Oral PrEP reduces risk of HIV and does not result in riskier sex

Effectiveness and safety of oral HIV pre-exposure prophylaxis (PrEP) for all populations: A systematic review and meta-analysis.

Fonner VA, Dalglish SL, Kennedy CE, Baggaley R, O'Reilly K R, Koechlin FM, Rodolph M, Hodges-Mameletzis I, Grant RM. AIDS. 2016 May 5. [Epub ahead of print]

Objective: Pre-exposure prophylaxis (PrEP) offers a promising new approach to HIV prevention. This systematic review and meta-analysis evaluated the evidence for use of oral PrEP containing tenofovir disoproxil fumarate (TDF) as an additional HIV prevention strategy in populations at substantial risk for HIV based on HIV acquisition, adverse events, drug resistance, sexual behavior, and reproductive health outcomes.

Design: Rigorous systematic review and meta-analysis.

Methods: A comprehensive search strategy reviewed three electronic databases and conference abstracts through April 2015. Pooled effect estimates were calculated using random-effects meta-analysis.

Results: Eighteen studies were included, comprising data from 39 articles and six conference abstracts. Across populations and PrEP regimens, PrEP significantly reduced the risk of HIV acquisition compared to placebo. Trials with PrEP use >70% demonstrated the highest PrEP effectiveness (RR = 0.30, 95% CI: 0.21-0.45, p < 0.001) compared to placebo. Trials with low PrEP use did not show a significantly protective effect. Adverse events were similar between PrEP and placebo groups. More cases of drug-resistant HIV infection were found among PrEP users who initiated PrEP while acutely HIV-infected, but incidence of acquiring drug-resistant HIV during PrEP use was low. Studies consistently found no association between PrEP use and changes in sexual risk behavior. PrEP was not associated with increased pregnancy-related adverse events or hormonal contraception effectiveness.

Conclusion: PrEP is protective against HIV infection across populations, presents few significant safety risks, and no evidence of behavioral risk compensation. The effective and cost-effective use of PrEP will require development of best practices for fostering uptake and adherence among people at substantial HIV-risk.

Abstract access [1]

Editor’s notes: This systematic review is the first to aggregate data from across oral pre-exposure prophylaxis (PrEP) studies, including randomized control trials and observational studies, to present clear evidence on the effectiveness of oral PrEP use. The findings confirm that oral PrEP significantly reduces the risk of acquiring HIV if taken consistently and correctly across populations, countries, and most age groups. Differences in efficacy directly correlate with adherence, which accounts for the lower efficacy seen in some subgroups. Perhaps two of the most compelling analyses presented in this paper relate to resistance and behavioural disinhibition. The risk of resistance was shown to be quite low, and study participants exhibiting resistant HIV either enrolled in the studies during an acute infection stage or acquired resistant strains during the course of the research. Regarding behavioural disinhibition, indicators measured such as rates of sexually transmitted infections revealed that PrEP use in the efficacy trials was not associated with behavioural disinhibition and in some studies, resulted in even safer sexual behaviour than what was reported at baseline. Recently completed demonstration projects have reported increased rates of STIs among gay men and other men who have sex with men. However, in the open-label extensions included in this review, where counselling was more intensive, safer sex practices were maintained, thus suggesting that counselling can be effective in preventing behavioural disinhibition. 

Africa [5], Latin America [6], Northern America [7]
Botswana [8], Brazil [9], Cambodia [10], Canada [11], Ecuador [12], France [13], Ghana [14], Kenya [15], Nigeria [16], Peru [17], South Africa [18], Thailand [19], Uganda [20], United Kingdom [21], United Republic of Tanzania [22], United States of America [23], Zimbabwe [24]
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