Gomes RR, Antunes DE, dos Santos DF, et al. - In this retrospective cohort study, researchers focused mainly on the occurrence of leprosy as well as on the presence or absence of Bacillus Calmette–Guérin (BCG) scars verified at the first assessment among household contacts (HHCs) of leprosy patients, given BCG vaccine-induced immunoprophylaxis continues to be the most effective intervention in the prevention of leprosy among HHCs of leprosy patients. Data were analyzed from 5.061 HHCs for a duration of 16 years (follow-up of 7 years per leprosy HHCs). Sickened contacts were 92 in total. The development of borderline tuberculoid was reported in 62% (57/92) of those who became sick. A shorter survival time (average time of 22 months between t₀ and outcome) was experienced by leprosy HHCs with 0 BCG scar at time zero (t₀) vs those with 2 BCG scars (average time of 36 months between t₀ and outcome). Extreme significance of vaccination of healthy people without signs and symptoms of leprosy was highlighted since the BCG vaccine conferred an additional protective impact in those cases with 2 BCG scars during follow-up. Prophylactic actions such as immunoprophylaxis and index cases treatment were found to be determinative for attenuating the risk of leprosy HHCs becoming sick.