Anti-HIV pill PrEP linked to lower condom use among gay and bisexual men

A recent study in the Lancet has found that those Using pre-exposure prophylaxis (PrEP) – a once-daily pill to prevent HIV infection – could be linked to a drop in condom use among gay and bisexual men.

The researchers say the quick uptake of the pill happened around the same time as 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, the authors warn.

The study involved Melbourne and Sydney men and funded by funded by the Australian Government Department of Health, Victorian Department of Health and Human Services, and New South Wales Ministry of Health.

Although the overall level of protection in the population remained at around 70% over the 5-year study, the authors warn that the decline in condom use could reduce the beneficial, population-level effect of PrEP in the long term. They suggest that introducing campaigns to promote condom use as PrEP is rolled out in countries around the world could be important in ensuring the effectiveness of the programme.

“Our findings suggest that the rapid uptake of PrEP disrupted condom use at a community level,” explains Professor Martin Holt at the University of New South Wales, Sydney, Australia, who led the research. “However, it’s too early to tell the long-term effects of increasing PrEP use and declining condom use on HIV diagnoses in Victoria and New South Wales.”

“PrEP has been heralded as a game-changer for HIV, but declining condom use may impede its long-term population-level effectiveness. We need better monitoring and evaluation to assess the effect of PrEP on sexual practices at the community level in both PrEP and non-PrEP users. If sustaining condom use is important, it would be wise to implement community education campaigns to promote condom use as PrEP is being introduced.”

Before PrEP’s efficacy was demonstrated in clinical trials, there were concerns that it might promote more risky sexual behaviour. Studies of PrEP users have shown that condomless sex becomes more frequent over time, but this does not seem to diminish the effectiveness of PrEP in preventing HIV infection, if taken consistently.

However up to now, little was known about how PrEP might influence community behaviour, particularly condom use by gay and bisexual men not using PrEP. This is important because a decline in condom use by those not taking PrEP could undermine the population-level effect of PrEP by increasing the number of unprotected sex acts during which HIV transmission can occur.

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, before (2013-2016) and after (2017) large-scale roll out of PrEP in publicly-funded projects across Victoria and New South Wales.

Participants who identified as male and reported sex with male partners in the past 5 years were recruited online (aged 16 or older) or at gay venues or events (aged 18 or older). They completed questionnaires about HIV prevention practices and recent sexual behaviour. They assessed trends in condom use, condomless anal intercourse with casual partners, and PrEP use in 16827 gay and bisexual men.

Looking only at men with casual sex partners, the proportion of men on PrEP who reported condomless anal sex with casual partners rose from 1% (26 of 2692) in 2013 to 16% (652 of 4018) in 2017 (figure 1 and table 3); whilst consistent condom use declined markedly from 46% (1360 of 2692 men) to 31% (1229 of 4018).

Importantly, among HIV-negative and untested men not protected by PrEP, condomless anal sex with casual partners increased from 30% (800 of 2646) in 2013 to 39% (1166 of 2986) in 2017 .

The increase in PrEP uptake and fall in condom use coincided with a fall in the number of new HIV diagnoses in men who have sex with men (MSM) at a state level, although this observational study did not directly measure HIV infections among MSM [3]. Over this same period, there were also substantial but gradual increases in HIV testing, HIV treatment, and viral suppression. This suggests that rapidly increasing PrEP use was effective in preventing new HIV infections and catalysed or built upon improvements in HIV testing and treatment. The authors note that the rapid increase in PrEP use seems to have outweighed the rapid decrease in condom use in this early phase of PrEP implementation, but that further monitoring over the long-term will be important.

According to Professor Holt: “Our study found a striking rate of reduction in consistent condom use when PrEP was introduced in Melbourne and Sydney between 2016 and 2017. 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 long-term consequences of this shift in community behaviour are unclear. It’s possible for HIV transmission to rebound in HIV-negative and untested men not using PrEP. Our findings will be key to helping other cities and countries implement successful PrEP programmes.”