Last updated June 8, 2018 at 11:47 am
Australian study correlates PrEP uptake to a fall in condom use.
It has been heralded as a game-changer, the popularity of a once-daily pill to prevent HIV infection has significant benefits but it has been linked to complacency at a community level, Australian researchers have warned.
Their observational study of nearly 17,000 gay and bisexual men in Sydney and Melbourne suggests that the rapid uptake of a pre-exposure prophylaxis (PrEP) coincided with an equally quick fall in consistent condom use, even among those not taking the pill.
The drop in condom use could lower population-level protection by PrEP in the long term, they say, and it would be wise to introduce campaigns to promote condom use as PrEP is rolled out in other countries.
However, it should be noted that the overall level of protection in the population remained at around 70 per cent over the five years of the study, which tracked safe-sex behaviours before and after the widespread introduction of PrEP in Victoria and NSW in March 2016.
The study involved researchers from the University of NSW, Catholic University of Applied Sciences, AIDS Council of NSW, University of Sydney, Living Positive Victoria, International Council of AIDS Service Organizations, the Victorian Department of Health and Human Services, and Utrecht University.
Regular use of antiretroviral drugs such as PrEP is highly effective at preventing HIV infection, and WHO recommends it be made available to people at highest risk of getting HIV, including gay and bisexual men, sex workers and people who use drugs.
Studies of PrEP users have shown that condomless sex becomes more frequent over time, but this does not seem to diminish its effectiveness in preventing HIV infection if taken consistently. However, until now little was known about how PrEP might influence community behaviour.
In this study, researchers analysed data from the yearly Melbourne and Sydney Gay Community Periodic Surveys to investigate the uptake and effect of PrEP on condom use in the community. Participants were recruited online (aged 16 or older) or at gay venues or events (18 or older) and asked to complete questionnaires about HIV prevention practices and recent sexual behaviour.
‘Striking’ rate of reduction
“Our study found a striking rate of reduction in consistent condom use when PrEP was introduced in Melbourne and Sydney between 2016 and 2017,” said project leader Professor Martin Holt. “If individuals not taking PrEP feel safer, they might use condoms less often because they perceive that sex without a condom has become less risky as PrEP use by others increases.”
The researchers note some limitations to the study, including that it did not track the behaviour of individuals over time and was based on cumulative behaviour over the previous 6-12 months (rather than event-level data), which might lead to overestimations of the level of HIV risk by classifying men who had any condomless sex as potentially at risk.
They also note that they mainly included gay and bisexual men from metropolitan areas, rather than a representative sample of Australian gay and bisexual men that would encompass a broader age range and more men from regional areas.
However, key strengths include the large sample size, the standardised, repeated method, and adjustment for sampling variation over time.
The paper published in The Lancet HIV.