Contact with Mycobacterium leprae (M. leprae) infected individuals is a risk factor for development of leprosy. Thus, detection of asymtomatically M. leprae infected individuals, allowing informed decision making on who needs treatment at a preclinical stage, is vital to interrupt transmission and can help prevent leprosy. In a previous field trial the BCG vaccine was applied alone and combined with a single dose of rifampin (SDR) as prophylactic interventions in contacts of leprosy patients in Bangladesh. Concurrently, blood-derived host immune-profiles specific for M. leprae infection or leprosy disease were assessed in the same population by merging detection of innate, adaptive cellular as well as humoral immunity. This has led to the identification of selected host-immune markers, currently applied in a low complexity lateral flow assay based on up-coverting particles (UCP-LFA), providing a convenient tool to assess M. leprae infection, allowing assessment of efficacy of prophylactic interventions in a point-of-care setting. The proposed study aims to determine the effect of post-exposure prophylaxis by SDR on M. leprae infection rate using UCP-LFA before and after prophylaxis.