Antiretroviral therapy (ART) was highly efficacious in preventing HIV transmission in stable serodiscordant couples in the HPTN-052 study, a resource-rich randomized controlled trial. However, minimal evidence exists of the effectiveness of ART in preventing HIV acquisition in stable serodiscordant couples in real-life population-based settings in hyperendemic communities of Sub-Saharan Africa, where health systems are typically resource-poor and overburdened, adherence to ART is subpotimal, and HIV status disclosure to sexual partners is inconsistent.
Data arose from a population-based open cohort in KwaZulu-Natal, South Africa. HIV-uninfected individuals present between January 2005 and December 2013 (n=17,016) were included. Interval-censored time-updated proportional hazards regression was used to assess how the ART status affected HIV transmission risk in stable serodiscordant relationships.
Of 17,016 individuals, 1,846 had an HIV-uninfected and 196 had an HIV-infected stable partner over the follow-up period. HIV incidence was 3.8 per 100 person-years (100PY) among individuals with an HIV-infected partner (95% confidence interval [CI] 2.3-5.6), corresponding to 1.4 per 100PY (95% CI 0.4-3.5) among those with HIV-infected partners on ART and 5.6 per 100PY (95% CI 3.5-8.4) among those with partners not on ART. Use of ART was associated with a 77% decrease in HIV acquisition risk amongst serodiscordant couples (aHR=0.23, 95% CI 0.07-0.80).
ART initiation was associated with a very large reduction in HIV aquisition in serodiscordant couples in rural KwaZulu-Natal. However, real-life effectiveness was substantially lower than in the HPTN-052 trial. To eliminate HIV transmission in sero-discordant couples, additional prevention interventions are likely needed.