HIV serosorting as a harm reduction strategy: evidence from Seattle, Washington

Abstract

Objective We sought to estimate how serosorting may affect HIV prevalence and individual risk among MSM in Seattle, Washington, and how the results vary under different assumptions of HIV testing frequency, heterogeneity in sexual behavior, and condom use. Methods We developed a deterministic mathematical model of HIV transmission dynamics. Data from the 2003 random digit dial study of MSM conducted in Seattle, Washington (n = 400) are used to parameterize the model. Results Predicted population-level HIV prevalence as well as an individual’s risk of HIV acquisition decreases when the odds of serosorting are increased in the mathematical model. In our model based on observed levels of serosorting, we predict an HIV prevalence of 16%. In contrast, if serosorting were eliminated in the population, we predict that HIV prevalence would increase to 24.5%. However, our findings depend on rates of condom use, mean anal sex contact rates, and HIV testing in the population. Conclusions Under realistic scenarios of sexual behavior and testing frequency for MSM in the US, serosorting can be an effective harm reduction strategy.

Mathematical models for the study of HIV spread and control amongst men who have sex with men

“…The profound effects of sexual contact rate reductions were confirmed [47,51,58,63,64,79,88,96,97,115,116], and even stronger impacts were reported if the reductions occurred in both infected and at-risk individuals, or earlier in the epidemic [37,39,42]. In terms of unsafe sex, both direct [24,27,32,36,70,116] and indirect effects (increasing prevalence other sexually transmitted infections [33,67,68,111]) on causing more HIV infections have been suggested.…”

“…The positive impact of HIV testing on preventing infection have been clearly illustrated in many studies [24,33,41,48,72,79,112], the total number of infections averted due to HIV testing has been estimated to be dramatically larger than the total number of those have been infected since the epidemic has settled amongst Australian MSM [72]. The epidemiological benefit would be greater if infected individual is tested earlier after infection [36,113].…”

“…Recently, a model that is capable of capturing the evolution of three drug-resistant strains under three types of resistance classes has been developed [20]. Other current developments include investigating the potential effects of new HIV prevention measures such as microbicides [21], chemoprophylaxis [22], circumcision [23], and serosorting [24].…”

Relationship Dynamics and Sexual Risk Reduction Strategies Among Heterosexual Young Adults: A Qualitative Study of Sexually Transmitted Infection Clinic Attendees at an Urban Chicago Health Center

“…[11][12][13][14][15][16][17] While intended to reduce HIV risk, such strategies may fail in practice due to factors such as inaccurate assessment of individual and partner serostatus, infrequent testing, failure to maintain the agreement, and lack of protection against STIs. [18][19][20][21] Shortcomings in assessing partner HIV risk have also been reported among heterosexuals. Research among STI clinic attendees has indicated that patients often misjudge their partners' past and current risk behavior 22 and sexual exclusivity.…”

Racial Differences in the Accuracy of Perceived Partner HIV Status among Men who have Sex with Men (MSM) in Atlanta, Georgia

“…10 Although some researchers have cautioned against serosorting, 11,12 studies and models have indicated that it can be an effective method of reducing HIV transmission compared to having unprotected anal intercourse (UAI) with men of unknown or discordant statuses. 13,14 To make it a viable option for risk reduction, individuals must know their own HIV status, accurately disclose their status, and learn their partner's status before making a decision about which sexual activities to engage in (if any), which role to take (if engaging in anal sex), and whether to use condoms. studies indicate racial differences in its effectiveness in preventing HIV, with serosorting being less protective among black MSM than among white MSM.…”