A Breath of Fresh Air: BCG Prevents Adult Pulmonary Tuberculosis.

•Numerous well-designed and rigorous prospective trials demonstrate that childhood BCG immunization provides protection against pulmonary tuberculosis.•Recent national retrospective reviews confirm the efficacy of BCG against pulmonary TB.•The efficacy of BCG against pulmonary TB remains high for at least 15–20 years and is substantial for as long as 50 years.•Accurate, contemporary understanding of the efficacy of BCG against pulmonary tuberculosis is critical to the development and evaluation of investigational vaccines intended to replace or boost BCG.