Adverse reactions to the ivermectin treatment of onchocerciasis patients: does infection with the human immunodeficiency virus play a role?

To assess and compare the adverse effects resulting from ivermectin treatment of onchocerciasis patients with and without infection with human immunodeficiency virus (HIV-1), 1256 Ugandan cases of onchocerciasis were investigated as they were treated for the first time with the drug. Treatment followed the protocol of the Mectizan Expert Committee (i.e. a single dose of 150 mug/kg body weight). Adverse reactions to the ivermectin were determined, within 48 h of treatment, through questioning and clinical examinations during house-to-house visits. The HIV-1 status of each patient aged >15 years was initially determined using indirect ELISA, and any ELISA-positives were then confirmed in a western-blot assay. Among the cases aged >15 years, the frequency of adverse reactions to ivermectin was higher among those seropositive for HIV-1 (53.4%) than among the seronegative (45.7%) but the difference was not statistically significant (P = 0.25). The severity of the adverse reactions observed was, however, significantly lower in the HIV-1-positive patients than in the seronegative patients, with median scores of 1.37 and 1.68, respectively (P = 0.044). The conclusion is that ivermectin can be safely used for mass treatment in areas where the prevalences of onchocerciasis and HIV-1 infection are both high.