A phase 2b trial of the M72/AS01E candidate vaccine showed an efficacy of 49·7% (95% CI 2·1–74·2) for preventing disease in adults positive by interferon-gamma release assay after 3 years of follow-up,6 and a trial of BCG-revaccination appeared efficacious at preventing sustained infection in a cohort of adolescents negative for interferon-gamma release assay, with an efficacy of 45·4% (6·4–68·1).7 The gene discussed is IFNG; the disease is infection.