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

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

OBJECTIVES

Sexual 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 partnership types within these networks.

METHODS

Our cross-sectional survey analysed data from 1376 MSM screened for a partner management intervention in Lima, Peru. Participants were tested for HIV, syphilis, gonorrhoea (NG) and chlamydia (CT) and completed surveys on their demographics, sexual identity/role, HIV status, partnership types and sexual network from the prior 90 days. χ2 and Wilcoxon rank-sum tests compared participants without an STI to those diagnosed with (1) syphilis, (2) NG and/or CT (NG/CT) and (3) syphilis and NG/CT coinfection (coinfection).

RESULTS

40.8% (n=561/1376) of participants were diagnosed with an STI (syphilis: 14.9%, NG/CT: 16.4%, coinfection: 9.5%). 47.9% of all participants were living with HIV and 8.9% were newly diagnosed. A greater proportion of participants with syphilis and coinfection were living with HIV (73.5%, p<0.001; 71.0%, p<0.001) compared with those with NG/CT (47.8%) or no STI (37.8%). Participants with syphilis more often reported sex-on-premises venues (SOPVs) as the location of their last sexual encounter (51.7%, p=0.038) while those with NG/CT tended to meet their last sexual partner online (72.8%, p=0.031). Respondents with coinfection were the only STI group more likely to report transactional sex than participants without an STI (31.3%, p=0.039).

CONCLUSIONS

Sexual networks and partnership types of Peruvian MSM are associated with differential risks for STIs. Participants diagnosed with syphilis tended to meet single-encounter casual partners at SOPV, while MSM with NG/CT were younger and often contacted casual partners online. Coinfection had higher frequency of transactional sex. These findings suggest the potential importance of public health interventions through combined syphilis/HIV screening at SOPV, syphilis screening at routine clinic appointments for MSM living with HIV and directed advertisements and/or access to NG/CT testing through online platforms.

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

Background:

Sexually transmitted infections (STIs), STI reinfection, Human Immunodeficiency Virus (HIV) acquisition and changes in behaviors following an STI were examined in a cohort of men who have sex with men (MSM) in Los Angeles, CA.

Methods:

Data from a longitudinal study of MSM enrolled from 2014 with at least one follow-up visit through March 2020 were analyzed (n=447; 1,854 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 McNemar’s test and participants not diagnosed with an STI served as controls for a difference-in-differences (DiD) analysis of changes over time.

Results:

Cumulative incidence of an STI was 55% (248/447). At 24-months post STI diagnosis methamphetamine use declined from 50% to 35% (p<.01), and median number of sex partners declined from 5 (IQR: 2–11) to 2 (IQR: 1–6)(p<.01). Among participants at risk for HIV and diagnosed with an STI (n=102), PrEP use was 35% and HIV-seroconversion was 6%. Based on DiD analyses, participants diagnosed with an STI had higher levels of substance and higher number of sex partners when compared to those with no STIs, however, declines in these behaviors were comparable to participants not diagnosed with an STI (pDID>0.05).

Conclusions:

Despite behavior modifications following 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.

Despite declines in substance use and sexual behaviors following an STI, reinfections were high suggesting that MSM with STIs occupy sexual networks with high transmission probabilities and prevention efforts should consider sexual network characteristics.

Maximizing the impact of limited vaccine supply under different early epidemic conditions: a 2-city modelling analysis of monkeypox virus transmission among men who have sex with men

BACKGROUND

The current global monkeypox virus (MPXV) outbreak has disproportionately affected gay, bisexual and other men who have sex with men (GBMSM). Given that many jurisdictions have been faced with limited supplies of MPXV vaccine, we aimed to explore optimal vaccine allocation between 2 linked GBMSM transmission networks over a short-term time horizon, across several epidemic conditions.

METHODS

We constructed a deterministic compartmental MPXV transmission model. We parameterized the model to reflect 2 representative, partially connected GBMSM sexual networks ( cities), using 2022 data from Ontario. We simulated a roll-out of 5000 vaccine doses over 30 days that started 45 days after epidemic seeding with 10 imported cases. Within this model, we varied the relative city (network) sizes, epidemic potentials (R ₀), between-city mixing and distribution of seed cases between cities. For each combination of varied factors, we identified the allocation of doses between cities that maximized infections averted by day 90.

RESULTS

Under our modelling assumptions, we found that a limited MPXV vaccine supply could generally avert more early infections when prioritized to networks that were larger, had more initial infections or had greater R ₀. Greater between-city mixing decreased the influence of initial seed cases and increased the influence of city R ₀ on optimal allocation. Under mixed conditions (e.g., fewer seed cases but greater R ₀), optimal allocation required doses shared between cities.

INTERPRETATION

In the context of the current global MPXV outbreak, we showed that prioritization of a limited supply of vaccines based on network-level factors can help maximize infections averted during an emerging epidemic. Such prioritization should be grounded in an understanding of context-specific risk drivers and should acknowledge potential connectedness of multiple transmission networks.

Examining inequities in rates of undiagnosed HIV and rectal STIs in a large nationwide cohort study of sexual minority men

Objective

Sexual minority men (SMM) of colour are disproportionately impacted by HIV and bacterial STIs (bSTIs). To better understand within-group heterogeneity and differential risk factors by race and ethnicity, we sought to examine rates of undiagnosed HIV and rectal bSTI at the intersection of racial and ethnic identity with other sociodemographic factors.

Methods

We examined data from 8105 SMM conducting home-based self-testing at enrolment in a nationwide cohort study collected from November 2017 to August 2018. We conducted analyses stratified by racial and ethnic groups to examine within-group (ie, subgroup) unadjusted rates of HIV and rectal bSTI infection across a range of characteristics.

Results

Rates of undiagnosed HIV were highest among Black (4.3%, n=39) and Latino (2.4%, n=38) SMM, with lower rates among those identified as multiracial (1.6%, n=15), white (1.3%, n=56) and other races (1.3%, n=6). Across the stratified analyses of HIV infection, 15 significant associations emerged showing that age, region, insurance type, sexual positioning and incarceration history had differential impacts across racial and ethnic groups. In particular, private and public insurance were protective against HIV for white but not Black and Latino SMM, and incarceration was associated with substantially higher rates of HIV infection for Black and Latino SMM relative to white SMM. We found significant co-occurrence of HIV and bSTI rates for participants who identified as Latino (OR=7.5, 95% CI 2.12 to 26.54), white (OR=3.19, 95% CI 1.14 to 8.98) and multiracial (OR=5.5, 95% CI 1.08 to 27.90), but not those who identified as Black (OR=0.82, 95% CI 0.10 to 6.56) or other races (OR=3.56 95% CI 0.31 to 40.80).

Conclusions

Stratified analyses showed differential rates of HIV infection at the intersection of racial and ethnic groups with other characteristics, particularly insurance status and incarceration history, pointing to structural inequities rather than individual behaviours underlying disproportionately high rates of HIV for Black and Latino SMM.

Intersection of Syphilis and HIV Networks to Identify Opportunities to Enhance HIV Prevention

BACKGROUND

HIV and syphilis infection continue at disproportionate rates among minority men who have sex with men (MSM) in the United States. The integration of HIV genetic clustering with partner services can provide important insight into local epidemic trends to guide interventions and control efforts.

METHODS

We evaluated contact networks of index persons defined as minority men and transgender women diagnosed with early syphilis and/or HIV infection between 2018-2020 in two North Carolina regions. HIV clusters were constructed from pol sequences collected through statewide surveillance. A combined "HIV-risk" network, which included persons with any links (genetic or sexual contact) to HIV-positive persons, was evaluated by component size, demographic factors, and HIV viral suppression.

RESULTS

In total, 1,289 index persons were identified and 55% named 1,153 contacts. Most index persons were Black (88%) and young (median age 30 years); 70% had early syphilis and 43% had prevalent HIV infection. Most people with HIV (65%) appeared in an HIV cluster. The combined HIV-risk network (1,590 contact network and 1,500 cluster members) included 287 distinct components; however, 1,586 (51%) were in a single component. Fifty-five percent of network members with HIV had no evidence of viral suppression. Overall, fewer index persons needed to be interviewed to identify one HIV-positive member without viral suppression (1.3 versus 4.0 for contact tracing).

CONCLUSIONS

Integration of HIV clusters and viral loads illuminate networks with high HIV prevalence, indicating recent and ongoing transmission. Interventions intensified towards these networks may efficiently reach persons for HIV prevention and care re-engagement.

Transactional Sex and Incident Chlamydia and Gonorrhea Among Black Men Who Have Sex With Men in Atlanta, Georgia

BACKGROUND

Black men who have sex with men (BMSM) are disproportionately affected by sexually transmitted infections (STI), including chlamydia and gonorrhea. Transactional sex is an hypothesized risk factor for STI acquisition in BMSM.

METHODS

We estimated the association of transactional sex with incident chlamydia/gonococcal infection among BMSM using longitudinal data from a randomized trial in Atlanta (2012-2015). BMSM were eligible for inclusion if they tested human immunodeficiency virus (HIV)-antibody-negative and reported both ≥2 male sex partners and any condomless anal sex in the last year. We defined chlamydia/gonorrhea incidence as the first occurrence of either rectal or urogenital chlamydia or gonococcal infections after a negative result at enrollment. We used Poisson regression to estimate the incidence rate (IR) for chlamydia/gonorrhea over 12 months. Incidence rate ratios (IRR) compared estimates by reported experience of transactional sex. Subgroup analyses assessed potential heterogeneity by age and sexual identity.

RESULTS

This analysis included 416 BMSM, of whom 191 (46%) were gay-identified, 146 (42%) reported a history of transactional sex, and 57 (14%) had prevalent chlamydia/gonococcal infection at baseline. Over a median of 1 year of follow-up, an additional 55 men tested laboratory-positive for chlamydia/gonorrhea (IR, 17.3 per 100 person-years). Transactional sex was not associated with chlamydia/gonorrhea incidence overall. However, among gay-identified BMSM, transactional sex was associated with incident chlamydia/gonorrhea (IRR, 2.9; 95% confidence interval, 1.2-6.8).

CONCLUSIONS

Economic and social vulnerabilities may motivate engagement in high-risk sexual behaviors through commodified sex, potentially increasing the burden of STIs among BMSM. In this investigation, the relationship between transactional sex and chlamydia/gonorrhea was not homogenous across BMSM with diverse sexual identities in Atlanta, suggesting that within select sexual networks, transactional sex may drive STI risks. Delivering accessible and targeted STI screening for marginalized BMSM should be prioritized for STI and HIV prevention.

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.

Factors associated with declining to report the number of sexual partners using computer-assisted self-interviewing: a cross-sectional study among individuals attending a sexual health centre in Melbourne, Australia

Background The number of sexual partners is one of the most important risk factors for sexually transmissible infections (STIs), including HIV. The aim of the present study was to examine the association between declining to report the number of partners using computer-assisted self-interviewing (CASI) and HIV or STI positivity at a public sexual health centre in Melbourne, Australia, in 2016.

METHODS

Individuals were categorised into three risk populations: women, men who have sex with women only (MSW) and men who have sex with men (MSM). Logistic regression analysis was used to examine the association between declining to report the number of sexual partners in the past 12 months and HIV or STI positivity for women and MSW, with generalised estimating equations (GEE) used for estimation in MSM to address repeated-measures within individuals.

RESULTS

In all, 18085 individuals (5579 women, 6013 MSW, 6493 MSM) were included in the final analysis. There was no association between chlamydia positivity and declining to respond among women and MSW. MSM who declined to respond were more likely to be chlamydia positive (adjusted odds ratio1.21; 95% confidence interval (CI) 1.01-1.43). Known HIV-positive MSM and MSM newly diagnosed with HIV had 3.31-fold (95% CI 2.48-4.42) and 2.82-fold (95% CI 1.84-4.32) greater odds respectively of declining to respond compared with HIV-negative MSM. Gonorrhoea and syphilis positivity in MSM were not associated with declining to respond.

CONCLUSIONS

There was no association between declining to report the number of partners and chlamydia positivity among women and MSW. However, MSM who declined to report the number of partners were slightly more likely to have chlamydia and substantially more likely to be HIV positive.

The characteristics of mixing patterns of sexual dyads and factors correlated with condomless anal intercourse among men who have sex with men in Guangzhou, China

Background

The HIV prevalence among men who have sex with men (MSM) in China has increased yearly. This study aimed to explore the association between the characteristics of social communication and condomless anal intercourse (CAI) among MSM and the implications for prevention and control of HIV among MSM in China using an egocentric network framework.

Methods

The data were collected in Guangzhou between November 2016 and May 2017 through standardized face-to-face interviews. The participants were recruited among MSM who received voluntary counselling and testing services (VCT) provided by nongovernmental organizations (NGOs) and the local Centers for Disease Control and Prevention (CDC). We used the framework of the egocentric network analysis, the odd ratios of CAI were analyzed using generalized estimating equations (GEE).

Results

In total, 1073 MSM who nominated 2667 sexual partners were sampled. MSM who were approximately 30 years old and chose sexual partners of different age category were more likely to engage in CAI. Participants with high level education who were in partnerships with individuals with lower education levels had a higher risk of CAI. Participants who reported having a strong relationship with their sexual partners(AOR = 1.31) were associated with a higher probability of experiencing CAI during sex; while having sexual partners who were unmarried (OR = 0.56), and participants who reported meeting sexual partners online (AOR = 0.74) or, having sex with an occasional partner (AOR = 0.44)were less likely to engage in CAI.

Conclusion

Our study indicates that the strength of sexual dyadic relational ties and different social communication mixing patterns across ages, educational categories, and marital status were associated with CAI.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7082-9) contains supplementary material, which is available to authorized users.

Sexual network and detection of anogenital human papillomavirus in a community cohort of men who have sex with men in Taiwan

OBJECTIVES

We examined the association between anogenital human papillomavirus (HPV) infection and sexual networks in men who have sex with men (MSM).

METHODS

A total of 253 MSM, 20 years of age and older, were recruited from the community in Southern Taiwan in 2015-2016. At baseline and at each follow-up visit, MSM were screened for HPV to identify 37 HPV genotypes. At the six-month follow-up, MSM were asked to fill out an egocentric network assessment and to report the last five persons with whom they had sex regarding the characteristics of sexual behavior with each network member.

RESULTS

A total of 182 participants (71.9%) returned for the follow-up and one third had at least one HPV type detected. A higher level of bridging network position calculated by the level of constraints in the network was significantly less likely to have HPV detection at the anal site. A high level of concurrency was associated with penile HPV detection (AOR = 3.16, 95% CI = 1.01-9.86).

CONCLUSIONS

Identifying network-related characteristics can advance our understanding of high-risk populations and for prioritizing HPV vaccine recommendations.

Syphilis: an atypical case of sepsis and multiple anogenital lesions in secondary syphilis

The incidence of syphilis has historically been cyclical in nature, often in relation to the rise and fall of public health initiatives directed toward eradication along with social attitudes toward sexual practices. The incidence of syphilis has increased by 15% in the last 6 years in the United States, with similar increases worldwide. Herein, we present an atypical case of syphilis presenting with severe septic shock and multiple anogenital lesions in an immunocompetent host. A 22-year-old male with no significant past medical history presented with fevers, chills, sore throat, diaphoresis, and diarrhea. He was febrile, tachycardic, hypotensive, and unresponsive to fluid resuscitation requiring short-term vasopressor support. Physical exam revealed diffuse lymphadenopathy; lower extremity macular rash involving the soles of the feet; papular non-pustular lesions on the scrotum; and a 0.5 cm non-tender irregular, healing lesion on the shaft of the penis. Laboratory analysis was significant for leukocytosis and elevated creatinine. Serum screening rapid plasma reagin was positive, and further testing revealed a titer of 1:32, with confirmation via fluorescent treponemal antibody absorption test. The patient was diagnosed with secondary syphilis, which was determined to be the underlying etiology of the sepsis as all other serological evaluations were negative. He was treated with penicillin G benzathine 2.4 million units intramuscular and supportive management, with improvement of symptoms. The patient engaged in high-risk sexual behaviors, including prior unprotected sexual contact with males. New research indicates that up to one-third of patients may present with atypical cutaneous manifestations, as demonstrated by this patient. It is important for physicians to familiarize themselves with the varied clinical presentations of syphilis, which include multiple anogenital lesions and tender primary lesions in primary or secondary syphilis.

Oxytocin modulation of neural circuits for social behavior

Oxytocin is a hypothalamic neuropeptide that has gained attention for the effects on social behavior. Recent findings shed new light on the mechanisms of oxytocin in synaptic plasticity and adaptively modifying neural circuits for social interactions such as conspecific recognition, pair bonding, and maternal care. Here, we review several of these newer studies on oxytocin in the context of previous findings, with an emphasis on social behavior and circuit plasticity in various brain regions shown to be enriched for oxytocin receptors. We provide a framework that highlights current circuit-level mechanisms underlying the widespread action of oxytocin. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 169-189, 2017.