Context

Additional interventions to combat the HIV/AIDS epidemic are needed urgently. Prevention interventions using antiretroviral agents to prevent sexually acquired HIV are being studied in humans. Current evidence suggests that, by reducing viral load to undetectable level, combination antiretroviral therapy used to treat and extend the life of HIV-infected individuals may also reduce their infectivity thereby reducing the risk of transmission to their uninfected partners.1 In 2010, a topical antiretroviral-based vaginal microbicide, Tenofovir 1% gel, was shown to reduce HIV acquisition among South African women.2 The iPrEX study is the first multicentre double-blinded randomised trial evaluating the efficacy and safety of antiretroviral drugs used as oral pre-exposure prophylaxis (PrEP) to prevent HIV infections.