Antiretroviral pre-exposure prophylaxis (PrEP) for preventing HIV in high-risk individuals

Twenty-five years into the global HIV/AIDS epidemic, infection rates remain alarmingly high, with over 4 million people becoming infected every year. There is a need for HIV prevention strategies that are more effective. Oral antiretroviral pre-exposure prophylaxis (PrEP) in high-risk individuals may be a reliable tool in preventing the transmission of HIV.

To evaluate the risk reduction and side effects of antiretroviral chemoprophylaxis in preventing HIV infection in high-risk individuals

We conducted electronic searches of MEDLINE (1980 through June 2008); the Cochrane Central Register of Controlled Trials (March 2008); EMBASE (June 2008); and AIDSearch (June 2008). We also searched the WHO International Clinical Trials Registry Platform in June 2008 for ongoing or prospective trials.

Randomized controlled trials that evaluated the effects of any antiretroviral agent in preventing HIV infection in high-risk individuals

Data concerning outcomes, details of the interventions, and other study characteristics were extracted by two independent authors using a standardized data extraction form. The information gathered from each included trial were location of the trial, date, publication status, demographics of participants (e.g. age, gender, risk behaviour), exposure modality, type of antiretroviral drug used, duration of drug use, and outcomes. Relative risk with a 95% confidence interval (CI) was used as the measure of effect. Only one trial met our inclusion criteria, so we did not perform a meta-analysis.

One randomised controlled trial met the criteria for the review, although it was not completed as planned. The trial did not have the statistical power to answer questions about the efficacy of antiretroviral PrEP for HIV prevention in the assessed risk group.

Presently there is no reliable evidence to support the use of any antiretroviral agent for HIV chemoprophylaxis.The value of chemoprophylaxis for HIV prevention cannot be assessed on the basis of the included trial. The result was not statistically significant and, moreover, the trial was not completed as planned; therefore, the use of antiretroviral agents for HIV chemoprophylaxis cannot be recommended at present. To assess the value of antiretroviral agents for HIV chemoprophylaxis, we advocate well-conducted trials with the statistical power to answer questions about PrEP efficacy and safety in various populations and risk groups. These trials also should evaluate other important issues of concern, such as drug safety, adherence, drug resistance, and the effect of PrEP on risk behaviour.