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

This review evaluated the effects of giving people at high risk for HIV infection drugs to prevent infection (called antiretroviral pre-exposure prophylaxis, or PrEP). We found six randomised controlled trials that assessed the effects of oral tenofovir disoproxil fumarate (TDF) plus emtricitabine (FTC) versus placebo; TDF versus placebo, and daily TDF-FTC versus intermittent TDF-FTC. One of the trials had three study arms (TDF, TDF-FTC and placebo arm). The trials were carried out amongst different risk groups, including HIV-uninfected men who have sex with men, people in serodiscordant sexual relationships where one partner is infected and the other is not, and other high risk men and women. The findings suggests that the use of TDF alone or TDF+FTC reduces the risk of becoming infected with HIV. However, further studies are need to evaluate the method of administration (daily versus intermittent dosing), long-term safety and cost effectiveness of PrEP in different risk groups and settings.

Authors' conclusions: 

Finding from this review suggests that pre-exposure prophylaxis with TDF alone or TDF-FTC reduces the risk of acquiring HIV in high-risk individuals including people in serodiscordant relationships, men who have sex with men and other high risk men and women.

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Background: 

More than 30 years into the global HIV/AIDS epidemic, infection rates remain alarmingly high, with over 2.7 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.

Objectives: 

To evaluate the effects of oral antiretroviral chemoprophylaxis in preventing HIV infection in HIV-uninfected high-risk individuals.

Search strategy: 

We revised the search strategy from the previous version of the review and conducted an updated search of MEDLINE, the Cochrane Central Register of Controlled Trials and EMBASE in April 2012. We also searched the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing trials.

Selection criteria: 

Randomised controlled trials that evaluated the effects of any antiretroviral agent or combination of antiretroviral agents in preventing HIV infection in high-risk individuals

Data collection and analysis: 

Data concerning outcomes, details of the interventions, and other study characteristics were extracted by two independent authors using a standardized data extraction form. Relative risk with a 95% confidence interval (CI) was used as the measure of effect.

Main results: 

We identified 12 randomised controlled trials that meet the criteria for the review. Six were ongoing trials, four had been completed and two had been terminated early. Six studies with a total of 9849 participants provided data for this review. The trials evaluated the following: daily oral tenofovir disoproxil fumarate (TDF) plus emtricitabine (FTC) versus placebo; TDF versus placebo and daily TDF-FTC versus intermittent TDF-FTC. One of the trials had three study arms: TDF, TDF-FTC and placebo arm. The studies were carried out amongst different risk groups, including HIV-uninfected men who have sex with men, serodiscordant couples and other high risk men and women.

Overall results from the four trials that compared TDF-FTC versus placebo showed a reduction in the risk of acquiring HIV infection (RR 0.49; 95% CI 0.28 to 0.85; 8918 participants). Similarly, the overall results of the studies that compared TDF only versus placebo showed a significant reduction in the risk of acquiring HIV infection (RR 0.33; 95% CI 0.20 to 0.55, 4027 participants). There were no significant differences in the risk of adverse events across all the studies that reported on adverse events. Also, adherence and sexual behaviours were similar in both the intervention and control groups.

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