Risk and protective factors for leprosy development determined by epidemiological surveillance of household contacts.

Household contacts of leprosy patients are the group with the highest risk of developing the disease, and although many risk or prevention factors have been identified, they have not been employed in leprosy-monitoring programs. This investigation aimed to establish the relative risks or the preventive effects of the presence of BCG vaccination, the Mitsuda test, and the ML-Flow assay. Household contacts (1,396) were monitored for a 5-year period.