Effectiveness of single dose rifampicin after BCG-vaccination to prevent leprosy in close contacts of patients with newly diagnosed leprosy: a cluster randomized controlled trial

ABSTRACT Objective To assess the effectiveness of SDR after BCG-vaccinationin preventing leprosyin contacts. Design Single-centre, cluster-randomized controlled trial. Setting Leprosycontrol programme in northwest Bangladesh. Participants 14,988 contacts of 1,552 new leprosypatients; randomized in the SDR- arm (7,379) and SDR + arm (7,609). Interventions Intervention group: BCG-vaccinationfollowed by SDR 8-12 weeks later. Control group: BCG only. Follow-up: at one and two years after intake. Main outcome measure The occurrence of leprosy. Results The incidence rate per 10,000 person-years-at-risk was 44 in the SDR- arm and 31 in the SDR + at 1 year, and 34 in the SDR- arm and 41 in the SDR + arm at 2 years. There was a statistically non-significant (p = 0.148; 42%) reduction for PB leprosyin the SDR + arm at 1 year. Of all new cases, 33.6% appeared within 8-12 weeks after BCG-vaccination. Conclusion In the first year, SDR after BCG-vaccinationreduced PB leprosyincidence among contacts by 42%. This was a statistically non-significant reduction due to the limited number of cases after SDR was administered. To which extent SDR suppresses excess leprosycases after BCG-vaccinationis difficult to establish because many appeared before the SDR intervention. Trial registrationNetherlands Trial Register: NTR3087