Investigators recruited 2797 infants aged approximately 5 months from the Cape Town area of South Africa. All participants were HIV-free and previously received the standard Bacillus Calmette-Guérin (BCG) vaccination. Overall, 1399 were allocated to receive A new vaccine, modified Vaccinia Ankara virus expressing antigen 85A (MVA85A); 1398 received a placebo.
At the median follow-up of 24.6 months, 39 infants in the placebo group and 32 in the MVA85A group were diagnosed with incident TB. Infection with Mycobacterium tuberculosis, as defined by QuantiFERON-TB Gold In-tube (QFT) conversion, was observed in 171 children in the placebo group and 178 children in the MVA85A group.
“The vaccine induced modest immune responses against TB in the infants, but these were much lower than those previously seen in adults, and were insufficient to protect against the disease,” according to the authors.