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Pre-exposure prophylaxis (PrEP) rollout efforts thus far have inadequately reached young people from underrepresented backgrounds. This study explores PrEP engagement among young Black and Latinx men who have sex with men, transgender women, and gender diverse individuals in three U.S. cities using an adapted PrEP continuum measure. We analyze data from the recruitment phase of an ongoing PrEP engagement intervention (n = 319) using partial proportional odds logistic regression. Participants reported high willingness and intention to use PrEP, yet most (82%) were not currently taking PrEP. Being insured (aOR = 2.95, 95%-CI = 1.60-5.49), having one or more PrEP users in one's sexual network (aOR = 4.19, 95%-CI = 2.61-6.79), and higher individual HIV risk scores (aOR = 1.62, 95%-CI = 1.34-1.97) were each associated with being further along the PrEP continuum. Strategies are needed to address barriers to healthcare access and leverage connections within social and sexual networks in order to bolster PrEP engagement among marginalized young people from diverse backgrounds.Los esfuerzos de dar a conocer la profilaxis prexposición (PrEP) hasta el momento han llegado de forma inadecuada a los jóvenes de entornos desfavorecidos. Este estudio explora en tres ciudades de los EE. UU. el compromiso con la PrEP entre los jóvenes de raza negra y latino quienes son minorías sexuales o de género, utilizando una medida de seguimiento de la PrEP adaptada. Analizamos los datos de la fase de reclutamiento de una participación en la PrEP en curso (n = 319) utilizando una regresión logística parcial de probabilidades proporcionales. Los participantes manifestaron una alta disposición e intención de utilizar la PrEP, aunque la mayoría (82%) no tomaba actualmente la PrEP. Estar asegurado (aOR = 2,95, 95%-CI = 1,60–5,49), tener uno o más usuarios de la PrEP en su red sexual (aOR = 4,19, 95%-CI = 2,61–6,79), y mayores puntuaciones individuales de riesgo de VIH (aOR = 1,62, 95%-CI = 1,34–1,97) se asociaron con el hecho de llevar un seguimiento estrecho con la PrEP. Se necesitan estrategias para abordar las barreras de acceso a la atención médica y aprovechar las conexiones entre las redes sociales y las de carácter sexual, con el fin de reforzar el compromiso con la PrEP entre los jóvenes marginados de diversas procedencias.

In the context of China's gender imbalance, this study addresses the characteristics of sexual networks and their association with condom use in a sample of 713 male migrants (aged 28-64) who have rural hukou (household registration) in China. Descriptive statistics, univariate analyses, and multilevel random intercept models were used to investigate the characteristics of sexual networks and their associations with condom use. We found that age, marital status, type of sex partners, support (the main help given to each sex partner by the participant), type of sexual intercourse, and stability of sexual relationships were associated with condom use. The sexual networks were mainly composed of sex partners of similar age (58.46%), unmarried people (50.53%), and regular partners (49.38%). Married male migrants were more likely to use condoms with casual partners; unmarried male migrants were less likely to use condoms in emotional and stable relationships. Variation in individual factors, sex partners, and sexual relationship characteristics contribute to participation in condomless sex by male migrants. HIV prevention strategies should target unmarried male migrants and their casual sex partners by increasing their awareness of the risk of HIV transmission and the availability of free condoms.

BACKGROUND Chlamydia and gonorrhea have increased nationally and in the US Army. Rates reported in the Army are elevated relative to the general population, partly because of differing population demographics. METHODS Age- and sex-specific chlamydia and gonorrhea case rates among Army active component soldiers and the wider 18- to 64-year-old US adult population were computed from reports submitted through national and military surveillance systems in 2015 to 2019. Rates were standardized using the 2015 Army age and sex population distribution. Multivariable generalized linear models were generated to evaluate associated risk factors. RESULTS Army age- and sex-adjusted chlamydia rates (per 100,000 person-years) were nearly twice those of US adults (2019 rates, 2317 vs. 1241), whereas US age- and sex-adjusted gonorrhea rates surpassed Army rates (2019 rates, 536 vs. 396). Chlamydia and gonorrhea rates were significantly elevated in Army women younger than 25 years relative to US women aged 18 to 24 years (2015-2019 crude rates, 10,404 Army/4243 US for chlamydia and 1014 Army/694 US for gonorrhea). Gonorrhea rates were significantly elevated in US men aged 25 to 44 years (2015-2019 crude rates, 506 US/251 Army and 223 US/86 Army for men aged 25-34 and 35-44 years, respectively). Age, sex, and race-ethnicity were significantly associated with infection among soldiers. CONCLUSIONS Observed increases in chlamydia and gonorrhea and identified risk factors are consistent with those reported nationally. Higher adjusted chlamydia rates among soldiers may reflect greater individual or sexual network risks, screening biases, or increased health care access. The Army's lower adjusted gonorrhea rates may reflect differences in high-risk subgroups (e.g., men who have sex with men), differing sexual networks, or other confounders.

Although pre-exposure prophylaxis (PrEP) is a key tool in HIV prevention efforts, little is known about PrEP as a prevention strategy for criminal justice-involved (CJI) women. The purpose of this study was to examine multilevel factors shaping PrEP awareness and acceptability among CJI women. Between January 2017 and December 2017, we conducted 52 interviews with CJI women at high risk for HIV and stakeholders from the criminal justice (CJ) and public health (PH) systems. Interviews explored awareness of PrEP and the multilevel factors shaping PrEP acceptability. Data were analyzed using inductive thematic analysis and executive summaries. Atlas.ti facilitated analyses. The majority of CJI women (n = 27) were, on average, 41.3 years, from racial and ethnic minority groups (56% Black/African-American; 19% Latinx) and reported engaging in recent high-risk behavior (nearly 60% engaged in transactional sex, 22% reported ≥ 4 sexual partners, and 37% reported injection drug use). Of system stakeholders (n = 25), 52% represented the CJ sector. Although CJI women were generally unaware of PrEP, attitudes toward PrEP were enthusiastic. Barriers to PrEP acceptability included medication side effects (individual level); distrust in HIV prevention mechanisms (community level); lack of local HIV prevention efforts among high-risk women (public policy/HIV epidemic stage level). Factors promoting PrEP included perceived HIV risk (individual level); PrEP being an HIV prevention method that women can control without partner negotiation (social and sexual network level); and availability of public health insurance (community level). Despite low awareness of PrEP, CJI women expressed positive attitudes toward PrEP. To improve PrEP access for CJI women, implementation efforts should address barriers and leverage facilitators across multiple levels to be maximally effective.

BackgroundKey components of Ending the HIV Epidemic (EHE) plan include increasing HIV antiretroviral therapy (ART) and HIV preexposure prophylaxis (PrEP) coverage. One complication to addressing this service delivery challenge is the wide heterogeneity of HIV burden and healthcare access across the U.S. It is unclear how the effectiveness and efficiency of expanded PrEP will depend on different baseline ART coverage.MethodsWe used a network-based model of HIV transmission for men who have sex with men (MSM) in San Francisco. Model scenarios increased varying levels of PrEP coverage relative under current empirical levels of baseline ART coverage and two counterfactual levels. We assessed the effectiveness of PrEP with the cumulative percent of infections averted (PIA) over the next decade and efficiency with the number needed to treat (NNT) by PrEP required to avert one HIV infection.ResultsIn our projections, only the highest levels of combined PrEP and ART coverage achieved the EHE goals. Increasing PrEP coverage up to 75% showed that PrEP effectiveness was higher at higher baseline ART coverage with the PIA ranging from 61% in the lowest baseline ART coverage population to 75% in the highest ART coverage. The efficiency declined with increasing ART (NNT range from 41 to 113).ConclusionsImproving both PrEP and ART coverage would have a synergistic impact on HIV prevention even in a high baseline coverage city like San Francisco. Efforts should focus on narrowing the implementation gaps to achieve higher levels of PrEP retention and ART sustained viral suppression.

Mathematical models are powerful tools in HIV epidemiology, producing quantitative projections of key indicators such as HIV incidence and prevalence. In order to improve the accuracy of predictions, such models need to incorporate a number of behavioural and biological heterogeneities, especially those related to the sexual network within which HIV transmission occurs. An individual-based model, which explicitly models sexual partnerships, is thus often the most natural type of model to choose. In this paper we present PopART-IBM, a computationally efficient individual-based model capable of simulating 50 years of an HIV epidemic in a large, high-prevalence community in under a minute. We show how the model calibrates within a Bayesian inference framework to detailed age- and sex-stratified data from multiple sources on HIV prevalence, awareness of HIV status, ART status, and viral suppression for an HPTN 071 (PopART) study community in Zambia, and present future projections of HIV prevalence and incidence for this community in the absence of trial intervention., Author summary In this paper we present PopART-IBM, an individual-based model used to simulate HIV transmission in communities in high prevalence settings. We show that PopART-IBM can simulate transmission over a span of decades in a large community in less than a minute. This computational efficiency allows us to calibrate the model within an inference framework, and we show an illustrative example of calibration using an adaptive population Monte Carlo Approximate Bayesian Computation algorithm for a community in Zambia that was part of the HPTN-071 (PopART) trial. We compare the detailed model output to real-world data collected during the trial from this community. Finally, we project how the HIV epidemic would have changed over time in this community if no intervention from the trial had occurred.

We determined whether racial disparities in HIV infection among gay and bisexual men (MSM) may be partially explained by racial differences in the HIV transmission potential (i.e. mixing of people living with HIV and people not living with HIV or of unknown HIV serostatus) and density (i.e. sex partner concurrency) of sexual networks. Data included a behavioral survey, testing for HIV, and an egocentric sexual network survey. Mixed effects logistic regressions were used for hypothesis testing. Black (vs. non-Black) MSM were more likely to not know their partner's HIV serostatus (21.8% vs. 9.6%). Similar proportions reported sex partner concurrency (67.1% vs. 68.0%). In adjusted analyses, among Black MSM, sex partner concurrency significantly increased the odds of an HIV transmission potential partnership (TPP), and this association was not significant among non-Black indexes. The association between an HIV TPP and sex partner concurrency may help explain persistent racial disparities in HIV prevalence.Determinamos si las disparidades raciales en infecciones del VIH entre hombres homosexuales y bisexuales (hombres que tienen sexo con hombres) puede ser parcialmente explicado por diferencias raciales en el potencial de transmisión del VIH (es decir, mezcla de personas viviendo con VIH y personas que no viven con VIH o cuyo estado serológico del VIH es desconocido) y densidad (es decir, concurrencia de pareja sexual) de redes sexuales. Los datos incluyeron una encuesta de comportamiento, pruebas para el VIH y una encuesta de redes sexuales egocéntrica. Regresiones logísticas de efectos mixtos fueron usados para la prueba de hipótesis. HSH negros (vs. HSH no-negros) eran más propensos a no saber el estado serológico del VIH de su pareja (21.8% vs. 9.6%). Proporciones similares reportaron concurrencia de pareja sexual (67.1% vs. 68.0%). En análisis ajustados, entre HSH negros, la concurrencia de pareja sexual aumentó significativamente las probabilidades de una asociación potencial de transmisión del VIH (TPP por sus siglas en inglés), y esta asociación no fue significativa entre índices de no-negros. La asociación entre una TPP VIH y concurrencia de pareja sexual puede ayudar a explicar disparidades raciales persistentes en la prevalencia del VIH.

BACKGROUND Sexual networks are difficult to construct because of incomplete sexual partner data. The proximity of people within a network may be inferred from genetically similar infections. We explored genomic data combined with partner services investigation (PSI) data to extend our understanding of sexual networks affected by Neisseria gonorrhoeae (NG). METHODS We used 2017-2019 PSI and whole-genome sequencing (WGS) data from 8 jurisdictions participating in Centers for Disease Control and Prevention's Strengthening the US Response to Resistant Gonorrhea (SURRG) project. Clusters were identified from sexual contacts and through genetically similar NG isolates. Sexual mixing patterns were characterized by describing the clusters by the individual's gender and gender of their sex partners. RESULTS Our study included 4627 diagnoses of NG infection (81% sequenced), 2455 people received a PSI, 393 people were negative contacts of cases, and 495 were contacts with an unknown NG status. We identified 823 distinct clusters using PSI data combined with WGS data. Of cases that were not linked to any other case using PSI data, 37% were linked when using WGS data. Overall, 40% of PSI cases were allocated to a larger cluster when PSI and WGS data were combined compared with PSI data alone. Mixed clusters containing women, men who report sex with women, and men who report sex with men were common when using the WGS data either alone or in combination with the PSI data. CONCLUSIONS Combining PSI and WGS data improves our understanding of sexual network connectivity.

BackgroundHIV preexposure prophylaxis (PrEP) has been associated with changes in sexual behavior after PrEP initiation. However, behavioral differences may also emerge among PrEP non-users in communities with high PrEP coverage.MethodsWe used demographic, behavioral, and sexual network data from ARTnet, a cross-sectional study of US men who have sex with men conducted during 2017–2019. Multivariable regression models with a Bayesian modeling framework in which individuals were nested within their residential geographic areas were used to estimate associations between area-level PrEP coverage and five sexual behavior outcomes (number of total, main, and casual male partners [network degree]; count of one-time partnerships; and consistent condom use in one-time partnerships), controlling for individual PrEP use.ResultsPrEP coverage ranged from 10.3% (Philadelphia) to 38.9% (San Francisco). Total degree was highest in Miami (1.35) and lowest in Denver (0.78), while the count of one-time partners was highest in San Francisco (11.7/year) and lowest in Detroit (1.5/year). Adjusting for individual PrEP use and demographics, community PrEP coverage was associated with higher total degree (adjusted incidence rate ratio [aIRR]=1.73; 95% CrI, 0.92–3.44), casual degree (aIRR=2.05; 95% CrI, 0.90–5.07), and count of one-time partnerships (aIRR=1.90; 95% CrI, 0.46–8.54). Without adjustment for individual PrEP use, these associations were amplified. There were weaker associations with main degree (aIRR=1.21; 95% CrI, 0.48–3.20) and consistent condom use in one-time partnerships (aIRR=1.68; 95% CrI, 0.86–3.35).ConclusionsMost of the associations between community PrEP coverage and sexual behavior were explained by individual PrEP use. However, there were residual associations after controlling for individual PrEP use, suggesting that PrEP coverage may partially drive community-level changes in sexual behavior.

Background As part of an ongoing sexual network study, we assessed the impact of COVID-19 on sexual behavior of men who have sex with men (MSM). Methods The Columbus, Ohio arm of the multi-site Network Epidemiology of Syphilis Transmission (NEST) study is following 241 MSM over two years. Participants attend quarterly visits with behavioral surveys and HIV/STI testing. In April 2020, we implemented an additional survey to measure the impact of COVID-19 on sexual behavior. Our analysis compared participants’ reported sexual behavior during two periods: April-July 2020 (T1) and August-December 2020 (T2). Results Of the 200 participants who completed at least one COVID-19 survey in either time period, 10 (5%) self-reported a previous COVID-19 diagnosis. We compared behaviors reported by 174 respondents who submitted surveys in both time periods. During T1, about half (46%) said they felt more anxious about sex since COVID-19; anxiety was similar during T2 (43%). Many reported engaging in online sexual activities, though we saw no meaningful differences by time period for starting or increasing chatting on hookup apps (T1=30%, T2=30%), sexting (T1=30%, T2=25%), or video chat sex (T1=16%, T2=14%). Watching pornography was reported more often in T1 than T2 (53% vs. 42%). Nearly a third of respondents (30%) in T1 reported that they were not having sex; this decreased to 17% in T2. Compared to pre-pandemic behavior, in T1 a majority of participants (74%) said they were less likely to have sex with a new partner, compared to 61% during T2. Conclusion During COVID-19, nearly half of MSM reported feeling more anxious about sex, and many turned to online activities in lieu of in-person sex. However, when comparing the early months of the pandemic to later months of 2020, more participants are resuming in-person sex, and willingness to have sex with new partners also rose.

Background Condomless anal intercourse (CAI) appears to be increasing among men who have sex with men (MSM) globally, and is reported to be as high as 70% in recent studies in Peru. To improve understanding of the evolving context of CAI among MSM in Peru, we studied associations between partner type, substance use, and condomless anal intercourse (CAI) in locations where MSM commonly report having sexual encounters. Methods In a 2017 cross-sectional study of rectal STI screening and HIV prevention, a convenience sample of MSM recruited from community venues in Lima completed a survey of demographic characteristics and sexual risk behavior with their three most recent partners. Generalized estimating equations estimated correlations of CAI with location of last sexual contact, participant substance use prior to sex, and negotiation of condom use before or during sex. The network data integration application, Cytoscape, mapped intersections of partner type, sexual orientation, substance use, and CAI by four types of locations where sex occurred: 1) Home, 2) Hotel, 3) Sauna or Internet Cabin, and 4) Public Spaces. Results Of 447 MSM (median age 27 years), 76.9% reported CAI with ≥1 of their last three partners. Participants reported sex with casual partners most commonly in homes (64.6%) and hotels (60.4%), and with anonymous partners most often in saunas/Internet cabins (57.5%) and public spaces (52.6%). CAI was less commonly reported in hotels (aPR, 95% CI: 0.85, 0.75–0.97) compared to homes. Participants who used marijuana before sex at home were more likely to report CAI than MSM who did not use marijuana (1.36, 1.01–1.92). Partner alcohol use before sex was associated with CAI in saunas/Internet cabins (3.17, 1.45–6.91) and public spaces (2.65, 1.41–4.98). In the sexual network maps, almost all MSM who used drugs prior to their sexual encounters used drugs with more than one of their last three partners. Conclusions CAI was common and associated with different risk factors, like partner type and substance use, based on location where sex occurred. Novel combination HIV, STI, and substance use prevention interventions must consider how the social environments of MSM influence condom use and other sexual risk behaviors. Trial registration ClinicalTrials.gov Identifier NCT03010020, January 4, 2017.

We describe a sexual network consisting of 1 nonbinary-gendered participant and 2 male and 4 female participants in Australia, 2018. Six of 7 participants had oropharyngeal gonorrhea in the absence of urogenital gonorrhea. This observation supports a new paradigm of gonorrhea transmission in which oropharyngeal gonorrhea can be transmitted through tongue kissing.

Background. Young people in Sub-Saharan Africa are affected by HIV pandemic to a greater extent than elsewhere. Transactional sex among adolescent school girls with older men commonly called “sugar daddies” is one of the major factors fueling the spread of the infection due to the extended sexual network. Thus, this study aimed to assess the magnitude and factors associated with transactional sex among adolescent girls and “sugar daddies” in relation to HIV/AIDS. Methods. Mixed method cross-sectional study was done among 620 female students in Hawassa town, South Ethiopia, from September 2010 to May 2011. A structured questionnaire and in-depth interview check list were used to collect the quantitative and qualitative data, respectively. Survey participants were selected randomly from five preparatory schools whereas ten in-depth interview participants were recruited by a snowball sampling technique from the same schools. Data were entered using Epi-Info and analyzed by SPSS. A descriptive statistics followed by multivariable logistic regression analyses were conducted to identify factors associated with transactional sex with “sugar daddy’’. Both crude and adjusted odds ratios with 95% confidence interval were reported. We used OpenCode software for coding and categorizing the in-depth interviews and quotes that represent the informants opinion were used to support the quantitative findings. Results. A substantial number of female students, 71(11.5%), reported to have had transactional sex with older men. Most of the respondents who dated “sugar daddies” (93%) had multiple sexual partners concurrently and sequentially, and among them, only 22.7% had consistent condom use. Girls who were in older age group [OR (CI) 6.87 (3.48-13.58)], who had lost both parents [OR (CI) 2.99 (1.14-7.84)], had perceived less economic status [OR: 25.41; 95% CI: 7.80-82.76] and engaged in substance abuse [OR (CO) 5.8 (2.1-15.77)] had higher odds of practicing transactional sex with “sugar daddies”. In-depth interviewed participants also revealed that they were involved in transactional sex for monetary while having concurrent and subsequent sexual network with their schoolmates and other young partners. Conclusion. Transactional sex among female students was high, and the sexual network they had with the young men put young people in the network at risk of HIV and other sexually transmitted infections. Therefore, HIV prevention programs shall focus on transactional sex among adolescent school girls to halt transmission of HIV among the generation.

Infectious syphilis has increased substantially over the past decade. Targeting limited public health resources toward subpopulations with multiple reinfections may have a large impact in reducing onward transmission within a community.A chart review was conducted for individuals with 4 or more infectious syphilis diagnoses between 2005 and 2014 (the top 1% of all syphilis diagnoses in British Columbia, Canada). We characterized the sociodemographics, partner notification outcomes and social network.Between 2005 and 2014, there were 30 individuals with 4 or more syphilis diagnoses, accounting for 139 diagnoses. All were men who have sex with men and 29 (96%) were human immunodeficiency virus-positive. Of the 139 diagnoses, 65% occurred in the early latent stage of infection, 22% in the secondary stage, and 14% in the primary stage. The median number of sexual partners per diagnosis was 5 (range, 1-50). Among the 838 partners reported, 79% were notifiable, 53% were notified, and 23% were reported to be tested or treated. Sexual network mapping showed that almost half of the members of this group could be linked to one another either directly or indirectly via partners over 10 years. Social network mapping demonstrated high connectivity, with 4 venues associated with almost two thirds of the study population.The connectivity and recurrent diagnoses in this study population suggest potential benefits of targeted interventions to individuals with multiple diagnoses and their partners. Our study highlights the need for enhanced care, increased syphilis testing frequency, and exploring alternative preventative methods among individuals with syphilis rediagnoses to reduce syphilis incidence.

Despite demonstrated efficacy, uptake of HIV pre-exposure prophylaxis (PrEP) remains low, particularly among high risk demographics such as transgender women, Black men who have sex with men (BMSM) and young MSM (YMSM). Research thus far has largely focused on individual factors that may impede PrEP uptake in these demographics, leaving social network factors relatively unexplored. The present study used data collected from participants within RADAR, a longitudinal cohort study in Chicago focused on understanding the individual, dyadic, network, social, and biologic factors associated with HIV infection within YMSM. Of the 906 study participants who did not report an HIV diagnosis at baseline, 7.0% reported using PrEP in the prior six months. Recent PrEP use was associated with both individual-level (age and gender) and network-level factors (mean relationship strength, sexual network degree, etc.). These findings highlight the need to expand beyond focusing on individual-level drivers of PrEP uptake, as well as changing our understanding of who is most important within a network (centrality vs. strength of weak ties). Future work is needed to determine whether variables associated with PrEP uptake are similarly connected to PrEP adherence.

With the rapid increase in HIV prevalence of men who have sex with men (MSM) in recent years and common human migration and travelling across different provinces in China, MSM are now finding it easier to meet each other, which might contribute to local HIV epidemics as well as fueling cross-province transmission. We performed a cross-sectional survey in 2018–2019 to investigate the current HIV subtype diversity and inferred HIV strain transmission origin among MSM in Guangxi province, China based on a phylogenetic analysis. Based on 238 samples, we found that the HIV-1 subtype diversity was more complicated than before, except for three major HIV subtypes/circulating recombinant forms (CRFs): CRF07_BC, CRF01_AE, CRF55_01B, five other subtypes/CRFs (CRF59_01B, B, CRF08_BC, CRF67_01B, CRF68_01B) and five unique recombinant forms (URFs) were detected. In total, 76.8% (169/220) of samples were infected with HIV from local circulating strains, while others originated from other provinces, predominantly Guangdong and Shanghai. The high diversity of HIV recombinants and complicated HIV transmission sources in Guangxi MSM indicates that there has been an active sexual network between HIV positive MSM both within and outside Guangxi without any effective prevention. Inter-province collaboration must be enforced to provide tailored HIV prevention and control services to MSM in China.

Introduction HIV pre‐exposure prophylaxis (PrEP) is effective in preventing HIV transmission. United States Public Health Service (USPHS) clinical practice guidelines define biobehavioral indications for initiation. To assess guideline implementation, it is critical to quantify PrEP nonusers who are indicated and PrEP users who are not indicated. We sought to estimate current PrEP use among US men who have sex with men (MSM), characterize whether their PrEP use aligned with their current indications for PrEP, and assess whether the association between PrEP indications and PrEP use differed by demography or geography. Methods Using data from a US web‐based sexual network study of MSM between 2017 and 2019, we measured PrEP usage and assessed whether respondents met indications for PrEP. Log‐binomial regression was used to estimate the relationship between PrEP indications and PrEP use, with adjustment for geography, age and race/ethnicity. Results Of 3508 sexually active, HIV‐negative MSM, 34% met indications for PrEP. The proportion with current PrEP use was 32% among MSM meeting indications and 11% among those without indications. Nearly 40% of those currently using PrEP did not meet indications for PrEP, and 68% of MSM with indications for PrEP were not currently using PrEP. After adjusting for geography and demographics, MSM with PrEP indications were about three times as likely to be currently using PrEP. This association varied slightly, but not significantly, by geographic region, age and race/ethnicity. Conclusions Indications for PrEP strongly predicted current PrEP use among US MSM. However, we identified substantial misalignment between indications and use in both directions (indicated MSM who were not benefitting from PrEP, and MSM taking PrEP while not presently being indicated). PrEP underuse by those at greatest risk for HIV acquisition may limit the projected impact of PrEP implementation, despite reported increases in PrEP provision. This calls for further implementation efforts to improve PrEP delivery to those most in need during periods of elevated sexual risk and to close the gap between indications and uptake.

[EN] A major challenge in human papillomavirus (HPV) vaccine programs is the universal gender-neutral recommendation, as well as estimation of its long-term effect. The objective of this study is to predict the added benefit of male vaccination, especially in men who have sex with men (MSM), and to analyze the impact of the program on society. We propose a mathematical model of the HPV infection based on a network paradigm. Data from Spain allowed constructing the sexual network. HPV force of infection was taken from literature. Different scenarios using variable vaccine coverage in both males and females were studied. Strong herd immunity is shown in the heterosexual population, with an important decrease of HPV 6/11 infections both in men and in unvaccinated women with an only-women vaccination at 14 years of age. No impact of this program occurred in the infection incidence in MSM. This group would only benefit from a vaccination program that includes males. However, the impact at short term would be lower than in heterosexual men. The protection of MSM can only be achieved by direct vaccination of males. This may have important consequences for public health., This paper has been supported by the Spanish Ministerio de Economía, Industria y Competitividad (MINECO), the Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER UE) grant MTM2017-89664-P. This paper has been supported by the European Union through the Operational Program of the [European Regional Development Fund (ERDF)/European Social Fund (ESF)] of the Valencian Community 2014¿2020. Files: GJIDI/2018/A/010 and GJIDI/2018/A/009

HIV set point viral load (SPVL), the viral load established shortly after initial infection, is a proxy for HIV virulence: higher SPVLs lead to higher risk of transmission and faster disease progression. Three models of test-and-treat scenarios, mainly in heterosexual populations, found that increasing treatment coverage selected for more virulent viruses. We modeled virulence evolution in a population of men who have sex with men (MSM) with increasing test-and-treat coverage. We extended a stochastic, dynamic network model (EvoNetHIV). We varied relationship patterns (MSM vs. heterosexual), HIV transmission models (increasing vs. plateauing probability of transmission at very high viral loads), and treatment roll-out (with explicit testing or fixed intervals between infection and treatment). In scenarios most similar to previous models (longer relational durations and the plateauing transmission function), we replicated trends previously found: increasing treatment coverage led to increased virulence (0.12 log10 increase in mean population SPVL between 20% and 100% treatment coverage). In scenarios reflecting MSM behavioral data using the increasing transmission function, increasing treatment coverage selected for viruses with lower virulence (0.16 log10 decrease in mean population SPVL between 20% and 100% treatment coverage). These findings emphasize the impact of sexual network conditions and transmission function details on predicted epidemiological and evolutionary outcomes. Varying these features creates very different evolutionary environments, which in turn lead to opposite effects in mean population SPVL evolution. Our results suggest that, under some realistic conditions, effective test-and-treat strategies may not face the previously reported tradeoff in which increasing coverage leads to evolution of greater virulence. This suggests instead that a virtuous cycle of increasing treatment coverage and diminishing virulence is possible.

Pathogen populations can evolve in response to selective pressure from vaccine-induced immune responses. For HIV, models predict that viral adaptation, either via strain replacement or selection on de novo mutation, may rapidly reduce the effectiveness of an HIV vaccine. We hypothesized that behavioral risk compensation after vaccination may accelerate the transmission of vaccine resistant strains, increasing the rate of viral adaptation and leading to a more rapid decline in vaccine effectiveness. To test our hypothesis, we modeled: a) the impact of risk compensation on rates of HIV adaptation via strain replacement in response to a partially effective vaccine; and b) the combined impact of risk compensation and viral adaptation on vaccine-mediated epidemic control. We used an agent-based epidemic model that was calibrated to HIV-1 trends in South Africa, and includes demographics, sexual network structure and behavior, and within-host disease dynamics. Our model predicts that risk compensation can increase the rate of HIV viral adaptation in response to a vaccine. In combination, risk compensation and viral adaptation can, under certain scenarios, reverse initial declines in prevalence due to vaccination, and result in HIV prevalence at 15 years equal to or greater than prevalence without a vaccine.

BackgroundThe potential speed through which a pathogen may circulate in a network is a function of network connectivity. Network features like degree (number of ongoing partnerships) determine the cross-sectional network connectivity. The overall transmission potential of a pathogen involves connectivity over time, which can be measured using the forward reachable path (FRP). We modeled dynamic sexual networks of MSM in San Francisco and Atlanta to estimate the FRP as a predictor of HIV/STI epidemic potential.MethodsWe used exponential random graph models to obtain parameter estimates for each city’s sexual network and then simulated the complete networks over time. The FRP was estimated in each city overall and stratified by demographics.ResultsThe overall mean and median FRPs were higher in San Francisco than in Atlanta, suggesting a greater epidemic potential for HIV and STIs in San Francisco. At one year, in both cities, the average FRP among casual partnerships was highest in the youngest age group and lowest in the oldest age group, contrasting with the cross-sectional network parameters we estimated, where the youngest age category had the lowest mean degree and the oldest age category had the highest mean degree.ConclusionsThe FRP results correspond to the observed STI epidemics but not HIV epidemics between the cities. In San Francisco, rates of HIV have been declining over the last few years, whereas they have been steady in Atlanta. The FRP by age group resulted in fundamentally different conclusions about connectivity in the network compared with the cross-sectional network measures.

ObjectivesMathematical modelling and genomic analyses are powerful methods for investigating the transmission dynamics ofNeisseria gonorrhoeae, however, often make the implicit assumption thatN. gonorrhoeaeisolates at different anatomical sites within the same individual are the same strain.MethodsIn this study, two approaches were used to explore genetic diversity. First, we examined a collection of stored, clinicalN. gonorrhoeaeisolates sourced from multiple anatomical sites of single individuals attending a sexual health clinic in Melbourne from 2011-2019. Second, we obtained multiple colony picks from primary clinical samples from individuals attending a sexual health clinic in Melbourne from 2019-2020. Whole genome sequencing and a variety of bioinformatics approaches were used to determine both within-host and within-sample genetic diversity.ResultsThirty-seven individuals were identified that had culturedN. gonorrhoeaefrom two or more anatomical sites (urogenital, anorectal, or oropharyngeal), with a final dataset of 105 isolates. In 35/37 (94.6%) individuals, infections were highly similar at the genetic level, with identical MLST and NG-MAST profiles. Pairwise comparisons of isolates within each individual indicated that the maximum within-host pairwise SNP distance was 13 SNPs (median = 1, IQR: 0-3). Notably, four distinct multi-individual phylogenetic clusters were identified, where the maximum pairwise SNP distance was 19 SNPs (median = 6, IQR = 2-11). Similarly, comparisons of isolates within each primary sample indicated that the maximum pairwise SNP distance was 8 SNPs (median = 2, IQR:1-3).ConclusionsThis study suggests that in most cases of multi-site infection, the same strain ofN. gonorrhoeaecauses the infection at each anatomical site. However, WGS data alone cannot differentiate between the same infecting strain or (re)infections from the same transmission network. These data guide recommendations regarding optimal bioinformatic approaches to infer genetic relatedness ofN. gonorrhoeaeand will help inform future studies of gonorrhoea transmission and epidemiology.KEY MESSAGESIn most cases of multi-site infection, the same strain ofN. gonorrhoeaecauses infection at each anatomical site (urogenital, anorectal, and oropharyngeal) within an individual.It is not possible, using genomics alone, to determine if an infection is from a single individual or multiple individuals within the same sexual network.Current literature reports an array of different bioinformatic methods for describing genetic diversity, highlighting that SNP thresholds are not directly transferable between studies.

Purpose This study aimed to determine individual- and partner-level factors associated with human papillomavirus (HPV) infection in vaccinated and unvaccinated men. Methods A total of 747 men, aged 13–26 years, completed a survey of sexual behaviors and were tested for genital and perianal/anal HPV (36 types). Sexual network variables included recent and lifetime concurrency (being in more than one sexual relationship at the same time) and recent sex partner discordance (by race, ethnicity, age, and number of sexual partners). We determined individual-level and sexual network variables associated with ≥1 HPV type and HPV16/18, stratified by vaccination status, using separate multivariable logistic regression models. Results Participants' mean age was 21.2 years; 64% were positive for ≥1 HPV type and 21% for HPV16/18. Factors associated with ≥1 HPV type in unvaccinated men included recruitment site and lifetime concurrency. Factors associated with ≥1 HPV type among vaccinated men included recruitment site, Chlamydia history, main male partner, number of lifetime female partners, and no condom use with female partner. Factors associated with HPV16/18 in unvaccinated men included race and partner concurrency. Factors associated with HPV16/18 in vaccinated men included ethnicity, main male partner, and recent concurrency. Conclusions Sexual network variables associated with HPV infection were different based on vaccination status and HPV type, suggesting risk factors for HPV infection may change as the proportion of vaccinated men increases. In addition, participant report of concurrency and not knowing whether one had practiced concurrency were consistent risk factors; clinicians should consider including concurrency in the sexual history to determine the risk of HPV.

Background Long-acting injectable (LAI) human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) is reportedly efficacious, although full trial results have not been published. We used a dynamic network model of HIV transmission among men who have sex with men to assess the population impact of LAI-PrEP when available concurrently with daily-oral (DO) PrEP. Methods The reference model represents the current HIV epidemiology and DO-PrEP coverage (15% among those with behavioral indications for PrEP) among men who have sex with men in the southeastern United States. Primary analyses investigated varied PrEP uptake and proportion selecting LAI-PrEP. Secondary analyses evaluated uncertainty in pharmacokinetic efficacy and LAI-PrEP persistence relative to DO-PrEP. Results Compared with the reference scenario, if 50% chose LAI-PrEP, 4.3% (95% simulation interval, −7.3% to 14.5%) of infections would be averted over 10 years. The impact of LAI-PrEP is slightly greater than that of the DO-PrEP–only regimen, based on assumptions of higher adherence and partial protection after discontinuation. If the total PrEP initiation rate doubled, 17.1% (95% simulation interval, 6.7%–26.4%) of infections would be averted. The highest population-level impact occurred when LAI-PrEP uptake and persistence improved. Conclusions If LAI-PrEP replaces DO-PrEP, its availability will modestly improve the population impact. LAI-PrEP will make a more substantial impact if its availability drives higher total PrEP coverage, or if persistence is greater for LAI-PrEP.

Background A 2015 CDC analysis estimated that 24.7% of sexually active men who have sex with men (MSM) had indications for HIV pre-exposure prophylaxis (PrEP) based on 2014 US Public Health Service (USPHS) clinical practice guidelines. Given that the USPHS revised these guidelines in 2017, updated estimates of the fraction of MSM indicated for PrEP overall and stratified by demographic factors and geography are needed to scale-up PrEP for MSM in the US. Methods We conducted a national web-based study of 4904 MSM aged 15-65 who had ever had sex with another man between July 2017 and January 2019. We estimated the percentage of HIV-negative, sexually active MSM meeting USPHS indications for PrEP by demographic category. Results Of 3511 sexually active, HIV-negative MSM, 34.0% (95% confidence interval: 32.4 to 35.6) met USPHS indications for PrEP, with percentages consistent across US census region and varying slightly by race/ethnicity (Black: 32.2%, White: 33.7%, Hispanic: 36.4%, Other: 33.6%). Among individuals meeting USPHS PrEP indications, 93.5% reported condomless anal intercourse in the prior 6 months. Among all survey respondents, PrEP eligibility was lowest among non-Hispanic black (18.4%) and younger respondents (15-17: 4.1%; 18-24: 18.1%). Conclusions Estimated percentages of MSM meeting indications for PrEP exceeded the previous CDC estimate across race/ethnicity, age, and census regions, with one-third of adult, sexually active, HIV-negative MSM exhibiting indications for PrEP. This study suggests, given current guidelines for PrEP indications, that a different fraction of eligible MSM could be receiving PrEP than previously estimated.

People involved in commercial sex are thought to be at high risk for human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) transmission. To explore the characteristics of female sex workers’ (FSWs) sexual networks and how FSWs and their sex partners could serve as ‘bridges’ in HIV/AIDS transmission, egocentric sexual networks (where a subject is asked to identify his or her sexual contacts and their relationships) of 66 FSWs in Xi'an city, Shaanxi Province of China, were studied. Convenience sampling was used to collect FSWs’ socio-demographic and sexual behavior data, which we analyzed using social network and descriptive statistical methods. Results show that some egocentric sexual networks were connected by sex partners, and these were integrated into several components of a sexual network. According to centrality indicators, FSWs and their commercial sex partners (especially regular clients) served as key nodes within high-risk groups and as bridges between high-risk groups and the general population. The cluster of high-risk groups with cohesive sub-networks had larger network size (P

Background Traditional partner notification methods have been implemented for HIV-infected patients, as well as HIV treatment, in order to identify people at risk of HIV infection, especially men who have sex with men (MSM), since they are more likely to have casual sex partners. These traditional methods have some limitations. Objective Our study focused on developing an mHealth app to improve partner notification in practice for MSM; the study then focused on evaluating the effects of the app. Methods We developed an mHealth app with different modules using Java and HTML5 and tested it in an MSM community to prevent HIV transmission. The HIV incidence stratified by different follow-up periods were calculated. Poisson regression and social networks were used to estimate the risk ratios and to identify the connection among MSM, respectively. Results In addition to the partner notification module, which is the kernel of the app, we developed a test result self-query module to enable MSM to get their approved test results in a timely manner, a prompt and warning module to alert users to protect themselves from high-risk conditions, and a health education module to teach users more skills regarding HIV/AIDS prevention. Over a 1-year duration, a total of 3186 MSM used the app, of which 678 had at least two HIV test results since becoming app users; they were included in the final analysis. Among 678 users, a total of 6473 self-queries and 623 partner notifications were recorded, which identified 180 social networks of MSM app users. Those who used the partner notification function were more likely to have self-queries (P5 months vs ≤5 months: 2.22 per 100 person-years vs 6.99 per 100 person-years; risk ratio 0.32, 95% CI 0.12- 0.87). Conclusions The app developed in this study is consistent with the World Health Organization’s sensitivity and confidentiality recommendations; it has the potential to reduce the risk of HIV infection among MSM.

Tailoring public health responses to growing HIV transmission clusters depends on accurately mapping the risk network through which it spreads and identifying acute infections that represent the leading edge of cluster growth. HIV transmission links, especially those involving persons with acute HIV infection (AHI), can be difficult to uncover, or confirm during partner services investigations. We integrated molecular, epidemiologic, serologic and behavioral data to infer and evaluate transmission linkages between participants of a prospective study of AHI conducted in North Carolina, New York City and San Francisco from 2011&ndash, 2013. Among the 547 participants with newly diagnosed HIV with polymerase sequences, 465 sex partners were reported, of whom only 35 (7.5%) had HIV sequences. Among these 35 contacts, 23 (65.7%) links were genetically supported and 12 (34.3%) were not. Only five links were reported between participants with AHI but none were genetically supported. In contrast, phylodynamic inference identified 102 unreported transmission links, including 12 between persons with AHI. Importantly, all putative transmission links between persons with AHI were found among large clusters with more than five members. Taken together, the presence of putative links between acute participants who did not name each other as contacts that are found only among large clusters underscores the potential for unobserved or undiagnosed intermediaries. Phylodynamics identified many more links than partner services alone and, if routinely and rapidly integrated, can illuminate transmission patterns not readily captured by partner services investigations.

Pre-exposure chemical prophylaxis has been proposed as a way to slow the growth of the HIV epidemic in the US. This medication reduces the chances of an at-risk, susceptible individual acquiring HIV from an infected partner. The effectiveness of this preventative medication is dependent upon the population that uses it. Individuals susceptible to acquire HIV may engage in risky behaviors such as high partner number. We analyze the effectiveness of chemical prophylaxis on the populations involved in the HIV epidemic in the US using a hierarchical differential equation model. We create a system of nonlinear differential equations representing the system of populations involved in the HIV epidemic, focusing on susceptible and infected individuals. We stratify the susceptible population by behavior risk, and the infected population by behavior risk and HIV status awareness. We further define model parameters for both the national and the urban case, representing low and high sexual network densities. We apply a preventative medication protocol to the susceptible populations to understand the effectiveness. These parameter sets are used to study the predicted population dynamics over the next 5 years. Our results indicate that the undiagnosed high risk infected group is the largest contributor to the epidemic under both national and urban conditions. When medication that prevents contraction of HIV is applied to 35% of the high-risk susceptible population we observe a 40–50% reduction in the growth of the infected population. Little impact is observed when the medication is focused on the low-risk susceptible population. The simulations suggest that preventative medication effectiveness extends outside of the group that is taking the drug (herd immunity). Our model suggests that a strategy targeting the high-risk susceptible population would have the largest impact in the next 5 years. We also find that such a protocol has similar effects for the national as the urban case in our model, despite the smaller sexual network and lower transmission chance for rural areas.

ObjectiveYoung black men who have sex with men (YBMSM) in the USA represent a subgroup that has the highest HIV incidence among the overall population. In the USA, pre-exposure prophylaxis (PrEP) is an effective prevention intervention to prevent HIV acquisition when taken regularly. Neighbourhood and network factors may relate to PrEP awareness, but have not been studied in YBMSM. This study aimed to examine the relationship of neighbourhood and network characteristics with PrEP awareness among YBMSM.MethodsWe used data collected from a sample of 618 YBMSM in Chicago (2013–2014). Home addresses were collected for participants and enumerated network members. Administrative data (eg, 2014 American Community Survey, Chicago Department of Public Health) were used to describe residence characteristics. Network member characteristics were also collected (eg, sexual partners’ sex-drug use, confidant network members who were also MSM). Multilevel analysis was performed to examine the relationships of neighbourhood and network characteristics to PrEP awareness.ResultsHigher neighbourhood-level educational attainment (adjusted odds ratio (aOR) 1.02, p=0.03) and greater primary care density (aOR 1.38, p=0.01) were associated with greater PrEP awareness; greater neighbourhood alcohol outlet density (aOR 0.52, p=0.004) was associated with less PrEP awareness. Sexual network members residing in the same neighbourhood as the participants (aOR 2.58, p=0.03) and discussions around avoiding HIV acquisition with confidants (aOR 2.26, p=0.04) were associated with greater PrEP awareness.ConclusionsThe results suggest that neighbourhood and network characteristics can influence PrEP awareness in YBMSM. Additional studies are needed to understand the influences of neighbourhood (eg, MSM serving venues) and network (eg, peer to peer communication) characteristics on dissemination of PrEP information, uptake and adherence and the related mechanisms behind the associations.

Background: Little research has evaluated the social and sexual network-related health outcomes of young black transgender women (TGW) or compared these outcomes with those of black men who have sex with men (MSM). Social network analysis offers one potent means of understanding the dynamics driving the broad spectrum of adverse outcomes experienced by these subgroups. Methods: We examined the social and sexual health network traits of 618 black individuals assigned male at birth who have sex with men, 47 (7.6%) of whom identified as TGW. Using respondent-driven sampling, data collection occurred over three waves between 2013 and 2016, in Chicago, Illinois. Univariate, logistic regression, and confidant and sexual network analyses were conducted to characterize dynamic network features. Results: TGW's mean age was 22.1 (standard deviation ±2.6). TGW's sexual networks were significantly less stable (stability ratio of 0.175 vs. 0.278 among MSM, p=0.03) and had greater network turnover (turnover ratio of 0.825 vs. 0.735, p=0.04). TGW also had significantly more sex partners (7.6 vs. 4.0, p=0.0002) and exchange sex (odds ratio=2.97; 95% confidence interval: 1.66–5.32, p

Kenya has been home to one of the most severe HIV/AIDS epidemics in Sub-Saharan Africa. This persistent epidemic requires interventions tailored to affected populations, particularly men who have sex with men (MSM). Given the resource constraints of many clinics and ecological challenges of Kenya, such as the illegality of sex among MSM, interventions to address HIV must strategically engage this population. This quasi-experimental pilot study of N = 497 sought to explore differences in discovering previously unknown HIV-positive MSM in Nairobi, Kenya. The study used four clinical sites to compare a social and sexual network index testing (SSNIT) strategy compared to traditional HIV screening. Clinics using the SSNIT strategy had significantly higher incidence rates of HIV diagnoses than control clinics (IRR = 3.98, p

Prior studies have demonstrated that both bacterial vaginosis (BV) and sexually transmitted infections (STIs) are strong independent risk factors for subsequent STI. In observational studies of this biological enhancement (BE) hypothesis, it is important to adjust for the risk of STI exposure so that the independent effect of BE can be assessed. We sought to model if two markers of local sexual network (partner concurrency and cumulative number of STIs) represented residual confounding in the models of risk for subsequent infection in a study that screened 3620 women for STIs every 3 months for a year. Mixed-effects logistic regression was used to calculate the odds ratios for an incident diagnosis ofChlamydia trachomatis,Neisseria gonorrhoeae,Trichomonas vaginalisand BV following a diagnosis of any of these four at the prior visit, controlling for the cumulative number of STIs and partner concurrency variables. We found that partner concurrency and cumulative number of STIs were each associated with incident infection, and in general, controlling for these variables reduced the strength of the association between prior and incident infections. We conclude that the frequently found association between prior and incident STIs is associated with both BE and sexual network structure.

Because data on the determinants of the HIV care continuum from key populations such as men who have sex with men (MSM) in resource-limited settings are limited, the study aimed to characterize HIV care continuum outcomes and assess individual and network barriers to progression through the HIV care continuum among MSM in Abuja and Lagos, Nigeria.TRUST/RV368 study used respondent-driven sampling to accrue MSM into community-based clinics in Nigeria. Participants received HIV testing at enrollment. HIV-infected participants were offered antiretroviral therapy (ART) with HIV RNA testing every 3 months (Abuja) or 6 months (Lagos). Multiple logistic regression models were used to calculate adjusted odds ratios for factors associated with each point in the HIV care continuum, including HIV testing, ART initiation, and 6-month viral suppression.A total of 1506 MSM were recruited, 1178 (78.2%) tested for HIV and 369 (31.3%) were HIV positive newly diagnosed. Of these, 188 (50.1%) initiated ART, 136 (72.3%) completed 6 months, and 96 (70.6%) were virally suppressed. Larger network size and stronger social network support were each positively associated with HIV testing uptake. Factors associated with ART initiation were higher education and stronger social network support. Having stronger social network support was associated with increased odds of viral suppression at 6 months.Social determinants of health potentiated increased HIV care continuum outcomes. Integration of HIV prevention, HIV counseling and testing services, and universal coverage of ART into a community-based clinic is critical in achieving better HIV care continuum outcomes.

Contemporary strategies to curtail the emergence of antimicrobial resistance in Neisseria gonorrhoeae include screening for and treating asymptomatic infections in high-prevalence populations in whom antimicrobial drug-resistant infections have typically emerged. We argue that antimicrobial resistance in these groups is driven by a combination of dense sexual network connectivity and antimicrobial drug exposure (for example, through screen-and-treat strategies for asymptomatic N. gonorrhoeae infection). Sexual network connectivity sustains a high-equilibrium prevalence of N. gonorrhoeae and increases likelihood of reinfection, whereas antimicrobial drug exposure results in selection pressure for reinfecting N. gonorrhoeae strains to acquire antimicrobial resistance genes from commensal pharyngeal or rectal flora. We propose study designs to test this hypothesis.

Neighborhood social and physical factors shape sexual network characteristics in HIV-seronegative adults in the United States. This multilevel analysis evaluated whether these relationships also exist in a predominantly HIV-seropositive cohort of women. This cross-sectional multilevel analysis included dm 734 women enrolled in the Women's Interagency HIV Study's sites in the U S South. Center track-level contextual data captured socioeconomic disadvantage (e.g., tract poverty), number of alcohol outlets, and number of nonprofits 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. 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.

Six geosexual archetypes were identified: hosters, house-callers, rovers, privates, travellers, and geoflexibles, each with different characteristic profiles. Prioritizing interventions to hosters, rovers, and geoflexibles may reduce sexually transmitted infection transmission. Supplemental digital content is available in the text., Background There are complex, synergistic, and persistent sexually transmitted infection (STI) epidemics affecting gay, bisexual and other men who have sex with men (gbMSM) in every major urban centre across North America. We explored the spatial architecture of egocentric sexual networks for gbMSM in Toronto, Canada. Methods Our integrative mixed methods study included in-depth interviews with 31 gbMSM between May and July 2016. During interviews, participants mapped their egocentric sexual network for the preceding 3 months geographically. At the end, a self-administered survey was used to collect sociodemographic characteristics, online technology use, and STI testing and history. Results We identified 6 geosexual archetypes: hosters, house-callers, privates, rovers, travellers, and geoflexibles. Hosters always, or almost always (≥80%), hosted sex at their home. House-callers always, or almost always (≥80%), had sex at their partner’s home. Rovers always or almost always (≥80%) had sex at public venues (eg, bath houses, sex clubs) and other public spaces (eg, parks, cruising sites). Privates had sex in private—their own home or their partner's (part hoster, part house-caller). Travellers had sex away from their home, either at a partner’s home or some other venue or public space (part house-caller, part rover). Geoflexibles had sex in a variety of locations—their home, their partner’s home, or public venues. All hosters and rovers, and to a lesser extent, geoflexibles, reported a history of syphilis and human immunodeficiency virus. Conclusions Prioritizing interventions to hosters, rovers, and geoflexibles may have an important impact on reducing STI transmission.

Background Female sex workers (FSWs) are an important population for HIV acquisition and transmission. Their risks are shaped by behavioral, sexual network, and structural level factors. Violence is pervasive and associated with HIV risk behavior and infection, yet interventions to address the dual epidemics of violence and HIV among FSWs are limited. Methods We used participatory methods to develop a brief, trauma-informed intervention, INSPIRE (Integrating Safety Promotion with HIV Risk Reduction), to improve safety and reduce HIV risk for FSWs. A quasi-experimental, single group pretest-posttest study evaluated intervention feasibility, acceptability and efficacy among FSWs in Baltimore, MD, most of whom were drug-involved (baseline n = 60; follow-up n = 39 [65%]; non-differential by demographics or outcomes). Qualitative data collected at follow-up contextualizes findings. Results Based on community partnership and FSW input, emergent goals included violence-related support, connection with services, and buffering against structural forces that blame FSWs for violence. Qualitative and quantitative results demonstrate feasibility and acceptability. At follow-up, improvements were seen in avoidance of client condom negotiation (p = 0.04), and frequency of sex trade under the influence of drugs or alcohol (p = 0.04). Women’s safety behavior increased (p

Objectives HIV and herpes simplex virus type 2 (HSV-2) infections are sexually transmitted and propagate in sexual networks. Using mathematical modeling, we aimed to quantify effects of key network statistics on infection transmission, and extent to which HSV-2 prevalence can be a proxy of HIV prevalence. Design/methods An individual-based simulation model was constructed to describe sex partnering and infection transmission, and was parameterized with representative natural history, transmission, and sexual behavior data. Correlations were assessed on model outcomes (HIV/HSV-2 prevalences) and multiple linear regressions were conducted to estimate adjusted associations and effect sizes. Results HIV prevalence was one-third or less of HSV-2 prevalence. HIV and HSV-2 prevalences were associated with a Spearman's rank correlation coefficient of 0.64 (95% confidence interval: 0.58-0.69). Collinearities among network statistics were detected, most notably between concurrency versus mean and variance of number of partners. Controlling for confounding, unmarried mean/variance of number of partners (or alternatively concurrency) were the strongest predictors of HIV prevalence. Meanwhile, unmarried/married mean/variance of number of partners (or alternatively concurrency), and clustering coefficient were the strongest predictors of HSV-2 prevalence. HSV-2 prevalence was a strong predictor of HIV prevalence by proxying effects of network statistics. Conclusion Network statistics produced similar and differential effects on HIV/HSV-2 transmission, and explained most of the variation in HIV and HSV-2 prevalences. HIV prevalence reflected primarily mean and variance of number of partners, but HSV-2 prevalence was affected by a range of network statistics. HSV-2 prevalence (as a proxy) can forecast a population's HIV epidemic potential, thereby informing interventions.

HIV diagnoses among females in the USA declined 40% during 2005-2014 with the largest decline (42%) among Black/African Americans. African American females remain disproportionately affected. We explored contributions of STD rates and sexual risk behaviors among African American females, HIV diagnoses among potential male partners, and sexual risk behaviors and viral suppression rates among HIV-positive potential male partners to declining rates of HIV diagnoses among African American females. Results suggest temporal trends in the factors that increase HIV infectiousness and transmissibility within sexual networks, i.e., decreases in rates of other sexually transmitted infections among African American females, decreases in HIV diagnoses among potential male partners, and increases in viral suppression among heterosexual and bisexual HIV-positive potential male partners in care, may explain the decline. Findings highlight a need for future research that provides context to the sexual risk behaviors and sexual network factors in order to continue progress.

Background STIs including Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) potentiate HIV acquisition and transmission especially among gay men and other men who have sex with men (MSM). We investigated the influence of sexual network composition on incident rectal NG and/or CT infections among Nigerian MSM. Methods TRUST/RV368 is a cohort of MSM recruited using respondent-driven sampling at trusted community centres in Abuja and Lagos, Nigeria. MSM respondents (egos) provided STI risk factors and demographic information for up to five of their most recent sexual partners (alters) within their sexual networks. Egos were tested for HIV, NG and CT every 3 months. Log-binomial regression was used to assess associations between alter characteristics and incident NG and/or CT. Results Between March 2013 and October 2015, 492 MSM were longitudinally screened for STIs, of which 28.0% (n=138) were positive for incident rectal STI (61 NG only, 42 CT only and 35 NG and CT). Among egos, condom use was associated with STIs (half of the time vs never (adjusted risk ratio (aRR) 0.5; 95% CI 0.3 to 0.8), always/almost always vs never (aRR 0.7; 95% CI 0.5 to 1.0)). Incident STIs were associated with having a younger alter ≤19 versus 30 years (aRR 0.6; 95% CI 0.4 to 1.0), HIV infection (aRR 1.5; 95% CI 1.1 to 2.0) and engaging in sex under the influence of alcohol (aRR 1.4 95% CI 1.1 to 1.7) among regular alters and age ≤19 versus 30 years (aRR 0.3; 95% CI 0.2 to 0.6), HIV infection (aRR 1.4; 95% CI 1.1 to 1.8) and engaging in sex under the influence of alcohol (aRR 1.2 95% CI 1.0 to 1.4) among casual alters. Conclusions Given the centrality of sexual partner characteristics as risks for incident STIs among Nigerian MSM, there is a need to move beyond individual interventions and syndromic surveillance and get ‘out there’ in the STI management.

Critical to the development of improved HIV elimination efforts is a greater understanding of how social networks and their dynamics are related to HIV risk and prevention. In this paper, we examine network stability of confidant and sexual networks among young black men who have sex with men (YBMSM). We use data from uConnect (2013–2016), a population-based, longitudinal cohort study. We use an innovative approach to measure both sexual and confidant network stability at three time points, and examine the relationship between each type of stability and HIV risk and prevention behaviors. This approach is consistent with a co-evolutionary perspective in which behavior is not only affected by static properties of an individual's network, but may also be associated with changes in the topology of his or her egocentric network. Our results indicate that although confidant and sexual network stability are moderately correlated, their dynamics are distinct with different predictors and differing associations with behavior. Both types of stability are associated with lower rates of risk behaviors, and both are reduced among those who have spent time in jail. Public health awareness and engagement with both types of networks may provide new opportunities for HIV prevention interventions.

Objective: MSM are at increased risk for infection with HIV-1 and hepatitis C virus (HCV). Is HIV/HCV coinfection confined to specific HIV transmission networks? Design and methods: A HIV phylogenetic tree was constructed for 5038 HIV-1 subtype B polymerase (pol) sequences obtained from MSM in the AIDS therapy evaluation in the Netherlands cohort. We investigated the existence of HIV clusters with increased HCV prevalence, the HIV phylogenetic density (i.e. the number of potential HIV transmission partners) of HIV/HCV-coinfected MSM compared with HIV-infected MSM without HCV, and the overlap in HIV and HCV phylogenies using HCV nonstructural protein 5B sequences from 183 HIV-infected MSM with acute HCV infection. Results: Five hundred and sixty-three of 5038 (11.2%) HIV-infected MSM tested HCV positive. Phylogenetic analysis revealed 93 large HIV clusters (>= 10 MSM), 370 small HIV clusters (2-9 MSM), and 867 singletons with a median HCV prevalence of 11.5, 11.6, and 9.3%, respectively. We identified six large HIV clusters with elevated HCV prevalence (range 23.5-46.2%). Median HIV phylogenetic densities for MSM with HCV (3, interquartile range 1-7) and without HCV (3, interquartile range 1-8) were similar. HCV phylogeny showed 12 MSM-specific HCV clusters (clustersize: 2-39 HCV sequences); 12.7% of HCV infections were part of the same HIV and HCV cluster. Conclusion: We observed few HIV clusters with elevated HCV prevalence, no increase in the HIV phylogenetic density of HIV/HCV-coinfected MSM compared to HIV-infected MSM without HCV, and limited overlap between HIV and HCV phylogenies among HIV/HCV-coinfected MSM. Our data do not support the existence of MSM-specific sexual networks that fuel both the HIV and HCV epidemic. Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved

Commercial sex shares a role in HIV and sexually transmitted infections (STI) transmission. Men who pay for sex (MPS) may transmit HIV/STI to other populations which are low-risk. This study aimed to test our hypothesis that MPS engage in high-risk sexual behaviors associated with HIV/STI transmission more so than non-MPS.This cross-sectional study included heterosexual men who attended an STI clinic between 2003 and 2010. Demographic, clinical, behavioral and laboratory data were compared between MPS and non-MPS to identify factors associated with high-risk sexual behavior and STI-burden.Of the first visits of 6156 heterosexual men who attended the STI-clinic during the study period, 1649 (26.7%) were MPS. MPS were more commonly older, married and non-Israeli born compared with non-MPS. MPS were more likely to engage in risk-behaviors associated with HIV/STI-transmission, including a greater number of lifetime sexual partners, substance use and previous STI diagnoses. Determinants associated with STI-diagnoses at the current visit included being non-Israeli born, presenting with STI symptoms, reporting a greater number of lifetime sexual partners and having sexual encounters with non-Israeli individuals.Approximately 25% of all men who attended the clinic were MPS. They were more likely to engage in risk-behaviors associated with HIV/STI transmission compared to non-MPS. These findings highlight the need to establish interventions for MPS that both continue to encourage condom use and address the potential perils pertaining to risky sexual behaviors.

Chlamydia trachomatis (Ct) is the most reported sexually transmitted infection in the United States, with a major cause of infertility, pelvic inflammatory disease, and ectopic pregnancy among women. Despite decades of screening women for Ct, rates increase among young African Americans (AA). We create and analyze a heterosexual agent-based network model to help understand the spread of Ct. We calibrate the model parameters to agree with survey data showing Ct prevalence of 12% of the women and 10% of the men in the 15-25 year-old AA in New Orleans, Louisiana. Our model accounts for both long-term and casual partnerships. The network captures the assortative mixing of individuals by preserving the joint-degree distributions observed in the data. We compare the effectiveness of intervention strategies based on randomly screening men, notifying partners of infected people, which includes partner treatment, partner screening, and rescreening for infection. We compare the difference between treating partners of an infected person both with and without testing them. We observe that although increased Ct screening, rescreening, and treating most of the partners of infected people will reduce the prevalence, these mitigations alone are not sufficient to control the epidemic. The current practice is to treat the partners of an infected individual without first testing them for infection. The model predicts that if a sufficient number of the partners of all infected people are tested and treated, then there is a threshold condition where the epidemic can be mitigated. This threshold results from the expanded treatment network created by treating an individual's infected partners' partners. Although these conclusions can help design future Ct mitigation studies, we caution the reader that these conclusions are for the mathematical model, not the real world, and are contingent on the validity of the model assumptions.

Preexposure prophylaxis (PrEP) for prevention of human immunodeficiency virus (HIV) infection may benefit not only the person who uses it but also their uninfected sexual risk contacts. We developed an agent-based model using a novel trial emulation approach to quantify disseminated effects of PrEP use among men who have sex with men in Atlanta, Georgia, from 2015 to 2017. Model components (subsets of agents connected through partnerships in a sexual network but not sharing partnerships with any other agents) were first randomized to an intervention coverage level or the control group; then, within intervention components, eligible agents were randomized to receive or not receive PrEP. We calculated direct and disseminated (indirect) effects using randomization-based estimators and report corresponding 95% simulation intervals across scenarios ranging from 10% coverage in the intervention components to 90% coverage. A population of 11,245 agents was simulated, with an average of 1,551 components identified. When comparing agents randomized to no PrEP in 70% coverage components with control agents, there was a 15% disseminated risk reduction in HIV incidence (risk ratio = 0.85, 95% simulation interval: 0.65, 1.05). Persons not on PrEP may receive a protective benefit by being in a sexual network with higher PrEP coverage. Agent-based models are useful for evaluating possible direct and disseminated effects of HIV prevention modalities in sexual networks.

BackgroundSexual network degree, a count of ongoing partnerships, plays a critical role in the transmission dynamics of human immunodeficiency virus (HIV) and other sexually transmitted infections (STI). Researchers often quantify degree using self-reported cross-sectional data on the day of survey, which may result in bias because of uncertainty about future sexual activity.MethodsWe evaluated the bias of a cross-sectional degree measure with a prospective cohort study of men who have sex with men (MSM). At baseline, we asked men about whether recent sexual partnerships were ongoing. We confirmed the true, ongoing status of those partnerships at baseline at follow-up. With logistic regression, we estimated the partnership-level predictors of baseline measure accuracy. With Poisson regression, we estimated the longitudinally confirmed degree as a function of baseline predicted degree.ResultsAcross partnership types, the baseline ongoing status measure was 70% accurate, with higher negative predictive value (91%) than positive predictive value (39%). Partnership exclusivity and racial pairing were associated with higher accuracy. Baseline degree generally overestimated confirmed degree. Bias, or number of ongoing partners different than predicted at baseline, was -0.28 overall, ranging from -1.91 to -0.41 for MSM with any ongoing partnerships at baseline. Comparing MSM of the same baseline degree, the level of bias was stronger for black compared to white MSM, and for younger compared to older MSM.ConclusionsResearch studies may overestimate degree when it is quantified cross-sectionally. Adjustment and structured sensitivity analyses may account for bias in studies of HIV or STI prevention interventions.

BackgroundThe World Health Organization has recommended HIV self-testing (HIVST) as an alternative testing strategy given the limitations of facility-based testing. While the benefits of HIV self-testing have been demonstrated at the individual level among men who have sex with men (MSM), limited data exist on if this testing approach can be effectively diffused through individuals' social or sexual networks. The objectives of this study were to examine patterns and correlates of HIVST distribution within Chinese MSM's sexual networks.MethodsData used for this analysis was a part of the process evaluation of an HIVST intervention trial among MSM in Nanjing, China. Between May and October 2017, we enrolled 400 men into the trial. Participants assigned to the intervention group (N = 200) were given three HIVST kits at baseline and could request more during the follow-up periods. We incorporated measures for process evaluation in the self-administered online follow-up surveys. This analysis reported findings from the three-month follow-up survey in the intervention group. Frequencies and percentages were used to describe characteristics of participants who distributed kits to their sexual partners as well as patterns of distribution. Multivariable logistic regression was conducted to identify independent correlates of participants who distributed the kits.ResultsOf the 177 participants retained (88.5%) at the three-month follow-up, 72 (40.7%) distributed one or more kits to either primary or casual partners. About half of distributors (51.4%) gave one HIVST kit to their sexual partners while 15.3% distributed 3 or more. Over half gave these kits (58.3%) to primary sexual partners while 27.8% reported giving the kits to both primary and casual partners. About half (54.2%) of distributors used the kits together with their partners. Compared to participants who had an HIV test in the past six months, those who tested over six months ago or never tested had significantly lower odds of distributing the kits (AOR = 0.484, 95% CI: 0.250-0.983, p = 0.032). Compared to those who had not used the kits themselves, participants who did had significantly higher odds of distributing the kits (AOR = 3.345, 95% CI: 1.488-7.517, p = 0.003). Participants who reported higher HIV testing efficacy had 2.051 fold greater odds (95% CI: 1.062-3.961, p = 0.033) of distributing the kits compared to those who had lower efficacy.ConclusionOur study demonstrated that a sexual network-based approach to distributing HIVST among Chinese MSM is feasible and can be a promising strategy to improve the effectiveness of HIVST programs including its reach to untested men. Such approach should be complimented by intervention components that enhance HIV testing efficacy and improve experiences of HIVST.

Background Estimation of epidemic potential of a sexually transmitted infection (STI) is difficult due to difficulty in measuring and quantifying the sexual network and implications for infection transmission. We demonstrate an approach for predicting the epidemic potential of an STI using data on another STI for men who have sex with men. Methods An individual-based mathematical model was constructed to describe sex partnering and STI concurrent transmission, namely HIV, herpes simplex virus type 2 (HSV-2), gonorrhea, chlamydia, and syphilis. The model was parameterized with representative biological and behavioral data. 500 heterogeneous sexual networks were simulated, on each of which STI transmission was also simulated. Correlations were assessed on model simulations (STI prevalences). Regressions were conducted to evaluate the predictability of HIV prevalence from each of the other STI prevalences. Results Across these simulations, Spearman’s rank correlation coefficient was 0.46 (95% CI: 0.37- 0.55) between HIV and HSV-2, 0.90 (95% CI: 0.88–0.91) between HIV and gonorrhea, 0.82 (95% CI: 0.78–0.86) between HIV and chlamydia, 0.82 (95% CI: 0.78–0.84) between HIV and syphilis, 0.31 (95% CI: 0.21–0.40) between HSV-2 and gonorrhea, 0.82 (95% CI: 0.78–0.86) between HSV-2 and chlamydia, 0.15 (95% CI: 0.05–0.25) between HSV-2 and syphilis, 0.70 (95% CI: 0.65–0.75) between gonorrhea and chlamydia, 0.93 (95% CI: 0.92–0.95) between gonorrhea and syphilis, and 0.56 (95% CI: 0.49–0.61) between chlamydia and syphilis. The adjusted R-squared for predicting HIV prevalence using each individual STI prevalence was 0.40 for HSV-2, 0.77 for gonorrhea, 0.71 for chlamydia, and 0.57 for syphilis. The adjusted R-squared for predicting HIV prevalence in a model that includes all other STI prevalences was 0.92. Conclusion STI prevalence is a proxy biomarker of HIV prevalence across heterogeneous sexual networks, explaining a considerable fraction of HIV prevalence variation. However, the strength of the association between each pair of STIs varies across STIs. Disclosure No significant relationships.