Quantifying the Harms and Benefits from Serosorting Among HIV-Negative Gay and Bisexual Men: A Systematic Review and Meta-analysis.

We conducted a systematic review and meta-analysis of the association between serosorting and HIV infection among HIV-negative men who have sex with men (MSM). Compared to no condomless anal sex (i.e., consistent condom use or no anal sex), serosorting was associated with increased HIV risk (RR = 1.64, 95% CI 1.37-1.96). Compared to condomless discordant anal sex, serosorting was associated with reduced HIV risk (RR = 0.46, 95% CI 0.33-0.65). Serosorting may be an important harm reduction strategy when condoms are not consistently used, but can be harmful if HIV-negative MSM who consistently use condoms shift to using serosorting as their primary prevention strategy. The protective effects of serosorting and ways in which MSM are operationalizing serosorting are becoming more complex as additional factors affecting risk are considered (e.g., durable viral load suppression, PrEP). Understanding the potential risk and benefit of serosorting continues to be important, particularly within the context of other prevention strategies.