Background: An increasing incidence of tuberculosis has been observed in the New York City correctional system.
Methods: The diagnosis of active tuberculosis in persons within the correctional setting results in an investigation, with the identification and screening of contacts.
Results: Thirty-four such investigations in the past 2 years in the New York City correctional system, where all inmates are screened for tuberculosis on admission, have resulted in an overall tuberculin skin test conversion rate of 6.74% in 1306 inmates. In 21 of these investigations the index had both smears and cultures positive for Mycobacterium tuberculosis and the conversion rate was 7.37% in 719 contacts tested. In seven investigations the index patient had a culture only positive for M. tuberculosis and the conversion rate was 6.58% in 243 inmates. In six investigations in which the index patients were subsequently found to have nontuberculous pneumonia or mycobacteria other than M. tuberculosis the conversion rate was 5.52% in 344 inmates. These rates are not statistically different.
Conclusions: Whether the observed conversions in these events or in any of the contact investigations are due to intramural spread, anergy on admission, the booster phenomenon, or incubation of disease on admission is not known. The 5.5% conversion rate in those exposed to inmates confirmed not to have tuberculosis suggests the influence of booster phenomenon and consideration of two-step testing on admission.