Hepatitis C Virus Reinfection Among Men Who Have Sex With Men With HIV in New York City.

BACKGROUND: Hepatitis C virus (HCV) reinfection rates are substantially higher than primary infection rates among men who have sex with men (MSM) with human immunodeficiency virus (HIV) in European cohorts. The behaviors mediating this high rate of transmission among MSM are poorly characterized. METHODS: We performed a prospective cohort study in New York City (NYC) of MSM with HIV who cleared HCV to determine the incidence of and risk factors for HCV reinfection. We assessed the risk behaviors for primary HCV in NYC: receipt of semen in the rectum, and sexualized methamphetamine use, along with route of use. Multivariable analysis was performed with Andersen-Gill extension of the Cox proportional hazards model. RESULTS: From 2000 through 2018, among 304 MSM with HIV who cleared HCV, 42 reinfections occurred over 898 person-years, for an incidence rate of 4.7 per 100 person-years. Assessing 1245 postclearance visits, only receipt of semen into the rectum was associated with reinfection (hazard ratio, 9.7 [95% confidence interval: 3.3-28.3], P < .001); methamphetamine use was not. CONCLUSIONS: The high HCV reinfection rate over almost 2 decades demonstrates that sexual transmission of HCV is not inefficient or unusual and that direct-acting antiviral treatment is not sufficient for HCV elimination among MSM in NYC. The contrasts between both the rates of and risk factors for primary and HCV reinfection suggest that HCV prevalence is highly heterogenous among sexual networks and that sexualized methamphetamine use, rather than mediating transmission, is instead a surrogate marker for the highest HCV prevalence networks. As neither condoms nor treatment have been successful strategies for HCV prevention in NYC, novel interventions are needed to stem this sexually transmitted HCV epidemic.

Changes in Sexual Behaviors with Opposite-Sex Partners and Sexually Transmitted Infection Outcomes Among Females and Males Ages 15-44 Years in the USA: National Survey of Family Growth, 2008-2019.

Rates of reported gonorrhea and chlamydial infections have increased substantially over the past decade in the USA and disparities persist across age and race/ethnicity. We aimed to understand potential changes in sexual behaviors, sexual network attributes, and sexually transmitted infection (STI) screening that may be contributing to these trends. We analyzed data from 29,423 female and 24,605 male respondents ages 15-44 years from the National Survey of Family Growth, 2008-2019. We used survey-weighted linear or logistic regression to evaluate linear temporal trends in sexual behaviors with opposite-sex partners, network attributes, and STI testing, treatment, and diagnosis. Significant declines were observed in condom use at last vaginal sex, mean number of vaginal sex acts, proportion of condom-protected sex acts in the past 4 weeks, and racial/ethnic homophily with current partners among males and females from 2008-2010 through 2017-2019. Among males, mean number of female partners in the past 12 months and concurrency also declined, while the percent reporting ever having sex with another male increased. Past-year testing for chlamydia and any STI increased among females. Research is needed to understand how these changes interact and potentially contribute to increasing reported gonorrhea and chlamydia diagnoses and identify avenues for future intervention.

HIV Transmission Potential and Sex Partner Concurrency: Evidence for Racial Disparities in HIV Risk Among Gay and Bisexual Men (MSM).

We determined whether racial disparities in HIV infection among gay and bisexual men (MSM) may be partially explained by racial differences in the HIV transmission potential (i.e. mixing of people living with HIV and people not living with HIV or of unknown HIV serostatus) and density (i.e. sex partner concurrency) of sexual networks. Data included a behavioral survey, testing for HIV, and an egocentric sexual network survey. Mixed effects logistic regressions were used for hypothesis testing. Black (vs. non-Black) MSM were more likely to not know their partner's HIV serostatus (21.8% vs. 9.6%). Similar proportions reported sex partner concurrency (67.1% vs. 68.0%). In adjusted analyses, among Black MSM, sex partner concurrency significantly increased the odds of an HIV transmission potential partnership (TPP), and this association was not significant among non-Black indexes. The association between an HIV TPP and sex partner concurrency may help explain persistent racial disparities in HIV prevalence.

RESUMEN: Determinamos si las disparidades raciales en infecciones del VIH entre hombres homosexuales y bisexuales (hombres que tienen sexo con hombres) puede ser parcialmente explicado por diferencias raciales en el potencial de transmisión del VIH (es decir, mezcla de personas viviendo con VIH y personas que no viven con VIH o cuyo estado serológico del VIH es desconocido) y densidad (es decir, concurrencia de pareja sexual) de redes sexuales. Los datos incluyeron una encuesta de comportamiento, pruebas para el VIH y una encuesta de redes sexuales egocéntrica. Regresiones logísticas de efectos mixtos fueron usados para la prueba de hipótesis. HSH negros (vs. HSH no-negros) eran más propensos a no saber el estado serológico del VIH de su pareja (21.8% vs. 9.6%). Proporciones similares reportaron concurrencia de pareja sexual (67.1% vs. 68.0%). En análisis ajustados, entre HSH negros, la concurrencia de pareja sexual aumentó significativamente las probabilidades de una asociación potencial de transmisión del VIH (TPP por sus siglas en inglés), y esta asociación no fue significativa entre índices de no-negros. La asociación entre una TPP VIH y concurrencia de pareja sexual puede ayudar a explicar disparidades raciales persistentes en la prevalencia del VIH.

Sexual network and condom use among male migrants in the context of China's gender imbalance.

In the context of China's gender imbalance, this study addresses the characteristics of sexual networks and their association with condom use in a sample of 713 male migrants (aged 28-64) who have rural hukou (household registration) in China. Descriptive statistics, univariate analyses, and multilevel random intercept models were used to investigate the characteristics of sexual networks and their associations with condom use. We found that age, marital status, type of sex partners, support (the main help given to each sex partner by the participant), type of sexual intercourse, and stability of sexual relationships were associated with condom use. The sexual networks were mainly composed of sex partners of similar age (58.46%), unmarried people (50.53%), and regular partners (49.38%). Married male migrants were more likely to use condoms with casual partners; unmarried male migrants were less likely to use condoms in emotional and stable relationships. Variation in individual factors, sex partners, and sexual relationship characteristics contribute to participation in condomless sex by male migrants. HIV prevention strategies should target unmarried male migrants and their casual sex partners by increasing their awareness of the risk of HIV transmission and the availability of free condoms.

Exploring HIV risk behavior and sexual/gender identities among transgender women and their sexual partners in Peru using respondent-driven sampling.

HIV prevalence is high among transgender women, but little is known about cisgender men who have sex with transgender women (MSTW). The objective of this study was to investigate characteristics and behavior of MSTW compared to transgender women and men who have sex with men (MSM) using a modified respondent-driven sampling design. Seed participants completed a survey and invited up to three sex partners. Forward recruitment continued in waves through the referral of sex partners. Cross-sectional data were assessed using mixed effects models. From February to July 2018, 479 participants in Lima, Peru enrolled (n = 199 transgender women, n = 196 MSTW, and n = 45 MSM). MSTW behavior and identity differed significantly from that of transgender women and MSM. MSTW primarily identified as bisexual (69%) or heterosexual (15%) and only 6% reported male partners. Insertive condomless anal intercourse was reported by 61% of MSTW; 46% did not know their HIV serostatus. Compared to MSTW without male partners, those with recent male partners were more likely to sell sex (OR 15.7, 95% CI 4.1-60.5), and report condomless receptive anal intercourse (OR 89.0, 95% CI 19.1-414.8). This evidence suggests that MSTW are a distinct population from MSM, and highlights the critical need to include MSTW in HIV research and interventions.

Integrated molecular and affiliation network analysis: Core-periphery social clustering is associated with HIV transmission patterns.

This study investigates the two-mode core-periphery structures of venue affiliation networks of younger Black men who have sex with men (YBMSM). We examined the association between these structures and HIV phylogenetic clusters, defined as members who share highly similar HIV strains that are regarded as a proxy for sexual affiliation networks. Using data from 114 YBMSM who are living with HIV in two large U.S. cities, we found that HIV phylogenetic clustering patterns were associated with social clustering patterns whose members share affiliation with core venues that overlap with those of YBMSM. Distinct HIV transmission patterns were found in each city, a finding that can help to inform tailored venue-based and network intervention strategies.

Projected HIV and Bacterial Sexually Transmitted Infection Incidence Following COVID-19-Related Sexual Distancing and Clinical Service Interruption.

BACKGROUND: The global COVID-19 pandemic has the potential to indirectly impact transmission dynamics and prevention of HIV and other sexually transmitted infections (STI). It is unknown what combined impact reductions in sexual activity and interruptions in HIV/STI services will have on HIV/STI epidemic trajectories. METHODS: We adapted a model of HIV, gonorrhea, and chlamydia for a population of approximately 103 000 men who have sex with men (MSM) in the Atlanta area. Model scenarios varied the timing, overlap, and relative extent of COVID-19-related sexual distancing and service interruption within 4 service categories (HIV screening, preexposure prophylaxis, antiretroviral therapy, and STI treatment). RESULTS: A 50% relative decrease in sexual partnerships and interruption of all clinical services, both lasting 18 months, would generally offset each other for HIV (total 5-year population impact for Atlanta MSM, -227 cases), but have net protective effect for STIs (-23 800 cases). If distancing lasted only 3 months but service interruption lasted 18 months, the total 5-year population impact would be an additional 890 HIV cases and 57 500 STI cases. CONCLUSIONS: Immediate action to limit the impact of service interruptions is needed to address the indirect effects of the global COVID-19 pandemic on the HIV/STI epidemic.

Effects of enhanced STI partner notification counselling and provider-assisted partner services on partner referral and the incidence of STI diagnosis in Cape Town, South Africa: randomised controlled trial.

OBJECTIVES: We investigated the effects of an enhanced partner notification (PN) counselling intervention with the offer of provider-assisted referral among people diagnosed with STI in a Cape Town public clinic. METHODS: Participants were adults diagnosed with STI at a community clinic. After the standard STI consultation, participants were randomly allocated in a 1:1:1 ratio to (1) 'HE': 20 min health education; (2) 'RR': 45 min risk reduction skills counselling; or (3) 'ePN': 45 min enhanced partner notification communication skills counselling and the offer of provider-assisted referral. The primary outcome was the incidence of repeat STI diagnoses during the 12 months after recruitment, and the secondary outcome was participants' reports 2 weeks after diagnosis of notifying recent partners. Incidence rate ratios (IRRs) were used to compare the incidence rates between arms using a Poisson regression model. RESULTS: The sample included 1050 participants, 350 per group, diagnosed with STI between June 2014 and August 2017. We reviewed 1048 (99%) participant records, and identified 136 repeat STI diagnoses in the ePN arm, 138 in the RR arm and 141 in the HE arm. There was no difference in the annual incidence of STI diagnosis between the ePN and HE arms (IRR: 1.0; 95% CI 0.7 to 1.3), or between the RR and HE arms (IRR: 0.9; 95% CI 0.7 to 1.2). There was a greater chance of a partner being notified in the ePN condition compared with the HE condition, 64.3% compared with 53.8%, but no difference between the RR and HE arms. CONCLUSIONS: PN counselling and education with provider-assisted services has the potential to change the behaviour of people diagnosed with STIs, increasing the number of partners they notify by more than 10%. However, these changes in behaviour did not lead to a reduction of repeat STI diagnoses. TRIAL REGISTRATION NUMBER: PACTR201606001682364.

Sexual and social networks, venue attendance, and HIV risk among young men who have sex with men.

OBJECTIVE: This study used a Social network analysis (SNA) approach to describe HIV transmission and venue affiliations among social and sexual networks of young men who have sex with men (YMSM) in Houston, TX. METHODS: A total of 34 YMSM indices aged 18-23 years and 23 of their network members were interviewed about their social and sexual networks and venues at which they met and spent time. RESULTS: Participants reported information on 220 friends (mean age = 25.3 years) and 112 sexual partners (mean age = 26.3 years). Participants spent time with friends and sexual partners at similar venues but relied more heavily on social media and dating applications to meet sexual partners. Participants lived in zip codes consistent with high concentrations of HIV positivity. Popularly frequented clubs/gay bars were often 10-20 miles away, also in zip codes with high densities of seropositivity. CONCLUSION: Both friendship and sexual networks are large, diffuse, and not limited by geography. Participants came from areas with high rates of HIV/AIDS. The venues at which participants recruited sexual partners may present increased opportunities for HIV transmission. HIV prevention interventions should focus on the heightened risk of unknown HIV serostatus.

Ethnically diverse urban transmission networks of Neisseria gonorrhoeae without evidence of HIV serosorting.

OBJECTIVE: We aimed to characterise gonorrhoea transmission patterns in a diverse urban population by linking genomic, epidemiological and antimicrobial susceptibility data. METHODS: Neisseria gonorrhoeae isolates from patients attending sexual health clinics at Barts Health NHS Trust, London, UK, during an 11-month period underwent whole-genome sequencing and antimicrobial susceptibility testing. We combined laboratory and patient data to investigate the transmission network structure. RESULTS: One hundred and fifty-eight isolates from 158 patients were available with associated descriptive data. One hundred and twenty-nine (82%) patients identified as male and 25 (16%) as female; four (3%) records lacked gender information. Self-described ethnicities were: 51 (32%) English/Welsh/Scottish; 33 (21%) white, other; 23 (15%) black British/black African/black, other; 12 (8%) Caribbean; 9 (6%) South Asian; 6 (4%) mixed ethnicity; and 10 (6%) other; data were missing for 14 (9%). Self-reported sexual orientations were 82 (52%) men who have sex with men (MSM); 49 (31%) heterosexual; 2 (1%) bisexual; data were missing for 25 individuals. Twenty-two (14%) patients were HIV positive. Whole-genome sequence data were generated for 151 isolates, which linked 75 (50%) patients to at least one other case. Using sequencing data, we found no evidence of transmission networks related to specific ethnic groups (p=0.64) or of HIV serosorting (p=0.35). Of 82 MSM/bisexual patients with sequencing data, 45 (55%) belonged to clusters of ≥2 cases, compared with 16/44 (36%) heterosexuals with sequencing data (p=0.06). CONCLUSION: We demonstrate links between 50% of patients in transmission networks using a relatively small sample in a large cosmopolitan city. We found no evidence of HIV serosorting. Our results do not support assortative selectivity as an explanation for differences in gonorrhoea incidence between ethnic groups.

Partnership-level correlates of sexual risk taking within the sexual partnerships of young transwomen in San Francisco, California.

OBJECTIVES: Little is known about the sexual networks of young transwomen, leaving a major gap in what we know about transmission dynamics and the elevated rates of HIV in this population. The objective of this study was to understand partnership-level factors associated with condomless anal sex among young transwomen. METHODS: A secondary data analysis of the sexual partnerships of young transwomen was conducted using baseline data from the SHINE study. Generalised estimating equation logistic regressions were used to assess for partnership-level associations between partnership type, age, injection drug use and racial concordance, HIV seroconcordance, sexual role and condomless receptive (CRAI) and insertive anal intercourse (CIAI). RESULTS: Our analysis included 187 young transwomen that reported a total of 464 sexual partnerships where they had at least one episode of anal sex in the past 6 months. We found casual (n=232 or 50%) and commercial partnerships (n=106 or 22.8%) to be significantly associated with a lower odds of CIAI (OR=0.53, 95% CI 0.32 to 0.86 and OR=0.39, 95% CI 0.18 to 0.82) and CRAI (OR=0.30, 95% CI 0.19 to 0.47 and OR=0.35, 95% CI 0.2 to 0.62) compared with main partnerships (n=126 or 27.2%). Additionally, HIV-positive seroconcordant (n=25 or 5.4%, OR=4.05, 95% CI 1.44 to 11.40) and injection-drug using partnerships (n=25 or 5.4%, OR=3.66, 95% CI 1.34 to 9.95) were found to be significantly associated with an increased odds of CIAI among participants compared with HIV-negative seroconcordant (n=330 or 71.1%) and non-using partnerships (n=338 or 72.8%), respectively. CONCLUSION: Young transwomen, like other populations, engage in condomless sex more often with main than casual and commercial partners, suggesting a need for interventions that address sexual practices with steady main partners.

Characterizing Men Who Have Sex with Transgender Women in Lima, Peru: Sexual Behavior and Partnership Profiles.

HIV prevalence is high among transgender women (TW), but how HIV is transmitted to this population is not well understood. This analysis aims to characterize sexual partners of TW (PTW) to understand how their behavior contributes to HIV risk among TW. We examined baseline data from TW, PTW, and men who have sex with men (MSM) from a treatment-as-prevention study in Lima, Peru. Individual and partnership characteristics were compared across groups, and Poisson regression was used to calculate prevalence ratios for associations between sexual concurrency and potential correlates. We found that 81% of PTW had no cisgender male partners. Prevalence of alcohol dependency, concurrency, and condomless anal intercourse was high and HIV testing was low compared to the other groups. Our results suggest that PTW are a distinct population from MSM and TW, engage in behavior associated with HIV transmission, and are likely not well reached by HIV prevention interventions.

A New Era of HIV Risk: It's Not What You Know, It's Who You Know (and How Infectious).

HIV is transmitted in social and sexual relationships, and HIV transmission risks, as well as protective actions, are evolving as HIV epidemics unfold. The current focus of HIV prevention is centered on antiretroviral medications used to reduce HIV infectiousness in persons already infected with HIV [treatment as prevention (TasP)]. The same medications used to treat infected persons can also be used by uninfected persons as pre-exposure prophylaxis (PrEP) to reduce the infectivity of HIV. Both PrEP and TasP are effective when adherence is high and individuals do not have co-occurring sexually transmitted infections. HIV prevention is most effective and efficient when delivered within sexual networks with high HIV prevalence. Specific network characteristics are recognized as important facilitators of HIV transmission; these characteristics include the degree of similarity among network members (homophily), gender role norms, and belief systems. Since 2011, HIV risk has been redefined based on infectiousness and infectivity, ushering in a new era of HIV prevention with the potential to end HIV epidemics.

No Evidence of Bias in Sexual Partnership Corroboration by Race and Ethnicity Among a Diverse Cohort of Young Men Who Have Sex with Men and Transgender Women.

Black men who have sex with men (MSM) continue to experience disproportionately high HIV incidence rates relative to their white peers. Yet, Black MSM do not report higher levels of sexual risk behavior, and contextual factors such as access to care and sexual networks only partially explain these disparities. However, risk misclassification could help explain this paradox, if measurement biases systematically underestimate sexual risk behavior among Black MSM relative to their peers. The current study examined variation in sexual partnership corroboration in the RADAR study, a large and diverse cohort of young MSM and transgender women. Network data were elicited regarding all sexual partners in the prior 6 months, including instances where participants reported other participants as sexual partners. Using these data, anal and condomless anal sex partners were separately examined using a series of exponential random graph models to estimate the rate of corroboration of sexual connections between participants and examine whether this parameter varied by race/ethnicity. For both types of behavior, providing separate estimates for corroboration across race/ethnicity groups reduced model fit and did not significantly vary across groups. Accordingly, we found no evidence of measurement bias by race/ethnicity in the current data. However, overall rates of corroboration (41.2-50.3%) were low, suggesting substantial levels of measurement error. Accordingly, it is vital that researchers continue to improve upon methods to measure risk behavior in order to maximize their validity. We discuss the implications of these findings, including potential alternative causes of risk misclassification (e.g., sampling bias) and future directions to reduce measurement error.

Differential female sociality is linked with the fine-scale structure of sexual interactions in replicate groups of red junglefowl, Gallus gallus.

Recent work indicates that social structure has extensive implications for patterns of sexual selection and sexual conflict. However, little is known about the individual variation in social behaviours linking social structure to sexual interactions. Here, we use network analysis of replicate polygynandrous groups of red junglefowl (Gallus gallus) to show that the association between social structure and sexual interactions is underpinned by differential female sociality. Sexual dynamics are largely explained by a core group of highly social, younger females, which are more fecund and more polyandrous, and thus associated with more intense postcopulatory competition for males. By contrast, less fecund females from older cohorts, which tend to be socially dominant, avoid male sexual attention by clustering together and perching on branches, and preferentially reproduce with dominant males by more exclusively associating and mating with them. Collectively, these results indicate that individual females occupy subtly different social niches and demonstrate that female sociality can be an important factor underpinning the landscape of intrasexual competition and the emergent structure of animal societies.

Sexual network characteristics of men who have sex with men with syphilis and/or gonorrhoea/chlamydia in Lima, Peru: network patterns as roadmaps for STI prevention interventions.

OBJECTIVE: While men who have sex with men (MSM) are disproportionately affected by Peru's overlapping HIV and STI epidemics, there are few data on how partnership-level and network-level factors affect STI transmission in Peru. We explored partnership-level and network-level factors associated with gonorrhoea/chlamydia (Neisseria gonorrhoeae and/or Chlamydia trachomatis (NG/CT)) and/or syphilis infection among MSM in Peru. METHODS: We present the results of a cross-sectional secondary analysis of MSM (n=898) tested for syphilis and NG/CT infection as part of the screening process for two STI control trials in Lima, Peru. Participants completed questionnaires on demographics, sexual identity and role, characteristics of their three most recent sexual partners (partner sexual orientation, gender, role, partnership type, partner-specific sexual acts) and 30-day sexual network characteristics (number of sexual partners, partnership types, frequency of anal/vaginal intercourse). Participants were tested for syphilis and urethral, rectal and oropharyngeal NG/CT. Differences in network characteristics were analysed with χ2 and Kruskal-Wallis tests. RESULTS: Approximately 38.9% of participants had a new STI diagnosis (syphilis (rapid plasma reagin ≥16): 10.6%; NG/CT: 22.9%; syphilis-NG/CT coinfection: 5.4%). Condomless anal intercourse (CAI) was not significantly associated with an STI diagnosis. Gay-identified participants with exclusively homosexual networks had a higher prevalence of STIs (47.4%) than gay-identified MSM with only heterosexual/bisexual partners (34.6%, p=0.04), despite reporting fewer sexual partners (any partners: 2, 1-4 vs 3, 2-6; p=0.001; casual partners: 1, 0-3 vs 2, 1-4; p=0.001) and more stable partnerships (1, 0-1 vs 0, 0-1; p=0.003) in the last month. CONCLUSIONS: Network size and the number of casual sexual partners were associated with NG/CT infection among MSM in Peru. Despite reporting fewer sexual risk behaviours (smaller network size, more stable partnerships, less CAI), MSM with homosexual-only sexual networks had a higher prevalence of NG/CT and syphilis. These findings suggest network composition among MSM in Peru plays an important role in the risk for STI acquisition.

Use of gay app and the associated HIV/syphilis risk among non-commercial men who have sex with men in Shenzhen, China: a serial cross-sectional study.

OBJECTIVES: Geosocial networking application specific to men who have sex with men (MSM) (gay app) has revolutionised the social networking of MSM globally, much concern was raised over its linkage to HIV/syphilis risk. This study sought to examine the association between use of gay app and sexual behaviours and HIV/syphilis risk among Chinese MSM. METHODS: Eligible MSM were recruited through combined offline methods from 2015 to 2017 in Shenzhen, China, with data collected including demographics, sexual behaviours, app use, recreational drug use and HIV testing. All participants are required to sign a written informed consent and take a confidential HIV and syphilis testing. RESULTS: The prevalence of app use among non-commercial MSM (NcMSM) has rapidly increased from 12.5% in 2015 to 52.6% in 2017. The primary four apps used were Blued (97.2%), Aloha (18.4%), Jack'd (14.1) and Zank (14.1%). After controlling for confounders, HIV prevalence was still significantly lower among app users than non-app users (adjusted odds ratios [AOR]: 0.77, 95% CI 0.61 to 0.97), yet the lower prevalence of syphilis was not significant (AOR: 0.97, 95% CI 0.76 to 1.23). App-using NcMSM were more likely to be younger, unmarried, self-identified as homosexuality and having higher education level and income than non-app-using NcMSM. App-using NcMSM had higher rate of consistent condom use and HIV testing, higher level of knowledge on HIV/AIDS prevention and condom use; however, they were more likely to have multiple sexual partners, practice receptive role in anal sex and use recreational drug. CONCLUSIONS: App-using NcMSM are more likely to have sexual risk behaviours as well as risk-reduction behaviours such as consistent condom use and HIV testing. Scaled-up and innovative venue-based HIV interventions are warranted for these high-risk MSM frequent social venues with less condom use and fewer HIV tests. Meanwhile, gay app should alternatively serve as an intervention and education platform for the MSM hard-to-reach via venue-based approaches.

Intersectional Identities and HIV: Race and Ethnicity Drive Patterns of Sexual Mixing.

Large disparities exist in HIV across racial and ethnic populations-with Black and Latino populations disproportionately affected. This study utilizes a large cohort of young men who have sex with men (YMSM) to examine how race and ethnicity drive sexual partner selection, and how those with intersecting identities (Latinos who identify as White or Black) differ from Latinos without a specific racial identification (Latinos who identify as "Other"). Data come from YMSM (N = 895) who reported on sexual partners (N = 3244). Sexual mixing patterns differed substantially by race and ethnicity. Latinos who self-identified as "Black" reported mainly Black partners, those who self-identified as "White" predominantly partnered with Whites, while those who self-identified as "Other" mainly partnered with Latinos. Results suggested that Black-Latino YMSM are an important population for prevention, as their HIV prevalence neared that of Black YMSM, and their patterns of sexual partnership suggested that they may bridge Black YMSM and Other-Latino YMSM populations.

Network Properties Among Gay, Bisexual and Other Men Who Have Sex with Men Vary by Race.

The HIV burden among gay, bisexual, and other men who have sex with men (GBM) may be related to variations in network characteristics of the individual's social and sexual network. This study investigates variations in network properties among 188 Black and 295 White GBM recruited in New Orleans during the National HIV Behavioral Surveillance in 2014. Participants described up to five people who provided social support and five sex partners in the past 3 months. Network properties and network dissimilarity indicators were aggregated to the participant level as means or proportions and examined using PROC GLM. White participants reported larger networks (p = 0.0027), had known network members longer (p = 0.0033), and reported more substance use (p < 0.0001) within networks. Black participants reported networks with fewer men (p = 0.0056) and younger members (p = 0.0110) than those of White GBM. Network properties among GBM differ by race in New Orleans which may inform prevention interventions.

Role of Social and Sexual Network Factors in PrEP Utilization Among YMSM and Transgender Women in Chicago.

Despite demonstrated efficacy, uptake of HIV pre-exposure prophylaxis (PrEP) remains low, particularly among high-risk demographics such as transgender women, Black men who have sex with men (BMSM), and young MSM (YMSM). Research thus far has largely focused on individual factors that may impede PrEP uptake in these demographics, leaving social network factors relatively unexplored. The present study used data collected from participants within RADAR, a longitudinal cohort study in Chicago focused on understanding the individual, dyadic, network, social, and biologic factors associated with HIV infection within YMSM. Of the 906 study participants who did not report an HIV diagnosis at baseline, 7.0% reported using PrEP in the prior 6 months. Recent PrEP use was associated with both individual-level (age and gender) and network-level factors (mean relationship strength, sexual network degree, etc.). These findings highlight the need to expand beyond focusing on individual-level drivers of PrEP uptake, as well as changing our understanding of who is most important within a network (centrality vs. strength of weak ties). Future work is needed to determine whether variables associated with PrEP uptake are similarly connected to PrEP adherence.