Tuberculin reactivity in adults after 50 years of universal bacille Calmette–Guérin vaccination in Taiwan

Abstract
We aimed to assess whether tuberculin reactivity in adults is affected by bacille Calmette–Guérin (BCG) vaccination after 50 years of universal BCG vaccination with 80–95% coverage. A community-based study on tuberculin reactivity in 619 participants was conducted in February 2000 in Keelung city, Taiwan. Information on BCG vaccination policies and annual risk of infection (ARI) in the underlying population was extracted from consecutive national prevalence surveys relating to the period 1952–1997. Compared with the expected ARI estimate, the standardized morbidity ratio of positive tuberculin response for vaccination in infancy was 2.2 (95% CI 0.3–15.5) for those aged 30 years is probably negligible irrespective of age at vaccination or revaccination and that the tuberculin skin test can be used to diagnose TB in control programmes in countries with moderate or high incidence of TB.