Objektif Kami mengambil hipotesis bahwa, pertama , transmisi M.leprae dari pasien indeks sampai pasien kontak akan ditempatkan sebelum didiagnosa dan mulai di terapi pada kasus indeks danObjeiveWe hypothesised that, firstly, transmission of M lepraefrom the index patient to contacts would take placebefore the diagnosis and start of treatment in the indexcase, and, secondly, that a single dose of rifampicinwould be effective in eradicating small numbers of Mleprae that were possibly present in the contacts. In thisway rifampicin could be effective as a measure toprevent clinical leprosy among close contacts ofpatients with leprosy. Our objective was to determinethe effectiveness of chemoprophylaxis using a singledose of rifampicin to prevent leprosy in close contacts.We formed subgroups of contacts according to theircontact status, age, genetic relation to the index patient,sex, disease classification of the index patient, presenceof a BCG scar, and serological status.