The Original Study
Although post-exposure chemoprophylaxis is recommended after occupational or non-occupational exposure to HIV-infected fluids, no trial has previously explored the impact of pre-exposure chemoprophylaxis on HIV infection rates. This study examines the impact of administering antiretroviral chemoprophylaxis before exposure on HIV acquisition among HIV-seronegative men or transgender women who have sex with men in six countries (Peru, Ecuador, Brazil, US, Thailand and South Africa). In this study, half of the population were randomly assigned to receive a combination of two oral antiretroviral drugs, emtricitabine and tenofovir disoproxil fumarate (FTC–TDF). The control group received a placebo drug once daily. The authors used an analytic approach to estimate the modified intention-to-treat analysis and the as-treated analysis to determine the impact of the intervention on HIV acquisition. The study shows that subjects who were treated with antiretroviral chemoprophylaxis before exposure had lower rates of HIV infection.