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“Biomed-matching” Emerges among Gay Men Who Say to Partners, “I’m also on PrEP”

, by Emily Land

Gay men are engaging in even more nuanced decision-making about sex, report Michael Newcomb, PhD and colleagues in a paper published in Epidemiology and Prevention. They found that it is common for men to disclose PrEP use or that they have an undetectable viral load on mobile dating apps, and that men use this knowledge to guide decisions they make about how they have sex. While strategies such as seropositioning (risk-reducing sexual positions) and seroadaptation (choosing same-status partners) have been used for years, new prevention strategies including PrEP and treatment as prevention (TasP) also play a role in how men talk about HIV and make decisions about the type of sex to have.

man looking at phoneIn an online survey conducted from November 2014 to February 2015, Newcomb and colleagues surveyed 668 men who find sex partners using mobile dating apps. They asked if study participants had ever had a potential sex partner connected through a mobile app disclose PrEP use or being HIV-positive with an undetectable viral load, and if so, if they had condomless anal sex with this person (or people).

Over half (62%) of HIV-positive men reported ever having a potential sex partner disclose PrEP use; slightly less than half (43%) of HIV-negative men reported ever having a potential sex partner disclose PrEP use. Out of all participants who reported a potential sex partner disclosing PrEP use, 16% of HIV-negative men and 45% of HIV-positive men said they had condomless anal sex with a partner they knew was on PrEP.

The majority of men, both HIV-negative (68%) and HIV-positive (90%) said they had ever had a potential sex partner disclose that they were HIV-positive with an undetectable viral load on a mobile app. Out of these men, 8.7% of HIV-negative men and 60% of HIV-positive men reported ever having condomless anal sex with one of those partners with an undetectable viral load.

Men in the study who had condomless sex with partners on PrEP or with undetectable viral loads appeared, most often, to let their assessment of HIV risk guide their decisions. In other words, most men weren’t having condomless sex because of negative attitudes toward condoms or lack of partner communication. They decided to have condomless sex after evaluating the protection afforded by their sex partner’s PrEP or TasP use, their own PrEP or TasP use, and knowledge that they could further reduce their HIV risk in the absence of condoms with seropositioning and serosorting.

“The most frequently endorsed theme across all categories was, ‘HIV risk is lower with biomedical prevention,’” said Newcomb and colleagues. One HIV-negative study participant said, “Based on the recent studies regard[ing] undetectable transmission stats I felt it [condomless sex with an undetectable partner] is an acceptable risk.”

The study authors introduce the term “biomed-matching” to refer to sex partners that either both take PrEP or both are HIV-positive with undetectable viral loads.

One HIV-positive study participant reported that he, “only sleep[s] [with] guys who are on PrEP or undetectable”—substantially reducing the risk that he will transmit HIV to a sex partner whether or not condoms are used.

“HIV-positive MSM are choosing to have condomless anal sex with partners to whom they are less likely to transmit HIV because of partners’ use of biomedical strategies,” the authors write. “Mobile dating apps may provide a more efficient and less stigmatizing environment in which HIV-positive MSM can disclose their status and seek partners to whom transmission is less likely because of their use of PrEP or because their viral load is suppressed.”

Read more about how PrEP providers talk to clients about condoms on BETA. Find more information on how to access PrEP services at the gay men’s health and wellness center in the Castro, Strut, visit www.strutsf.org.


Newcomb, M. E. and others. Partner disclosure of PrEP use and undetectable viral load on geosocial networking apps: Frequency of disclosure and decisions about condomless sex. Epidemiology and Prevention. 2016.


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