A recent cluster-randomized trial assessed the effectiveness of single double-dose rifampicin post-exposure prophylaxis in preventing leprosy. Conducted in 16 villages in Madagascar and 48 villages in Comoros, the study screened over 109,000 participants annually over four years.
Published in The Lancet, the study included four arms: a control group with no post-exposure prophylaxis (PEP), household contacts receiving single double-dose rifampicin post-exposure prophylaxis (SDDR-PEP), individuals within 100 meters of an index case receiving SDDR-PEP, and the same group plus those testing positive for anti-phenolic glycolipid-I.
The primary analysis revealed non-significant reductions in incidence rates in the intervention arms compared to the control. The incidence rate ratio (IRR) was 0.95 for arm 2, 0.80 for arm 3, and 0.58 for arm 4. After adjusting for baseline prevalence, the reduction in arm 3 became significant (IRR 0.56, p=0.003).
Individual-level analysis demonstrated that SDDR-PEP provided a protective effect, with an IRR of 0.55 (p=0.005). The study also found that the risk of leprosy was significantly higher for individuals living within 75 meters of an index patient at baseline.
The researchers have initiated a second trial to compare the effects of standard dose SDR-PEP with a combination regimen of rifampicin and bedaquiline. They noted that targeted door-to-door screening around index patients, complemented by a blanket SDDR-PEP approach, may have a substantial effect on transmission.
The authors reported no potential conflicts of interest.