Glynn JR, Fielding K, Mzembe T, et al. - In this rural African population with a high prevalence of HIV, there was no indication that repeated BCG vaccination gives significant protection against overall tuberculosis. Given the many studies performed, subgroup effects should not be overinterpreted. The evidence for limited protection against HIV-negative tuberculosis and a delayed benefit in individuals who were vaccinated as children, on the other hand, is consistent with other findings in the literature.

• Between 1986 and 1989, over 47,000 people of all ages living in northern Malawi with a BCG vaccine scar were randomly assigned (1:1) to receive a second BCG or a placebo.

• During the study's follow-up period, 824 people got tuberculosis, including 786 with pulmonary disease, and 383 (63%) of 607 with known HIV status were HIV positive.

• A second BCG dose had no effect on overall or pulmonary tuberculosis, nor on lymph node tuberculosis.

• The OR was lower in individuals with known HIV-negative tuberculosis (0·77; 0·59–1·00), in those vaccinated as children (aged < 5 years, 0·74; 0·41–1·35; aged 5–14 years, 0·77; 0·60–0·99), and in cases occurring at least 20 years following vaccination (0·79; 0·63–1·01).

• There were no changes based on tuberculin status or lineage at the time of vaccination.

• There was no evidence of leprosy protection after 10 years of vaccination (although there have been only nine diagnostically certain cases since 1995).