Social networks as drivers of syphilis and HIV infection among young men who have sex with men

Effects of Online Friendships on Safer Sex Communication and Behavior among Black Sexual Minority Men: A Study of Network Exposure

This study draws on social normative and social learning theories to examine the masspersonal safer sex communication (i.e., Facebook posts about safer sex) and safer sex behavior (i.e., condom use) in a cohort of Black sexual minority men (BSMM) (N = 340), with an eye toward understanding their relationship with the safer sex communication and behaviors of their BSMM Facebook friends. Using linear network autocorrelation regression models, results showed that BSMM's safer sex communication and condom use behavior were each associated with the communication and behavior of their online peers. Specifically, BSMM's condom use was positively associated with their friends' condom use and friends' safer sex communication, and BSMMs' safer sex communication was positively associated with friends' safer sex communication. Moreover, contrary to prior research, BSSM's safer sex communication and condom use were not related to one another, suggesting that talking about safer sex on social media should not be interpreted to be an indication of engageDment in safer sex behavior. These findings underscore an opportunity to leverage peer influence in social media networks, particularly in the form of masspersonal communication, to encourage cascades of safer sex messaging among peers and adoption of safer sex behavior.

A systematic review and guide for using multi-response statistical models in co-infection research

The simultaneous infection of organisms with two or more co-occurring pathogens, otherwise known as co-infections, concomitant infections or multiple infections, plays a significant role in the dynamics and consequences of infectious diseases in both humans and animals. To understand co-infections, ecologists and epidemiologists rely on models capable of accommodating multiple response variables. However, given the diversity of available approaches, choosing a model that is suitable for drawing meaningful conclusions from observational data is not a straightforward task. To provide clearer guidance for statistical model use in co-infection research, we conducted a systematic review to (i) understand the breadth of study goals and host-pathogen systems being pursued with multi-response models and (ii) determine the degree of crossover of knowledge among disciplines. In total, we identified 69 peer-reviewed primary studies that jointly measured infection patterns with two or more pathogens of humans or animals in natural environments. We found stark divisions in research objectives and methods among different disciplines, suggesting that cross-disciplinary insights into co-infection patterns and processes for different human and animal contexts are currently limited. Citation network analysis also revealed limited knowledge exchange between ecology and epidemiology. These findings collectively highlight the need for greater interdisciplinary collaboration for improving disease management.

Anal human papillomavirus (HPV) disagreement by Linear Array compared to SPF10 PCR-DEIA-LiPA25 system in young sexual minority men

Introduction

Young sexual minority men (SMM) bear the greatest burden of anal human papillomavirus (HPV) infections. We assessed anal HPV genotype discordance between the Linear Array (LA) and SPF10 PCR-DEIA-LiPA25 (LiPA25).

Methods

Discordance was assessed between LA and LiPA25 using self-collected anal swabs from 120 SMM aged 18-29 who were recruited in 2014-2016. Multiple-type infection was explored as a potential confounder of testing agreement, along with clinical and behavioral factors such as HIV status, syphilis status, incarceration history, health insurance coverage, having 3 or more sex partners in the past 6 months, and co-infection with HPV-16.

Results

Significant discordance was found for HPV-6, -11, -16, -31, -42, -54, and -59. Exploratory analyses suggest higher prevalence of genotype discordance in those living with HIV, those with 3 or more sex partners, and those who were positive for 4 or more HPV types.

Conclusions

Our results highlight the importance of HPV detection methods which may inform different interpretations of research assessing anal HPV natural history among SMM at highest risk for HPV.

Predictors of HIV Molecular Cluster Membership and Implications for Partner Services

Public health surveillance data used in HIV molecular cluster analyses lack contextual information that is available from partner services (PS) data. Integrating these data sources in retrospective analyses can enrich understanding of the risk profile of people in clusters. In this study, HIV molecular clusters were identified and matched to information on partners and other information gleaned at the time of diagnosis, including coinfection with syphilis. We aimed to produce a more complete understanding of molecular cluster membership in Houston, Texas, a city ranking ninth nationally in rate of new HIV diagnoses that may benefit from retrospective matched analyses between molecular and PS data to inform future intervention. Data from PS were matched to molecular HIV records of people newly diagnosed from 2012 to 2018. By conducting analyses in HIV-TRACE (TRAnsmission Cluster Engine) using viral genetic sequences, molecular clusters were detected. Multivariable logistic regression models were used to estimate the association between molecular cluster membership and completion of a PS interview, number of named partners, and syphilis coinfection. Using data from 4,035 people who had a viral genetic sequence and matched PS records, molecular cluster membership was not significantly associated with completion of a PS interview. Among those with sequences who completed a PS interview (n = 3,869), 45.3% (n = 1,753) clustered. Molecular cluster membership was significantly associated with naming 1 or 3+ partners compared with not naming any partners [adjusted odds ratio, aOR: 1.27 (95% confidence interval, CI: 1.08-1.50), p = .003 and aOR: 1.38 (95% CI: 1.06-1.81), p = .02]. Alone, coinfection with syphilis was not significantly associated with molecular cluster membership. Syphilis coinfection was associated with molecular cluster membership when coupled with incarceration [aOR: 1.91 (95% CI: 1.08-3.38), p = .03], a risk for treatment interruption. Enhanced intervention among those with similar profiles, such as people coinfected with other risks, may be warranted.

Social Network Influence on Syphilis Testing for Black Sexual Minority Men in Baltimore, Maryland: A Cross-sectional Social Network Analysis

ABSTRACT

Black sexual minority men (BSMM), including those with HIV, have disproportionate rates of syphilis infection. This study examines the associations of social network characteristics on syphilis testing, given that social network approaches are well established as effective methods to establish health-promoting social norms. We analyzed baseline data from a sexual health behavioral intervention. Using multivariable logistic regression, we modeled individual and social network characteristics on syphilis testing. Of the 256 participants, 37% tested for syphilis in the past year. In the adjusted model controlling for individual factors, odds of syphilis testing increased 89% for each increase in network member participants being encouraged to get a syphilis test (95% confidence interval [1.19-3.00]). Feeling comfortable accompanying a friend for HIV/sexually transmitted infection testing was associated with 2.47 increased odds of syphilis testing. Encouraging and training individuals to discuss sexual health topics with their network members may lead to the establishment of testing in social networks of Black sexual minority men.

Social networks, high-risk anal HPV and coinfection with HIV in young sexual minority men

OBJECTIVES

Young sexual minority men (SMM) exhibit a high prevalence and incidence of high-risk genotypes of human papillomavirus (hrHPV) anal infections and a confluence of a high prevalence of HIV and rectal STIs. Social determinants of health (SDOHs) are linked to social network contexts that generate and maintain racial disparities in HIV and STIs. A network perspective was provided to advance our knowledge of drivers of genotype-specific hrHPV infection and coinfection with HIV. The study also examined whether socially connected men are infected with the same high-risk HPV genotypes and, if so, whether this tendency is conditioned on coinfection with HIV.

METHODS

Our sample included 136 young SMM of predominantly black race and their network members of other races and ethnicities, aged 18-29 years, who resided in Houston, Texas, USA. These participants were recruited during 2014-2016 at the baseline recruitment period by network-based peer referral, where anal exfoliated cells and named social and sexual partners were collected. Exponential random graph models were estimated to assess similarity in genotype-specific hrHPV anal infection in social connections and coinfection with HIV in consideration of the effects of similarity in sociodemographic, sexual behavioural characteristics, SDOHs and syphilis infection.

RESULTS

Pairs of men socially connected to each other tend to be infected with the same hrHPV genotypes of HPV-16, HPV-45 and HPV-51 or HPV-16 and/or HPV-18. The tendency of social connections between pairs of men who were infected with either HPV-16 or HPV-18 were conditioned on HIV infection.

CONCLUSIONS

Networked patterns of hrHPV infection could be amenable to network-based HPV prevention interventions that engage young SMM of predominantly racial minority groups who are out of HIV care and vulnerable to high-risk HPV acquisition.

Spatiotemporal distribution analysis of syphilis in Brazil: Cases of congenital and syphilis in pregnant women from 2001-2017

In Brazil, the notification of congenital (CS) and syphilis in pregnant women (SiP) is compulsory. Notification data provided by the Ministry of Health in combination with the mapping of vulnerable geographic areas is essential to forecasting possible outbreaks and more effectively combating infection through monitoring. We aim to evaluate the spatiotemporal distribution and epidemiological aspects of reported cases of CS and SiP in Brazil. A retrospective ecological study was carried out using secondary surveillance data obtained from the Brazilian National Notifiable Diseases Information System (SINAN) database, considering all reported cases of CS and SiP between 2001 to 2017. Epidemiological characteristics and time trends were analyzed using joinpoint regression models and spatial distribution, considering microregions or states/macroregions as units of analysis. A total of 188,630 (359/100,000 birth lives) CS and 235,895 of SiP (6.3/100,000 inhabitants) were reported during the period studied. In general, the epidemiologic profile of Brazil indicates most reported CS cases occurred in "mixed-race" newborns who were diagnosed within seven days of birth and whose mothers had received prenatal care, but the epidemiologic profile varies by Brazilian macroregion. Regarding SiP, most cases were among women who self-reported 'mixed-race', were aged 20-39 years, had up to eight years of formal education and were diagnosed with primary or latent syphilis. Approximately 549 (98.4%) and 558 (100%) microregions reported at least one case of CS and SiP, respectively. From 2012 to 2016, CS cases increased significantly in almost all Brazilian states, most notably in the South, Southeast, and Central-West macroregions, from 2001-2017 and the relative risk (RR) of SiP increased around 400% (RR: 1,00 to 445,50). Considering the epidemiological scenario of the infection in Brazil, it is necessary to enhance preventive, control and eradication measures.

Spatio-temporal variation on syphilis from 2005 to 2018 in Zhejiang Province, China

Background

Syphilis has spread throughout China, especially in Zhejiang Province which endangers the health and lives of people. However, the spatial and temporal epidemiological studies of syphilis in Zhejiang are not thorough enough. The temporal and spatial variation and the relevant factors of syphilis incidence should be analyzed for more effective prevention and control in Zhejiang, China.

Methods

Data on confirmed cases of syphilis in Zhejiang Province from 2005 to 2018 was used and the spatio-temporal distributions were described. The spatial autocorrelation analysis and SaTScan analysis were performed to identify spatio-temporal clusters. A Bayesian spatial Conditional Autoregression (CAR) model was constructed to explore the relationships between syphilis incidence and common social and natural indicators.

Results

474,980 confirmed cases of syphilis were reported between 2005 and 2018 with a large peak in 2010. Farmers and unemployed people accounted for the largest proportion of confirmed cases. And the significant spatial clusters of syphilis were concentrated in the north of Zhejiang Province, especially in more economically developed regions. Seven spatio-temporal clusters were identified and the main three high-risk areas were located in Hangzhou (RR = 1.62, P < 0.05), Zhoushan and Ningbo (RR = 1.99, P < 0.05), and Lishui (RR = 1.68, P < 0.05). The findings showed that the morbidity of syphilis was positively correlated with the Gross Domestic Product (GDP) per capita, the number of health technicians per 10,000 people, the proportion of the elderly and air temperature were negatively correlated with the proportion of the urban population, the proportion of men and precipitation.

Conclusions

The spatio-temporal analysis revealed that the prevalence of syphilis was still serious in Zhejiang Province. Syphilis high-risk areas were mainly located in the more developed coastal regions where more targeted intervention measures were required to be implemented. The study highlighted the need to strengthen Sexually Transmitted Diseases (STD) screening and health education for high-risk groups and improve the coverage of syphilis testing to reduce hidden syphilis cases.

Network centrality for the identification of biomarkers in respondent-driven sampling datasets

Networks science techniques are frequently used to provide meaningful insights into the populations underlying medical and social data. This paper examines SATHCAP, a dataset related to HIV and drug use in three US cities. In particular, we use network measures such as betweenness centrality, closeness centrality, and eigenvector centrality to find central, important nodes in a network derived from SATHCAP data. We evaluate the attributes of these important nodes and create an exceptionality score based on the number of nodes that share a particular attribute. This score, along with the underlying network itself, is used to reveal insight into the attributes of groups that can be effectively targeted to slow the spread of disease. Our research confirms a known connection between homelessness and HIV, as well as drug abuse and HIV, and shows support for the theory that individuals without easy access to transportation are more likely to be central to the spread of HIV in urban, high risk populations.

Sexual Mixing and HIV Transmission Potential Among Greek Men Who have Sex with Men: Results from SOPHOCLES

HIV incidence among men who have sex with men (MSM) in Greece remains unchanged despite effective response to a recent outbreak among people who inject drugs (PWID). Network factors are increasingly understood to drive transmission in epidemics. The primary objective of the study was to characterize MSM in Greece, their sexual behaviors, and sexual network mixing patterns. We investigated the relationship between serostatus, sexual behaviors, and self-reported sex networks in a sample of MSM in Athens, Greece, generated using respondent driven sampling. We estimated mixing coefficients (r) based on survey-generated egonets. Additionally, multiple logistic regression was used to estimate adjusted odds ratios (AOR) and to assess relationships between serostatus, sexual behaviors, and sociodemographic indicators. A sample of 1,520 MSM participants included study respondents (n = 308) and their network members (n = 1,212). Mixing based on serostatus (r = 0.12, σr = 0.09-0.15) and condomless sex (r = 0.11, σr = 0.07-0.14) was random. However, mixing based on sex-drug use was highly assortative (r = 0.37, σr = 0.32-0.42). This study represents the first analysis of Greek MSM sexual networks. Our findings highlight protective behavior in two distinct network typologies. The first typology mixed assortatively based on serostatus and sex-drug use and was less likely to engage in condomless sex. The second typology mixed randomly based on condomless sex but was less likely to engage in sex-drug use. These findings support the potential benefit of HIV prevention program scale-up for this population including but not limited to PrEP.

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.

Identifying influential neighbors in social networks and venue affiliations among young MSM: a data science approach to predict HIV infection

OBJECTIVE

Young MSM (YMSM) bear a disproportionate burden of HIV infection in the United States and their risks of acquiring HIV may be shaped by complex multilayer social networks. These networks are formed through not only direct contact with social/sex partners but also indirect anonymous contacts encountered when attending social venues. We introduced a new application of a state-of-the-art graph-based deep learning method to predict HIV infection that can identify influential neighbors within these multiple network contexts.

DESIGN AND METHODS

We used empirical network data among YMSM aged 16-29 years old collected from Houston and Chicago in the United States between 2014 and 2016. A computational framework GAT-HIV (Graph Attention Networks for HIV) was proposed to predict HIV infections by identifying influential neighbors within social networks. These networks were formed by multiple relations constituted of social/sex partners and shared venue attendances, and using individual-level variables. Further, GAT-HIV was extended to combine multiple social networks using multigraph GAT methods. A visualization tool was also developed to highlight influential network members for each individual within the multiple social networks.

RESULTS

The multigraph GAT-HIV models obtained average AUC values of 0.776 and 0.824 for Chicago and Houston, respectively, performing better than empirical predictive models (e.g. AUCs of random forest: 0.758 and 0.798). GAT-HIV on single networks also delivered promising prediction performances.

CONCLUSION

The proposed methods provide a comprehensive and interpretable framework for graph-based modeling that may inform effective HIV prevention intervention strategies among populations most vulnerable to HIV.

Frequent Methicillin-Resistant Staphylococcus aureus Introductions Into an Inner-city Jail: Indications of Community Transmission Networks

BACKGROUND

Jails may facilitate spread of methicillin-resistant Staphylococcus aureus (MRSA) in urban areas. We examined MRSA colonization upon entrance to a large urban jail to determine if there are MRSA transmission networks preceding incarceration.

METHODS

Males incarcerated in Cook County Jail (Chicago) were enrolled, with enrichment for people living with human immunodeficiency virus (PLHIV), within 72 hours of intake. Surveillance cultures assessed prevalence of MRSA colonization. Whole-genome sequencing (WGS) identified preincarceration transmission networks.We examined methicillin-resistant Staphylococcus aureus (MRSA) isolates to determine if there are transmission networks that precede incarceration. A large proportion of individuals enter jail colonized with MRSA. Molecular epidemiology and colonization risk factors provide clues to community reservoirs for MRSA.

RESULTS

There were 718 individuals (800 incarcerations) enrolled; 58% were PLHIV. The prevalence of MRSA colonization at intake was 19%. In multivariate analysis, methamphetamine use, unstable housing, current/recent skin infection, and recent injection drug use were predictors of MRSA. Among PLHIV, recent injection drug use, current skin infection, and HIV care at outpatient clinic A that emphasizes comprehensive care to the lesbian, gay, bisexual, transgender community were predictors of MRSA. Fourteen (45%) of 31 detainees with care at clinic A had colonization. WGS revealed that this prevalence was not due to clonal spread in clinic but rather to an intermingling of distinct community transmission networks. In contrast, genomic analysis supported spread of USA500 strains within a network. Members of this USA500 network were more likely to be PLHIV (P < .01), men who have sex with men (P < .001), and methamphetamine users (P < .001).

CONCLUSIONS

A large proportion of individuals enter jail colonized with MRSA. Molecular epidemiology and colonization risk factors provide clues to identify colonized detainees entering jail and potential community reservoirs of MRSA.

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.

The Co-evolution of online social networks and syphilis incidence among young black men who have sex with men

Network contexts have been implicated in the facilitation of syphilis transmission, however little is known about the relationship between online social networks, a proxy for physical networks, and rates of syphilis infection and how they co-evolve over time. To these ends, this study explored the interdependent relationship between Facebook friendship network dynamics and rates of syphilis incidence among young Black men who have sex with men (YBMSM). Specifically, we investigated the extent to which syphilis status, as a latent profile of network members, serves as a selection mechanism of Facebook tie formation and the degree to which Facebook friendships influenced dynamics of syphilis seroconversion. Sexual health, behavioral, and social network data were collected from a cohort of YBMSM (N = 286, Mean age = 22.8) at two time points between 2013 and 2015 in Chicago, IL, USA. The interdependencies between Facebook friendship networks and syphilis infection were assessed using stochastic actor-based models for social networks and behavior. Results showed that YBMSM tended to form Facebook friendships with other YBMSM who had similar syphilis and HIV status profiles, and the hazard of contracting syphilis was likewise influenced by their Facebook friendships, albeit subtly, by being connected to infectious network members. Meanwhile, intrinsic characteristics like condomless sex, HIV status, and online partner-seeking were not associated with dynamics in syphilis incidence. These findings show that there is a mutually dependent relationship between the online network dynamics of YBMSM and rates of syphilis incidence. Findings also direct attention to network-based strategies for intervention.

An Investigation of Early Syphilis Among Men Who have Sex with Men: Alaska, 2018: Findings from a 2018 Rapid Ethnographic Assessment

The state of Alaska had a sharp increase in cases of primary and secondary syphilis among gay, bisexual, and other men who have sex with men (GBMSM) in 2018, centered in Anchorage. A rapid ethnographic assessment was conducted in October 2018 to examine contextual factors contributing to local increases in syphilis. The assessment team conducted qualitative interviews with 64 (N=49 interviews) key informants in Anchorage and Matanuska-Susitna Valley identified through the STD/HIV program at the Alaska Department of Health and Social Services, Division of Public Health (ADPH):  ADPH staff (n = 11; 22%) Medical Providers (n = 18; 37%), Community-Based Organizations/Partners (n = 9; 18%), and GBMSM Community Members (n = 11; 22%). This project was deemed exempt from IRB review. Primary factors affecting syphilis transmission, care, and treatment among GBMSM were: (1) Low awareness about the current syphilis outbreak and ambivalence about syphilis and other STIs; (2) Aspects of sexual partnering such as travel, tourism, and the use of online sites and apps to facilitate anonymous sex and multiple (both sequential/concurrent) partnering; (3) The synergistic effects of substance use, homelessness, and transactional sex; (4) Choosing condomless sex; and (5) Challenges accessing healthcare, including the ability to find appropriate and culturally competent care. Syphilis increases may have been influenced by factors which spanned multiple sectors of the Anchorage community, including individual behavior, community-level risk and protective factors, and use of and interactions with resources offered by ADPH, community-based organizations, and medical providers.

Network context matters: graph convolutional network model over social networks improves the detection of unknown HIV infections among young men who have sex with men

OBJECTIVE

HIV infection risk can be estimated based on not only individual features but also social network information. However, there have been insufficient studies using n machine learning methods that can maximize the utility of such information. Leveraging a state-of-the-art network topology modeling method, graph convolutional networks (GCN), our main objective was to include network information for the task of detecting previously unknown HIV infections.

MATERIALS AND METHODS

We used multiple social network data (peer referral, social, sex partners, and affiliation with social and health venues) that include 378 young men who had sex with men in Houston, TX, collected between 2014 and 2016. Due to the limited sample size, an ensemble approach was engaged by integrating GCN for modeling information flow and statistical machine learning methods, including random forest and logistic regression, to efficiently model sparse features in individual nodes.

RESULTS

Modeling network information using GCN effectively increased the prediction of HIV status in the social network. The ensemble approach achieved 96.6% on accuracy and 94.6% on F1 measure, which outperformed the baseline methods (GCN, logistic regression, and random forest: 79.0%, 90.5%, 94.4% on accuracy, respectively; and 57.7%, 80.2%, 90.4% on F1). In the networks with missing HIV status, the ensemble also produced promising results.

CONCLUSION

Network context is a necessary component in modeling infectious disease transmissions such as HIV. GCN, when combined with traditional machine learning approaches, achieved promising performance in detecting previously unknown HIV infections, which may provide a useful tool for combatting the HIV epidemic.

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.

Barriers to syphilis testing among men who have sex with men: a systematic review of the literature

Men who have sex with men (MSM) represent the highest risk group for syphilis in the United States and several other countries. Improving uptake of syphilis testing among MSM requires understanding key barriers to testing in this population. Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic review to assess proportions of syphilis testing among MSM and identify social, structural, and individual barriers to syphilis testing was conducted. All searches were conducted through the University of Maryland world catalogue search engine. Studies that measured syphilis testing in a sample of MSM were included. All studies were assessed for bias using JBI-MAStARI instruments. Studies were synthesised based on sample size, years of data collection, study selection method (e.g. hospital or clinic-based, community/venue-based), location (e.g. USA-based, other countries) and results of the bias assessment. For studies measuring barriers associated with testing, the measure of association, point estimate and statistical significance was assessed. Of 848 studies found in the initial search, 24 were included in the final review. The largest difference in syphilis testing proportions was based on hospital or clinic-based sampling (50-87%) compared with venue/community-based and online sampling (31-38%). Socioeconomic factors (four items, four studies, OR 0.23 to 0.68), healthcare interactions six items, five studies, OR 0.09 to 0.69) and community/interpersonal factors (seven items, five studies, OR 0.07 to 0.58) were identified as barriers to testing. Barriers to syphilis testing among MSM include socioeconomic factors, healthcare-related factors and community/interpersonal factors. Improving overall routine utilisation of healthcare services is an especially important focal point in testing promotion.

Collective Avoidance of Social and Health Venues and HIV Racial Inequities: Network Modeling of Venue Avoidance on Venue Affiliation, Social Networks, and HIV Risk

Many younger Black men who have sex with men (YBMSM) are exposed to homonegativity, societal stigma, and racial discrimination in their social environment. This study uses a social network modeling methodology to identify aspects of the social environment that are not often described, that is, the places and spaces or "venues" where YBMSM socialize or where they receive HIV prevention services. In particular, we identify the structural features of avoidance of these venues as an indicator of negative experiences, using bipartite exponential random graph models. Our study theorizes that YBMSM avoid certain venues en masse through information diffusion among social network members. We specify two social mechanisms of collective venue avoidance-(1) homophily (i.e., ego-alter similarity in venue avoidance) and (2) popular opinion leaders (as early adopters)-and test the corresponding hypotheses that (Hypothesis 1) socially connected individuals avoid venues together and that (Hypothesis 2) popular individuals would be more likely to avoid venues. Based on data collected from YBMSM aged 16 to 29 years between 2014 and 2016 in Houston, Texas (N = 227) and Chicago, Illinois (N = 241), results indicate that Hypothesis 1 was supported in both cities but that Hypothesis 2 was supported only in Chicago. The findings suggest that the structural patterns of venue avoidance are different between cities and may inform dissemination of prevention messages and delivery of venue- and social influence-based HIV interventions.

Repeated Syphilis Episodes in HIV-Infected Men Who Have Sex With Men: A Multicenter Prospective Cohort Study on Risk Factors and the Potential Role of Syphilis Immunity

Background

Syphilis is re-emerging globally in general and HIV-infected populations, and repeated syphilis episodes may play a central role in syphilis transmission among core groups. Besides sexual behavioral factors, little is known about determinants of repeated syphilis episodes in HIV-infected individuals—including the potential impact of preceding syphilis episodes on subsequent syphilis risk.

Methods

In the prospective Swiss HIV cohort study, with routine syphilis testing since 2004, we analyzed HIV-infected men who have sex with men (MSM). Our primary outcome was first and repeated syphilis episodes. We used univariable and multivariable Andersen-Gill models to evaluate risk factors for first and repeated incident syphilis episodes.

Results

Within the 14-year observation period, we included 2513 HIV-infected MSM with an initially negative syphilis test. In the univariable and multivariable analysis, the number of prior syphilis episodes (adjusted hazard ratio [aHR] per 1-episode increase, 1.15; 95% confidence interval [CI], 1.01–1.31), having occasional sexual partners with or without condomless anal sex (aHR, 4.99; 95% CI, 4.08–6.11; and aHR, 2.54; 95% CI, 2.10–3.07), and being currently on antiretroviral therapy (aHR, 1.62; 95% CI, 1.21–2.16) were associated with incident syphilis.

Conclusions

In HIV-infected MSM, we observed no indication of decreased syphilis risk with repeated syphilis episodes. The extent of sexual risk behavior over time was the strongest risk factor for repeated syphilis episodes. The observed association of antiretroviral therapy with repeated syphilis episodes warrants further immunological and epidemiological investigation.

Intersection of HIV and community-associated methicillin-resistant Staphylococcus aureus

The epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has evolved over the past approximately 20 years, with certain populations appearing to have disproportionate risk. Of concern is the potential worsening of S. aureus infections in light of the continued opioid crisis. This review will discuss how CA-MRSA has significantly impacted HIV-infected individuals and address additional factors and populations that are associated with increased risk for MRSA. It will review therapeutic options and infection control strategies as well as highlight how whole genome sequencing can be used to extend traditional epidemiologic analysis and ultimately, inform infection prevention efforts. Continued work identifying those at the highest risk for MRSA, what the best infection prevention settings are in community settings and how to effectively implement and target these strategies is needed. Ultimately, infection control efforts will likely need to extend beyond healthcare settings to effectively and sustainably reduce MRSA infections.

Associations Between Neighborhood Problems and Sexual Behaviors Among Black Men Who Have Sex with Men in the Deep South: The MARI Study

There is a disproportionately high HIV incidence among Black men who have sex with men (MSM) despite equal or lower levels of HIV risk behaviors compared to White MSM. Due to high levels of racial segregation in the U.S., Black MSM have an elevated likelihood of living in neighborhoods that contain psychosocial stressors, which, in turn, may increase behaviors promoting HIV infection. We examined associations between perceived neighborhood problems and sexual behaviors among Black MSM in the Deep South, a population at highest risk of HIV. Data came from the MARI Study, which included Black MSM ages 18-66 years recruited from the Jackson, MS, and Atlanta, GA, metropolitan areas (n = 377). Participants completed questions about neighborhood problems (e.g., excessive noise, heavy traffic/speeding cars and trash/litter) and sexual behaviors (e.g., condomless sex and drug use before or during sex). We used Poisson's regression model with robust standard errors to estimate the adjusted prevalence ratio (aPR; 95% confidence intervals [CI]) of neighborhood problems (coded as tertiles [tertile 1 = low neighborhood problems, tertile 2 = medium neighborhood problems, tertile 3 = high neighborhood problems] as well as continuously) with sexual behaviors, after adjustment for sociodemographic characteristics and other variables. About one-fourth of the sample reported at least one neighborhood problem, with the most common (31.6%) being no/poorly maintained sidewalks, which indicates an infrastructural problem. In multivariable models, compared to those in the lowest tertile, those reporting more neighborhood problems (tertile 2: aPR = 1.49, 95% CI = 1.04, 2.14 and tertile 3: aPR = 1.53, 95% CI = 1.05, 2.24) reported more drug use before or during sex (p for trend = .027). Neighborhood problems may promote behaviors (e.g., drug use before or during sex) conducive to HIV infection. Structural interventions could improve community infrastructure to reduce neighborhood problems (e.g., no/poorly maintained sidewalks and litter). These interventions may help to reduce HIV incidence among Black MSM in the Deep South.

Resurgence of Syphilis in the United States: An Assessment of Contributing Factors

In the last decade, there has been a marked resurgence of syphilis in the United States despite the availability of effective treatments and previously reliable prevention strategies. The majority of cases are among the population of men who have sex with men (MSM); however, there has also been a recent increase among premenopausal women, coinciding with a concerning rise of congenital cases. The resurgence of syphilis can be largely attributed to changing social and behavioral factors, especially among young MSM. The biological association of syphilis with human immunodeficiency virus (HIV) transmission and acquisition is particularly alarming because of the increased individual and healthcare burden. In addition, some individual actions and public health efforts that are meant to reduce the risk of acquiring HIV may actually lead to risk compensation that facilitates the transmission of syphilis. Untreated syphilis is associated with detrimental health outcomes; therefore, both effective prevention strategies and treatment of this systemic disease have important short-term and long-term public health implications. This article offers a review of social and behavioral factors contributing to the current resurgence and recommendations for reducing syphilis incidence through medical and public health prevention strategies.

The multiplex social environments of young Black men who have sex with men: How online and offline social structures impact HIV prevention and sex behavior engagement

In the United States, young Black men who have sex with men (YBMSM) remain disproportionately affected by HIV. The social networks in which YBMSM are embedded are generally understood to be critical factors in understanding their vulnerability. In this study, we acknowledge the relational richness of YBMSMs' social environments (what we define as multiplexity) and their increasing prioritization of online social networking sites (SNS). Specifically, we investigate whether protective and/or risky features of YBMSMs' Facebook friendships and group affiliations are related to their HIV prevention and sex behavior engagement, while also accounting for features of their offline confidant (or support) and sex networks. Using data from a population-based cohort study of YBMSM living in Chicago (N=268), we perform a series of multiple logistic regression analyses to examine associations between features of YBMSMs' Facebook, confidant, and sexual networks with three prevention outcomes and three sex behavior outcomes, while also controlling for factors at the individual and structural levels. Results show that network features play a more significant role in predicting engagement in sex behaviors than prevention behaviors. Specifically, having more confidants, having confidants who are family members, meeting sex partners online, having more YBMSM Facebook friends, belonging to Facebook groups with an LGBTQ focus, and having greater subject diversity in one's Facebook group affiliations were significantly associated with one or more sex behavior outcomes. We conclude with a discussion of the implications of our findings for HIV prevention intervention efforts.

Network Modeling of PrEP Uptake on Referral Networks and Health Venue Utilization Among Young Men Who Have Sex with Men

The objective of this study is to identify individual-level factors and health venue utilization patterns associated with uptake of pre-exposure prophylaxis (PrEP) and to evaluate whether PrEP uptake behavior is further diffused among young men who have sex with men (YMSM) through health venue referral networks. A sample of 543 HIV-seronegative YMSM aged 16-29 were recruited in 2014-2016 in Chicago, IL, and Houston, TX. Stochastic social network models were estimated to model PrEP uptake. PrEP uptake was associated with more utilization of health venues in Houston and higher levels of sexual risk behavior in Chicago. In Houston, both Hispanic and Black YMSM compared to White YMSM were less likely to take PrEP. No evidence was found to support the spread of PrEP uptake via referral networks, which highlights the need for more effective PrEP referral network systems to scale up PrEP implementation among at-risk YMSM.

Syphilis associated with recreational drug use, depression and high-risk sexual behaviour in men who have sex with men: a case-control study in China

OBJECTIVE

We investigated syphilis prevalence among men who have sex with men (MSM) in China, as well as potential risk factors. Our principal hypothesis was that syphilis would be associated with the use of recreational drugs such as methamphetamines.

METHODS

From April to October 2013, we used several methods to recruit MSM in Qingdao, collecting demographic/behavioural information via self-administrated questionnaires. Trained health workers collected blood for the Treponema pallidum particle assay (TPPA) with positives confirmed by a toluidine red unheated serum test. We used an unmatched case-control study to identify factors that might predict syphilis infection using multivariable logistic regression.

RESULTS

We recruited 447 MSM who agreed to participate and who completed syphilis testing. Of 71 (15.9%) syphilis-positive MSM, 44 (62.0%) used drugs. Of 376 (84.1%) syphilis-negative MSM, 186 (49.5%) used drugs. We found a positive association with syphilis for any recreational drug use (crude OR (cOR) 1.7, 95 % CI 1.0 to 2.8), frequent methamphetamine use (cOR 2.4, 95% CI 1.1 to 5.3) and multiple drug use (adjusted OR (aOR) 3.4, 95% CI 1.3 to 9.2). Syphilis-positive men were more likely to have a higher physical depression score (aOR 5.2, 95% CI 1.1 to 24.4), be > 30 years old (aOR 2.7, 95% CI 1.5 to 4.8), report a prior STI (aOR 4.1, 95% CI 2.3 to 7.3) and report a sex party experience (aOR 2.2, 95% CI 1.1 to 4.4).

CONCLUSIONS

Recreational drug use, depression and high-risk sexual behaviours were associated with syphilis infection among MSM in China. Only a multifaceted approach is likely be effective in control of both syphilis and HIV .

The Social Context of HIV Prevention and Care among Black Men Who Have Sex with Men in Three U.S. Cities: The Neighborhoods and Networks (N2) Cohort Study

Background: In many parts of the world, stark racial disparities in human immunodeficiency virus (HIV) prevalence, incidence, prevention, and care outcomes persist among gay, bisexual, and other men who have sex with men (MSM), with Black MSM significantly impacted in the United States (U.S.). Individual-level characteristics, including sexual behaviors and socioeconomic status, do not fully account for racial/ethnic disparities in HIV among MSM. We hypothesize that neighborhood contexts and network characteristics influence risk for HIV infection as well as HIV-related prevention and care behaviors. As such, the study design includes the use of real-time geospatial methods and in-depth assessments of multiple network typologies to investigate the impact of neighborhood and network-level factors on HIV prevention and treatment among Black MSM residing in longstanding priority HIV elimination areas in the U.S., namely Chicago, Illinois and in the Deep South (Jackson, Mississippi and New Orleans, Louisiana) (n = 450, n = 50, and n = 100, respectively). We describe the design, sampling methods, data collection, data management methods, and preliminary findings of the ongoing 'Neighborhoods and Networks (N2) Cohort Study'. Methods/Design: N2 employs a prospective longitudinal design. The sample includes Black MSM participants in Chicago recruited via respondent-driven sampling and assessed every six months over two years of follow-up. Participants enrolled in Jackson and New Orleans are being recruited through existing health and community services and assessed every six months over one year of follow-up. Mobility within and between neighborhoods is being assessed using global positioning system (GPS) technology. Social and sexual networks among Black MSM are being studied through egocentric network inventories as well as newer methods of creating meso-level networks that involve social media (Facebook) and mobile phone contacts. Key HIV prevention outcomes such as pre-exposure prophylaxis (PrEP) care engagement, and HIV/STI (sexually transmitted infections) biomarkers will be examined at baseline and follow-up. Results: As of 31 December 2018, a total of 361 men were enrolled across all study sites: 259 in Chicago and 102 in the Deep South (75 in New Orleans and 27 in Jackson). At baseline, participants ranged in age from 17 to 65 years old (mean = 34.3, standard deviation = 5.1) with 123 men (34.1%) self-reported as HIV positive. While HIV treatment levels were similar between sites, men in the Deep South reported higher rates of adherence than men in Chicago (63.3% versus 49.4%, p = 0.03). Sexual risk profiles were mainly the same between men from different study sites, with 22.9% of men in Chicago and 28.9% in the Deep South reporting consistent condom use during vaginal and anal sex (p = 0.26). Regarding their home neighborhoods, men in the Deep South were more likely than those in Chicago to characterize theirs as having a good reputation (43.1% versus 24.7%, p < 0.001) and as being safe (37.3% versus 21.2%, p = 0.002). Conclusions: The focus on Black MSM in the N2 Study will allow for a nuanced exploration of the attitudes, beliefs, behaviors, and practices of a diverse group of Black MSM. The study is also positioned to provide novel insight about neighborhood and network characteristics that influence HIV-related behaviors. A health equity framework ensures that Black MSM are not explicitly or implicitly deemed as deviant, disordered, or the non-reference group. Findings from N2 will provide guidance for the implementation of more impactful HIV prevention interventions that engage a diverse population of Black MSM as we work toward HIV elimination in the U.S.

Network overlap and knowledge of a partner's HIV status among young men who have sex with men

For individuals living with HIV, disclosure of HIV status to their partners can be a source of psychological and emotional stress. Minimal information about serostatus disclosure is available for young men who have sex with men (YMSM). This study examined the disclosure of HIV status to social and sexual partners among YMSM using social and sexual network data. Respondent-driven sampling was used to collect data from YMSM aged 16-29 in Houston, Texas and Chicago, Illinois. Social network data from 746 respondents and 2035 social and/or sexual partners were collected from 2014 to 2016, of whom 27.9% were HIV seropositive, with 9.4% of their partners being both sexually and socially connected to respondents (overlapping network status), and 90.6% either sexually or socially connected. Generalized estimating equation analysis was conducted based on respondents' knowledge of their sexual partners' HIV status. Results showed that respondents with overlapping sexual and social relationships with their partners were less likely to not know their partners' HIV status (AOR = 0.26 95% CI: 0.18-0.40). Results highlight the association between overlapping partnership and knowledge of partner's HIV status among YMSM. These findings are useful when selecting potential network members to disclose HIV status and support YMSM's health and well-being.

ACE gene haplotypes and social networks: Using a biocultural framework to investigate blood pressure variation in African Americans

Deaths due to hypertension in the US are highest among African Americans, who have a higher prevalence of hypertension and more severe hypertensive symptoms. Research indicates that there are both genetic and sociocultural risk factors for hypertension. Racial disparities in hypertension also likely involve genetic and sociocultural factors, but the factors may interact and manifest differently across racial groups. Here we use a biocultural approach to integrate genetic and social network data to better understand variation in blood pressure. We assay genetic variation at the angiotensin I converting enzyme gene (ACE) and analyze social network composition and structure in African Americans living in Tallahassee, FL (n = 138). We demonstrate that models including both genetic and social network data explain significantly more variation in blood pressure and have better model diagnostics than do models including only one datatype. Specifically, optimal models for systolic and diastolic blood pressure explain a notable 35% and 21%, respectively, of blood pressure variation. Analysis of the social networks reveals that individuals whose networks are dominated by family connections and are more fragmented have higher blood pressure. Historically, family support has been associated with better mental and physical health, but our results suggest that those family connections can also take a toll on health. These findings raise compelling questions regarding the roles of genetics, family, and social environment in hypertension in the African American community and suggest that interactions among these factors may help explain racial disparities in hypertension more accurately than any of the factors alone.

Statistical adjustment of network degree in respondent-driven sampling estimators: venue attendance as a proxy for network size among young MSM

We introduce a new venue-informed network degree measure, which we applied to respondent-driven sampling (RDS) estimators. Using data collected from 746 young MSM in 2014-2016 in Chicago, IL, and Houston, TX, we estimated the population seroprevalence of HIV and syphilis and risk/protective behaviors, using RDS estimates with self-reported network size as a standard degree measure as well as our proposed venue-informed degree measure. The results indicate that the venue-informed degree measure tended to be more efficient (smaller variance) and less biased than the other measure in both cities sampled. Venue attendance-adjusted network size may provide a more reliable and accurate degree measure for RDS estimates of the outcomes of interest.