Sexual network characteristics, condomless anal intercourse, and the HIV care cascade among MSM living with controlled versus uncontrolled HIV infection in Lima, Peru: a population-based cross-sectional analysis.

Background: Despite high rates of HIV transmission among men who have sex with men (MSM) in Lima, Peru, limited data exist on the sexual network characteristics or risk factors for secondary HIV transmission among MSM with uncontrolled HIV infection. We report the frequency of serodiscordant, condomless anal intercourse (CAI) and associated sexual network characteristics among MSM in Lima with detectable HIV viremia and compare to those with undetectable viremia. Methods: This cross-sectional analysis includes MSM who tested positive for HIV-1 during screening for a trial of partner management and STI control (June 2022-January 2023). Participants were tested for HIV, gonorrhoea, chlamydia, and syphilis, and completed questionnaires on their demographic characteristics, sexual identity and behaviour, sexual network structures and engagement in HIV care. Findings: Of 665 MSM, 153 (23%) had detectable (>200 copies/mL) viremia. 75% (499/662) of men living with HIV were previously diagnosed, with 94% (n = 469/499) reporting that they were on ART, and 93% (n = 436/469) virally suppressed. 96% (n = 147/153) of men with detectable viremia reported serodiscordant CAI with at least one of their last three sexual partners, and 74% (n = 106/144) reported the same with all three of their recent partners. In contrast, 62% (n = 302/489) of men with undetectable viral load reported serodiscordant CAI with all of their last three partners (p < 0.01). Interpretation: 23% of men living with HIV in Peru had detectable viremia, of whom almost all (96%) reported recent serodiscordant CAI. The primary gap in the HIV care cascade lies in awareness of HIV serostatus, suggesting that improved access to HIV testing could be a key prevention strategy in Peru. Funding: Funding for this study was provided by NIH/NIMH grants R01 MH118973 (PI: Clark) and R25 MH087222 (PI: Clark).

Sexual Networks and STI Infection Among Young Black Men Who Have Sex With Women in a Southern U.S. City.

PURPOSE: The configuration of one's sexual network has been shown to influence sexually transmitted infection (STI) acquisition in some populations. Young Black men who have sex with women (MSW) have high rates of STIs, yet little is known about their sexual networks. The purpose of this study is to describe the characteristics of sexual networks and their association with selected STI infections among young Black MSW. METHODS: Black MSW aged 15-26 years who were enrolled in the New Orleans community-based screening program named Check It from March 2018 to March 2020 were tested for C. trachomatis and N. gonorrhoeae infection and asked about the nature of their sexual partnerships. Sexual partnerships with women were defined as dyadic, somewhat dense (either themselves or their partner had multiple partners), and dense (both they and their partner(s) had multiple partners). RESULTS: Men (n = 1,350) reported 2,291 sex partners. The percentage of men who reported their networks were dyadic, somewhat dense, and dense was 48.7%, 27.7%, and 23.3%, respectively; 11.2% were STI-positive and 39.2% thought their partner(s) had other partners. Compared to men in dyadic relationships, those in somewhat dense network did not have increased risk of STI infection, but those in dense networks were more likely to have an STI (adjusted odds ratio = 2.06, 95% confidence interval [1.35-3.13]). DISCUSSION: Young Black MSW, who had multiple partners and who thought their partner(s) had other sex partners were at highest risk for STIs. Providers should probe not only about the youth's personal risk but should probe about perceived sexual partners' risk for more targeted counseling/STI testing.

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.

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.

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.

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.

Lost and found: applying network analysis to public health contact tracing for HIV.

Infectious disease surveillance is often case-based, focused on people diagnosed and their contacts in a predefined time window, and treated as independent across infections. Network analysis of partners and contacts joining multiple investigations and infections can reveal social or temporal trends, providing opportunities for epidemic control within broader networks. We constructed a sociosexual network of all HIV and early syphilis cases and contacts investigated among residents of 11 contiguous counties in North Carolina over a two-year period (2012-2013). We anchored the analysis on new HIV diagnoses ("indexes"), but also included nodes and edges from syphilis investigations that were within the same network component as any new HIV index. After adding syphilis investigations and deduplicating people included in multiple investigations (entity resolution), the final network comprised 1470 people: 569 HIV indexes, 700 contacts to HIV indexes who were not also new cases themselves, and 201 people who were either indexes or contacts in eligible syphilis investigations. Among HIV indexes, nearly half (48%; n = 273) had no located contacts during single-investigation contact tracing, though 25 (9%) of these were identified by other network members and thus not isolated in the final multiple investigation network. Constructing a sociosexual network from cases and contacts across multiple investigations mitigated some effects of unobserved partnerships underlying the HIV epidemic and demonstrated the HIV and syphilis overlap in these networks.

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.

Projected HIV and Bacterial STI Incidence Following COVID-Related Sexual Distancing and Clinical Service Interruption.

BACKGROUND: The global COVID-19 pandemic has the potential to indirectly impact the transmission dynamics and prevention of HIV and other sexually transmitted infections (STI). Studies have already documented reductions in sexual activity ("sexual distancing") and interruptions in HIV/STI services, but it is unknown what combined impact these two forces will have on HIV/STI epidemic trajectories. METHODS: We adapted a network-based model of co-circulating 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-related sexual distancing in casual and one-time partnership networks and service interruption within four service categories (HIV screening, HIV PrEP, HIV ART, 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). Greater relative reductions and longer durations of service interruption would increase HIV and STI incidence, while greater relative reductions and longer durations of sexual distancing would decrease incidence of both. 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: The counterbalancing impact of sexual distancing and clinical service interruption depends on the infection and the extent and durability of these COVID-related changes. If sexual behavior rebounds while service interruption persists, we project an excess of hundreds of HIV cases and thousands of STI cases just among Atlanta MSM over the next 5 years. Immediate action to limit the impact of service interruptions is needed to address the indirect effects of the global COVID pandemic on the HIV/STI epidemic.

Introducing pre-exposure prophylaxis to prevent HIV acquisition among men who have sex with men in Sweden: insights from a mathematical pair formation model.

OBJECTIVES: Since 2017, the Public Health Agency of Sweden recommends that pre-exposure prophylaxis (PrEP) for HIV should be offered to high-risk individuals, in particular to men who have sex with men (MSM). The objective of this study is to develop a mathematical model investigating the effect of introducing PrEP to MSM in Sweden. DESIGN: A pair formation model, including steady and casual sex partners, is developed to study the impact of introducing PrEP. Two groups are included in the model: sexually high active MSM and sexually low active MSM. Three mixing assumptions between the groups are considered. SETTING: A gay-friendly MSM HIV/sexually transmitted infection testing clinic in Stockholm, Sweden. This clinic started offering PrEP to MSM in October 2018. PARTICIPANTS: The model is calibrated according to detailed sexual behaviour data gathered in 2015 among 403 MSM. RESULTS: By targeting sexually high active MSM, a PrEP coverage of 3.5% of the MSM population (10% of all high actives) would result in the long-term HIV prevalence to drop considerably (close to 0%). While targeting only low actives would require a PrEP coverage of 35% for a similar reduction. The main effect of PrEP is the reduced susceptibility, whereas the increased HIV testing rate (every third month) among PrEP users plays a lesser role. CONCLUSIONS: To create a multifaceted picture of the effects of interventions against HIV, we need models that include the different stages of HIV infection and real-world data on detailed sexual behaviour to calibrate the mathematical models. Our findings conclude that targeting HIV high-risk individuals, within HIV risk populations such as MSM, with PrEP programmes could greatly decrease the long-term HIV prevalence in Sweden. Therefore, risk stratification of individuals is of importance in PrEP implementation programmes, to ensure optimising the effect and cost-effectiveness of such programmes.

Egocentric sexual networks of men who have sex with men in the United States: Results from the ARTnet study.

In this paper, we present an overview and descriptive results from one of the first egocentric network studies of men who have sex with men (MSM) from across the United States: the ARTnet study. ARTnet was designed to support prevention research for human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) that are transmitted across partnership networks. ARTnet implemented a population-based egocentric network study design that sampled egos from the target population and asked them to report on the number, attributes, and timing of their sexual partnerships. Such data provide the foundation needed for parameterizing stochastic network models that are used for disease projection and intervention planning. ARTnet collected data online from 2017 to 2019, with a final sample of 4904 participants who reported on 16198 sexual partnerships. The aims of this paper were to characterize the joint distribution of three network parameters needed for modeling: degree distributions, assortative mixing, and partnership age, with heterogeneity by partnership type (main, casual and one-time), demography, and geography. Participants had an average of 1.19 currently active partnerships ("mean degree"), which was higher for casual partnerships (0.74) than main partnerships (0.45). The mean rate of one-time partnership acquisition was 0.16 per week (8.5 partners per year). Main partnerships lasted 272.5 weeks on average, while casual partnerships lasted 133.0 weeks. There was strong but heterogenous assortative mixing by race/ethnicity for all groups. The mean absolute age difference for all partnership types was 9.5 years, with main partners differing by 6.3 years compared to 10.8 years for casual partners. Our analysis suggests that MSM may be at sustained risk for HIV/STI acquisition and transmission through high network degree of sexual partnerships. The ARTnet network study provides a robust and reproducible foundation for understanding the dynamics of HIV/STI epidemiology among U.S. MSM and supporting the implementation science that seeks to address persistent challenges in HIV/STI prevention.

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.

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.

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.

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.

Group Sex Events Among Cisgender Men Who Have Sex With Men: Cross-Sectional and Longitudinal Survey Study to Explore Participation and Risk-Taking Behaviors.

BACKGROUND: Group sex events (GSEs) are common among cisgender men who have sex with men (MSM), pose a unique risk profile for HIV and sexually transmitted disease (STD) transmission, and may be on the rise, in part because of Web-based networking platforms. However, collecting data on GSEs can be challenging, and many gaps exist in our knowledge about GSE participation among MSM. OBJECTIVE: The objective of this study was to develop survey questions addressing aggregate and partner-specific group sex behaviors to measure prevalence of GSEs and associated risks in persons participating in Project Diagnostic Evaluation To Expand Critical Testing Technologies (DETECT), including MSM seeking HIV and STD testing at a public clinic in Seattle, Washington. METHODS: We developed a computer self-assisted survey that included questions about participant demographics, sexual history, and risk behaviors, including group sex, as a part of Project DETECT, a Centers for Disease Control and Prevention-funded study evaluating point-of-care HIV tests. Aggregate and partner-specific questions asked about participation in all GSEs, threesomes, and four-or-more-somes including questions about number and HIV status of sex partners and condom use during the events. To evaluate question performance, we assessed the discrepancies in reporting between the aggregate and partner-specific questions, quantified question refusal rates, and calculated the additional time required to answer the GSE questions. Information about network density (number of partnerships of overlapping duration) was estimated and compared for MSM who did and did not report GSEs. RESULTS: Among 841 visits by 690 MSM who were asked any group sex survey question, participation in a GSE of any type in the past 3 months was reported at 293 visits (293/841, 34.8%). We found that 9.0% (76/841) of MSM in the sample reported ≥1 four-or-more-some in the partner-specific questions but did not report in the aggregate. The proportion of refusals on any given aggregate GSE-related question ranged from 0% (0/273) to 10.6% (15/141) (median 2.6%) and partner-specific questions ranged from 0% (0/143) to 22% (5/23) (median 3.0%), with questions about four-or-more-somes having the highest proportions of refusals. Completing the aggregate group sex questions added 1 to 2 minutes and the partner-specific questions added an additional 2 to 4 minutes per partner to the total survey length. As expected, the partner-specific GSE questions documented higher density of sexual networks that was not captured by asking about total partner counts and overlap of specific partnerships. CONCLUSIONS: We found that the Project DETECT survey was able to obtain nuanced information about GSEs. The question skip patterns and consistency checks were effective, and survey fatigue was minimal. More research is needed on GSEs, and our survey represents a promising data collection tool to help fill gaps in knowledge about the subject.