HIV treatment as prevention: how scientific discovery occurred and translated rapidly into policy for the global response.

In 2011 interim results of HIV Prevention Trials Network study 052, a National Institutes of Health study designed to test the effectiveness of antiretroviral treatment against the spread of HIV, were reported. These results showed that in a stable relationship in which one member of the couple was infected with HIV, treatment of the infected partner with antiretroviral drugs, combined with couples counseling and condom use, resulted in a 96 percent reduction in sexual transmission of HIV-1. This finding led to the use of antiretroviral treatment as a cornerstone of HIV prevention. Independent advisory committees of the President's Emergency Plan for AIDS Relief (PEPFAR) and the World Health Organization (WHO) have since issued analyses that set the stage for broader use of antiretroviral agents in treatment and prevention. This article describes the separate PEPFAR and WHO recommendations and outlines the design of prospective new trials to test how best to maximize the benefits of early treatment for prevention.