A major event for new tuberculosis vaccines

In their elegant randomised, placebo-controlled trial, Tameris and colleagues followed up 2794 BCG-vaccinated infants for up to 37 months (median 24·6, IQR 19·2-28·1) in two nearly equal groups. 39 (2·8%) of 1395 infants in the placebo group (Candida skin test antigen) satisfied the primary definition of active tuberculosis, of whom 20 were microbiologically confirmed. 32 (2·3%) of 1399 infants in the vaccine group (MVA85A) satisfied the primary definition of active tuberculosis, of whom 22 were microbiologically confirmed. [...]vaccine efficacy was 17·3%, which was not distinguishable from zero (95% CI -31·9 to 48·2). [...]could MVA85A, working as a booster to BCG, protect adolescents and adults against pulmonary tuberculosis in a way that it cannot protect infants?