New Study Examines When Serosorting Is Beneficial
Serosorting is the practice of selecting sexual partners based on a common HIV status. When implemented in conjunction with frequent testing and open communication between partners, serosorting reduces the HIV risk from condomless anal intercourse.
Hackneyed proclamations such as “DDF” (drug- and disease-free) pervading Grindr and other mobile dating apps imply that HIV status plays at least some role in partner selection for many gay and bisexual men. In previous years, serosorting has been lauded for contributing to the decline in new HIV infections among gay and bisexual men in San Francisco. However, a recent review of nationwide HIV acquisition data by the Centers for Disease Control and Prevention (CDC) shows mixed results for the effectiveness of serosorting as an HIV prevention strategy.
The data, published in the journal AIDS and Behavior, come from a meta-analysis – a study of previously published studies – on serosorting among men who have sex with men (MSM). Each of the six studies included in the meta-analysis compared the rates of HIV infection among three groups: men who use condoms consistently, men who use serosorting, and men who neither serosort nor use condoms consistently.
By averaging the findings of these studies, researchers concluded that serosorting was correlated with a 54% decrease in HIV risk when compared to condomless anal sex with serodiscordant partners. However, when compared with no condomless anal intercourse, serosorting was correlated with a 64% increase in HIV risk. In other words, serosorting is effective at significantly reducing HIV infection among men who don’t use condoms consistently. For consistent condom users, though, switching to serosorting as one’s main HIV prevention strategy would increase HIV risk drastically.
Theoretically, selecting only sexual partners who share one’s same HIV status should result in no new infections. But in practice, serosorting is actually quite challenging. In a 2013 interview with The New York Times, former CDC director Thomas Frieden voiced concerns about the effectiveness of serosorting.
“The problem with sero-sorting is that it’s really easy to get it wrong,” noted Frieden. “When one-third of men aren’t even tested in the last year and a tenth of those who thought they were negative were actually positive, you don’t want to risk your life on a guess.”
The study’s first author, David Purcell, is the Deputy Director for Behavioral and Social Science at the CDC’s Division of HIV/AIDS Prevention. His unit studies the role behavioral sciences and health communications in HIV prevention.
Echoing Frieden’s reservations about serosorting, Purcell said, “We have cautioned against serosorting in the past because it is difficult to know for certain the serostatus of oneself, as well as every sex partner – so the strategy can be challenging to implement effectively and can lead to increased risk.”
“These data speak to the importance of prevention tailored to the individual. If serosorting is included among other prevention options, it is imperative that individuals understand the potential for both benefit and harm.”
To facilitate gay and bisexual men tailoring their own HIV prevention, the CDC has developed an online HIV Risk Reduction Tool. The beta version of this tool allows men to input several variables about their sexual practice, such as pre-exposure prophylaxis (PrEP) status, condom usage, and partner HIV treatment status, to calculate the relative risk of each permutation of anal sex. The tool shows that receptive anal sex, for example, is about 45 times less risky when using a condom and PrEP compared to using neither of these methods. When the insertive partner is also on antiretroviral therapy, the same sex act becomes 1,116 times less risky than condomless anal intercourse with no PrEP.
As biomedical prevention technologies have become more widely used, such as PrEP and treatment as prevention (TasP), men are now able to select partners based on factors other than HIV status alone. According to Purcell, future research is needed to determine the effectiveness of sorting partners based on whether they are taking PrEP or ART.
The growing number of HIV prevention options, now including condoms, serosorting, PrEP, TasP, and other harm reduction strategies, means that sexual decision-making for gay and bisexual men is increasingly more complicated. Nevertheless, studies like the one described in this article point to a developing corpus of literature that men can use to personalize an HIV prevention plan that best suits their preferences.