Tuberculin skin testing to assess the occupational risk of Mycobacterium tuberculosis infection among health care workers in Abidjan, Cote d'Ivoire

SETTING: Tuberculin skin test (TST) survey of health care workers (HCWs) in selected clinical services in Abidjan, Cote d'Ivoire. OBJECTIVE: TO assess whether HCWs in Abidjan are at increased risk for occu pationally acquired Mycobacterium tuberculosis infection. DESIGN: From October 1996 to January 1997, consenting HCWs from four servic es where tuberculosis (TB) prevalence among patients was high and two servi ces where it was low were evaluated with a questionnaire, TST (including ev aluation of anergy) and chest radiograph. RESULTS: Of the 512 participants, 405 (73%) had a TST reaction of greater t han or equal to 10 mm, eight (2%) were anergic, five (1%) had a radiograph compatible with TB, and two had confirmed TB. Using a cut-off of 10 mm, we found a higher prevalence of TST positivity in services with high TB preval ence than in those with low TB prevalence (92% vs 72%; odds ratio [OR] 4.3; 95% confidence interval [CI] 2.3-8.0) and among HCWs with direct (87%; OR 2.9; 95% CI 1.6-5.1) and indirect patient contact (80%, OR 1.7; 95% CI 1.0- 2.3) than among those with minimal patient contact (69%). CONCLUSION: These findings indicate that TST positivity among HCWs is relat ed to level of exposure to TB patients, and suggest that HCWs in Abidjan ar e at risk for the nosocomial transmission of TB.