A study of relapse in paucibacillary leprosy in a multidrug therapy project, Baroda District, India.

In order to judge the value of therapeutic regimens in paucibacillary leprosy, knowledge of incubation time of relapses is essential, as this will define the length of time patients have to be followed up after treatment has been stopped. The prospective study of relapse includes paucibacillary cases of leprosy belonging to a non-lepromatous group consisting of tuberculoid, neuritic and indeterminate. Data are presented on the incubation time of 21 relapses after multidrug therapy in Baroda district; 76.19% of relapses occur during the first 2 years. This figure is most important in the analysis of results of drug trials in paucibacillary leprosy. This figure should also be relevant to regimens including drugs that are more bacteriocidal than dapsone, since the bacteriocidal activity has a bearing on the minimal necessary duration of treatment, but not on the incubation time of relapses. With the introduction of bactericidal drugs e.g. rifampicin in multidrug therapy, the incidence of relapse are very low, hence relapse rates fall down to a very low level after multidrug therapy. Our study shows a mean relapse rate of 0.19% after multidrug therapy. Factors associated with the occurrence of relapse are discussed.