Self-Study Modules for Effective TB Interviewing
Outbreak Investigation Interviewing
Conducting TB interviews under outbreak circumstances provides
a special challenge. While the objectives and communication skills
remain the same for all TB interviews, the situations under which
outbreak interviews occur are different.
What Is an Outbreak?
An outbreak is a greater-than-normal or greater-than-expected
number of individuals infected or diagnosed with suspected or verified
TB in a given period of time, or a particular place, or both. This
can occur in a community or larger geographic area or as part of
a single contact investigation. In the first situation, routine
surveillance provides an opportunity to identify outbreaks, since
the greater-than-expected number of cases may not be readily available.
Delays in reporting, cases occurring in multiple communities or
TB control jurisdictions, and the new occurrence of a large number
of latent TB infections, which are not reportable in many areas,
make outbreak identification a difficult task.
Identifying an Outbreak
Outbreaks may be identified by detecting
- A greater-than-expected rate of M. tuberculosis transmission,
as defined by health department or institutional standards, e.g.,
from one index case, through routine interviewing and evaluation
- A greater-than-normal rate of skin test conversions as indicated
by institutional standards;
- An increase in TB cases noted through surveillance via required
reporting of TB suspects and verified cases, and in some instances,
latent TB infection; or
- The same strain of TB detected in various locations through
analysis of the genetic structure of specific bacteria from multiple
patients (restriction fragment length polymorphism [RFLP]
Outbreak Interviewing Challenges
In any contact investigation, the TB interview is the first step
in identifying all contacts at risk of exposure and transmission
to others. However, unique challenges in outbreaks can slow this
process, including a greater number of interviews and numerous follow-up
interviews of the same index patients to gain additional information.
Other issues include
- Having multiple index patients; however, these links may not
be evident at first as infected patients who are linked to each
- Contacts not being linked through the “obvious” and usual settings
such as home, work, or school;
- Links that are difficult to establish due to illicit activities;
- Occurrence of TB disease in individuals not required to be interviewed
(e.g., extrapulmonary cases). Subsequently, links to a source
case and his or her infected contacts may not occur; or
- Index patients’ inability or unwillingness to name contacts
and where they can be located.
Conducting the Outbreak Interview
Most outbreaks are identified after routine TB interview data have
been collected. The analysis of the routine interview data to conduct
subsequent interviews and re-interviews requires a different approach.
However, comparisons of named contacts and places that patients
frequent can yield similar data. For example, several persons with
TB or infected contacts may commonly mention one person as a priority
contact; this individual may be the source case. A follow-up interview
with this individual should be done to determine if there are other
contacts who have not been identified. Use of a common place to
focus the nature of contact identification can assist in identifying
other possible priority contacts. Follow-up interviews can occur
as information becomes available and is analyzed. The focus of
these interviews, however, may be more specific than previous interviews.
Interviewers should be prepared to provide extensive education
about outbreaks in a congregate setting. If an outbreak has been
detected and additional patients are being interviewed, the interviewer
should explain to these patients, as appropriate, about possible
media and press attention that may occur in connection with this
outbreak. There may also need to be explanations about possible
negative attitudes of those being tested, particularly in a workplace,
where speculation about the source case (i.e., the index patient)
will occur. The interviewer should acknowledge that a breach in
confidentiality by others may occur; however, the health department’s
dedication to maintaining confidentiality under all circumstances
will be maintained.
Congregate-Setting Investigations and Interviews
Commonly identified places should be prioritized and investigated
further through a congregate-setting investigation per health department
guidelines. Key to these on-site investigations is the identification
of additional priority contacts. This is also the procedure in
a standard contact investigation in which a congregate-setting investigation
would take place. Prioritization entails looking for places having
the likelihood of the highest chances for transmission, i.e., where
the index patient(s) spent the most time, and where high priority
contacts may be.
Interviewing Priority Contacts
In an outbreak scenario, individuals identified as priority contacts
may also become the subjects of interviews due the high rate of
transmission. This will routinely occur if the contact has developed
active TB. However, if transmission is high or seems to be unusual
for the identified circumstances in the congregate setting, even
with infection, not disease, contacts should be interviewed. Interviews
of an infected contact should include
- Review of tuberculin skin test result, latent TB infection,
and TB disease history. This history will assist in determining
whether the contact has been recently infected or not;
- Places in which, and persons with whom, he or she spends prolonged
periods of time. This may eventually lead to determining if the
contact has been infected by the identified index case or another
- Asking who the contact knows who has TB or TB-like symptoms;
listing the symptoms should help identify others with TB. If
the contact names the index patient, further questioning about
the index patient’s whereabouts, lifestyle, and other potential
contacts can be explored. However, it is important that this
be done without confirming the identity of the index patient.
The interviewer can also inquire about any other persons’ whereabouts,
symptoms, and lifestyle mentioned during the interview so as not
to appear to focus on the index patient; and
- Discussion with the contact about people with whom he or she
shares drugs and alcohol, and where, if applicable. Acknowledging
the sensitivity of this line of questioning and reiterating confidentiality
can assist in obtaining this information.
The purpose of this type of interviewing is to further identify
contacts and other places that the index case has not previously
mentioned that can provide information for further investigation.
This needs to be done without revealing the name of the index patient(s).
In order to find out the most accurate information about where transmission
occurred, it is critical that both skin test positive and negative
contacts be interviewed, if possible. Deciding which contacts should
be interviewed can be facilitated through network analysis, discussed
in the next section.