Sexual Network Characteristics Research Articles

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

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. 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. 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). 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 for this study was provided by NIH/NIMH grants R01 MH118973 (PI: Clark) and R25 MH087222 (PI: Clark).

Sexual network characteristics and partnership types among men who have sex with men diagnosed with syphilis, gonorrhoea and/or chlamydia in Lima, Peru

ObjectivesSexual networks are known to structure sexually transmitted infection (STI) transmission among men who have sex with men (MSM). We sought to estimate the risks of STI diagnosis for various...

1517. Sexual Network Characteristics of MSM with Detectable Viremia Living with HIV in Lima, Peru

Abstract Background In Lima, Peru, the HIV epidemic is concentrated among men who have sex with men (MSM) and transgender women (TW). Few data exist on the sexual network characteristics of MSM with detectable HIV-1 viremia, yet these networks have important implications to control transmission. We report data on frequency of sero-discordant, condomless anal intercourse (CAI) among MSM in Lima with detectable viremia. Methods This cross-sectional secondary analysis includes MSM screened for a STI trial in Lima, Peru between June 2022 and January 2023. Participants completed questionnaires on demographics, sexual identity and role, and sexual network characteristics. Participants were screened for HIV infection and those who tested positive were included and HIV-1 RNA was measured. Descriptive and comparative statistics are reported for those with detectable and undetectable viremia. Results 665 MSM with HIV were included. 153 (23%) had detectable ( &amp;gt;200 copies/mL) viremia. Among those with detectable viremia, the median (IQR) age was 29 (25, 35) years. 70% identified as homosexual and 57% identified their sexual role during intercourse as “moderno” or “versatil”. The median (IQR) number of sexual partners in the last 3 months was 15 (5,20). 55/153 (35.6%) of the detectable group were aware of their HIV diagnosis, 33/55 (60%) reported being on anti-retroviral therapy (ART) and 15/32 (47%) believed they were virally suppressed. Among all participants living with HIV, 499/662 (75%) were aware of their HIV status, 469/499 (94%) reported to be on ART and 436/469 (93%) were virally suppressed. 147/153 (96%) of men with detectable viremia reported sero-discordant CAI with at least one of their last three sexual partners, and 106/144 (74%) reported this with all three of their last partners. In the undetectable group, 302/489 (62%) reported sero-discordant CAI with all three of their last partners (p &amp;lt; 0.01). Conclusion In this sample of MSM living with HIV in Lima, Peru, almost all men with detectable HIV-1 viremia reported sero-discordant CAI, more often than those with undetectable viremia. The primary gap in the HIV care cascade was participant awareness of their HIV status, suggesting that broader HIV testing and improved access to resources for secondary HIV prevention are key objectives in Peru. Disclosures Jordan Lake, MD, Gilead Sciences: Grant/Research Support|Theratechnologies: Advisor/Consultant

An agent-based multi-level model to study the spread of gonorrhea in different and interacting risk groups

IntroductionMathematical modeling has emerged as a crucial component in understanding the epidemiology of infectious diseases. In fact, contemporary surveillance efforts for epidemic or endemic infections heavily rely on mathematical and computational methods. This study presents a novel agent-based multi-level model that depicts the transmission dynamics of gonorrhea, a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. This infection poses a significant public health challenge as it is endemic in numerous countries, and each year sees millions of new cases, including a concerning number of drug-resistant cases commonly referred to as gonorrhea superbugs or super gonorrhea. These drug-resistant strains exhibit a high level of resistance to recommended antibiotic treatments.MethodsThe proposed model incorporates a multi-layer network of agents' interaction representing the dynamics of sexual partnerships. It also encompasses a transmission model, which quantifies the probability of infection during sexual intercourse, and a within-host model, which captures the immune activation following gonorrhea infection in an individual. It is a combination of agent-based modeling, which effectively captures interactions among various risk groups, and probabilistic modeling, which enables a theoretical exploration of sexual network characteristics and contagion dynamics.ResultsNumerical simulations of the dynamics of gonorrhea infection using the complete agent-based model are carried out. In particular, some examples of possible epidemic evolution are presented together with an application to a real case study. The goal was to construct a virtual population that closely resembles the target population of interest.DiscussionThe uniqueness of this research lies in its objective to accurately depict the influence of distinct sexual risk groups and their interaction on the prevalence of gonorrhea. The proposed model, having interpretable and measurable parameters from epidemiological data, facilitates a more comprehensive understanding of the disease evolution.

Egocentric sexual network analysis among gay and bisexual men who have sex with men with and without mpox infection

ObjectivesRecent outbreaks of the mpox (monkeypox) virus have been detected in dense sexual networks of gay and bisexual men who have sex with men (GBMSM). The objective of this study...

Changes in Substance Use and Sexual Behaviors After a Sexually Transmitted Infection Diagnosis Among a Cohort of Men Who Have Sex With Men in Los Angeles, CA.

Despite declines in substance use and sexual behaviors after a sexually transmitted infection, reinfections were high suggesting that men who have sex with men with sexually transmitted infections occupy sexual networks with high transmission probabilities and prevention efforts should consider sexual network characteristics.BackgroundSexually transmitted infections (STIs), STI reinfection, human immunodeficiency virus (HIV) acquisition, and changes in behaviors after an STI were examined in a cohort of men who have sex with men (MSM) in Los Angeles, CA.MethodsData from a longitudinal study of MSM enrolled from 2014 with at least 1 follow-up visit through March 2020 were analyzed (n = 447; 1854 visits). Study visits every 6 months included self-interviews for sexual behaviors, substance use, and specimen collection for chlamydia, gonorrhea, syphilis, and HIV testing. Changes in behaviors were assessed using the McNemar test, and participants not diagnosed with an STI served as controls for a difference-in-difference (DiD) analysis of changes over time.ResultsCumulative incidence of an STI was 55% (248 of 447). At 24 months after STI diagnosis, methamphetamine use declined from 50% to 35% (P&lt; 0.01), and median number of sex partners declined from 5 (interquartile range, 2–11) to 2 (interquartile range, 1–6;P&lt; 0.01). Among participants at risk for HIV and diagnosed with an STI (n = 102), postexposure prophylaxis use was 35% and HIV seroconversion was 6%. Based on DiD analyses, participants diagnosed with an STI had higher levels of substance and a higher number of sex partners when compared with those with no STIs; however, declines in these behaviors were comparable to participants not diagnosed with an STI (PDID&gt; 0.05).ConclusionsDespite behavior modifications after an STI diagnosis, STI/HIV incidence was high, suggesting that MSM with STIs occupy sexual networks where reductions in sexual and substance using behaviors do not protect them from ongoing exposure to STIs and HIV.

The sexual network and risky sexual behaviours among male migrant workers in China’s gender imbalance context.

In the context of China's gender imbalance and marriage squeeze, this study measured the overall characteristics of egocentric sexual networks, and examined the associations between sexual network characteristics and risky sexual behaviours, including commercial sex, concurrent partners and homosexual sex, among rural-urban male migrant workers. This cross-sectional study was based on data obtained from 713 Chinese men (age ≥28years) with rural household registration and who were migrants (or had rural-urban migration experience) in 2017. Logistic regression models were used to examine the associations between participants' sexual network characteristics and risky sexual behaviours. Adjusting for participants' sociodemographic characteristics, the sexual network variables of partner age, partner marital status, partner type and relationship stability were found to be significantly associated with commercial sex. Partner type and relationship stability were also associated with concurrent partners and homosexual sex. The network characteristics of male migrant workers not only differed by marital status, but the associations between sexual network characteristics and risky sexual behaviours were more pronounced among unmarried male migrant workers. Overall, sexual networks with mixed patterns of partner age, partner marital status, partner type and relationship stability may explain the HIV transmission from male migrants to other populations at the population level. Future research should focus on the determinants of structured sexual networks, and be used to identify key groups at risk for cross-population HIV transmission and implement intervention measures.

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

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

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

ObjectiveWhile 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...

One step ahead: timing and sexual networks in population mobility and HIV prevention and care.

Population mobility comes in heterogeneous forms and is triggered by many drivers. The diverse contexts of mobility can significantly influence the effectiveness of HIV prevention and care, as the contributions to this volume highlight. Nevertheless, some fundamental concepts are common across various forms of mobility. Two such concepts are time and sexual networks: mobility occurs in a space‐time continuum, and migrants are situated within social and sexual networks. In this viewpoint, we argue that a closer examination of how (1) time scales of mobility and (2) sexual network characteristics of migrants present challenges to effective HIV prevention can help to optimize interventions.

Couple serostatus patterns in sub-Saharan Africa illuminate the relative roles of transmission rates and sexual network characteristics in HIV epidemiology

HIV prevalence has surpassed 30% in some African countries while peaking at less than 1% in others. The extent to which this variation is driven by biological factors influencing the HIV transmission rate or by variation in sexual network characteristics remains widely debated. Here, we leverage couple serostatus patterns to address this question. HIV prevalence is strongly correlated with couple serostatus patterns across the continent; in particular, high prevalence countries tend to have a lower ratio of serodiscordancy to concordant positivity. To investigate the drivers of this continental pattern, we fit an HIV transmission model to Demographic and Health Survey data from 45,041 cohabiting couples in 25 countries. In doing so, we estimated country-specific HIV transmission rates and sexual network characteristics reflective of pre-couple and extra-couple sexual contact patterns. We found that variation in the transmission rate could parsimoniously explain between-country variation in both couple serostatus patterns and prevalence. In contrast, between-country variation in pre-couple or extra-couple sexual contact rates could not explain the observed patterns. Sensitivity analyses suggest that future work should examine the robustness of this result to between-country variation in how heterogeneous infection risk is within a country, or to assortativity, i.e. the extent to which individuals at higher risk are likely to partner with each other.

Associations Between Neighborhood Characteristics, Social Cohesion, and Perceived Sex Partner Risk and Non-Monogamy Among HIV-Seropositive and HIV-Seronegative Women in the Southern U.S.

Neighborhood social and physical factors shape sexual network characteristics in HIV-seronegative adults in the U.S. This multilevel analysis evaluated whether these relationships also exist in a predominantly HIV-seropositive cohort of women. This cross-sectional multilevel analysis included data from 734 women enrolled in the Women's Interagency HIV Study's sites in the U.S. South. Census tract-level contextual data captured socioeconomic disadvantage (e.g., tract poverty), number of alcohol outlets, and number of non-profits in the census tracts where women lived; participant-level data, including perceived neighborhood cohesion, were gathered via survey. We used hierarchical generalized linear models to evaluate relationships between tract characteristics and two outcomes: perceived main sex partner risk level (e.g., partner substance use) and perceived main sex partner non-monogamy. We tested whether these relationships varied by women's HIV status. Greater tract-level socioeconomic disadvantage was associated with greater sex partner risk (OR 1.29, 95% CI 1.06-1.58) among HIV-seropositive women and less partner non-monogamy among HIV-seronegative women (OR 0.69, 95% CI 0.51-0.92). Perceived neighborhood trust and cohesion was associated with lower partner risk (OR 0.83, 95% CI 0.69-1.00) for HIV-seropositive and HIV-seronegative women. The tract-level number of alcohol outlets and non-profits were not associated with partner risk characteristics. Neighborhood characteristics are associated with perceived sex partner risk and non-monogamy among women in the South; these relationships vary by HIV status. Future studies should examine causal relationships and explore the pathways through which neighborhoods influence partner selection and risk characteristics.

HIV transmission and pre-exposure prophylaxis in a high risk MSM population: A simulation study of location-based selection of sexual partners.

ObjectiveIn France, indications for pre-exposure prophylaxis (PrEP) for HIV prevention are based on individual-level risk factors for HIV infection. However, the risk of HIV infection may also depend on characteristics of sexual partnerships. Here we study how place-based selection of partners change transmission and the overall efficiency of PrEP.MethodsWe used the PREVAGAY survey of sexual behavior and HIV serostatus in men who have sex with men (MSM) in a Parisian district to look for associations between sexual network characteristics and HIV infection. We then simulated HIV transmission in a high-risk MSM population. We used information about venues visited to meet casual sexual partners (clubs, backrooms or saunas) to define sexual networks. We then simulated HIV transmission in these networks and assessed the impact of PrEP in this population.ResultsIn the PREVAGAY study, we found that HIV serostatus changed with the type of venues visited, in addition to other individual risk factors. In simulations, we found similar differences in HIV incidence when the choice of venues visited was not random. The use of PrEP allowed reducing incidence, irrespective of the venues visited by PrEP users. However, with the same amount of PrEP, the number of infections adverted could almost double depending on network structure and venues visited by PrEP users.ConclusionThis study shows that characteristics of the sexual network structure can strongly impact the effectiveness of PrEP interventions. These should be considered further to refine individual risk assessment and maximize the effect of individual-based prevention policies.

Gender, Transience, Network Partnerships and Risky Sexual Practices Among Young Persons who Inject Drugs.

Persons who inject drugs (PWID) may be at risk of acquiring HIV and sexually transmitted infections (STIs) from risky sexual practices and elevated disease prevalence within their drug injection and sexual networks. We conducted a personal (egocentric) network study of young PWID (aged 18-30) from the Chicago metropolitan area. Logistic regression with generalized estimating equations evaluated associations between individual and network factors and sexual behaviors. Of 162 participants, 116 (71.6%) were non-Hispanic White and 135 reported on 314 sexual network members. Multiplexity-having network members with overlapping roles as injection and sexual partners-was associated with more condomless vaginal sex (aOR 5.55; 95% CI 1.62-19.0) and anal sex (aOR 6.79; 95% CI 2.49-18.5) and less exchange sex among women (aOR 0.12; 95% CI 0.03-0.40), adjusting for sociodemographic and sexual network characteristics. The contribution of individual and sexual network factors to HIV/STI transmission among young PWID warrants further research.

Sexually acquired hepatitis C virus infection: a review.

Sexually acquired hepatitis C virus (HCV) infection remains a public health problem, with significant disease burden primarily in HIV-positive men who have sex with men (MSM). Over the past decades, the epidemic of sexually transmitted HCV infection has continued to expand and the epidemiology of HCV in HIV has changed significantly. In the post-combination antiretroviral therapy era, sexual network characteristics within the specific core group of MSM with increased sexual risk behaviours, including serosorting on the basis of HIV-positive status and intense mucosally traumatic sexual practices, confer increased HCV acquisition and transmission. This review summarizes the current epidemiology of sexually acquired HCV infection and the clinical and immunological contexts of acute HCV infection, and describes the biological, social, and behavioural factors that have facilitated permucosal transmission of HCV in MSM. While the advent of direct-acting antivirals has improved treatment responses significantly, sexually transmitted HCV reinfections occur in a substantial proportion of HIV-positive MSM following clearance of a primary infection. Effective strategies and preventive interventions that are tailored to the MSM communities to facilitate the control of sexually acquired HCV infection cannot be overemphasized.

Engagement of Gay Men and Other Men Who Have Sex with Men (MSM) in the Response to HIV: A Critical Step in Achieving an AIDS-Free Generation.

Men who have sex with men (MSM) continue to be at elevated risk for HIV acquisition and transmission secondary to biological and behavioral characteristics, social and sexual network characteristics, community environmental factors, and structural factors. HIV incidence rates remain high among MSM in both low- and high-income settings, and in both concentrated and more generalized HIV epidemic settings. While data quality tends to be poorer, the best estimates collectively suggest that MSM have up to 20 times the odds of living with HIV as compared to other reproductive aged adults across low- and middle-income countries. Recent prevention strategies to lower biological HIV transmission and acquisition risks, including the early use of antiretrovirals to decrease infectiousness for those living with HIV, and pre-exposure prophylaxis for those at significant risk of HIV acquisition, have demonstrated the potential to change the trajectory of the HIV epidemics among MSM. However, the coverage and effectiveness of these approaches is limited by structural factors including the punitive legal frameworks and institutional discrimination that contribute to limited uptake, challenges to adherence, and suboptimal health-seeking behaviors among MSM. More intensive efforts will be required to reach MSM who do not currently have access to relevant and effective prevention and treatment services or elect not to access these services given enacted and/or perceived stigma. Respect for human rights, including efforts to aggressively confront and combat the forms of stigma that are preventing us from achieving an AIDS-Free generation, are needed for all people including gay men and other MSM.

Changing Places and Partners: Associations of Neighborhood Conditions With Sexual Network Turnover Among African American Adults Relocated From Public Housing.

Neighborhood conditions and sexual network turnover have been associated with the acquisition of HIV and other sexually transmitted infections (STIs). However, few studies investigate the influence of neighborhood conditions on sexual network turnover. This longitudinal study used data collected across 7 visits from a predominantly substance-misusing cohort of 172 African American adults relocated from public housing in Atlanta, Georgia, to determine whether post-relocation changes in exposure to neighborhood conditions influence sexual network stability, the number of new partners joining sexual networks, and the number of partners leaving sexual networks over time. At each visit, participant and sexual network characteristics were captured via survey, and administrative data were analyzed to describe the census tracts where participants lived. Multilevel models were used to longitudinally assess the relationships of tract-level characteristics to sexual network dynamics over time. On average, participants relocated to neighborhoods that were less economically deprived and violent, and had lower alcohol outlet densities. Post-relocation reductions in exposure to alcohol outlet density were associated with fewer new partners joining sexual networks. Reduced perceived community violence was associated with more sexual partners leaving sexual networks. These associations were marginally significant. No post-relocation changes in place characteristics were significantly associated with overall sexual network stability. Neighborhood social context may influence sexual network turnover. To increase understanding of the social-ecological determinants of HIV/STIs, a new line of research should investigate the combined influence of neighborhood conditions and sexual network dynamics on HIV/STI transmission over time.

Sexual Behavior and Network Characteristics and Their Association with Bacterial Sexually Transmitted Infections among Black Men Who Have Sex with Men in the United States.

BackgroundBlack men who have sex with men (MSM) have a high prevalence of bacterial sexually transmitted infections (STIs), and individual risk behavior does not fully explain the higher prevalence when compared with other MSM. Using the social-ecological framework, we evaluated individual, social and sexual network, and structural factors and their association with prevalent STIs among Black MSM.MethodsThe HIV Prevention Trials Network 061 was a multi-site cohort study designed to determine the feasibility and acceptability of a multi-component intervention for Black MSM in six US cities. Baseline assessments included demographics, risk behavior, and social and sexual network questions collected information about the size, nature and connectedness of their sexual network. Logistic regression was used to estimate the odds of having any prevalent sexually transmitted infection (gonorrhea, chlamydia, or syphilis).ResultsA total of 1,553 Black MSM were enrolled in this study. In multivariate analysis, older age (aOR = 0.57; 95% CI 0.49–0.66, p<0.001) was associated with a lower odds of having a prevalent STI. Compared with reporting one male sexual partner, having 2–3 partners (aOR = 1.74; 95% CI 1.08–2.81, p<0.024) or more than 4 partners (aOR = 2.29; 95% CI 1.43–3.66, p<0.001) was associated with prevalent STIs. Having both Black and non-Black sexual partners (aOR = 0.67; 95% CI 0.45–0.99, p = 0.042) was the only sexual network factor associated with prevalent STIs.ConclusionsAge and the number and racial composition of sexual partners were associated with prevalent STIs among Black MSM, while other sexual network factors were not. Further studies are needed to evaluate the effects of the individual, network, and structural factors on prevalent STIs among Black MSM to inform combination interventions to reduce STIs among these men.

Sexual Networks and HIV Risk among Black Men Who Have Sex with Men in 6 U.S. Cities.

BackgroundSexual networks may place U.S. Black men who have sex with men (MSM) at increased HIV risk.MethodsSelf-reported egocentric sexual network data from the prior six months were collected from 1,349 community-recruited Black MSM in HPTN 061, a multi-component HIV prevention intervention feasibility study. Sexual network composition, size, and density (extent to which members are having sex with one another) were compared by self-reported HIV serostatus and age of the men. GEE models assessed network and other factors associated with having a Black sex partner, having a partner with at least two age category difference (age difference between participant and partner of at least two age group categories), and having serodiscordant/serostatus unknown unprotected anal/vaginal intercourse (SDUI) in the last six months.ResultsOver half had exclusively Black partners in the last six months, 46% had a partner of at least two age category difference, 87% had ≤5 partners. Nearly 90% had sex partners who were also part of their social networks. Among HIV-negative men, not having anonymous/exchange/ trade partners and lower density were associated with having a Black partner; larger sexual network size and having non-primary partners were associated with having a partner with at least two age category difference; and having anonymous/exchange/ trade partners was associated with SDUI. Among HIV-positive men, not having non-primary partners was associated with having a Black partner; no sexual network characteristics were associated with having a partner with at least two age category difference and SDUI.ConclusionsBlack MSM sexual networks were relatively small and often overlapped with the social networks. Sexual risk was associated with having non-primary partners and larger network size. Network interventions that engage the social networks of Black MSM, such as interventions utilizing peer influence, should be developed to address stable partnerships, number of partners, and serostatus disclosure.

Changes in Exposure to Neighborhood Characteristics are Associated with Sexual Network Characteristics in a Cohort of Adults Relocating from Public Housing

Changes in Exposure to Neighborhood Characteristics are Associated with Sexual Network Characteristics in a Cohort of Adults Relocating from Public Housing