Do Sexual Networks of Men Who Have Sex with Men in New York City Differ by Race/Ethnicity?

Recruiting Black Men Who Have Sex With Men (MSM) Couples via Dating Apps: Pilot Study on Challenges and Successes

Background

HIV disproportionately impacts Black men who have sex with men (MSM), and targeting the primary relationship (ie, couples) using mobile technology for health holds promise for HIV prevention. Web-based recruitment of MSM is commonly employed in HIV prevention and intervention research. However, little known about recruiting Black MSM couples on the internet in the United States.

Objective

This study describes the process of recruiting Black MSM couples over social networking and dating apps frequented by MSM. We describe the activities for recruiting, screening, and enrolling participants as part of a randomized trial employing a multipronged recruitment approach.

Methods

Black MSM in couples were recruited via three apps (ie, Jack’d, Adam4Adam, and Growlr) between May 2020 and March 2021 during the COVID-19 pandemic in the United States. Black MSM couples were eligible if one or both partners are Black, MSM, and living with HIV, and if both partners were 18 years or older, and have been together for at least 2 months in what they both consider a primary relationship (ie, one in which both partners reported feeling most committed to over any other partner or relationship).

Results

A total of 10 Black MSM couples (n=20) were enrolled via social networking apps. App recruitment activities were a combination of passive (eg, in-app advertisements) and active (eg, direct messaging of users) engagement. Recruitment approaches varied by the social networking app owing to differences in app features. A full-time recruiter experienced challenges such as bugs (ie, technical errors in computer program or system), navigating technical requirements specific to each app, and web-based harassment.

Conclusions

Despite challenges, it was possible to recruit Black MSM couples virtually into research as part of a multipronged recruitment strategy. We identify tips for using web-based dating and other social networking apps as part of a recruitment strategy in future research with Black MSM couples.

Risk assessment for HIV infection in men who have sex with men and the contribution of sexual partner networks

This study aimed to evaluate the risk of HIV infection in men who have sex with men (MSM) by developing an index that considers sex partner networks. The index variables were age, ethnicity/skin color, schooling, relationship type, condom use in receptive and insertive relationships, self-perception of the possibility of HIV infection, sexually transmitted infections, and rapid HIV testing results. We used data from a cross-sectional MSM egocentric network survey conducted in Rio de Janeiro between 2014 and 2015. The initial research volunteer is called ego, each partner is called alter, and each pair of people in a relationship is called the dyad. Multiple logistic regression was used to define the coefficients of the equations for the elaboration of the indices. The index ranged from 0 to 1; the closer to 1, the higher the risk of HIV infection. HIV prevalence was 13.9% among egos. The mean egos index with an HIV-reactive test was 57% higher than non-reactive, and the same profile was observed in the index values of dyads. The index allowed the incorporation of network data through the dyads and contributed to the identification of individuals with a higher likelihood of acquiring HIV.

A Multidimensional Model of Sexual Empowerment Among Young Black Men Who have Sex with Men: A Latent Profile Analysis

Sexual empowerment is a key strategy in HIV prevention intervention design, yet its measurement has been conceptualized as homogeneous. To date, no studies have examined whether young Black men who have sex with men (YBMSM) exhibit heterogeneity across sexual empowerment. Using baseline data from a randomized controlled trial (N = 275, HIV-negative YBMSM), we classified YBMSM into sexual empowerment profiles based on five indicators using a latent profile analysis and assessed the associations between the sexual empowerment profiles and stigma-related experiences using multinomial logistic regression. Three profiles were identified: psychologically empowered with safer sex intentions (profile 1); psychologically disempowered with safer sex intentions (profile 2); and psychologically disempowered without safer sex intentions (profile 3). YBMSM reporting fewer stigma-related experiences were more likely to be profile 1 than profile 2 and profile 3. To empower YBMSM, interventions based on sexual empowerment profile targeting the psychological/behavioral aspects of empowerment and addressing stigma are needed.

Networks Among Racial and Ethnic Minority Men Who Have Sex With Men in HIV Research in the United States: A Concept Analysis

In the past 10 years, research has proliferated investigating the effects of sexual and social networks on the transmission of HIV, especially among racial/ethnic minority men who have sex with men (MSM). This research, however, has been inconsistent in its application of social network theory leading to variations in the measurement of networks and a lack of clarity in the interpretation of results from studies of network data. Efforts to delineate how networks are defined, measured, and interpreted are needed to advance the science of HIV prevention and promote health equity. The aims of this article are to review the literature around networks among racial/ethnic minority MSM, use concept analysis methods to clarify the definition and scope of the concept of networks, and to develop a network typology that can be used to guide measurement and interpretation of networks for HIV research with racial/ethnic minority MSM.

The Role of Networks in Racial Disparities in HIV Incidence Among Men Who Have Sex with Men in the United States

Network factors have been proposed as potential drivers of racial disparities in HIV among Black and Latino men who have sex with men (MSM). This review aimed to synthesize the extant literature on networks and racial disparities in HIV among MSM and identify potential directions for future research. We searched databases for peer-reviewed articles published between January 1, 2008 and July 1, 2018. Articles were included if the sample was comprised primarily of racial/ethnic minority MSM and measured one or more network characteristics. (n = 25). HIV prevalence in networks, social support, and structural barriers were linked to disparities in HIV for Black MSM. Future research should focus on intervention development around social support and other strategies for risk reduction within networks. Given the contribution of structural factors to racial/ethnic HIV disparities, network-level interventions should be paired with policies that improve access to housing, jobs, and education for MSM.

Network-Level Correlates of Sexual Risk Among Male Sex Workers in the United States: A Dyadic Analysis

BACKGROUND

Male sex workers (MSWs) are at increased risk of HIV infection in the United States. Research is limited on sexual and drug use network characteristics of MSWs.

SETTING

Community-based organization and health center in 2 US Northeast cities.

METHODS

One hundred MSWs completed a behavioral assessment and sexual and drug network inventory. Using dyadic analyses, we assessed whether network characteristics, including sex worker-male client age, race, and HIV status homophily and risk multiplexity (ie, overlap in drug-use and sex networks), were associated with condom use.

RESULTS

MSW participants' mean age was 33.6. Two-thirds identified as Black or Latino, 12% identified as heterosexual, and 90% reported recent drug use. Participants reported an average of 5.3 male clients in the past month (SD = 3.4), and having anal sex with 74% of these clients, at a rate of 2.2 times per month (SD = 4.6). Participants reported inconsistent condom use during anal sex with 53% of clients. In multivariable models, inconsistent condom use was more common in relationships with presumed HIV status homophily [odds ratio (OR): 1.25; 95% confidence interval (CI): 1.07 to 1.46] and sexual and drug network multiplexity (OR: 1.19; 95% CI: 1.09 to 1.30); and less common within relationships where the client is older than the MSW participant (OR: 0.83; 95% CI: 0.74 to 0.93). Number of multiplex relationships was positively associated with number of condomless anal sex acts with male clients (incidence rate ratio: 1.35; 95% CI: 1.19 to 1.54).

CONCLUSIONS

Network characteristics may contribute to disproportionate HIV risk among MSWs. Modeling studies should include network characteristics when simulating HIV transmission, and future HIV interventions should address the role of networks.

Young black MSM's exposures to and discussions about PrEP while navigating geosocial networking apps

Young Black gay, bisexual and other men who have sex with men (YBMSM) carry a disproportionate HIV burden perpetuated by exposure to sexual networks with higher untreated HIV prevalence and incidence. In Baltimore, these sexual networks include high utilization of geosocial networking apps (GSN-apps). Our prior work suggests these apps can be important access points for targeted interventions like PrEP. To inform online PrEP outreach we explored YBMSM GSN-app users' exposure to and discussions about PrEP while navigating apps. We actively recruited YBMSM (n=17) age 18-24 from the GSN-app most frequently reported by newly diagnosed HIV-infected MSM in Baltimore. Participants were recruited through direct messaging within the GSN-app while logged-on in high HIV transmission areas. Participants completed 60-90 minute semi-structured interviews, which were analyzed using a 3-stage analytic coding strategy. While some participants had not heard of PrEP, the majority described mentions or conversations about PrEP on GSN-apps. Three themes emerged: (1) Mistrust of PrEP, (2) Association with sexual promiscuity, and (3) Concerns about lack of protection from other STIs. Proper messaging, accurate information, and education are needed to account for the negative perceptions that surround PrEP; otherwise, continued underuse among YBMSM will expand rather than reduce HIV disparities.

Interaction Patterns of Men Who Have Sex With Men on a Geosocial Networking Mobile App in Seven United States Metropolitan Areas: Observational Study

BACKGROUND

The structure of the sexual networks and partnership characteristics of young black men who have sex with men (MSM) may be contributing to their high risk of contracting HIV in the United States. Assortative mixing, which refers to the tendency of individuals to have partners from one's own group, has been proposed as a potential explanation for disparities.

OBJECTIVE

The objective of this study was to identify the age- and race-related search patterns of users of a diverse geosocial networking mobile app in seven metropolitan areas in the United States to understand the disparities in sexually transmitted infection and HIV risk in MSM communities.

METHODS

Data were collected on user behavior between November 2015 and May 2016. Data pertaining to behavior on the app were collected for men who had searched for partners with at least one search parameter narrowed from defaults or used the app to send at least one private chat message and used the app at least once during the study period. Newman assortativity coefficient (R) was calculated from the study data to understand assortativity patterns of men by race. Pearson correlation coefficient was used to assess assortativity patterns by age. Heat maps were used to visualize the relationship between searcher's and candidate's characteristics by age band, race, or age band and race.

RESULTS

From November 2015 through May 2016, there were 2,989,737 searches in all seven metropolitan areas among 122,417 searchers. Assortativity by age was important for looking at the profiles of candidates with correlation coefficients ranging from 0.284 (Birmingham) to 0.523 (San Francisco). Men tended to look at the profiles of candidates that matched their race in a highly assortative manner with R ranging from 0.310 (Birmingham) to 0.566 (Los Angeles). For the initiation of chats, race appeared to be slightly assortative for some groups with R ranging from 0.023 (Birmingham) to 0.305 (Los Angeles). Asian searchers were most assortative in initiating chats with Asian candidates in Boston, Los Angeles, New York, and San Francisco. In Birmingham and Tampa, searchers from all races tended to initiate chats with black candidates.

CONCLUSIONS

Our results indicate that the age preferences of MSM are relatively consistent across cities, that is, younger MSM are more likely to be chatted with and have their profiles viewed compared with older MSM, but the patterns of racial mixing are more variable. Although some generalizations can be made regarding Web-based behaviors across all cities, city-specific usage patterns and trends should be analyzed to create targeted and localized interventions that may make the most difference in the lives of MSM in these areas.

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.

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.

Couple-Level Dynamics and Multilevel Challenges Among Black Men Who Have Sex with Men: A Framework of Dyadic HIV Care

The primary romantic relationship may offer critical opportunities for improving HIV care among key populations affected by high rates of HIV infection and low rates of care engagement, such as black men who have sex with men. A conceptual framework is needed to identify dyadic processes involved in addressing challenges in retention in care and adherence to antiretroviral therapy. This study conducted dyadic and individual-level qualitative analyses of individual interviews with men living with HIV from 14 black gay couples (n = 28). Interviews explored each partner's perspectives on challenges to and supportive strategies for retention in care and medication adherence. Findings highlighted challenges at various levels of care engagement and patterns of dyadic interactions that impeded or facilitated HIV care. Couple-level processes (i.e., couple's resilience, interdependence) underlined a joint problem-solving approach toward addressing challenges in care engagement. Findings support a conceptual framework of dyadic HIV care that highlights the impacts of dyadic and individual factors on coordination of care and treatment to influence retention and adherence. The generalizability of study findings is limited by the small sample size. Implications for intervention design include leveraging drivers of partner support, including couples' resilience, in enhancing joint problem-solving in HIV care among black gay couples.

Prevalence and mapping of hepatitis C infections among men who have sex with men in New York City

Emerging sexually transmitted hepatitis C virus (HCV) epidemics among men who have sex with men (MSM) have been reported worldwide, with higher HCV infection rates among those who are HIV-infected. This study aims to determine prevalence of recent and chronic HCV infections among community-recruited MSM in New York City (NYC), map HCV infections by home, social, and sexual neighborhoods, and identify clusters of genetically linked HCV variants using phylogenetic analysis. The NYC M2M study recruited MSM via modified time-space, venue-based sampling and internet/mobile app-based recruitment during 2010–13. Participants completed a Google Earth map on neighborhoods of where they lived, socialized, and had sex in the last 3 months, an ACASI questionnaire, and a sexual network inventory about their sex partners. The men received HIV testing and provided serum samples. Testing on stored serum samples included HCV antibody and RNA viral load, HCV antibody avidity assay (avidity index <30% with positive viral load is considered recently infected), and HCV RNA extraction and amplification to generate a 432 base-pair region of Core/E1 for sequencing and phylogenetic analysis. Historic local controls were included in the phylogenetic analysis. Of 1,028 MSM, 79.7% were HIV-negative and 20.3% HIV-positive. Twenty nine MSM (2.8%) were HCV antibody-positive. MSM who were HCV antibody-positive reported a median of 2 male sex partners in last 3 months, with 6.9% aged 18–24, 17.2% 25–29, 13.8% 30–39, and 62.1% 40 and over. 8.1% of HIV-positive MSM were HCV antibody-positive vs. 1.5% of HIV-negative men (p<0.0001). Of 29 HCV-antibody positive MSM, 12 (41%) were HCV RNA-positive (11 subtype 1a and 1 subtype 1b). Two of 12 HCV RNA-positive participants had low antibody avidity values, suggesting recent HCV infection. HCV antibody seropositivity was significantly associated with older age >40 years, adjusted odds ratio (aOR) 3.56 (95% CI 1.57, 8.08), HIV-positive serostatus, aOR 3.18 (95% CI 1.40, 7.22), any sexually transmitted infection (STI) in the last 3 months, aOR 2.81 (95% CI 1.11, 7.13), and injection drug use (IDU) ever, aOR 4.34 (95% CI 1.69, 11.17). Mapping of HCV infections differed slightly by home, social, and sexual neighborhoods. Based on phylogenetic analysis from 12 HCV RNA-positive samples, no evidence of a clustered HCV epidemic was found. Overall HCV seroprevalence was 2.8% among community-recruited MSM in NYC, with higher prevalence among HIV-positive MSM compared to HIV-negative MSM. Only two participants were found to have recent HCV infection, with no evidence of a clustered HCV epidemic based on phylogenetic analysis. Our results support testing of HCV infection among HIV-negative MSM if they report having a recent STI and IDU in the past rather than universal HCV testing in all HIV-negative MSM.

Intimate relationship characteristics as determinants of HIV risk among men who have sex with regular male sex partners: a cross-sectional study in Guangzhou, China

Background

China faces a serious HIV epidemic among men who have sex with men (MSM), and a large proportion of new infections are attributed to their regular male sex partners (RP). The objective of this study was to investigate the association between intimate relationship characteristics and HIV-related behaviors among MSM with RP in Guangzhou, China.

Methods

A convenience-sampling method was used in data collection. A total of 608 MSM were screened, of whom 406 HIV negative MSM with at least one RP in the past six months were used for data analysis. Three-step logistic regressions were used to analyze the data.

Results

The prevalence of unprotected anal intercourse (UAI) with regular male sex partners, non-regular male sex partners, and concurrent UAI in the past six months was 53.9%, 23.6%, 20.7%, respectively. Variables associated with UAI with regular male sex partners included expectations for this relationship (adjusted odds ratio in multiple forward stepwise logistic regression, OR_m = 1.66) and open communication about the sexual relationship (OR_m = 1.79), while expectations for the relationship (OR_m = 0.46 to 0.54) and conflicts of interest (OR_m = 5.46 to 5.97) were associated with concurrent UAI and UAI with non-regular male sex partners.

Conclusion

Intimate relationship characteristics were related to HIV-related risk behaviors. Future HIV prevention interventions should take MSM couples into consideration, include a focus on the quality of their intimate relationships, and encourage open communication about their sexual relationships.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3044-6) contains supplementary material, which is available to authorized users.

Providers' Perceptions of Couples' HIV Testing and Counseling (CHTC): Perspectives From a U.S. HIV Epicenter

Current epidemiology demonstrate the significance of couple-based HIV transmission among vulnerable U.S. populations and its contribution to health disparity in HIV prevalence. Couples HIV testing and counseling (CHTC) can be used to address couple-based HIV risk in the U.S. Though a globally recognized service, the literature lacks U.S.-based healthcare providers' (HCP) perspectives of CHTC. To address this research gap, a qualitative descriptive design was used to ascertain HCPs' perceptions about CHTC. Semi-structured in-depth interviews were conducted with 22 HCPs who were experienced with engaging patients or clients across the HIV care continuum. Overall, HCPs supported CHTC among different U.S.

POPULATIONS

Content and thematic analysis revealed HCPs perceived CHTC to be an evolution from current HIV testing approaches and a mechanism to screen people who may not otherwise. CHTC was perceived to have biomedical and bio-behavioral merit that warranted consideration for implementation within health service settings and among populations with heightened HIV risk. This strategy was perceived to be a mechanism for introducing PrEP and conception health into one's practice. CHTC also signaled patients reorienting perceptions of personal health as being linked to the health of another individual. Providers recognized that couples have evolved to be increasingly non-heteronormative and thought that CHTC should be offered to all couples. However, participants also noted that HCPs in the U.S. need to be comfortable with promoting sexual health among various populations for implementation of CHTC to be successful.

Gay Identity and HIV Risk for Black and Latino Men Who Have Sex with Men

Strong gay identity among white men who have sex with men (MSM) has been associated with decreased HIV risk, but data for black and Latino MSM (BLMSM) are inconclusive. We examined gay identity and HIV risk among BLMSM to inform social and structural HIV intervention strategies. BLMSM were administered a computerized survey as part of an HIV research study during 2011-2012 conducted in New York City. We used a brief scale of Gay Identity Questionnaire. After data analysis, Stage I (not fully accepting) and Stage II (fully accepting) gay identity were determined based on participant responses. We used logistic regression to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the association between gay identity with HIV risk and social determinant factors. Among 111 self-identified BLMSM (median age = 32 years, 68.4% with some college or higher education), 34.2 reported receptive anal sex without condoms in the previous three months. Gay Identity Questionnaire Scale assessment indicated that 22 (19.8%) were Stage I, and 85 (76.6%) were Stage II in this BLMSM sample. Stage II gay identity was more likely seen among BLMSM with high involvement in the gay community (aOR 3.2; CI 1.00, 10.26) and less likely among BLMSM who exchanged sex for food or shelter (aOR 0.15; CI 0.02, 0.98). Fully accepting gay identity may be protective for BLMSM as it relates to transactional sex; these factors warrant further research and consideration as part of HIV prevention strategies.

The Effect of PrEP on HIV Incidence Among Men Who Have Sex With Men in the Context of Condom Use, Treatment as Prevention, and Seroadaptive Practices

BACKGROUND

HIV preexposure prophylaxis (PrEP) is an effective tool in preventing HIV infection among high-risk men who have sex with men (MSM). It is unknown how effective PrEP is in the context of other implemented HIV prevention strategies, including condom use, seroadaption, and treatment as prevention (TasP). We evaluate the impact of increasing uptake of PrEP in conjunction with established prevention strategies on HIV incidence in a high-risk population of MSM through simulation.

METHODS

Agent-based simulation models representing the sexual behavior of high-risk, urban MSM in the United States over the period of 1 year were used to evaluate the effect of PrEP on HIV infection rates. Simulations included data for 10,000 MSM and compared increasing rates of PrEP uptake under 8 prevention paradigms: no additional strategies, TasP, condom use, seroadaptive behavior, and combinations thereof.

RESULTS

We observed a mean of 103.2 infections per 10,000 MSM in the absence of any prevention method. PrEP uptake at 25% without any additional prevention strategies prevented 30.7% of infections. In the absence of PrEP, TasP, condom use, and seroadaptive behavior independently prevented 27.1%, 48.8%, and 37.7% of infections, respectively, and together prevented 72.2%. The addition of PrEP to the 3 aforementioned prevention methods, at 25% uptake, prevented an additional 5.0% of infections.

CONCLUSIONS

To achieve a 25% reduction in HIV infections by 2020, HIV prevention efforts should focus on significantly scaling up access to PrEP in addition to HIV testing, access to antiretroviral therapy, and promoting condom use.

Are Partner Race and Intimate Partner Violence Associated with Incident and Newly Diagnosed HIV Infection in African-American Men Who Have Sex with Men?

Black gay, bisexual, and other men who have sex with men (BMSM) experience a disparate rate of HIV infections among MSM. Previous analyses have determined that STI coinfection and undiagnosed HIV infection partly explain the disparity. However, few studies have analyzed the impact of partner-level variables on HIV incidence among BMSM. Data were analyzed for BMSM who attended the Los Angeles LGBT Center from August 2011 to July 2015 (n = 1974) to identify risk factors for HIV infection. A multivariable logistic regression was used to analyze predictors for HIV prevalence among all individuals at first test (n = 1974; entire sample). A multivariable survival analysis was used to analyze predictors for HIV incidence (n = 936; repeat tester subset). Condomless receptive anal intercourse at last sex, number of sexual partners in the last 30 days, and intimate partner violence (IPV) were significant partner-level predictors of HIV prevalence and incidence. Individuals who reported IPV had 2.39 times higher odds (CI 1.35-4.23) and 3.33 times higher hazard (CI 1.47-7.55) of seroconverting in the prevalence and incidence models, respectively. Reporting Black partners only was associated with increased HIV prevalence, but a statistically significant association was not found with incidence. IPV is an important correlate of both HIV prevalence and incidence in BMSM. Further studies should explore how IPV affects HIV risk trajectories among BMSM. Given that individuals with IPV history may struggle to negotiate safer sex, IPV also warrants consideration as a qualifying criterion among BMSM for pre-exposure prophylaxis (PrEP).

Sources of racial disparities in HIV prevalence in men who have sex with men in Atlanta, GA, USA: a modelling study

BACKGROUND

In the USA, men who have sex men (MSM) are at high risk for HIV, and black MSM have a substantially higher prevalence of infection than white MSM. We created a simulation model to assess the strength of existing hypotheses and data that account for these disparities.

METHODS

We built a dynamic, stochastic, agent-based network model of black and white MSM aged 18-39 years in Atlanta, GA, USA, that incorporated race-specific individual and dyadic-level prevention and risk behaviours, network attributes, and care patterns. We estimated parameters from two Atlanta-based studies in this population (n=1117), supplemented by other published work. We modelled the ability for racial assortativity to generate or sustain disparities in the prevalence of HIV infection, alone or in conjunction with scenarios of observed racial patterns in behavioural, care, and susceptibility parameters.

FINDINGS

Race-assortative mixing alone could not sustain a pre-existing disparity in prevalence of HIV between black and white MSM. Differences in care cascade, stigma-related behaviours, and CCR5 genotype each contributed substantially to the disparity (explaining 10·0%, 12·7%, and 19·1% of the disparity, respectively), but nearly half (44·5%) could not be explained by the factors investigated. A scenario assessing race-specific reporting differences in risk behaviour was the only one to yield a prevalence in black MSM (44·1%) similar to that observed (43·4%).

INTERPRETATION

Racial assortativity is an inadequate explanation for observed disparities. Work to close the gap in the care cascade by race is imperative, as are efforts to increase serodiscussion and strengthen relationships among black MSM particularly. Further work is urgently needed to identify other sources of, and pathways for, this disparity, to integrate concomitant epidemics into models, and to understand reasons for racial differences in behavioural reporting.

FUNDING

The Eunice Kennedy Shriver National Institute of Child Health and Development, the National Institute of Allergy and Infectious Diseases, the National Institute of Minority Health and Health Disparities, and the National Institute of Mental Health.

Sexual Networks, Dyadic Characteristics, and HIV Acquisition and Transmission Behaviors Among Black Men Who Have Sex With Men in 6 US Cities

The role of sexual networks in the epidemiology of human immunodeficiency virus (HIV) among black men who have sex with men (MSM) is poorly understood. Using data from 1,306 black MSM in the BROTHERS Study (2009-2010) in the United States, we examined the relationships between multiple sexual dyadic characteristics and serodiscordant/serostatus-unknown condomless sex (SDCS). HIV-infected participants had higher odds of SDCS when having sex at least weekly (odds ratio (OR) = 2.41, 95% confidence interval (CI): 1.37, 4.23) or monthly (OR = 1.94, 95% CI: 1.17, 3.24) versus once to a few times a year. HIV-uninfected participants had higher odds of SDCS with partners met offline at sex-focused venues (OR = 1.79, 95% CI: 1.15, 2.78) versus partners met online. In addition, having sex upon first meeting was associated with higher odds of SDCS (OR = 1.49, 95% CI: 1.21, 1.83) than was not having sex on first meeting, while living/continued communication with sexual partner(s) was associated with lower odds of SDCS (weekly: OR = 0.64, 95% CI: 0.47, 0.85; monthly: OR = 0.60, 95% CI: 0.44, 0.81; yearly: OR = 0.58, 95% CI: 0.39, 0.85) versus discontinued communication. Persons with primary/steady nonprimary partners versus commercial partners had lower odds of SDCS regardless of HIV serostatus. This suggests the need for culturally relevant HIV prevention efforts for black MSM that facilitate communication with sexual partners especially about risk reduction strategies, including preexposure prophylaxis.