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.

OBJECTIVE: To assess the effectiveness of SDR after BCG-vaccination in preventing leprosy in contacts.

DESIGN: Single-centre, cluster-randomized controlled trial.

SETTING: Leprosy control programme in northwest Bangladesh.

PARTICIPANTS: 14,988 contacts of 1,552 new leprosy patients; randomized in the SDR- arm (7,379) and SDR + arm (7,609).

INTERVENTIONS: Intervention group: BCG-vaccination followed 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 leprosy in 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-vaccination reduced PB leprosy incidence 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 leprosy cases after BCG-vaccination is difficult to establish because many appeared before the SDR intervention.

TRIAL REGISTRATION: Netherlands Trial Register: NTR3087.