A study presented at the 19th Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle Thursday demonstrated the first empirical evidence of a population-level reduction in risk of acquiring HIV infection in communities with antiretroviral therapy (ART) coverage of all HIV-infected people (greater than 20 percent).
Dr. Frank Tanser of the Africa Center for Health and Population Studies at the University of KwaZulu-Natal, South Africa, presented the study data from a rural community in KwaZulu-Natal. The Zulu-speaking community had an adult HIV prevalence of 24 percent, with high levels of unemployment and poverty. The study team used two sources of annual population-based HIV surveillance data of community members 15 years of age and older. They focused on 2004 to 2011 – during which time an “incredibly rapid” roll out of ART coverage took place in this community, Tanser said – and follow up data from 16,667 repeat HIV-negative testers in the community.
The study team proved their hypothesis that increasing coverage of ART among HIV-infected individuals would decrease the risk of acquiring of HIV infection among uninfected individuals at a population level. Investigators observed 1,413 HIV sero-conversions over 53,604 person-years of observation — and saw a “crude” HIV incidence rate of 2.63 per 100 person years. For every percentage point increase in ART coverage among all HIV-infected adults in the community, investigators found a corresponding 1.7 percent decline in the hazard of HIV acquisition faced by an uninfected adult living in the same community.
It is worth noting that the community initiated those HIV infected individuals with a CD4 count of 200 or less on ART – suggesting that greater reductions in incidence could be seen in communities following World Health Organization recommendations to put all persons with a CD4 of 350 or less on ART.