Protective effect of Bacillus Calmette Guerin (BCG) vaccination in prevention of pulmonary tuberculosis.

ABSTRACT

A hospital-based, pair-matched, case control study was carried out at Government Medical College Hospital, Nagpur to estimate the effectiveness of BCG vaccination in the prevention of pulmonary tuberculosis. The study included 412 incident cases of pulmonary tuberculosis, which were born onwards 1962. Each case was pair-matched with one control for age, sex and socio-economic status. Controls were selected from subjects attending study hospital for conditions other than tuberculosis and leprosy. The significant protective association between BCG vaccination and pulmonary tuberculosis was observed (OR = 0.47, 95% CI = 0.35-0.63). The overall vaccine effectiveness was 53% (36.5-65.3%). BCG vaccine was non-significantly more effective in age less than or equal to 20 years, among males and in upper and middle socio-economic stratum. The overall prevented fraction was estimated to be 38.6% (24.2-43.6%). Results of this study, thus, demonstrated a moderate effectiveness of BCG vaccination in prevention of pulmonary tuberculosis in study population.