Control of sexually transmitted diseases for AIDS prevention in Uganda: a randomised community trial. Rakai Project Study Group

Abstract

Background: The study tested the hypothesis that community-level control of sexually transmitted disease (STD) would result in lower incidence of HIV-1 infection in comparison with control communities.

Methods: This randomised, controlled, single-masked, community-based trial of intensive STD control, via home-based mass antibiotic treatment, took place in Rakai District, Uganda. Ten community clusters were randomly assigned to intervention or control groups. All consenting residents aged 15-59 years were enrolled; visited in the home every 10 months; interviewed; asked to provide biological samples for assessment of HIV-1 infection and STDs; and were provided with mass treatment (azithromycin, ciprofloxacin, metronidazole in the intervention group, vitamins/anthelmintic drug in the control). Intention-to-treat analyses used multivariate, paired, cluster-adjusted rate ratios.

Findings: The baseline prevalence of HIV-1 infection was 15.9%. 6602 HIV-1-negative individuals were enrolled in the intervention group and 6124 in the control group. 75.0% of intervention-group and 72.6% of control-group participants provided at least one follow-up sample for HIV-1 testing. At enrolment, the two treatment groups were similar in STD prevalence rates. At 20-month follow-up, the prevalences of syphilis (352/6238 [5.6%]) vs 359/5284 [6.8%]; rate ratio 0.80 [95% CI 0.71-0.89]) and trichomoniasis (182/1968 [9.3%] vs 261/1815 [14.4%]; rate ratio 0.59 [0.38-0.91]) were significantly lower in the intervention group than in the control group. The incidence of HIV-1 infection was 1.5 per 100 person-years in both groups (rate ratio 0.97 [0.81-1.16]). In pregnant women, the follow-up prevalences of trichomoniasis, bacterial vaginosis, gonorrhoea, and chlamydia infection were significantly lower in the intervention group than in the control group. No effect of the intervention on incidence of HIV-1 infection was observed in pregnant women or in stratified analyses.

Interpretation: We observed no effect of the STD intervention on the incidence of HIV-1 infection. In the Rakai population, a substantial proportion of HIV-1 acquisition appears to occur independently of treatable STD cofactors.