Tuberculosis prevention among foreign-born persons in Seattle-King County, Washington

The purpose of this study was to evaluate the outcomes of classified immigrant and refugee (I&R) screening and of contact investigation (CI) of foreign-born TB cases in Seattle--King County (SKC), Washington. We reviewed I&R evaluations from the SKC TB clinic for 1992-1994 and contact evaluation records for 54 randomly selected U.S.-born and foreign-born pulmonary TB patients from 1993. Among 942 I&R evaluated, 693 (74%) had positive tuberculin skin tests (TST). Preventive therapy (PT) was prescribed for 324 (34%) and treatment for 49 (5%). The remaining 377 were dismissed, of whom 96% did not meet American Thoracic Society PT criteria. Contacts of foreign-born cases were more numerous (6.0 versus 3.4 per case, p = 0.04), and significantly more likely to be TST-positive (50% versus 18%) and to be started on PT (40% versus 23%). The large number of I&R eligible for treatment or PT emphasizes the benefit of prompt evaluation of new arrivals. CI provides an excellent opportunity to screen foreign-born persons at high risk for active TB.