A serological divide: men who have sex with men's attitudes on HIV risk reduction strategies.

The expanding HIV risk reduction toolkit increases options for men who have sex men (MSM), but increasing options in combination with different preferences may complicate promoting risk reduction. To investigate what strategies MSM prefer, data of 3310 participants in the online survey "Men & Sexuality" (Median age = 37 years, 320 (9.7%) HIV positive) was analysed. Questions assessed attitudes towards HIV risk reduction strategies. Participants had the most positive attitudes regarding PrEP and HIV testing, while withdrawal and strategic positioning were least preferred (all p's < .001). Condoms were seen as acceptable to partners and effective but scored low on sexual pleasure. HIV-positive participants were more negative about condoms and more positive about viral load sorting than HIV-negative participants (F(12,3297) = 5.09, p < .001, [Formula: see text] = .02). Findings highlight a preference for HIV risk reduction strategies (PrEP and HIV testing) that do not diminish sexual pleasure and can be applied independent of sexual partners. A serological divide was apparent: HIV-negative MSM were less negative about condoms than HIV-positive MSM, suggesting that condom promotion remains a viable strategy for HIV-negative MSM. Taken together, results indicate a need for personalized approaches to the promotion of HIV risk reduction strategies, accounting for individual preferences and strategy effectiveness.

Population-Level Sexual Mixing According to HIV Status and Preexposure Prophylaxis Use Among Men Who Have Sex With Men in Montreal, Canada: Implications for HIV Prevention.

Using cross-sectional survey data (Engage, 2017-2018) from 1,137 men who have sex with men, ≥16 years old, in Montreal, we compared observed human immunodeficiency virus (HIV) seroconcordance in previous-6-months' sexual partnerships with what would have been observed by chance if zero individuals serosorted. Of 5 recent partnerships where both individuals were HIV-negative, we compared observed concordance in preexposure prophylaxis (PrEP) use with the counterfactual if zero individuals selected partners based on PrEP use. We estimated the concordance by chance using a balancing-partnerships approach assuming proportionate mixing. HIV-positive respondents had a higher proportion of HIV-positive partners (66.4%, 95% confidence interval (CI): 64.0, 68.6) than by chance (23.9%, 95% CI: 23.1, 24.7). HIV-negative respondents (both on and not on PrEP) had higher proportions of HIV-negative partners (82.9% (95% CI: 81.1, 84.7) and 90.7% (95% CI: 89.6, 91.7), respectively) compared with by chance (76.1%, 95% CI: 75.3, 76.9); however, those on PrEP had a higher proportion of HIV-positive partners than those not on PrEP (17.1% (95% CI: 15.3, 18.9) vs. 9.3% (95% CI: 8.3, 10.4). Those on PrEP also had a higher proportion of partners on PrEP among their HIV-negative partners (50.6%, 95% CI: 42.5, 58.8) than by chance (28.5%, 95% CI: 27.5, 29.4). The relationship between PrEP and sexual-mixing patterns demonstrated by less population-level serosorting among those on PrEP and PrEP-matching warrants consideration during PrEP roll-out.

Estimating the syphilis epidemic among gay, bisexual and other men who have sex with men in Australia following changes in HIV care and prevention.

Background Syphilis control remains a challenge in many high-income countries, including Australia, where diagnoses are concentrated among gay, bisexual men and other men who have sex with men (GBM). The aim of this study is to project the syphilis epidemic among GBM under a range of scenarios. METHODS: A dynamic coinfection model of HIV and syphilis transmission among GBM in Victoria, Australia, was parametrised to test data from clinics in Melbourne and syphilis case notifications in Victoria. Projected outcomes were new syphilis infections between 2018 and 2025 under seven testing and behaviour change scenarios. RESULTS: Among HIV-negative GBM, the model estimated that increasing syphilis testing coverage (69% - 75%) and frequency (~8-monthly - 6-monthly) could prevent 5% and 13% of syphilis cases respectively between 2018 and 2025 compared to the status quo. Among HIV-positive GBM, less syphilis testing due to changes in HIV care increased syphilis cases by 29% between 2018 and 2025 compared to the status quo. Under a scenario of 20% HIV pre-exposure prophylaxis (PrEP) coverage among HIV-negative GBM (and associated increased serodiscordant sex, reduced condom use and increased syphilis testing), syphilis cases were estimated to decrease by 6% among HIV-negative GBM and by 3% among HIV-positive GBM compared to the status quo, driven by increased testing among PrEP users. CONCLUSION: The present study findings support syphilis control policies focusing on increased testing among GBM. Current Australian PrEP guidelines of quarterly syphilis testing are likely to negate any increases in syphilis due to risk compensation occurring with PrEP scale-up.

Prevalence of and Factors Associated with the Use of HIV Serosorting and Other Biomedical Prevention Strategies Among Men Who Have Sex with Men in a US Nationwide Survey.

PrEP and treatment-as-prevention (TasP) are biomedical strategies to reduce HIV transmission. Some men who have sex with men (MSM) are combining biomedical strategies with HIV serosorting-termed "biomed matching" when both partners are either on PrEP or TasP, or "biomed sorting" when one partner is using PrEP and the other TasP. Nevertheless, there is limited data on the extent of biomed matching/sorting in large geographically diverse samples. In 2016-2017, 5021 MSM from across the US were surveyed about their HIV status and HIV viral load/PrEP use, as well as that of their recent casual male partners. For each participant, we calculated the proportion of his partners who were (1) HIV-positive and undetectable, (2) HIV-positive and detectable/unknown, (3) HIV unknown/undiscussed, (4) HIV-negative on PrEP, (5) HIV-negative, not on PrEP. In total, 66.6% (n = 3346) of participants were HIV-negative and not on PrEP, 11.9% (n = 599) on PrEP, 14.1% (n = 707) HIV-positive and undetectable, 1.1% (n = 55) HIV-positive and viral load detectable/unknown, and 6.2% (n = 313) HIV unsure/unknown. A participant's own HIV and PrEP status/was significantly associated with that of his partners (all p < 0.001), evincing evidence of both serosorting and biomed matching. Among men on PrEP and those who were HIV-undetectable, there was also some evidence to suggest these participants dually engaged in biomed matching as well as biomed sorting. We found evidence of biomed matching and sorting, which may compound its effectiveness for those using it (i.e., both partners bring biomedical protection). Unintended consequences of biomed matching/sorting include that men not using a biomedical strategy may be less likely to benefit from a partner's use of the strategy-potentially further driving disparities in HIV infections. Public health campaigns might be well served to highlight not only the benefits that biomedical HIV prevention strategies provide for their users (e.g., "being on PrEP protects me from getting HIV"), but also the benefits that a user brings to his partners (e.g., "my use of PrEP means my partners won't get HIV"), and the benefits of being with a partner who is using a biomedical strategy (e.g., "my partner's use of PrEP/TasP protects me from HIV").

A Single Question to Examine the Prevalence and Protective Effect of Seroadaptive Strategies Among Men Who Have Sex With Men.

BACKGROUND: Seroadaptive behaviors among men who have sex with men (MSM) are common, but ascertaining behavioral information is challenging in clinical settings. To address this, we developed a single seroadaptive behavior question. METHODS: Men who have sex with men 18 years or older attending a sexually transmitted disease clinic in Seattle, WA, from 2013 to 2015, were eligible for this cross-sectional study. Respondents completed a comprehensive seroadaptive behavior questionnaire which included a single question that asked HIV-negative MSM to indicate which of 12 strategies they used in the past year to reduce their HIV risk. HIV testing was performed per routine clinical care. We used the κ statistic to examine agreement between the comprehensive questionnaire and the single question. RESULTS: We enrolled HIV-negative MSM at 3341 (55%) of 6105 eligible visits. The agreement between the full questionnaire and single question for 5 behaviors was fair to moderate (κ values of 0.34-0.59). From the single question, the most commonly reported behaviors were as follows: avoiding sex with HIV-positive (66%) or unknown-status (52%) men and using condoms with unknown-status partners (53%); 8% of men reported no seroadaptive behavior. Men tested newly HIV positive at 38 (1.4%) of 2741 visits. HIV test positivity for the most commonly reported behaviors ranged from 0.8% to 1.3%. Men reporting no seroadaptive strategy had a significantly higher HIV test positivity (3.5%) compared with men who reported at least 1 strategy (1.3%; P = 0.02). CONCLUSIONS: The single question performed relatively well against a comprehensive seroadaptive behaviors assessment and may be useful in clinical settings to identify men at greatest risk for HIV.

Distribution of Behavioral Patterns Before Infection Among San Francisco Men Who Have Sex With Men Newly Infected With HIV in 2014.

BACKGROUND: Despite continued reductions in the number of HIV cases reported among San Francisco men who have sex with men (MSM) and the HIV-prevention potential offered by pharmaceutical tools such as pre-exposure prophylaxis (PrEP), there are uncertainties, particularly given reported decreases in consistent condom use. A key uncertainty is what groups of MSM should be targeted. This study estimates the distribution of behavioral patterns before infection among San Francisco MSM newly infected with HIV in 2014. METHODS: We used a novel modeling approach. The approach uses estimates from the National HIV Behavioral Surveillance System for MSM, the Medical Monitoring Project, 2 trials of PrEP, and a meta-analysis of per-act risks of HIV infection. RESULTS: The modeling study suggests that 76% of newly HIV-infected MSM in 2014 were individuals with no discernible strategy in the 6 months before infection: that is, they had condomless receptive anal intercourse with one or more partners not perceived to be HIV uninfected. An estimated 7% of newly infected MSM were serosorters before infection. CONCLUSIONS: Prevention efforts in San Francisco must reach HIV-uninfected MSM with no discernible behavioral strategy, a group that constitutes 8% of HIV-uninfected MSM in the city. Our study suggests that if all HIV-uninfected, San Francisco MSM with no discernible strategy had been on PrEP in 2014, there would have been 70% fewer HIV infections among San Francisco MSM. Uncertainty analysis suggests that PrEP's impact may be maximized by encouraging PrEP persistence and concomitant reductions in sexual risk behaviors.

Operationalizing the Measurement of Seroadaptive Behaviors: A Comparison of Reported Sexual Behaviors and Purposely-Adopted Behaviors Among Men who have Sex with Men (MSM) in Seattle.

Seroadaptive behaviors are traditionally defined by self-reported sexual behavior history, regardless of whether they reflect purposely-adopted risk-mitigation strategies. Among MSM attending an STD clinic in Seattle, Washington 2013-2015 (N = 3751 visits), we used two seroadaptive behavior measures: (1) sexual behavior history reported via clinical computer-assisted self-interview (CASI) (behavioral definition); (2) purposely-adopted risk-reduction behaviors reported via research CASI (purposely-adopted definition). Pure serosorting (i.e. only HIV-concordant partners) was the most common behavior, reported (behavioral and purposely-adopted definition) by HIV-negative respondents at 43% and 60% of visits, respectively (kappa = 0.24; fair agreement) and by HIV-positive MSM at 30 and 34% (kappa = 0.25; fair agreement). Agreement of the two definitions was highest for consistent condom use [HIV-negative men (kappa = 0.72), HIV-positive men (kappa = 0.57)]. Overall HIV test positivity was 1.4 but 0.9% for pure serosorters. The two methods of operationalizing behaviors result in different estimates, thus the choice of which to employ should depend on the motivation for ascertaining behavioral information.

Serosorting and recreational drug use are risk factors for diagnosis of genital infection with chlamydia and gonorrhoea among HIV-positive men who have sex with men: results from a clinical cohort in Ontario, Canada.

OBJECTIVES: Rates of chlamydia and gonorrhoea have been rising in urban centres in Canada, particularly among HIV-positive men who have sex with men (MSM). Our objective was to identify behavioural risk factors for diagnosis with chlamydia and gonorrhoea in this population, with a focus on the HIV status of sexual partners. METHODS: The OHTN Cohort Study follows people in HIV care across Ontario. We restricted the analysis to 1997 MSM who completed questionnaires in 2010-2013 at one of seven clinics that submit all chlamydia and gonorrhoea tests to the provincial public health laboratory; we obtained test results via record linkage. We estimated cumulative incidences using Kaplan-Meier methods and identified risk factors for diagnosis of a composite outcome (chlamydia or gonorrhoea infection) using Cox regression. RESULTS: At follow-up, there were 74 new chlamydia/gonorrhoea diagnoses with a 12-month cumulative incidence of 1.7% (95% CI 1.1% to 2.2%). Risk factors for chlamydia/gonorrhoea diagnosis were: 5+ HIV-positive partners (HR=3.3, 95% CI 1.4 to 7.8; reference=none) and recreational drug use (HR=2.2, 95% CI 1.2 to 3.9). CONCLUSIONS: Heightened risks with recreational drug use and multiple HIV-positive partners suggest that chlamydia/gonorrhoea may have achieved high prevalence in certain sexual networks among HIV-positive MSM. Interventions to promote safer sex and timely testing among MSM are needed.

Trends in Serosorting and the Association With HIV/STI Risk Over Time Among Men Who Have Sex With Men.

BACKGROUND: Serosorting among men who have sex with men (MSM) is common, but recent data to describe trends in serosorting are limited. How serosorting affects population-level trends in HIV and other sexually transmitted infection (STI) risk is largely unknown. METHODS: We collected data as part of routine care from MSM attending a sexually transmitted disease clinic (2002-2013) and a community-based HIV/sexually transmitted disease testing center (2004-2013) in Seattle, WA. MSM were asked about condom use with HIV-positive, HIV-negative, and unknown-status partners in the prior 12 months. We classified behaviors into 4 mutually exclusive categories: no anal intercourse (AI); consistent condom use (always used condoms for AI); serosorting [condom-less anal intercourse (CAI) only with HIV-concordant partners]; and nonconcordant CAI (CAI with HIV-discordant/unknown-status partners; NCCAI). RESULTS: Behavioral data were complete for 49,912 clinic visits. Serosorting increased significantly among both HIV-positive and HIV-negative men over the study period. This increase in serosorting was concurrent with a decrease in NCCAI among HIV-negative MSM, but a decrease in consistent condom use among HIV-positive MSM. Adjusting for time since last negative HIV test, the risk of testing HIV positive during the study period decreased among MSM who reported NCCAI (7.1%-2.8%; P= 0.02), serosorting (2.4%-1.3%; P = 0.17), and no CAI (1.5%-0.7%; P = 0.01). Serosorting was associated with a 47% lower risk of testing HIV positive compared with NCCAI (adjusted prevalence ratio = 0.53; 95% confidence interval: 0.45 to 0.62). CONCLUSIONS: Between 2002 and 2013, serosorting increased and NCCAI decreased among Seattle MSM. These changes paralleled a decline in HIV test positivity among MSM.

Seeking sex partners through the internet and mobile phone applications among men who have sex with men in Taiwan.

It has become popular for men who have sex with men (MSM) to use mobile-phone geosocial networking applications (mobile apps) to find sex partners. A cross-sectional online survey was conducted in Taiwan to compare the sexual and substance-use behaviors of MSM seeking sex partners through the internet and mobile apps. Of the 1060 participants, 65.8% used the internet via computer and 37.7% used a mobile app to find sexual partners, while 30.3% used recreational drugs or alcohol in the previous 6 months. MSM who exclusively used mobile apps to seek sex partners were significantly more likely than MSM seeking sex via computer to be older, to have used recreational drugs or alcohol, and to have sex with HIV-positive partners. Additionally, using mobile apps to seek sex partners was significantly associated with having sex with online partners through either mobile apps or computer-based internet use (adjusted odds ratio (AOR), 7.12 [3.87-13.11]), self-reporting as HIV-positive (AOR, 2.24 [1.12-4.12]), using recreational drugs (AOR, 1.67 [1.21-2.32]), having disclosed HIV status to sexual partners (AOR, 1.44 [1.03-2.02]), and having sex with HIV-positive partners (AOR, 1.81 [1.06-3.10]). In conclusion, the mobile apps may serve as a feasible platform for HIV-positive MSM to find other HIV-positive partners.

Seroadaptive Behaviors of Men Who Have Sex with Men in Myanmar.

Serosorting (i.e., choosing partners of the same HIV serostatus to reduce the risk of transmission with unprotected sex) and other forms of seroadaptation (i.e., engaging in diverse behaviors according to a hierarchy of risk by type of sex and partner serostatus) are phenomena widely described for men who have sex with men (MSM) in the developed world. We assessed seroadaptive behaviors among MSM surveyed in Yangon, Myanmar in 2013-2014. Among HIV-negative MSM, 43.1 % engaged in some form seroadaptation including serosorting (21.8 %), using condoms with potentially serodiscordant anal sex (19.3 %), and seropositioning (1.7 %). Among HIV-positive MSM, 3.5 % engaged in serosorting, 36.0 % in using condoms with potentially serodiscordant anal sex, 7.0 % in seropositioning, and 46.5 % in any form of seroadaptation. For HIV-negative and HIV-positive MSM, seroadaptation was more common than consistent condom use (38.0 and 26.7 %, respectively). MSM in Myanmar are engaging in seroadaptive behaviors in magnitude and ways similar to MSM in industrialized countries.

Prevalence, correlates and trends in seroadaptive behaviours among men who have sex with men from serial cross-sectional surveillance in San Francisco, 2004-2011.

OBJECTIVES: We sought to assess the prevalence and correlates of seroadaptive behaviours (i.e., sexual history incorporating some unprotected anal intercourse (UAI)) and conventional risk reduction behaviours (i.e., consistent condom use or no anal intercourse) among men who have sex with men (MSM) in San Francisco in 2011. We compared the prevalence of seroadaptive behaviours between serial cross-sectional surveys from 2004, 2008 and 2011. METHODS: We analysed data from the 2011 wave of the National HIV Behavioral Surveillance system in San Francisco. We categorised men's self-reported sexual behaviour history in the past 6 months into a schema of seroadaptive behaviours and conventional risk reduction behaviours. We compared the prevalence of behaviour categories by self-reported HIV serostatus, HIV testing history, awareness of pre-exposure HIV prophylaxis (PrEP) and diagnosis of a sexually transmitted infection (STI). RESULTS: Seroadaptive behaviours remained common in San Francisco MSM, with a 2011 prevalence of 46.6%, up from 35.9% in 2004. Consistent condom use or no anal intercourse was more common than seroadaptive behaviours in HIV-negative MSM, men who had not heard of PrEP and men without an STI diagnosis. Seroadaptive behaviours increased from 2004 to 2011. CONCLUSIONS: HIV seroadaptive behaviours remain common in San Francisco MSM, have increased in the last decade and are practiced differently by MSM with different sexual health knowledge and outcomes. Public health researchers and officials should continue to document the prevalence, intentionality, efficacy and safety of seroadaptive behaviours among diverse communities of MSM.

The role of intent in serosorting behaviors among men who have sex with men sexual partnerships.

BACKGROUND: Serosorting is increasingly assessed in studies of men who have sex with men (MSM). Most research studies have measured serosorting by combining reported unprotected anal intercourse (UAI) and the occurrence of participant and partner same HIV status (seroconcordance). The Centers for Disease Control and Prevention's definition of serosorting also incorporates intent to be in such a partnership, although few studies incorporate both intent and behavior into their measures. METHODS: Using data from a national, online survey of 3519 US MSM, we assessed the role of intention in seroconcordant partnerships, as measured by participant rating of the importance of shared serostatus when selecting a sex partner. RESULTS: For HIV+ men, 30% partnerships were seroconcordant; of these, 48% reported intent to be in such a partnership (intentional seroconcordance). For HIV- men, 64% partnerships were seroconcordant; of these, 80% reported intentional seroconcordance. Intentional seroconcordance was associated with UAI for HIV+ partnerships [odds ratio (OR): 1.9; 95% confidence interval (CI): 1.3 to 2.9] but not significant for HIV- partnerships (OR: 1.1; CI: 0.99 to 1.3). In separate models where intent was not considered, seroconcordance was associated with UAI for HIV+ partnerships (OR: 3.2; 95% CI: 2.2 to 4.6) and for HIV- partnerships (OR: 1.2; 95% CI: 1.0 to 1.3; P = 0.03). CONCLUSIONS: Regardless of intentionality, seroconcordance was strongly associated with UAI for HIV+ men and weakly associated with UAI for HIV- men. Intentional seroconcordance was not associated with UAI more strongly than was seroconcordance in absence of consideration of intent. Intentionality may not be a critical element of the relationship between seroconcordance and UAI.

HIV-negative and HIV-discordant gay male couples' use of HIV risk-reduction strategies: differences by partner type and couples' HIV-status.

Previous research has found that gay men and other men who have sex with men have adopted a variety of HIV risk-reduction strategies to engage in unprotected anal intercourse (UAI). However, whether gay male couples' use these strategies within and out of their relationships remains unknown. The present national cross-sectional study collected dyadic data from an online sample of 275 HIV-negative and 58 discordant gay male couples to assess their use of these strategies, and whether their use of these strategies had differed by partner type and couples' HIV-status. The sample used a variety of risk-reduction strategies for UAI. Some differences and patterns by partner type and couples' HIV-status were detected about men's use of these strategies. Findings indicate the need to bolster HIV prevention and education with gay male couples about their use of these strategies within and outside of their relationships.

High rates of unprotected sex and serosorting among men who have sex with men: a national online study in Norway.

UNLABELLED: Unprotected sexual contact between men remains the predominant means of HIV transmission in men. AIM: To ascertain predictors of unprotected anal intercourse between non-primary partners among a sample of 2096 men who have sex with men in Norway and to characterise the sociosexual profile of men who have sex with men who engage in this behaviour. METHODS: A cross-sectional survey, using an anonymous self-administered questionnaire, was conducted in 2010. RESULTS: Multivariate logistic regression showed that the likelihood of engaging in unprotected anal intercourse with non-primary partners was lower for men over 30 years (OR = 0.60), those with higher education (OR = 0.58), and higher HIV-related knowledge (OR = 0.98). The likelihood of engaging in unprotected anal intercourse with non-primary partners was higher among men who have sex with men reporting that condoms had not been available (OR = 1.58), who had a higher number of non-primary anal intercourse partners (OR = 1.20), and who reported use of party drugs (OR = 2.34). These men were not more likely to test for HIV/sexually transmitted infections, but they were more likely to have been diagnosed with sexually transmitted infections, engage in serosorting, and various other sexual behaviours. CONCLUSIONS: As we enter the fourth decade of the HIV epidemic, the results for Norwegian men who have sex with men underscore the need for a scaling-up of prevention campaigns, highlighting messages and behavioural strategies that encourage safer sex strategies.

Association between serosorting and bacterial sexually transmitted infection among HIV-negative men who have sex with men at an urban lesbian, gay, bisexual, and transgender health center.

BACKGROUND: Serosorting, selecting sex partners of the same HIV status, may be associated with increased risk of sexually transmitted infection (STI). We examined the association between unprotected anal intercourse (UAI) with a seroconcordant partner and STIs among HIV-negative men who have sex with men (MSM) at an urban lesbian, gay, bisexual, and transgender STI clinic. METHODS: Subjects reported how they assessed their most recent sex partner's HIV status. Those who reported getting tested together or asking were classified as known concordant; those who determined their partner's serostatus based on appearance, age, or social aspects were classified as assumed concordant. Generalized estimating equations generated prevalence ratios for associations between seroconcordance and STIs. RESULTS: From May 2010 through October 2011, 961 HIV-negative MSM were screened for gonorrhea, chlamydia, and syphilis at 1110 visits. Sexually transmitted infection prevalence was 20.1%: 20.2% at visits with known seroconcordant UAI, 35.3% at visits with assumed seroconcordant UAI, 29.5% at visits where UAI with an unknown status partner was reported, 34.8% at visits with serodiscordant UAI, and 16.1% at visits with no reported UAI. Assumed serodiscordant UAI (adjusted prevalence ratio [aPR], 2.51; 95% confidence interval [CI], 1.79-3.51), unknown status partner (aPR, 1.76; 95% CI, 1.31-2.38), and serodiscordant UAI (aPR, 2.57; 95% CI, 1.76-3.75) were significant predictors of STI after controlling for age and race/ethnicity, STI history, alcohol use, substance use, and multiple sex partners. Known seroconcordant UAI was not associated with STI. CONCLUSIONS: Assumed seroconcordant UAI was associated with increased STI prevalence, although known seroconcordant UAI was not. The risk associated with UAI with a partner of assumed seroconcordance should be emphasized for HIV-negative MSM.

Risk reduction practices in men who have sex with men in Switzerland: serosorting, strategic positioning, and withdrawal before ejaculation.

The aim of this study was to identify predictors of intentional use of the HIV risk reduction practices of serosorting, strategic positioning, and withdrawal before ejaculation during unprotected anal intercourse (UAI) with casual partners. A cross-sectional survey pertaining to the Swiss HIV behavioral surveillance system, using an anonymous self-administered questionnaire, was conducted in 2007 in a self-selected sample of men having sex with other men (MSM). Analysis was restricted to participants with UAI with casual partner(s) (N = 410). Logistic regression was used to estimate factors associated with intentional use of serosorting, strategic positioning, and withdrawal before ejaculation. In the previous 12 months, 71% of participants reported having UAI with a casual partner of different or unknown HIV-status. Of these, 47% reported practicing withdrawal, 38% serosorting, and 25% strategic positioning. In the 319 participants with known HIV-status, serosorting was associated with frequent Internet use to find partners (OR = 2.32), STI (OR = 2.07), and HIV testing in the past 12 months (OR = 1.81). Strategic positioning was associated with HIV-status (OR = 0.13) and having UAI with a partner of different or unknown HIV-status (OR = 3.57). Withdrawal was more frequently practiced by HIV-negative participants or participants reporting high numbers of sexual partners (OR = 2.48) and having UAI with a partner of unknown or different serostatus (OR = 2.08). Risk reduction practices are widely used by MSM, each practice having its own specificities. Further research is needed to determine the contextual factors surrounding harm reduction practices, particularly the strategic or opportunistic nature of their use.

Is injection serosorting occurring among HIV-positive injection drug users? Comparison by injection partner's HIV status.

Research needs to build evidence for the roles that HIV status of injection partners may or may not play in injection risk behaviors of injection drug users (IDUs). Using baseline data collected from a randomized controlled study (INSPIRE) conducted in four cities (Baltimore, Miami, New York, and San Francisco) from 2001 to 2005, we categorized 759 primarily heterosexual HIV-positive IDUs into four groups based on HIV serostatus of drug injection partners. Thirty-two percent of the sample injected exclusively with HIV-positive partners in the past 3 months and more than 60% had risky injection behavior with these partners. Eight percent injected exclusively with HIV-negative partners and 49% injected with any unknown status partners. The remaining 11% reported having both HIV-positive and -negative injection partners, but no partners of unknown HIV status. Riskier injection behavior was found among the group with mixed status partners. The risk among the group with any unknown status partners appeared to be driven by the greater number of injection partners. No major group differences were observed in socio-demographic and psychosocial factors. Our analysis suggests that serosorting appeared to be occurring among some, but not an overwhelming majority of HIV-positive IDUs, and knowledge of HIV status of all injection partners per se did not appear to be as important as knowledge of sexual partner's HIV status in its association with risk behavior.