Protective value of BCG vaccination in children in Bangkok, Thailand

The protective effect of bacille Calmette-Guerin (BCG) vaccination asainst tuberculosis is controversial. In a study, 330 patients less than 12 years of age with tuberculosis, 52.1% of whom had had BCG vaccination, were compared with a control group of 1106 patients free of tuberculosis, 81% of whom had BCG vaccination. The occurrence of disseminated forms of tuberculosis, tuberculous meningitis, tuberculous peritonitis, and tuberculosis of bone and joints in BCG-vaccinated patients was quite low. With BCG vaccination, the incidence of the disseminated form of tuberculosis was significantly lower than that of pulmonary tuberculosis with pulmonary parenchymal lesions, primary pulmonary complexes, and pleural effusion. Tuberculous peritonitis was significantly less frequent than pulmonary tuberculosis with pulmonary parenchymal lesions, enlarged hilar glands, pulmonary primary complex, and pleural effusions. The study demonstrated that BCG gave an overall protective effect of 74% and that a major effect of this immunity was to produce a localized form of tuberculosis.