Malaria Parasitemia and Parasite Density in Antiretroviral-Treated HIV-Infected Adults Following Discontinuation of Cotrimoxazole Prophylaxis

Background. Cotrimoxazole (CTX) discontinuation increases malaria incidence in human immunodeficiency virus (HIV)-infected individuals. Rates, quantity, and timing of parasitemia rebound following CTX remain undefined. Methods. Serial specimens from a trial of HIV-infected individuals receiving antiretroviral treatment (ART) randomized to continue (the CTX arm) or discontinue (the STOP-CTX arm) were examined for malaria parasites by quantitative reverse transcription polymerase chain reaction (PCR). Specimens obtained at enrollment and then quarterly for 12 months and at sick visits were assessed; multiplicity of infection was evaluated by PCR that targeted the polymorphic msp-1/msp-2 alleles. Results. Among 500 HIV-infected adults receiving ART (median ART duration, 4.5 years), 5% had detectable parasitemia at baseline. After randomization, parasite prevalence increased over time in the STOP-CTX arm, compared with the CTX arm, with values of 4% and < 1%, respectively, at month 3, 8% and 2% at month 6, 14% and 2% at month 9, and 22% and 4% at month 12 (P =.0034). The combined mean parasite density at the various time points was higher in the STOP-CTX arm (4.42 vs 3.13 log(10) parasites/mL; P <.001). The parasitemia incidence was 42.0 cases per 100 person-years in the STOP-CTX arm and 9.9 cases per 100 person-years in the CTX arm, with an incidence rate ratio of 4.3 (95% confidence interval, 2.7-7.1; P <.001). After enrollment, mixed infections (multiplicity of infection, > 1) were only present in the STOP-CTX arm. Conclusion. Discontinuation of CTX by HIV-infected adults receiving ART resulted in progressive increases in malaria parasitemia prevalence and burden.