ART initiation linked to a very large reduction in HIV acquisition in serodiscordant couples in rural KwaZulu-Natal, but real-life effectiveness was substantially lower than in the trial.
In KwaZulu-Natal, where rates of HIV are the highest in South Africa, close to a third of adults live with HIV, and only a little more than a third of adults in their working years have paying work. The rate of people with access to treatment for HIV has grown in the last dozen years, but antiretroviral medicine stockouts are common, and staying in care is challenged. The success that is measured by suppression of the virus, an outcome of antiretroviral treatment that is consistent, monitored and effective, is less common there than in places with more resources.
That’s where researchers went when they sought to examine the real-world impact of antiretroviral treatment on preventing HIV transmission from infected people to their uninfected partners in stable sexual relationships. Their goal was to compare the preventive impacts of treatment on the ground, when disclosure of HIV status also might be an issue, to the proven preventive impact of treatment found in research that includes the landmark HPTN 052 trial.
At the Africa Centre for Population Health, they examined seven years of data culled from a surveillance programme that included HIV testing, sexual histories, relationship status, and household demographic data. With data from more than 17,000 people between January 2005 and December 2013, they found that uninfected stable sexual partners of HIV-infected people receiving antiretroviral treatment had 77% fewer HIV infections than uninfected partners of people not receiving treatment.
As clinical trials have shown, antiretroviral treatment was associated with a significant drop in new infections among uninfected partners of people living with HIV, researchers concluded. But with HPTN 052 having demonstrated that early and optimal access to treatment led to near elimination of transmission from infected to uninfected partners, the real world still falls far short of what is possible.
Background: 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.
Methods: 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.
Results: 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).
Conclusions: 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.
Catherine E. Oldenburg, Till Bärnighausen, Frank Tanser, Collins C. Iwuji, Victor De Gruttola, George R. Seage III, Matthew J. Mimiaga, Kenneth H. Mayer, Deenan Pillay and Guy Harling