Background: Serosorting is the practice of choosing sex partners or selectively using condoms based on a sex partner's perceived HIV status. The extent to which serosorting protects African American (AA) and Hispanic men who have sex with men (MSM) is unknown.
Methods: We analyzed data collected from MSM sexually transmitted diseases clinic patients in Seattle, WA, 2001-2010. Men were asked about the HIV status of their anal sex partners in the prior year and about their condom use with partners by partner HIV status. We defined serosorters as MSM who had unprotected anal intercourse (UAI) only with partners of the same HIV status, and compared the risk of testing HIV positive among serosorters and men who reported having UAI with partners of opposite or unknown HIV status (ie, nonconcordant UAI). We used generalized estimating equations to evaluate the association of serosorting with testing HIV positive.
Results: A total of 6694 MSM without a prior HIV diagnosis were tested during 13,657 visits; 274 men tested HIV positive. Serosorting was associated with a lower risk of testing HIV positive than nonconcordant UAI among white MSM (2.1 vs. 4.5%, odds ratio [OR]: 0.45, 95% confidence interval [CI]: 0.34-0.61), but not AA MSM (6.8 vs. 6.0%, OR: 1.1, 95% CI: 0.57-2.2). Among Hispanics, the risk of testing HIV positive was lower among serosorters than men engaging in nonconcordant UAI, though this was not significant (4.1 vs. 6.0%, OR: 0.67, 95% CI: 0.36-1.2).
Conclusions: In at least some AA MSM populations, serosorting does not seem to be protective against HIV infection.