From 2005 to 2014, condomless anal sex rose among U.S. men who have sex with men (MSM) with or without HIV infection. Neither serosorting nor use of antiretroviral therapy (ART) explained falling condom use in this study of almost 36,000 MSM, according to the study.
Condom use cuts the risk of HIV transmission approximately 70% in MSM who practice anal sex. The Centers for Disease Control and Prevention (CDC) and other health authorities recommend condoms to prevent transmission of HIV and other sexually transmitted infections. Some MSM prefer other strategies to avoid HIV transmission, including serosorting (having sex only with men of the same HIV status), seropositioning (practicing insertive or receptive anal sex depending on HIV status) and pre-exposure prophylaxis (PrEP). In addition, antiretroviral-treated MSM and their sex partners may believe condoms are unnecessary if ART has made HIV undetectable in the treated partner.
CDC investigators conducted this study to chart trends in condom use among HIV-positive and negative U.S. men from 2005 to 2014 in four successive cross-sectional studies. The analysis also aimed to determine whether ART or seroadaptive strategies (serosorting or seropositioning) explain changes in condom use.
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Using data from cross-sectional surveys of MSM in 21 U.S. cities in 2005, 2008, 2011 and 2014, the study included all MSM who had a male sex partner in the past 12 months. Variables of interest for this analysis were self-reported HIV status, HIV status of the last anal sex partner, condom use with that partner and insertive or receptive position with that partner. The researchers considered a report of sex with an HIV-concordant partner as a proxy for serosorting.
Among 5371 HIV-positive men interviewed, proportions that practiced condomless anal sex rose from 34.2% in the 2005 cross-sectional survey to 37.3% in 2008, to 39.8% in 2011 and to 44.5% in 2014, a significant increase (P < .001). Proportions of HIV-positive MSM reporting concordant condomless anal sex climbed from 19.0% in 2005 to 25.4% in 2014 (P < .001), while proportions reporting discordant condomless anal sex rose from 15.0% in 2005 to 19.0% in 2014 (P < .001). These significant increases in condomless anal sex did not vary by ART use.
Among 30,547 HIV-negative men, proportions reporting condomless anal sex rose significantly from 28.7% in 2005 to 32.8% in 2008, to 34.7% in 2011 and to 40.5% in 2014 (P < .001). As with HIV-positive men, HIV-negative men reported increases in both concordant condomless anal sex (from 21.2% in 2005 to 27.4% in 2014, P < .001) and discordant condomless anal sex (from 7.6% in 2005 to 13.1% in 2014, P < .001). Across all study years, 41% of HIV-negative MSM had an HIV-discordant partner (37% with a partner of unknown HIV status and 4% with a known HIV-positive partner).
In the HIV-positive group, HIV-discordant receptive condomless anal sex increased over the years (from 6.8% in 2005 to 10.6% in 2014, P < .001), but discordant insertive condomless anal sex did not change significantly. In the HIV-negative group, rates HIV-discordant condomless insertive and receptive anal sex increased over the years (from 4.2% to 7.0% for insertive, and from 3.4% to 6.1% for receptive, P < .001 for both).
Among HIV-negative MSM, PrEP use rose from 0.5% in 2011 to 3.5% in 2014. Excluding PrEP users from the analyses did not affect increasing rates of concordant or discordant condomless anal sex.
The researchers believe their data "suggest that condom use decreased among MSM and that the trends are not explained by serosorting or ART." They add that other factors not explored in this study, such as changing social norms, may explain rising rates of condomless sex in these men. The CDC team called for continued promotion of condoms and increased PrEP access "to ensure that the benefits of ART in reducing transmission of HIV are not undermined."