Analysis of risk factors for tuberculous infection following exposure at a homeless shelter.

SETTING

A homeless shelter for men aged ⩾ 50 years in Seattle, Washington, USA.

OBJECTIVES

We examined risk factors for tuberculous infection following exposure to an active pulmonary tuberculosis (TB) case residing in a homeless shelter setting.

METHODS

A contact investigation identified shelter clients exposed to the index case; these contacts were then assessed for tuberculous infection. Risk factors, including proximity and duration of exposure to the index case, were evaluated for association with infection. A retrospective cohort study was conducted and a multivariate logistic regression model determined the magnitude of the association between tuberculous infection and significant risk factors.

RESULTS

Of the 64 contacts evaluated, 25 (39%) had latent tuberculous infection and one had active TB. The multivariate logistic regression model found that duration of exposure and birthplace were significantly associated with odds of infection.

CONCLUSIONS

Birthplace and duration of exposure were significant risk factors for tuberculous infection, underscoring the importance of this information when prioritizing contact investigations after TB exposure in congregate settings. We recommend that public health agencies work with homeless shelters to ensure that clients' attendance records contain the necessary information to facilitate contact tracing during public health TB investigations.