Sexual behaviour of heterosexual men and women receiving antiretroviral pre-exposure prophylaxis for HIV prevention: a longitudinal analysis

The Lancet Infectious Diseases, Early Online Publication, 17 October 2013

doi:10.1016/S1473-3099(13)70226-3 Cite or Link Using DOI

This article can be found in the following collections: Infectious Diseases (HIV/AIDS)

Copyright © 2013 Elsevier Ltd All rights reserved.

Original Text

Kenneth K Mugwanya MBChB a b, Deborah Donnell PhD c d, Prof Connie Celum MD a d e, Katherine K Thomas MS d, Patrick Ndase MBChB d, Nelly Mugo MBChB d f g, Prof Elly Katabira MBChB h, Kenneth Ngure PhD d g i, Dr Jared M Baeten MD a d e, for the Partners PrEP Study Team†

Summary

Background

Scarce data are available to assess sexual behaviour of individuals using antiretroviral pre-exposure prophylaxis for HIV prevention. Increased sexual risk taking by individuals using effective HIV prevention strategies, like pre-exposure prophylaxis, could offset the benefits of HIV prevention. We studied whether the use of pre-exposure prophylaxis in HIV-uninfected men and women in HIV-serodiscordant couples was associated with increased sexual risk behaviour.

Methods

We undertook a longitudinal analysis of data from the Partners PrEP Study, a double-blind, randomised, placebo-controlled trial of daily oral pre-exposure prophylaxis among HIV-uninfected partners of heterosexual HIV-serodiscordant couples (n=3163, ≥18 years of age). Efficacy for HIV prevention was publicly reported in July 2011, and participants continued monthly follow-up thereafter. We used regression analyses to compare the frequency of sex—unprotected by a condom—during the 12 months after compared with the 12 months before July 2011, to assess whether knowledge of pre-exposure prophylaxis efficacy for HIV prevention caused increased sexual risk behaviour.

Results

We analysed 56 132 person-months from 3024 HIV-uninfected individuals (64% male). The average frequency of unprotected sex with the HIV-infected study partner was 59 per 100 person-months before unmasking versus 53 after unmasking; we recorded no immediate change (p=0·66) or change over time (p=0·25) after July, 2011. We identified a significant increase in unprotected sex with outside partners after July, 2011, but the effect was small (average of 6·8 unprotected sex acts per year vs 6·2 acts in a predicted counterfactual scenario had patients remained masked, p=0·04). Compared with before July, 2011, we noted no significant increase in incident sexually transmitted infections or pregnancy after July, 2011.

Interpretation

Pre-exposure prophylaxis, provided as part of a comprehensive prevention package, might not result in substantial changes in risk-taking sexual behaviour by heterosexual couples.

Funding

The Bill & Melinda Gates Foundation and the US National Institute of Mental Health.

Source