A retrospective analysis of the Chingleput BCGvaccination trial (conducted in 1968) data was carried out. Data on participants with evidence of prior BCGvaccination at trial intake and randomized to BCG vaccine [low dose (0.01 mg), high dose (0.1 mg)] and placebo arms were analyzed. The incidence of TB disease, which was based on sputumculture and/or chestX-ray was compared between the BCG and placebo arms over a 15 yr follow up period.
Results:
Of the 269,727 individuals randomized in the trial; 263,158 had no evidence of TB at baseline, of which 4436 (1.68%) had evidence of BCGvaccination at trial intake (2890 in the BCG vaccine and 1546 in the placebo arms, respectively). There were 77 (190 per 100,000) and 64 (296 per 100,000) incident TB cases in the BCG and placebo arm, respectively, at 15 yr post-vaccination. The incidence of TB disease was significantly lower in the BCGarm [Hazard ratio of BCGarm (95% confidence interval) 0.64 (0.46-0.89)]. Interpretation &