More preventive therapy needed in foreign-born

One-third of new cases originate outside U.S.

Although cases of tuberculosis in the United States have dropped in the past four years, the numbers in foreign-born people who live in the United States continue to rise, accounting for more than one-third of cases in 1996. Improved screening and increased preventive therapy are needed to push this TB burden down, say officials from the Centers for Disease Control and Prevention.

A cross-sectional analysis of national TB surveillance data shows that the proportion of TB cases in the foreign-born has increased from 22% in 1986 (4,925 cases) to 37% in 1996 (7,783 cases). The figures, published in the Journal of the American Medical Association, show that "imported" TB, both active and latent, is responsible for most of the cases of TB in the foreign-born.

Most cases younger than 35

Moreover, the CDC reports that many of these cases are in people who were younger than 35 at time of entry, and their infection could have been avoided had they been provided with preventive therapy. On average, the annual TB rate for the foreign-born was 33 per 100,000 people or four times as high as U.S.-born populations. Patients from Mexico, Philippines, Vietnam, Korea, China, and Haiti accounted for 63% of all foreign-born cases.

Without improved screening at U.S. borders and better TB control in other countries, the high rate of TB in foreign-born patients who develop disease in this country will be difficult to reverse, the CDC reports. Indeed, because the rate has increased during the past 15 years, the agency warns that the number of long-term residents who develop latent and active TB will likely increase in upcoming years.

"A strategy combining tuberculin skin test screening and preventive therapy for foreign-born persons should take into account several important factors," the CDC notes. "The numbers, places of origin, migration patterns, and socio-economic status of foreign-born persons vary throughout the United States. State and local health departments should develop strategies adapted to their local circumstances."

Reference

1. Zuber P, McKenna M, Binkin N, et al. Long-term risk of tuberculosis among foreign-born persons in the United States. JAMA 1997; 278:304-307.