Frequency of sexual activity with most recent male partner among young, Internet-using men who have sex with men in the United States

Approximate inference for longitudinal mechanistic HIV contact network

Network models are increasingly used to study infectious disease spread. Exponential Random Graph models have a history in this area, with scalable inference methods now available. An alternative approach uses mechanistic network models. Mechanistic network models directly capture individual behaviors, making them suitable for studying sexually transmitted diseases. Combining mechanistic models with Approximate Bayesian Computation allows flexible modeling using domain-specific interaction rules among agents, avoiding network model oversimplifications. These models are ideal for longitudinal settings as they explicitly incorporate network evolution over time. We implemented a discrete-time version of a previously published continuous-time model of evolving contact networks for men who have sex with men and proposed an ABC-based approximate inference scheme for it. As expected, we found that a two-wave longitudinal study design improves the accuracy of inference compared to a cross-sectional design. However, the gains in precision in collecting data twice, up to 18%, depend on the spacing of the two waves and are sensitive to the choice of summary statistics. In addition to methodological developments, our results inform the design of future longitudinal network studies in sexually transmitted diseases, specifically in terms of what data to collect from participants and when to do so.

The need for pre-emptive control strategies for mpox in Asia and Oceania

Introduction

The transmission dynamics of the recent mpox outbreak highlights the lack of infrastructure available to rapidly respond to novel STI outbreaks, of which Asia and Oceania remains particularly susceptible. Here, we simulate outbreaks in this setting and propose the use of pre-emptive vaccination within the men who have sex with men (MSM) community before the arrival and establishment of the virus.

Materials and methods

Using data driven heterogeneous sexual contact networks, we simulated outbreaks of mpox in Singapore, Hong Kong, and Sydney. An individual based SEIR compartmental model was used to simulate epidemic trajectories and the impact of different vaccination uptakes was assessed in their ability to avert or suppress outbreaks upon the arrival of mpox within the MSM populations.

Results

The highly dense sexual networks of Singapore and Sydney experience rapid outbreaks, with infection peaks occurring at day 41 and 23 respectively, compared to Hong Kong which occurs at day 77. Across the simulations with no vaccination, 68.2%-89.7% of the MSM community will become infected with mpox across the different cities, over a simulation period of 1 year. By implementing vaccination strategies, the infection rate across the cities can be reduced to as low as 3.1% of the population (range: 3.1%-82.2%) depending on the implementation and uptake of the vaccine. Vaccination is also extremely effective in slowing the start of the epidemic, delaying the epidemic peak by 36-50 days in Hong Kong, or even preventing the outbreak of mpox.

Discussion

With extremely dense and well-connected sexual contact networks, where 65.2%-83.2% of the population are connected to a super-spreader in the different contact networks, pre-emptive or immediate vaccination upon identification of the first case is strongly recommended to help better manage the outbreak of mpox and prevent potential straining of healthcare systems.

The Incidence Rate of Sexual Behaviors Among Cisgender Men Who Have Sex with Men Attending a Sexual Health Clinic

Although nuanced parameterization of sexual behavior may improve estimates from mathematical models of human immunodeficiency virus and sexually transmitted infection transmission, prospective estimates of the incidence of specific sexual behaviors among men who have sex with men (MSM) are limited. From December 2014 to July 2018, MSM with and without nongonococcal urethritis (NGU) completed weekly diaries over 3-12 weeks. Incidence rates of any sex, receptive anal sex, insertive anal sex, insertive oral sex, receptive rimming, and receptive hand-penile contact were 1.19, 0.28, 0.66, 0.90, 0.24, and 0.85 episodes per person-week, respectively, among 104 MSM with NGU at baseline, and 1.33, 0.54, 0.32, 0.95, 0.44, and 0.88 episodes per person-week, respectively, among 25 MSM without NGU at baseline. Most receptive anal sex (NGU + 83%, NGU - 86%) and insertive anal sex (NGU + 85%, NGU - 76%) episodes were condomless. MSM engaged in sex just over once per week, and condom use was infrequent. Insertive oral sex and receptive hand-penile contact were the most common behaviors.

Spillover benefit of pre-exposure prophylaxis for HIV prevention: evaluating the importance of effect modification using an agent-based model

We developed an agent-based model using a trial emulation approach to quantify effect measure modification of spillover effects of pre-exposure prophylaxis (PrEP) for HIV among men who have sex with men (MSM) in the Atlanta-Sandy Springs-Roswell metropolitan area, Georgia. PrEP may impact not only the individual prescribed, but also their partners and beyond, known as spillover. We simulated a two-stage randomised trial with eligible components (≥3 agents with ≥1 HIV+ agent) first randomised to intervention or control (no PrEP). Within intervention components, agents were randomised to PrEP with coverage of 70%, providing insight into a high PrEP coverage strategy. We evaluated effect modification by component-level characteristics and estimated spillover effects on HIV incidence using an extension of randomisation-based estimators. We observed an attenuation of the spillover effect when agents were in components with a higher prevalence of either drug use or bridging potential (if an agent acts as a mediator between ≥2 connected groups of agents). The estimated spillover effects were larger in magnitude among components with either higher HIV prevalence or greater density (number of existing partnerships compared to all possible partnerships). Consideration of effect modification is important when evaluating the spillover of PrEP among MSM.

Risk Estimation of Sexual Transmission of Zika Virus-United States, 2016-2017

BACKGROUND

Zika virus (ZIKV) can be transmitted sexually but the risk of sexual transmission remains unknown. Most evidence of sexual transmission is from partners of infected travelers returning from areas with ZIKV circulation.

METHODS

We used data from the US national arboviral disease surveillance system on travel- and sexually acquired ZIKV disease cases during 2016-2017 to develop individual-level simulations for estimating risk of male-to-female, male-to-male, and female-to-male sexual transmission of ZIKV via vaginal and/or anal intercourse. We specified parametric distributions to characterize individual-level variability of parameters for ZIKV persistence and sexual behaviors.

RESULTS

Using ZIKV RNA persistence in semen/vaginal fluids to approximate infectiousness duration, male-to-male transmission had the highest estimated probability (1.3% [95% confidence interval, CI, .4%-6.0%] per anal sex act), followed by male-to-female and female-to-male transmission (0.4% [95% CI, .3%-.6%] per vaginal/anal sex act and 0.1% [95% CI, 0%-.8%] per vaginal sex act, respectively). Models using viral isolation in semen vs RNA detection to approximate infectiousness duration predicted greater risk of sexual transmission.

CONCLUSIONS

While likely insufficient to maintain sustained transmission, the estimated risk of ZIKV transmission through unprotected sex is not trivial and is especially important for pregnant women, as ZIKV infection can cause severe congenital disorders.

Countering the rise of syphilis: A role for doxycycline post-exposure prophylaxis?

Doxycycline post-exposure prophylaxis (PEP) holds the potential to mitigate increasing rates of syphilis among sexual minority men (SMM) in the US yet has received limited attention. Since evaluation of this intervention in actual populations is not currently feasible, we used agent-based models (ABM) to assess the population-level impact of this strategy. We adapted ABM of HIV and HPV transmission, representing a population of 10,230 SMM in Philadelphia, Pennsylvania, US. Parameter inputs were derived from the literature, and ABM outputs during the pre-intervention period were calibrated to local surveillance data. Intervention scenarios varied doxycycline uptake by 20, 40, 60, 80 and 100%, while assuming continued condom use and syphilis screening and treatment. Under each intervention scenario, we incorporated treatment adherence at the following levels: 0, 20, 40, 60, 80 and 100%. Long-term population impact of prophylactic doxycycline was measured using the cumulative incidence over the 10-year period and the percentage of infections prevented attributable to doxycycline at year 10. An uptake scenario of 20% with an adherence level of 80% would reduce the cumulative incidence of infections by 10% over the next decade, translating to 57 fewer cases per 1000 SMM. At year 10, under the same uptake and adherence level, 22% of infections would be prevented due to doxycycline PEP in the instances where condoms were not used or failed. Findings suggest that doxycycline PEP will have a modest impact on syphilis incidence when assuming a reasonable level of uptake and adherence. Doxycycline PEP may be most appropriate as a secondary prevention measure to condoms and enhanced syphilis screening for reducing infections among SMM.

Disseminated Effects in Agent-Based Models: A Potential Outcomes Framework and Application to Inform Preexposure Prophylaxis Coverage Levels for HIV Prevention

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.

Oral sex practices among men who have sex with men and transgender women at risk for and living with HIV in Nigeria

Background

Men who have sex with men (MSM) and transgender women (TGW) are at risk for sexually transmitted infections (STIs), including those of the oropharynx. We estimated the prevalence and factors associated with oral sex practices and characterized oropharyngeal STIs among a cohort of MSM and TGW in Nigeria.

Methods

From 2013 to 2018, TRUST/RV368 recruited MSM and TGW into HIV/STI diagnosis and treatment at community-based clinics in Nigeria. Participants who completed HIV testing and oral sex questions at enrollment were selected. Cross-sectional analyses with bivariate and multivariable logistic regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs). Oropharyngeal swab testing for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) began in 2014 and for those with diagnostic results at enrollment, the unadjusted association of oral sex practices with oropharyngeal STIs was conducted.

Results

A total of 1342 participants had a median age of 25 years (interquartile range: 22–29), 58% were living with HIV, and 69% reported oral sex practices. Factors associated with increased odds of engaging in oral sex included living with HIV (adjusted [a]OR: 1.4, 95% CI: 1.1–1.8), self-identifying as a woman (aOR:1.8, 95% CI: 1.1–2.8), mobile phone ownership (aOR:2.3, 95% CI: 1.3–3.9), receptive anal sex (aOR:1.7, 95% CI:1.3–2.3) and multiple male sexual partners (2 to 4 vs. ≤1, aOR:1.5, 95% CI: 1.0–2.2; 5+ vs ≤1, aOR:2.9, 95% CI:1.9–4.3). Oropharyngeal STI prevalence was 7% (52/752) and higher among those who engaged in oral sex compared to those who did not (unadjusted OR: 2.5, 95% CI:1.2–5.3).

Conclusions

Oral sex was common and associated with an increased odds of oropharyngeal STIs among MSM and TGW from Nigeria. In the absence of screening and treatment guidelines, condoms continue to be the mainstay for oral STI prevention. A pre-exposure prophylaxis for bacterial STIs would complement current prevention strategies to curb transmission.

Trends in Number and Composition of Sex Partners Among Men Who Have Sex With Men in the United States, National HIV Behavioral Surveillance, 2008-2014

BACKGROUND

Social and legal acceptance of long-term same-sex partnerships in the United States has increased over the past decade which may impact sexual partnering among men who have sex with men (MSM). Identifying whether and how partnering trends have evolved at a national level could improve understanding of HIV transmission and prevention among MSM partnerships.

METHODS

We used Centers for Disease Control and Prevention's National HIV Behavioral Surveillance data (2008, 2011, and 2014) to study trends in the number and partner type composition (main/casual) of male sex partners among US MSM. Changes over time were assessed in Poisson regression models with the link function tailored to the count and binary outcomes.

RESULTS

The mean total number of partners in the past year increased, while the mean number of main partners remained stable. The percentage of MSM with both main and casual partners increased, and we observed a shift from having ≥1 main and 0 casual partners to having ≥1 main and ≥2 casual partners. Condomless anal sex in the past year increased regardless of partner composition.

DISCUSSION

Findings suggest casual partnering among MSM has increased in recent years, including among those with ≥1 main partners. Both partner-based and individual prevention programs remain critical to reaching MSM.

Competing biomedical HIV prevention strategies: potential cost-effectiveness of HIV vaccines and PrEP in Seattle, WA

INTRODUCTION

Promising HIV vaccine candidates are steadily progressing through the clinical trial pipeline. Once available, HIV vaccines will be an important complement but also potential competitor to other biomedical prevention tools such as pre-exposure prophylaxis (PrEP). Accordingly, the value of HIV vaccines and the policies for rollout may depend on that interplay and tradeoffs with utilization of existing products. In this economic modelling analysis, we estimate the cost-effectiveness of HIV vaccines considering their potential interaction with PrEP and condom use.

METHODS

We developed a dynamic model of HIV transmission among the men who have sex with men population (MSM), aged 15-64 years, in Seattle, WA offered PrEP and HIV vaccine over a time horizon of 2025-2045. A healthcare sector perspective with annual discount rate of 3% for costs (2017 USD) and quality-adjusted life years (QALYs) was used. The primary economic endpoint is the incremental cost-effectiveness ratio (ICER) when compared to no HIV vaccine availability.

RESULTS

HIV vaccines improved population health and increased healthcare costs. Vaccination campaigns achieving 90% coverage of high-risk men and 60% coverage of other men within five years of introduction are projected to avoid 40% of new HIV infections between 2025 and 2045. This increased total healthcare costs by $30 million, with some PrEP costs shifted to HIV vaccine spending. HIV vaccines are estimated to have an ICER of $42,473/QALY, considered cost-effective using a threshold of $150,000/QALY. Results were most sensitive to HIV vaccine efficacy and future changes in the cost of PrEP drugs. Sensitivity analysis found ranges of 30-70% HIV vaccine efficacy remained cost-effective. Results were also sensitive to reductions in condom use among PrEP and vaccine users.

CONCLUSIONS

Access to an HIV vaccine is desirable as it could increase the overall effectiveness of combination HIV prevention efforts and improve population health. Planning for the rollout and scale-up of HIV vaccines should carefully consider the design of policies that guide interactions between vaccine and PrEP utilization and potential competition.

Modeling HPV vaccination scale-up among urban young men who have sex with men in the context of HIV

INTRODUCTION

Young men who have sex with men (YMSM) are at high risk to contract human papillomavirus (HPV). While an effective vaccination exists, its use among YMSM is markedly lower compared to non-MSM and women. This study compares scaling up HPV vaccination in conjunction with other prevention strategies.

METHODS

An agent-based model of urban YMSM (≤26 years of age) reflective of the demography of Philadelphia, PA, simulated for up to ten years of follow-up to examine anal and oral transmission of the HPV genotypes covered in the nonavalent (9v) vaccine: 6, 11, 16, 18, 31, 33, 45, 52, 58. Starting HPV prevalences ranged from a high of 18% (type 6) to a low of 6% (type 31); overall 65% of individuals carried any HPV genotype. Simulated levels of vaccination were ranged from 0% to 13% (present-day level), 25%, 50%, 80% (Healthy People 2020 target), and 100% in conjunction with condom use and HIV seroadaptive practices. The primary outcome was the relative reduction in HPV infection.

RESULTS

Compared to present-day vaccination levels (13%), scaling-up vaccination led to expected declines in 10-year post-simulation HPV prevalence. Anal HPV (any 9v types) declined by 9%, 27%, 46%, and 58% at vaccination levels of 25%, 50%, 80%, and 100%, respectively. Similarly, oral HPV (any 9v types) declined by 11%, 33%, 57%, and 71% across the same levels of vaccine uptake. Comparing the prevention strategies, condoms blocked the greatest number of anal transmissions when vaccination was at or below present-day levels. For oral transmission, vaccination was superior to condom use at all levels of coverage.

CONCLUSIONS

Public health HPV preventions strategies should continue to emphasize the complementary roles of condoms and vaccination, especially for preventing oral infection. Improving vaccination coverage will ultimately have the greatest impact on reducing HPV infection among YMSM.

Double-Blind, Single-Center, Randomized Three-Way Crossover Trial of Fitted, Thin, and Standard Condoms for Vaginal and Anal Sex: C-PLEASURE Study Protocol and Baseline Data

Background

Male condoms are underused despite their ability to prevent transmission of HIV and other sexually transmitted infections. The perception of decreased sexual pleasure and poor condom fit are major contributors to condom nonuse.

Objective

The purpose of this study was to compare event-level performance and pleasure using fitted, thin, and standard condoms among men who have sex with men (MSM) and men who have sex with women (MSW). We also sought to assess condom type preference. We present the study design and enrollment data from the trial.

Methods

This study recruited sexually active men aged 18 to 54 years in Atlanta, Georgia, United States. We enrolled 252 MSM and 252 MSW in a double-blind, 3-way randomized crossover trial with conditions of fitted, thin, and standard condoms. A permuted block randomization scheme was used to assign each participant to the sequence in which they received each type of study condom. After a baseline screening and enrollment visit, randomized participants were followed for at least 6 and up to 12 weeks depending on their use of study condoms in each 2-week period between scheduled, in-person study visits. Participants were instructed to complete mobile-optimized coital logs as soon as possible after using condoms for anal or vaginal sex acts. The logs collected event-level pleasure and performance measures for the study condoms as well as other relevant data. A questionnaire was administered at the final study visit to assess overall study condom preference.

Results

The study enrolled 252 MSM and 252 MSW, a total of 504 participants. MSM and MSW study arms were similar for a number of key traits including race and ethnicity, marital status, self-rated condom experience, and recent experience of condom failure. Men in the MSM arm were older, however, and fewer MSM were students. The majority of participants in both arms rated themselves as very experienced with using condoms, and the majority had used condoms recently. Over one-third of participants in each arm reported experiencing condom failure in the last 6 months.

Conclusions

This is the first condom trial to compare the performance of standard, thin, and fitted condoms and to use pleasure and preference as primary outcomes. Given the disparate impact of HIV on MSM, equal enrollment of MSM and MSW was a key feature of this study. Trial results may inform an FDA label indication for anal sex and provide new information regarding the relative performance of different types of condoms.

Trial Registration

ClinicalTrials.gov NCT02753842; https://clinicaltrials.gov/ct2/show/NCT02753842 (Archived by WebCite at http://www.webcitation.org/76RLTFyf0)

International Registered Report Identifier (IRRID)

DERR1-10.2196/12205

The Association Between Fraternal Birth Order and Anal-Erotic Roles of Men Who Have Sex with Men

The fraternal birth order effect (FBOE) describes the phenomenon that homosexual men tend to have a greater number of older brothers than do heterosexual men. The FBOE is a marker for an innate, biological predisposition for androphilia in genotypic males. The FBOE has been studied since the 1930s and is the most consistent biodemographic correlate of sexual orientation in men. This study sought to determine whether the FBOE applies equally to all men who have sex with men (MSM), or disproportionately to MSM whose anal intercourse behavior is predominantly receptive (Bottoms). Participants included 243 North American adult MSM who responded to advertisements posted on a Web site and other electronic media associated with the GALA festival, a quadrennial gathering of gay and lesbian choruses. Each was asked whether his anal intercourse behavior during the preceding year was predominantly receptive, predominantly penetrative, or about equally receptive and penetrative. Those who indicated their behavior was predominantly receptive were coded "Bottoms"; all others were coded "Not-Bottoms." Participants were also surveyed as to their sibship composition. Bottoms had a significantly greater mean number of older brothers than did Not-Bottoms. There was no significant difference with respect to older or younger sisters or younger brothers. Further, the older sibling sex ratio (OSSR) for the Bottom cohort, but not for the Not-Bottom cohort, was significantly higher than the expected OSSR for the general male population (OSSR = No. older brothers/No. older sisters × 100; expected OSSR for general population = 106). Thus, late fraternal birth order was correlated with receptive anal-erotic behavior among MSM.

Effect of Racial Inequities in Pre-exposure Prophylaxis Use on Racial Disparities in HIV Incidence Among Men Who Have Sex With Men: A Modeling Study

BACKGROUND

Pre-exposure prophylaxis (PrEP) uptake has been slow among African American men who have sex with men (AAMSM) in the United States. We used an agent-based model (ABM) to simulate race-specific PrEP coverage to estimate their impact on racial disparities in HIV incidence among MSM in Atlanta, GA.

METHODS

An ABM was constructed to simulate HIV transmission in a dynamic network of 10,000 MSM over 10 years, beginning in 2015. We modeled a base scenario with estimated PrEP coverage of 2.5% among AAMSM and 5.0% among white MSM (WMSM). We then compared HIV incidence over 10 years and calculated a disparity ratio of AAMSM to WMSM incidence rates across varying PrEP scale-up scenarios, with equal and unequal coverage among AAMSM and WMSM.

RESULTS

Assuming current coverage remains constant, the model predicts HIV incidence rates of 2.95 and 1.76 per 100 person-years among AAMSM and WMSM, respectively, with a disparity ratio of 1.68. If PrEP coverage was to increase 6-fold without addressing inequities in PrEP uptake, the model predicts incidences of 2.65 and 1.34, corresponding to a mean decrease of 10.4% and 24.0% in HIV incidence, respectively. This stronger benefit for WMSM increased the disparity ratio to 1.98. Equal PrEP coverage among AAMSM and WMSM resulted in lower incidence rates overall with lower disparity ratios.

CONCLUSIONS

Lower uptake among AAMSM relative to WMSM may limit the population-level impact of PrEP use among AAMSM, which may ultimately culminate in wider racial disparities in HIV incidence among MSM.

Improving the impact of HIV pre-exposure prophylaxis implementation in small urban centers among men who have sex with men: An agent-based modelling study

Objectives

Identifying prescribing strategies that improve the efficiency of PrEP should increase its impact at the population level. This study identifies PrEP allocation criteria that most effectively reduce 10-year HIV incidence by 25%, in accordance with the US National HIV/AIDS Strategy’s goal for the proportionate reduction in new diagnoses.

Methods

We used a discrete-time stochastic agent-based model to simulate several PrEP engagement strategies. The model represented MSM aged 15–74 in Rhode Island and was calibrated to statewide prevalence from 2009–2014. We simulated HIV transmission in the absence of PrEP and compared the following PrEP engagement scenarios: 1) allocation to the current patient population; 2) random allocation; 3) allocation to MSM with greater than 5 sexual partners in one year; 4) allocation to MSM with greater than 10 sexual partners in one year.

For each scenario and coverage level we estimated the number and proportion of infections averted and the person-years on PrEP per averted infection.

Results

In 2014, HIV prevalence before PrEP implementation was between 4% and 5%. In the No PrEP scenario 826 new infections (95% simulation limits [SL]: 711, 955) occurred over 10 years, with an incidence rate of 3.51 per 1000 person-years (95% SL: 3.00, 4.08). Prevalence rose to 7.4% (95% SL: 6.7, 8.1). None of the PrEP scenarios reduced new HIV infections by 25% while covering less than 15% of the HIV-uninfected population. At 15% coverage, allocating PrEP to the current patient population, MSM with greater than 5 sexual partners in a year, and MSM with greater than 10 partners reduced new infections by at least 25%, requiring 161 (95% SL: 115, 289), 150 (95% SL: 107, 252), and 128 (95% SL: 100, 184) person-years on PrEP per averted infection, respectively.

Conclusions

Engaging MSM with high numbers of sexual partners would improve the population-level impact and efficiency of PrEP in settings where PrEP coverage remains low. However, the sustained population-level PrEP coverage needed to reduce new infections by 25% is substantially higher than current levels of PrEP uptake.

Prevalence of drug use during sex amongst MSM in Europe: Results from a multi-site bio-behavioural survey

BACKGROUND

Substance use has been consistently reported to be more prevalent amongst Men who have Sex with Men (MSM) compared to the general population. Substance use, in particular polydrug use, has been found to be influenced by social and contextual factors and to increase the risk of unprotected intercourse among MSM. The objective of this analysis was to investigate the prevalence and predictors of drug use during a sexual encounter and to identify specific prevention needs.

METHODS/DESIGN

A multi-site bio-behavioural cross-sectional survey was implemented in 13 European cities, targeting MSM and using Time-Location Sampling and Respondent-Driven Sampling methods Multivariable multi-level logistic random-intercept model (random effect of study site) was estimated to identify factors associated with the use of alcohol, cannabis, party drugs, sexual performance enhancement drugs and chemsex drugs.

RESULTS

Overall, 1261 (30.0%) participants reported drug use, and 436 of 3706 (11.8%) reported the use of two or more drugs during their last sexual encounter. By drug class, 966 (23.0%) reported using sexual performance enhancement drugs, 353 (8.4%) - party drugs, and 142 (3.4%) the use of chemsex drugs. Respondents who reported drug use were more frequently diagnosed with HIV (10.5% vs. 3.9%) before and with other STIs during the 12 months prior to the study (16.7% vs. 9.2%). The use of all the analysed substances was significantly associated with sexual encounter with more than one partner.

DISCUSSION

Substance and polydrug use during sexual encounters occurred amongst sampled MSM across Europe although varying greatly between study sites. Different local social norms within MSM communities may be important contextual drivers of drug use, highlighting the need for innovative and multi-faceted prevention measures to reduce HIV/STI risk in the context of drug use.

HIV prevalence among men who have sex with men in Brazil: results of the 2nd national survey using respondent-driven sampling

This paper reports human immuno-deficiency virus (HIV) prevalence in the 2nd National Biological and Behavioral Surveillance Survey (BBSS) among men who have sex with men (MSM) in 12 cities in Brazil using respondent-driven sampling (RDS).Following formative research, RDS was applied in 12 cities in the 5 macroregions of Brazil between June and December 2016 to recruit MSM for BBSS. The target sample size was 350 per city. Five to 6 seeds were initially selected to initiate recruitment and coupons and interviews were managed online. On-site rapid testing was used for HIV screening, and confirmed by a 2nd test. Participants were weighted using Gile estimator. Data from all 12 cities were merged and analyzed with Stata 14.0 complex survey data analysis tools in which each city was treated as its own strata. Missing data for those who did not test were imputed HIV+ if they reported testing positive before and were taking antiretroviral therapy.A total of 4176 men were recruited in the 12 cities. The average time to completion was 10.2 weeks. The longest chain length varied from 8 to 21 waves. The sample size was achieved in all but 2 cities.A total of 3958 of the 4176 respondents agreed to test for HIV (90.2%). For results without imputation, 17.5% (95%CI: 14.7-20.7) of our sample was HIV positive. With imputation, 18.4% (95%CI: 15.4-21.7) were seropositive.HIV prevalence increased beyond expectations from the results of the 2009 survey (12.1%; 95%CI: 10.0-14.5) to 18.4%; CI95%: 15.4 to 21.7 in 2016. This increase accompanies Brazil's focus on the treatment to prevention strategy, and a decrease in support for community-based organizations and community prevention programs.

The risk of HIV transmission at each step of the HIV care continuum among people who inject drugs: a modeling study

Background

People who inject drugs (PWID) are at continued risk for HIV in the U.S., and experience disparities across the HIV care continuum compared to other high-risk groups. Estimates of the risk of HIV transmission at each stage of the care continuum may assist in identifying public health priorities for averting incident infections among PWID, in addition to transmissions to sexual partners of PWID.

Methods

We created an agent-based model simulating HIV transmission and the HIV care continuum for PWID in New York City (NYC) in 2012. To account for sexual transmission arising from PWID to non-PWID, the simulation included the entire adult NYC population. Using surveillance data and estimates from the National HIV Behavioral Surveillance system, we simulated a dynamic sexual and injecting network. We estimated the proportion of HIV transmission events attributable to PWID in the following categories, those: without an HIV diagnosis (‘Undiagnosed’); diagnosed but not on antiretroviral therapy (ART) (‘Diagnosed − not on ART’); those who initiated ART but were not virally suppressed (‘Unsuppressed’); and, those who achieved viral suppression (‘Suppressed’).

Results

We estimated HIV incidence among PWID to be 113 per 100,000 person-years in 2012, with an overall incidence rate for the entire adult NYC population of 33 per 100,000 person-years. Despite accounting for only 33% of the HIV-infected PWID population, the Undiagnosed were associated with 52.6% (95% simulation interval [95% SI]: 47.1–57.0%) of total transmission events. The Diagnosed − not on ART population contributed the second-largest proportion of HIV transmissions, with 36.6% (95% SI: 32.2–41.5%). The Unsuppressed population contributed 8.7% (95% SI: 5.6–11.8%), and Suppressed 2.1% (95% SI: 1.1–3.9%), relatively little of overall transmission.

Conclusions

Among PWID in NYC, more than half (53%) of transmissions were from those who were unaware of their infection status and more than 36% were due to PWID who knew their status, but were not on treatment. Our results indicate the importance of early diagnosis and interventions to engage diagnosed PWID on treatment to further suppress population-level HIV transmission. Future HIV prevention research should focus on the elimination of identified and potential barriers to the testing, diagnosis, and retention of PWID on HIV treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4528-9) contains supplementary material, which is available to authorized users.

The case for investing in the male condom

When used correctly and consistently, the male condom offers triple protection from unintended pregnancy and the transmission of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV). However, with health funding levels stagnant or falling, it is important to understand the cost and health impact associated with prevention technologies. This study is one of the first to attempt to quantify the cost and combined health impact of condom use, as a means to prevent unwanted pregnancy and to prevent transmission of STIs including HIV. This paper describes the analysis to make the case for investment in the male condom, including the cost, impact and cost-effectiveness by three scenarios (low in which 2015 condom use levels are maintained; medium in which condom use trends are used to predict condom use from 2016–2030; and high in which condom use is scaled up, as part of a package of contraceptives, to meet all unmet need for family planning by 2030 and to 90% for HIV and STI prevention by 2016) for 81 countries from 2015–2030. An annual gap between current and desired use of 10.9 billion condoms was identified (4.6 billion for family planning and 6.3 billion for HIV and STIs). Under a high scenario that completely reduces that gap between current and desired use of 10.9 billion condoms, we found that by 2030 countries could avert 240 million DALYs. The additional cost in the 81 countries through 2030 under the medium scenario is $1.9 billion, and $27.5 billion under the high scenario. Through 2030, the cost-effectiveness ratios are $304 per DALY averted for the medium and $115 per DALY averted for the high scenario. Under the three scenarios described above, our analysis demonstrates the cost-effectiveness of the male condom in preventing unintended pregnancy and HIV and STI new infections. Policy makers should increase budgets for condom programming to increase the health return on investment of scarce resources.

Racial Differences in Partnership Attributes, Typologies, and Risk Behaviors Among Men Who Have Sex With Men in Atlanta, Georgia

The role of main partnerships in shaping HIV transmission dynamics among men who have sex with men (MSM) has gained recognition in recent studies, but there is little evidence that existing definitions of partnership type are accurate or have consistent meaning for all men. Using data collected from 2011 to 2013 on 693 partnerships described by 193 Black and White MSM in Atlanta, GA, partnership attributes and risk behaviors were examined and compared by race, stratified in two ways: (1) by commonly used definitions of partnerships as "main" or "casual" and (2) by a new data-driven partnership typology identified through latent class analysis (LCA). Racial differences were analyzed using chi-square, Fisher's exact, and Wilcoxon-Mann-Whitney tests. Black participants were less likely to report condomless anal sex (CAS) within partnerships they labeled as main, yet they were also less likely to describe these partnerships as "primary" on a parallel question. In contrast, within strata defined by the LCA-derived typology, most partnership attributes were comparable and the likelihood of CAS was equivalent by race. These findings suggest that classification of partnerships as main or casual does not accurately capture the partnership patterns of MSM, resulting in differential misclassification by race. Future studies and interventions should refine and utilize more evidence-based typologies.

Seeking Male Sexual Partners via Internet and Traditional Venues among Chinese Men Who Have Sex with Men: Implications for HIV Risk Reduction Interventions

The dynamic nature of finding male sexual partners (sex-finding) among Chinese men who have sex with men (MSM) may play a substantial role in the HIV epidemic. We compared characteristics and behaviors of MSM who mostly sought sex via the Internet versus traditional venues in a cross-sectional survey among 3588 Chinese MSM. We assessed the sociodemographic predictors and compared high-risk behaviors of using Internet versus traditional venues for sex-finding. Compared to non-Internet MSM, Internet-user MSM were more likely to have been: younger, currently single, better educated, health-insured, with higher income, with Beijing residency ('Hukou'), living longer in the city, HIV-positive, ever using drug and engaging in condomless receptive anal sex. Internet sex-finding users were less likely to be sexually active for longer duration, drink alcohol, drink alcohol before sex, or ever have sex with women. Knowledge of differential characteristics of various sex-finding MSM can help design targeted interventions.

Recruiting a U.S. national sample of HIV-negative gay and bisexual men to complete at-home self-administered HIV/STI testing and surveys: Challenges and Opportunities

We describe enrollment for the One Thousand Strong panel, present characteristics of the panel relative to other large U.S. national studies of gay and bisexual men (GBM), and examine demographic and behavioral characteristics that were associated with passing enrollment milestones. A U.S. national sample of HIV-negative men were enrolled via an established online panel of over 22,000 GBM. Participants (n = 1071) passed three milestones to join our panel. Milestone 1 was screening eligible and providing informed consent. Milestone 2 involved completing an hour-long at-home computer-assisted self-interview (CASI) survey. Milestone 3 involved completing at-home self-administered rapid HIV testing and collecting/returning urine and rectal samples for gonorrhea and chlamydia testing. Compared to those who completed milestones: those not passing milestone 1 were more likely to be non-White and older; those not passing milestone 2 were less likely to have insurance or a primary care physician; and those not passing milestone 3 were less educated, more likely to be bisexual as opposed to gay, more likely to live in the Midwest, had fewer male partners in the past year, and less likely to have tested for HIV in the past year. Effect sizes for significant findings were small. We successfully enrolled a national sample of HIV-negative GBM who completed at-home CASI assessments and at-home self-administered HIV and urine and rectal STI testing. This indicates high feasibility and acceptability of incorporating self-administered biological assays into otherwise fully online studies. Differences in completion of study milestones indicate a need for further investigation into the reasons for lower engagement by certain groups.

Agent-based computational model of the prevalence of gonococcal infections after the implementation of HIV pre-exposure prophylaxis guidelines

Recently, the first comprehensive guidelines were published for pre-exposure prophylaxis (PrEP) for the prevention of HIV infection in populations with substantial risk of infection. Guidelines include a daily regimen of emtricitabine/tenofovir disoproxil fumarate (TDF/FTC) as well as condom usage during sexual activity. The relationship between the TDF/FTC intake regimen and condom usage is not yet fully understood. If men who have sex with men (MSM,) engage in high-risk sexual activities without using condoms when prescribed TDF/FTC they might be at an increased risk for other sexually transmitted diseases (STD). Our study focuses on the possible occurrence of behavioral changes among MSM in the United States over time with regard to condom usage. In particular, we were interested in creating a model of how increased uptake of TDF/FTC might cause a decline in condom usage, causing significant increases in non-HIV STD incidence, using gonococcal infection incidence as a biological endpoint. We used the agent-based modeling software NetLogo, building upon an existing model of HIV infection. We found no significant evidence for increased gonorrhea prevalence due to increased PrEP usage at any level of sample-wide usage, with a range of 0-90% PrEP usage. However, we did find significant evidence for decreased prevalence of HIV, with a maximal effect being reached when 5% to 10% of the MSM population used PrEP. Our findings appear to indicate that attitudes of aversion, within the medical community, toward the promotion of PrEP due to the potential risk of increased STD transmission are unfounded.

Attitudes towards couples HIV testing and counseling among Latino men who have sex with men in the Seattle area

Men who have sex with men (MSM) remain the most severely affected risk group in the US HIV/AIDS epidemic. One-third to two-thirds of HIV transmissions among MSM are estimated to come from primary sex partners. Couples HIV testing and counseling (CHTC), in which two individuals receive pre-test counseling, HIV testing and post-test prevention planning together, has been adapted for male couples in the USA, and is now available in more than 30 cities. Previous studies have demonstrated high levels of willingness to use CHTC among MSM, but to date no studies have explored this among Latino MSM (LMSM). To examine the willingness to use CHTC among and further cultural adaptation needed for LMSM, focus group discussions were held with men who self-identified as Latino, were in a relationship with another man, and resided in Seattle. Willingness to use CHTC was high. Participants reported that CHTC could strengthen and validate their relationships, help mitigate stigma, and provide a forum for support, protection, and information sharing. Barriers to CHTC use included fears of rejection, loneliness, and relationship dissolution, and concerns around deportation and financial burden. The high levels of reported willingness to use CHTC among this sample of LMSM point to the potential for CHTC to be further adapted to provide dyadic HIV testing services for LMSM.

HIV testing behaviors and perceptions of risk of HIV infection among MSM with main partners

Male couples represent a high priority group for HIV prevention interventions because primary partners have been identified as the source of one-third to two-thirds of HIV infections among men who have sex with men (MSM). HIV testing is an important component of the U.S. National AIDS Strategy. In previous research rates of HIV testing among partnered MSM have been found to be lower compared to other MSM. In this paper, we use a sample of 906 MSM recruited through internet advertisements to contrast HIV testing behavior, perceived risk of HIV infection and confidence in remaining HIV sero-negative between single MSM and MSM who report having a main partner. We also examine associations between sexual agreements and HIV testing and perceived risk among partnered MSM. Although results were marginally significant, men with a main partner had significantly higher odds of perceiving zero risk of HIV infection, higher odds of being very confident they will remain HIV-negative, and lower odds of testing for HIV in the past 6 months. Partnered men who reported they were in an open relationship had higher odds of recent HIV testing, lower odds of perceiving zero risk, and lower odds of being very confident in remaining HIV-negative, relative to those who reported monogamy. The results point to the need for dyadic interventions to tackle the underestimation of potential risk associated low HIV testing among partnered MSM. Couples HIV Testing and Counseling-CHTC-affords male couples the opportunity to learn their sero-status together and discuss the realities of their agreement and relationship and should be considered a priority intervention for male couples in the U.S.

Providing comprehensive health services for young key populations: needs, barriers and gaps

INTRODUCTION

Adolescence is a time of physical, emotional and social transitions that have implications for health. In addition to being at high risk for HIV, young key populations (YKP) may experience other health problems attributable to high-risk behaviour or their developmental stage, or a combination of both.

METHODS

We reviewed the needs, barriers and gaps for other non-HIV health services for YKP. We searched PubMed and Google Scholar for articles that provided specific age-related data on sexual and reproductive health; mental health; violence; and substance use problems for adolescent, youth or young sex workers, men who have sex with men, transgender people, and people who inject drugs.

RESULTS

YKP experience more unprotected sex, sexually transmitted infections including HIV, unintended pregnancy, violence, mental health disorders and substance use compared to older members of key populations and youth among the general population. YKP experience significant barriers to accessing care; coverage of services is low, largely because of stigma and discrimination experienced at both the health system and policy levels.

DISCUSSION

YKP require comprehensive, integrated services that respond to their specific developmental needs, including health, educational and social services within the context of a human rights-based approach. The recent WHO Consolidated Guidelines on HIV Prevention, Diagnosis, Treatment and Care for Key Populations are an important first step for a more comprehensive approach to HIV programming for YKP, but there are limited data on the effective delivery of combined interventions for YKP. Significant investments in research and implementation will be required to ensure adequate provision and coverage of services for YKP. In addition, greater commitments to harm reduction and rights-based approaches are needed to address structural barriers to access to care.

HIV transmission among men who have sex with men due to condom failure

Background

Despite preventive efforts, HIV incidence remains high among men who have sex with men (MSM) in industrialized countries. Condoms are an important element in prevention but, given the high frequency of condom use and their imperfect effectiveness, a substantial number and proportion of HIV transmissions may occur despite condoms. We developed a model to examine this hypothesis.

Methods

We used estimates of annual prevalent and incident HIV infections for MSM in Ontario. For HIV-negative men, we applied frequencies of sexual episodes and per-contact HIV transmission risks of receptive and insertive anal sex with and without a condom and oral sex without a condom. We factored in the proportion of HIV-infected partners receiving antiretroviral therapy and its impact in reducing transmissibility. We used Monte-Carlo simulation to determine the plausible range for the proportion of HIV transmissions for each sexual practice.

Results

Among Ontario MSM in 2009, an estimated 92,963 HIV-negative men had 1,184,343 episodes of anal sex with a condom and 117,133 anal sex acts without a condom with an HIV-positive partner. Of the 693 new HIV infections, 51% were through anal sex with a condom, 33% anal sex without a condom and 16% oral sex. For anal sex with a condom, the 95% confidence limits were 17% and 77%.

Conclusions

The proportion of HIV infections related to condom failure appears substantial and higher than previously thought. That 51% of transmissions occur despite condom use may be conservative (i.e. low) since we used a relatively high estimate (87.1%) for condom effectiveness. If condom effectiveness were closer to 70%, a value estimated from a recent CDC study, the number and proportion of HIV transmissions occurring despite condom use would be much higher. Therefore, while condom use should continue to be promoted and enhanced, this alone is unlikely to stem the tide of HIV infection among MSM.

Still a hard-to-reach population? Using social media to recruit Latino gay couples for an HIV intervention adaptation study

Background

Online social networking use has increased rapidly among African American and Latino men who have sex with men (MSM), making it important to understand how these technologies can be used to reach, retain, and maintain individuals in care and promote health wellness. In particular, the Internet is increasingly recognized as a platform for health communication and education. However, little is known about how primarily Spanish-speaking populations use and engage with each other through social media platforms.

Objective

We aimed to recruit eligible couples for a study to adapt “Connect ‘n Unite” (an HIV prevention intervention initially created for black gay couples) for Spanish-speaking Latino gay couples living in New York City.

Methods

In order to successfully design and implement an effective social media recruitment campaign to reach Spanish-speaking Latino gay couples for our ongoing “Latinos en Pareja” study, our community stakeholders and research team used McGuire’s communication/persuasion matrix. The matrix guided our research, specifically each marketing “channel”, targeted “message”, and target population or “receiver”. We developed a social media recruitment protocol and trained our research staff and stakeholders to conduct social media recruitment.

Results

As a result, in just 1 month, we recruited all of our subjects (N=14 couples, that is, N=28 participants) and reached more than 35,658 participants through different channels. One of the major successes of our social media recruitment campaign was to build a strong stakeholder base that became involved early on in all aspects of the research process—from pilot study writing and development to recruitment and retention. In addition, the variety of “messages” used across different social media platforms (including Facebook, the “Latinos en Pareja” study website, Craigslist, and various smartphone applications such as Grindr, SCRUFF, and Jack’d) helped recruit Latino gay couples. We also relied on a wide range of community-based organizations across New York City to promote the study and build in the social media components.

Conclusions

Our findings highlight the importance of incorporating communication technologies into the recruitment and engagement of participants in HIV interventions. Particularly, the success of our social media recruitment strategy with Spanish-speaking Latino MSM shows that this population is not particularly “hard to reach”, as it is often characterized within public health literature.

The implications of respondent concurrency on sex partner risk in a national, web-based study of men who have sex with men in the United States

BACKGROUND

Men who have sex with men (MSM) represent the largest HIV risk group in the United States. Sexual concurrency catalyzes HIV transmission in populations by increasing the indirect exposure of one's sex partners to one another. Although individual-level (egocentric) designs have demonstrated a high prevalence of concurrency among MSM respondents, methods are lacking for understanding the exposure implications for partners (dyads) reported in such studies.

METHODS

A new technique for manipulating egocentrically collected partnership timing data to measure the degree to which respondents' patterns of concurrency and serial monogamy resulted in the indirect exposure of respondents' partners to other partners was developed. Two outcomes were constructed for each partner: any concurrent or serially monogamous exposure to another partner (any exposure) and any concurrent exposure to another partner, irrespective of serial monogamy (any concurrent exposure). Reports of unprotected anal intercourse (UAI) were incorporated to construct the outcomes of 'any UAI exposure' and 'any concurrent UAI exposure.' This method was applied to an online study of MSM aged ≥18 years, with comparisons made by partner's race-ethnicity, age, type, and meeting location.

RESULTS

Among 4060 repeat partners of 2449 MSM, 73% had any exposure in the previous 6 months; 58% had any concurrent exposure. Among UAI partners, 37% had concurrent UAI exposure. Black UAI partners were more likely than whites to have any concurrent UAI exposure [unadjusted odds ratio (95% confidence interval) = 1.34 (1.05 to 1.70)], as were casual UAI partners relative to main partners [unadjusted odds ratio (95% confidence interval) = 4.37 (3.58 to 5.35)]. In adjusted models, black UAI partners were significantly more likely to have any UAI exposure, but not concurrent UAI exposure. Casual UAI partners remained more exposed by both outcomes.

CONCLUSIONS

Sex partners of MSM, particularly casual and black non-Hispanic partners, face a high degree of exposure to other partners.