Association between leprosy and HIV infection in Tanzania.

SETTING: An epidemiological study of the interaction of leprosy and HIV infection in Tanzania.

OBJECTIVE: To establish the prevalence of HIV infection among leprosy patients, and to measure the association of HIV and leprosy by comparing the HIV prevalence in leprosy patients and blood donors.

DESIGN: Testing for HIV infection in consecutively diagnosed leprosy patients (new and relapsed after MDT) in all regions in Tanzania successively for a period of 3 to 6 months during 1991, 1992 and 1993.

RESULTS: Out of the total estimated eligible leprosy patients, 697 patients (69%) entered the final analysis. The HIV prevalence among these leprosy patients was 12% (83/697) as compared to 6% (8960/ 158,971) in blood donors examined in Tanzania during the same period. There were no significant differences in HIV seroprevalence by age, sex, residence or type of disease. However, the adjusted odds ratio (OR) of the presence of a BCG scar was 1.9 [95% confidence interval (CI) 1.1-3.3] among HIV-positive leprosy cases compared to HIV-negative leprosy cases. Comparing leprosy cases with blood donors as controls, the logistic regression model, controlling for sex, age group and residence, showed the OR for HIV seropositivity among leprosy patients to be 2.5 (95% CI 2.0-3.2). This association existed in all strata, but was strongest in the 15-34-year age group. No difference of HIV status between multibacillary and paucibacillary leprosy could be shown to exist. The point estimate of the population attributable risk of HIV infection for leprosy was 7%.

CONCLUSION: HIV infection is associated with leprosy and might reverse the epidemiological trend of the slow decline in case notification in Tanzania if HIV infection is increasing greatly. Previous BCG vaccination loses its protection against leprosy in the presence of HIV infection. A repeated study is recommended in order to validate these findings, whereby recording of the disability grading of the cases is necessary to adjust for delay in diagnosis.