Abstract:
Background—
Few prospective studies have assessed whether antiretroviral therapy (ART) use
is associated with changes in sexual risk behavior of HIV-infected persons in known HIV-
serodiscordant partnerships.
Methods—
We conducted a longitudinal analysis of HIV-infected persons with known uninfected
partners enrolled in the Partners PrEP Study in Kenya and Uganda. ART use and self-reported
sexual behavior were ascertained every 3 months. We assessed the effect of ART on sexual risk
behaviors using zero-inflated negative binomial regression. Primary outcomes were condomless
vaginal sex acts, pregnancy incidence and new STI diagnoses.
Results—
We followed 1817 HIV-infected persons (58% women) for 864 person-years before
ART initiation and 771 person-years after ART. Median CD4 and plasma viral load at ART
initiation were 277 cells/μL and 4.18 log
10
copies/mL. ART use was associated with a significant
decrease in condomless vaginal sex acts with HIV-uninfected partners (0.65 vs. 0.39 per month;
rate ratio [RR] 0.64; 95% CI: 0.55–0.75; p<0.001), but not condomless vaginal sex acts with non-
primary partners (1.30 vs. 1.04 per month; RR 0.94; 95% CI: 0.94–1.20; p=0.62). Pregnancy
incidence was lower after ART (13.2 vs 8.4 per 100 person-years; HR 0.71, 95% CI: 0.60–0.84,
p<0.001). Incident STI diagnoses were similar (OR 1.05, 95% CI: 0.86–1.29; p=0.63).
Conclusions—
Substantial risk compensation did not occur following ART initiation among
East African HIV-infected persons with known HIV-uninfected partners. These data inform
modeling studies of ART for HIV prevention by suggesting that risky sexual behavior did not
appear to offset decreased HIV infectiousness in this key population
