Background: From 1978 through 1992, the number of patients with tuberculosis in New York City nearly tripled, and the proportion of such patients who had drug-resistant isolates of Mycobacterium tuberculosis more than doubled.
Methods: We reviewed, confirmed, and analyzed data obtained during the surveillance of patients with tuberculosis.
Results: From 1992 through 1994, there was a 21 percent decrease in reported cases of tuberculosis in New York City. An evaluation of the surveillance system revealed very few unreported cases. The number of cases decreased by more than 20 percent among blacks and Hispanics, persons with documented human immunodeficiency virus infection, homeless persons, and patients with multidrug-resistant tuberculosis; in all these groups, tuberculosis is likely to result from recent transmission. In contrast, the number of cases of tuberculosis increased among elderly and foreign-born persons, in whom the disease is likely to result from the reactivation of an infection acquired many years earlier. Enrollment in a program of directly observed therapy, in which health workers watch patients take their medications, increased from fewer than 100 patients to nearly 1300, with more than 32,000 patient-months of observation from 1992 through 1994.
Conclusions: Epidemiologic patterns strongly suggest that the decrease in cases resulted from an interruption in the ongoing spread of M. tuberculosis infection, primarily because of better rates of completion of treatment and expanded use of directly observed therapy. Another contributing factor may have been efforts to reduce the spread of tuberculosis in institutional settings, such as hospitals, shelters, and jails. Expansion of measures to prevent and control tuberculosis and support of international control efforts are needed to ensure continued progress.