Two studies from South Africa suggest that the scale-up of ART is increasing life expectancy and decreasing HIV transmission at the population level.
Because of the devastating HIV epidemic and the unavailability of antiretroviral therapy (ART) in government clinics and hospitals until 2004, life expectancy in South Africa declined significantly. Now, two studies suggest that this bleak picture is changing. Both were conducted in rural KwaZulu-Natal, where rates of poverty are high and >20% of adults are HIV infected. ART has been rapidly scaled up in this area — first for patients with CD4 counts <200 cells/mm3 and later for those with CD4 counts <350 cells/mm3 who either are pregnant or have tuberculosis.
Bor and colleagues examined changes in adult life expectancy in the area between 2003 — the year before public-sector provision of ART to adults began — and 2011. During this period, adult life expectancy rose from 49.2 to 60.5 years, and all-cause mortality among adults aged 25 to 44 declined by >50%. The authors estimated that approximately one third of the HIV-infected adults in the community were receiving ART. The cost of ART in this population was estimated at US$10.8 million over the study period, for a cost-effectiveness ratio of $1593 per year of life saved (considered cost effective, because it is less than <25% of South Africa’s 2011 per-capita gross national income).
Tanser and colleagues performed a population-based study to examine the effect of ART coverage in the surrounding community on HIV-uninfected individuals’ risk for HIV acquisition. Between 2004 and 2011, a total of 1413 HIV seroconversions occurred among 16,667 individuals who were HIV-uninfected on first testing, for a crude rate of 2.63 new infections per 100 person-years. After adjustment for age and sex, the risk for HIV acquisition was lowest in areas where the highest proportion of HIV-infected people were receiving ART. For example, such risk was 34% lower for a person living in an area with 30% to 40% ART coverage than for a person living in an area with <10% coverage.
Comment: These two studies provide strong evidence that the scale-up of ART in heavily affected communities in South Africa is saving lives, increasing life expectancy, and having a population-level preventive effect. The results of HPTN 052 conclusively demonstrated the efficacy of treatment as prevention in a clinical trial; Tanser and colleagues’ findings now provide evidence of effectiveness in a real-world setting. However, unlike HPTN 052, which included people with high CD4-cell counts, this population-based study was conducted in an area where ART was generally initiated at CD4 counts <200 cells/mm3, with the cutoff eventually increased to 350 cells/mm3 for pregnant women and tuberculosis patients. One can only guess how much higher the preventive effect might have been if ART had been started at higher CD4-cell counts. It is time to focus our efforts on early diagnosis, linkage and retention in care, and ART initiation at any CD4-cell count, both for individual patient health and for population-level prevention, if we are truly going to have an “AIDS-free generation.”