Treating HIV Helps Prevent New Infection

More HIV treatment in a community results in fewer new HIV infections, a South African study has revealed.

When HIV treatment coverage reached 20% of the infected population, a surveillance project indicated a 22% decline in HIV infections community-wide (P=0.002), said Frank Tanser, PhD, associate professor of health and population studies, University of KwaZulu-Natal, Richards Bay, South Africa.

"In communities where HIV treatment achieved 30%, the individuals' HIV acquisition was 38% less likely (P<0.001)," Tanser said in a press briefing here at the Conference on Retroviruses and Opportunistic Infections.

"These results clearly demonstrate that the rate of new HIV infections can be reduced and that this can be done in a typical sub-Saharan African setting," he said. "This is the first empirical evidence to date that treatment can be prevention."

Tanser and colleagues put together two databases involving treatment in an area of South Africa with high rates of HIV prevalence. When they analyzed the results, they were able to observe "a robust decline in transmission as the coverage of HIV treatment was rolled out."

In the KwaZulu area studied, HIV prevalence is 24% in an area with high levels of unemployment and poverty. The Hlabisa HIV Treatment and Care Programme, funded through the American-based President's Emergency Plan for AIDS Relief (PEPFAR), delivers HIV and AIDS treatment programs in 17 communities. Since 2004 and 2008, Tanser said, some 20,000 individuals were initiated on treatment among 228,000 people in the communities studied.

The data and treatment was married to population-based HIV surveillance since 2003, which studies HIV acquisition in the area. About 75% of the population found to be HIV negative retest each year, allowing epidemiologists to determine infection rates. In the study, the researchers followed 16,667 HIV-negative repeat-testers, Tanser said. All participants in the analysis had to have participated in the project at least twice and had to be 15 years of age or older.

"We observed 1,413 seroconversions over 53,605 person years, a crude incidence of 2.64 per 100 person years," Tanser said.

Strengths of the observational study include the direct measurement of HIV acquisition in a longitudinal prospective cohort of all adults in an entire population, as well as directly measured antiretrovirus status in every infected individual, he noted. In addition, the researchers controlled for a wide range of key determinants of HIV acquisition.

"Randomized controlled treatment-as-prevention trials are the next step," Tanser said. "Our findings suggest that attaining high levels of antiretroviral coverage through existing, decentralized, public-sector antiretroviral programs is an effective means of reducing the rate of new HIV infections in hyper-endemic rural settings in sub-Saharan Africa."