Researchers set out to evaluate whether changes in the use of condoms reflected increased adoption of serosorting (having sex only with those of similar HIV status) or biomedical preventions like antiretroviral treatment. Their report, published in May in the journal AIDS, concluded that condomless sex continues to increase among men who have sex with men, but "the trends are not explained by serosorting or ART."
The scientists reviewed data gathered by the National HIV Behavioral Surveillance Survey, which was conducted in up to 21 cities in 2005, 2008, 2011, and 2014. The survey asked more than a thousand men whether they used a condom with their latest anal sex partner.
They found that declines in condom usage were seen across the board among men, whether or not their sexual partners were of the same HIV status and regardless of whether they knew their partners' HIV status. This led researchers to conclude that the lack of condom use cannot be explained by serosorting.
In the near-decade between 2005 and 2014, the number of HIV-negative gay and bisexual men who reported having sex without a condom rose from 29% to 41%.
As Website NAM Aidsmap points out, "Condom use began to fall long before PrEP became available."
In the surveillance survey, PrEP usage was reported by 0.5% of the gay and bi men in 2011. That number rose to only 3.5% of men in 2014, making it highly unlikely that the HIV prevention protocol played a significant role in the decline of condom use.
When it came to HIV-positive men's usage of condoms, the trend was similar: poz gay and bi men also reported higher incidence of condomless sex (rising from 37% in 2008 to 45% in 2014). Again, this was true regardless of whether that man thought his partner's status was positive or negative or didn't know.
With HIV-positive men, NAM Aidsmap writes, "The only hint of a seroadaptive behavior is that condomless receptive anal sex with partners of unknown or different HIV status rose, while condomless insertive sex with those partners did not."
The risk of HIV transmission is higher for the receptive or bottom partner in anal sex, but the insertive or top partner can still get HIV in certain circumstances. In one study, tops were 86% less likely to contract HIV.
The decline of condom use was seen among HIV-positive men who weren't taking medication to treat their HIV, as well as those who were. This also suggests that the increase in sex without a condom isn't simply a reflection of the success of treatment as prevention (TasP). Those whose viral load has become undetectable due to antiretroviral treatment are 99% less likely to transmit HIV, regardless of whether a condom is used.
"Our data suggests that condom use has decreased among [men who have sex with men] and that the trends are not explained by serosorting, seropositioning, PrEP use, or HIV treatment," noted the researchers, who worried that "the benefits of [antiretrovirals] in reducing transmission of HIV" could be "undermined" without increased promotion of condoms and access to PrEP.
While the condom usage of 1,000 to 1,500 men who have sex with men may not reflect the behavior of all gay and bi men, the decline in usage could actually be higher, due to the impact of the self-reporting bias, in which respondents often underreport behavior that could be interpreted negatively.