Prevalence of tuberculin skin test positivity and conversions among healthcare workers in New York City during 1994 to 2001

OBJECTIVE: To determine the prevalence of and risk factors for tuberculin skin test positivity and conversion among New York City Department of Health and Mental Hygiene employees. DESIGN: Point-prevalence survey and prospective cohort analysis. Sentinel surveillance was conducted from March 1, 1994, to December 31, 2001. PARTICIPANTS: HCWs in high-risk and low-risk settings for occupational TB exposure. RESULTS: Baseline tuberculin positivity was 36.2% (600 of 1,658), 15.5% (143 of 922) among HCWs born in the United States, and 48.5% (182 of 375) among HCWs not born in the United States. There were 36 tuberculin conversions during 2,754 observation-years (rate, 1.3 per 100 person-years). For HCWs born in the United States, the risk for tuberculin conversion was greater in high-fisk occupational settings compared with low-risk settings (OR, 5.7; CI95, 1.7-19.2; P < .01). HCWs not born in the United States and those employed at the Office of the Chief Medical Examiner (OCME) were at high risk for baseline tuberculin positivity (OR, 3.2; CI95, 1.7-5.8; P < .001); OCME HCWs (OR, 4.7; CI95, 2.3-9.4; P < .001), those of Asian ethnicity (OR, 4.3; CI95, 1.4-13.5; P < .01), and older HCWs (OR, 1.0; CI95, 1.0-1.1; P < .05) were at a higher risk for conversion. CONCLUSIONS: Although the prevalence of tuberculin positivity decreased after the peak of the recent TB epidemic in New York City, the conversion rate among HCWs in high-risk occupational settings for TB exposure was still greater than that among HCWs in low-risk settings. Continued surveillance of occupational TB infection is needed, especially among high-risk HCWs.