following:
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Name-based information (including name, alias/nickname, phone, address, email/social media contact, age, nature of interaction):
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Description of the household/congregate setting; household contacts and their ages (includes anyone who regularly sleeps at the home)
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Other households the case visits frequently, particularly overnight
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Close friends, relatives and caregivers who are visited or are present in the home at least once per week (how often, for how long)
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Close colleagues at work (how often together, nature of interaction)
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Transportation to work/school (carpool, public transit, etc.)
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Any contacts who are ill with potential TB symptoms or who have known TB
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Any contacts who are children, and their ages
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Any contacts who are immunosuppressed (people with HIV, cancer patients, etc)
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Any major events (eg, weddings, funerals, parties) the case attended while infectious
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Location/site-based information
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Work/school location and description of setting (type of work, size of room, ventilation, lunch/break rooms, etc)
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Place of worship, volunteering, clubs, sports teams, recreation or drop-in programs, hobbies or other locations visited frequently
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Smoking tobacco or other substances (where, who else smokes in the same location at the same time)
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Any other homes, “party sites,” places or groups the patient has regularly been in or with while infectious
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Any recent travel or visitors staying at the home within the previous 2 years; if so, obtain details
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A site visit to assess the home is best practice, even if the initial interview is carried out in hospital, to assess feasibility of home isolation, identification of additional household contacts, identification of any social/practical issues relevant to treatment adherence, and so forth. Site visits to the school or workplace and other exposure locations are also helpful to make contact-investigation decisions (to assess environmental characteristics such as size, layout, use of the space and ventilation; interviews with a direct supervisor can help to identify potential contacts).52 Discretion is important, as a site visit may precipitate unnecessary anxiety and/or lead to a breakdown of confidentiality and repercussions for the patient. It is advisable to arrange site visits directly with senior personnel, such as a school principal, division manager or occupational health manager, and emphasize the importance of maintaining confidentiality as much as possible (see Site-based Screening, in the following sections).
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