The impact of the COVID-19 pandemic on social determinants of health, mental health, and substance use among key populations affected by sexually transmitted and blood-borne infections in Canada

OBJECTIVES

We assessed the impact of the COVID-19 pandemic on social determinants of health, mental health, substance use, and access to mental health and harm reduction services among key populations disproportionately impacted by sexually transmitted and blood-borne infections (STBBI).

METHODS

Online surveys (2021‒2022) were conducted in Canada among people who use drugs or alcohol (PWUD); African, Caribbean, and Black people (ACB); and First Nations, Inuit, and Métis peoples (FNIM). Descriptive analyses were conducted on social determinants of health, substance use, and access to services, stratified by changes in mental health status since the start of the pandemic.

RESULTS

A total of 3773 participants (1034 PWUD, 1556 ACB, and 1183 FNIM) completed the surveys, with 45.6% reporting a major/moderate impact of the pandemic on their ability to pay bills and 53% experiencing food insecurity since the start of the pandemic. Half (49.4%) of participants reported deteriorating mental health. A higher increase in substance use and related behaviours was seen in those with worsening mental health. Among those using substances, two thirds (69.4%) of those with worsening mental health reported increasing their use of substances alone, compared to 46.9% of those with better/similar mental health. Access to mental health and harm reduction services was low.

CONCLUSION

These intersecting health issues are among the risk factors for STBBI acquisition and act as barriers to care. Equitable interventions and policies addressing downstream and upstream determinants of health, with meaningful and sustainable leadership from key populations, may improve their health and well-being, to lower STBBI impact and improve future pandemic responses.

Attitudes of Gay, Bisexual, and Other Men Who Have Sex with Men (GBM) toward Their Use of Amphetamine-Type Stimulants and Relation to Reducing Use in Three Canadian Cities

BACKGROUND

We explored attitudes of gay, bisexual, and other men who have sex with men (GBM) toward their amphetamine-use and associations with reduced use over time.

METHODS

We recruited sexually-active GBM aged 16+ years in Montreal, Toronto, and Vancouver, Canada, from 02-2017 to 08-2019, with follow-up visits every 6-12 months until November 2020. Among participants who reported past-six-month (P6M) amphetamine-use at enrollment, we used logistic regression to identify demographic, psychological, social, mental health, other substance-use, and behavioral factors associated with reporting needing help reducing their substance-use. We used mixed-effects logistic regression to model reduced P6M amphetamine-use with perceived problematic-use as our primary explanatory variable.

RESULTS

We enrolled 2,449 GBM across sites. 15.5-24.7% reported P6M amphetamine-use at enrollment and 82.6 - 85.7% reported needing no help or only a little help in reducing their substance use. Reporting needing a lot/of help or completely needing help in reducing substance-use was associated with group sex participation (AOR = 2.35, 95%CI:1.25-4.44), greater anxiety symptomatology (AOR = 2.11, 95%CI:1.16-3.83), greater financial strain (AOR = 1.35, 95%CI:1.21-1.50), and greater Escape Motive scores (AOR = 1.07, 95%CI:1.03-1.10). Reductions in P6M amphetamine-use were less likely among GBM who perceived their amphetamine-use as problematic (AOR = 0.17 95% CI 0.10 - 0.29).

CONCLUSIONS

Most amphetamine-using GBM did not feel they needed help reducing their substance use, and many reported reduced amphetamine-use at subsequent visits. Those who perceived their use as problematic were less likely to reduce their use. Further interventions to assist GBM in reducing their use are needed to assist those who perceive their use as problematic.

Examining differential success in recruitment using respondent driven sampling (RDS) in a multi-site study of gay, bisexual and other men who have sex with men

BACKGROUND

The Engage Study is a longitudinal biobehavioral cohort study of gay, bisexual and other men who have sex with men (GBM) in Toronto, Montreal, and Vancouver. Baseline data (2,449 participants) were collected from February 2017 - August 2019 using respondent-driven sampling (RDS). Recruitment in Montreal required fewer seeds, had a much shorter recruitment period, and recruited the largest sample.

METHODS

To better understand why RDS recruitment was more successful in Montreal compared to other sites, we conducted an analysis to examine RDS recruitment characteristics for GBM in each of the three study sites, explore demographic characteristics and measures of homophily, that is, the tendency of individuals to recruit other study participants who are like themselves, and compared motivations for study participation.

RESULTS

Montreal had the greatest proportion of participants over the age of 45 (29.1% in Montreal, 24.6% in Vancouver, and 21.0% in Toronto) and the highest homophily for this age group, but homophily was high across the three cities. Montreal also reported the lowest percentage of participants with an annual income greater or equal to $60,000 (7.9% in Montreal, 13.1% in Vancouver and 10.6% in Toronto), but homophily was similar across all three cities. The majority of participants indicated interest in sexual health and HIV as the main reason for participating (36.1% in Montreal, 34.7% in Vancouver, and 29.8% in Toronto). Financial interest as the main reason for participation was low (12.7% in Montreal, 10.6% in Vancouver, and 5.7% in Toronto).

CONCLUSION

Taken together, although we found some differences in study demographic characteristics and homophily scores, we were unable to fully explain the different recruitment success based on the data available. Our study underlines the fact that success of RDS implementation may vary by unknown factors, and that researchers should be proactive and flexible to account for variability.

Examining Associations Between Resilience and PrEP Use Among HIV-negative GBM in Toronto, Montreal and Vancouver

This study evaluated the association between resilience and PrEP use among a population-based sample of Canadian gay, bisexual, and other men who have sex with men (GBM). Sexually active GBM aged ≥ 16 years old were recruited via respondent-driven sampling (RDS) in Toronto, Montreal, and Vancouver from 02/2017 to 07/2019. We conducted a pooled cross-sectional analysis of HIV-negative/unknown GBM who met clinical eligibility for PrEP. We performed multivariable RDS-II-weighted logistic regression to assess the association between scores on the Connor-Davidson Resilience-2 Scale and PrEP. Mediation analyses with weighted logistic and linear regression were used to assess whether the relationship between minority stressors and PrEP use was mediated by resilience. Of 1167 PrEP-eligible GBM, 317 (27%) indicated they took PrEP in the past six months. Our multivariable model found higher resilience scores were associated with greater odds of PrEP use in the past six months (aOR = 1.13, 95%CI = 1.00, 1.28). We found that resilience reduced the effect of the association between heterosexist discrimination and PrEP use. Resilience also mediated the relationship between internalized homonegativity and PrEP use and mediated the effect of the association between LGBI acceptance concern and PrEP use. Overall, PrEP-eligible GBM with higher resilience scores had a greater odds of PrEP use in the past six months. We also found mixed results for the mediating role of resilience between minority stress and PrEP use. These findings underline the continued importance of strength-based factors in HIV prevention.

Crystal methamphetamine use and bacterial sexually transmitted infections (STIs) among gay, bisexual and other sexual minority men in Canada

OBJECTIVE

While crystal methamphetamine use by gay, bisexual, and other men who have sex with men (GBM) is associated with increased risk for sexually transmitted infection (STI) transmission, less is understood about the causal pathways between crystal methamphetamine use and STIs. We examined whether the association between greater crystal methamphetamine risk and prevalent bacterial STI diagnosis among GBM was mediated by two types of attitudinal variables: attitudes toward condoms, and sexual escape motives, defined as the use of substances to escape self-awareness during sex, and by sexual behaviors.

METHODS

We used computer-assisted self-interview questionnaires from 2449 sexually active GBM (18% living with HIV; median age = 33, interquartile range, 27-45) recruited via respondent-driven sampling in Vancouver, Toronto, and Montreal, Canada. Using the baseline data from the Engage cohort study, we fit a series of structural mediation models of the associations between greater crystal methamphetamine risk and bacterial STI (syphilis, gonorrhea, and chlamydia) diagnosis. We estimated indirect paths from greater crystal methamphetamine risk, attitudes toward condoms, sexual escape motives, and sexual risk behaviors, adjusting for self-reported demographic variables.

RESULTS

In the mediated model, the direct association between greater crystal methamphetamine risk and bacterial STI diagnosis was non-significant; however, five indirect paths were significant. Greater crystal methamphetamine risk was associated with bacterial STIs via condom use attitudes and escape motives, which in turn were associated with number of male anal sex partners, condomless anal sex, and oral sex.

DISCUSSION

Public health and counselling interventions for GBM who use crystal methamphetamine and who are at higher risk for STIs should target evidence-based causal paths that consider sexual attitudes and sexual practices.

HIV incidence and related risks among gay, bisexual, and other men who have sex with men in Montreal, Toronto, and Vancouver: Informing blood donor selection criteria in Canada

BACKGROUND

An individualized behavior-based selection approach has potential to allow for a more equitable blood donor eligibility process. We collected biological and behavioral data from urban gay, bisexual, and other men who have sex with men (GBM) to inform the use of this approach in Canada.

STUDY DESIGN AND METHODS

Engage is a closed prospective cohort of sexually active GBM, aged 16+ years, recruited via respondent-driven-sampling (RDS) in Montreal, Toronto, and Vancouver, Canada. Participants completed a questionnaire on behaviors (past 6 months) and tested for HIV and sexually transmitted and blood-borne infections at each visit. Rate ratios for HIV infection and predictive values for blood donation eligibility criteria were estimated by RDS-adjusted Poisson regression.

RESULTS

Data on 2008 (study visits 2017-02 to 2021-08) HIV-negative participants were used. The HIV incidence rate for the three cities was 0.4|100 person-years [95%CI:0.3, 0.6]. HIV seroconversion was associated with age <30 years: adjusted rate ratio (aRR) 9.1 [95%CI:3.2, 26.2], 6-10 and >10 anal sex partners versus 1-6 aRR: 5.3 [2.1,13.5] and 8.4 [3.4, 20.9], and use of crystal methamphetamine during sex: 4.2 [1.5, 11.6]. Applying the combined selection criteria: drug injection, ≥2 anal sex partners, and a new anal sex partner, detected all participants who seroconverted (100% sensitivity, 100% negative predictive value), and would defer 63% of study participants from donating.

CONCLUSION

Using three screening questions regarding drug injection and sexual behaviors in the past 6 months would correctly identify potential GBM donors at high risk of having recently contracted HIV. Doing so would reduce the proportion of deferred sexually active GBM by one-third.

Examining provincial PrEP coverage and characterizing PrEP awareness and use among gay, bisexual and other men who have sex with men in Vancouver, Toronto and Montreal, 2017-2020

INTRODUCTION

Accessibility of pre-exposure prophylaxis (PrEP) in Canada remains complex as publicly funded coverage and delivery differs by province. In January 2018, PrEP became publicly funded and free of charge in British Columbia (BC), whereas PrEP coverage in Ontario and Montreal is more limited and may require out-of-pocket costs. We examined differences over time in PrEP uptake and assessed factors associated with PrEP awareness and use.

METHODS

Gay, bisexual and other men who have sex with men (GBM) were recruited through respondent-driven sampling (RDS) in Toronto, Vancouver and Montreal, Canada, in a prospective biobehavioural cohort study. We applied generalized estimating equations with hierarchical data (RDS chain, participant, visit) to examine temporal trends of PrEP use and correlates of PrEP awareness and use from 2017 to 2020 among self-reported HIV-negative/unknown GBM.

RESULTS

Of 2008 self-identified HIV-negative/unknown GBM at baseline, 5093 study visits were completed from February 2017 to March 2020. At baseline, overall PrEP awareness was 88% and overall PrEP use was 22.5%. During our study period, we found PrEP use increased in all cities (all p<0.001): Montreal 14.2% during the first time period to 39.3% during the last time period (p<0.001), Toronto 21.4-31.4% (p<0.001) and Vancouver 21.7-59.5% (p<0.001). Across the study period, more Vancouver GBM used PrEP than Montreal GBM (aOR = 2.05, 95% CI = 1.60-2.63), with no significant difference between Toronto and Montreal GBM (aOR = 0.90, 95% CI = 0.68-1.18).

CONCLUSIONS

Full free-of-charge public funding for PrEP in BC likely contributed to differences in PrEP awareness and use. Increasing public funding for PrEP will improve accessibility and uptake among GBM most at risk of HIV.

Pre-exposure prophylaxis and bacterial sexually transmitted infections (STIs) among gay and bisexual men

OBJECTIVES

While pre-exposure prophylaxis (PrEP) prevents HIV acquisition among gay, bisexual and other men who have sex with men (GBM), PrEP-using GBM may be more likely to engage in sexual behaviours associated with bacterial STIs. We examined associations between PrEP use, condomless anal sex (CAS), number of anal sex partners, oral sex and bacterial STI diagnoses among GBM living in Canada's three largest cities.

METHODS

Among HIV-negative/unknown-status GBM in the baseline of the Engage cohort study, we fit a structural equation model of the associations between any PrEP use, sexual behaviours and bacterial STI diagnosis. We estimated direct and indirect paths between PrEP use and STI via CAS, number of anal sex partners and oral sex.

RESULTS

The sample included 2007 HIV-negative/unknown status GBM in Montreal, Toronto and Vancouver. There was a significant direct association between PrEP use and current STI diagnosis (β=0.181; 95% CI: 0.112 to 0.247; p<0.001), CAS (β=0.275; 95% CI: 0.189 to 0.361; p<0.001) and number of anal sex partners (β=0.193; 95% CI: 0.161 to 0.225; p<0.001). In the mediated model, the direct association between PrEP use and STIs was non-significant. However, the indirect paths from PrEP to CAS to STIs (β=0.064; 95% CI: 0.025 to 0.120; p=0.008), and from PrEP to greater number of anal sex partners to CAS to STIs were significant (β=0.059; 95% CI: 0.024 to 0.108; p=0.007).

CONCLUSIONS

Our study adds to the growing awareness that PrEP use among GBM may be associated with bacterial STIs because PrEP users have more anal sex partners and are more likely to engage in CAS. The results underscore the importance of providing effective STI counselling and regular testing to PrEP users, adapting PrEP care and related STI testing to individual needs, and the need for effective prevention strategies for bacterial STIs.

Social support and HIV prevention behaviors among urban HIV-negative gay, bisexual, and other men who have sex with men

OBJECTIVE

Supportive social relationships can have direct positive effects on health and mitigate the negative impact of stressors. This study investigated the main effect of perceived social support on STI/HIV risk and prevention behaviors. The buffering effect of perceived social support on the impact of proximal minority stressors, like internalized homonegativity, was also examined on one risk behavior specifically, condomless anal sex (CAS) without HIV preexposure prophylaxis (PrEP) use.

METHOD

HIV-negative gay, bisexual, and other men who have sex with men (GBM) were recruited using respondent driven sampling from three major Canadian urban centers (n = 1,409). GBM completed measures of perceived social support, proximal minority stress, and engagement in STI/HIV risk and prevention behaviors.

RESULTS

Higher perceived social support was positively associated with a several health behaviors, including recent STI and HIV testing, discussing HIV status with prospective partners, the use of behavioral HIV-risk reduction strategies during sexual encounters, and a lower likelihood of engaging in CAS without PrEP. There was evidence of moderation as well. Among GBM with higher perceived social support, internalized homonegativity was no longer associated with increased odds of engaging in CAS without PrEP.

CONCLUSIONS

The results of the current study advance social support theory to GBM in the context of biomedical prevention, showing both evidence of both direct associations and buffering effects on STI/HIV risk and prevention behaviors. This highlights the importance of promoting social support seeking in interventions aimed at improving GBM health. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Community-Based Prevalence Estimates of Chlamydia trachomatis and Neisseria gonorrhoeae Infections Among Gay, Bisexual, and Other Men Who Have Sex With Men in Montréal, Canada

BACKGROUND

Reported cases of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are increasing among Canadian men. Estimates of community-based CT/NG prevalence are lacking among gay, bisexual, and other men who have sex with men (GBM).

METHODS

Respondent driven sampling was used to recruit GBM in Montréal, Canada between February 2017 and June 2018. Specimens provided from urogenital, rectal, and pharyngeal sites were analyzed using nucleic acid amplification test to detect CT/NG. Prevalence estimates of CT/NG, overall and by anatomical site were calculated. All estimates are respondent-driven sampling-adjusted.

RESULTS

Among 1177 GBM, the prevalence of rectal, urogenital, pharyngeal and overall were respectively 2.4%, 0.4%, 0.4%, and 2.8% for CT infections, and 3.1%, 0.4%, 3.5%, and 5.6% for NG infections. If testing had been limited to the urogenital site, 80% and 94% of CT and NG infections, respectively, would have been missed.

CONCLUSIONS

This community-based study among GBM shows that the CT prevalence was about half of that observed for NG. A large part of CT/NG infections involves only the extragenital sites, highlighting the need for systematic multisite screening regardless of symptoms. In the mist of the COVID-19 pandemic and the limited CT/NG screening capacity due to test kits shortage, it might be considered to prioritize rectal and pharyngeal CT/NG testing over urogenital testing in asymptomatic GBM.

General regression methods for respondent-driven sampling data

Respondent-driven sampling is a variant of link-tracing sampling techniques that aim to recruit hard-to-reach populations by leveraging individuals’ social relationships. As such, a respondent-driven sample has a graphical component which represents a partially observed network of unknown structure. Moreover, it is common to observe homophily, or the tendency to form connections with individuals who share similar traits. Currently, there is a lack of principled guidance on multivariate modelling strategies for respondent-driven sampling to address peer effects driven by homophily and the dependence between observations within the network. In this work, we propose a methodology for general regression techniques using respondent-driven sampling data. This is used to study the socio-demographic predictors of HIV treatment optimism (about the value of antiretroviral therapy) among gay, bisexual and other men who have sex with men, recruited into a respondent-driven sampling study in Montreal, Canada.

Prevalence of HIV and sexually transmitted and blood-borne infections, and related preventive and risk behaviours, among gay, bisexual and other men who have sex with men in Montreal, Toronto and Vancouver: results from the Engage Study

Objectives

The last Canadian biobehavioural surveillance study of HIV and other sexually transmitted and blood-borne infections (STBBI) among gay, bisexual and other men who have sex with men (GBM) was conducted in 2010. We designed a study to measure STBBI prevalence among GBM in metropolitan Montreal, Toronto and Vancouver and to document related preventive and risk behaviours.

Methods

The Engage Cohort Study used respondent-driven sampling (RDS) to recruit GBM who reported sex with another man in the past 6 months. At baseline, we examined recruitment characteristics of the samples, and the RDS-II-adjusted distributions of socio-demographics, laboratory-confirmed HIV and other STBBI prevalence, and related behaviours, with a focus on univariate differences among cities.

Results

A total of 2449 GBM were recruited from February 2017 to August 2019. HIV prevalence was lower in Montreal (14.2%) than in Toronto (22.2%) or Vancouver (20.4%). History of syphilis infection was similar across cities (14–16%). Vancouver had more HIV-negative/unknown participants who reported never being HIV tested (18.6%) than Toronto (12.9%) or Montreal (11.5%). Both Montreal (74.9%) and Vancouver (78.8%) had higher proportions of men who tested for another STBBI in the past 6 months than Toronto (67.4%). Vancouver had a higher proportion of men who used pre-exposure prophylaxis (PrEP) in the past 6 months (18.9%) than Toronto (11.1%) or Montreal (9.6%).

Conclusion

The three largest cities of Canada differed in HIV prevalence, STBBI testing and PrEP use among GBM. Our findings also suggest the need for scale-up of both PrEP and STI testing among GBM in Canada.

Use of HIV pre-exposure prophylaxis among urban Canadian gay, bisexual and other men who have sex with men: a cross-sectional analysis of the Engage cohort study

BACKGROUND

In Canada, gay, bisexual and other men who have sex with men (GBM) are disproportionately affected by HIV. Our objective was to describe access to HIV pre-exposure prophylaxis (PrEP) and identify factors associated with not using PrEP among self-reported HIV-negative or HIV-unknown GBM.

METHODS

This was a cross-sectional analysis of the Engage study cohort. Between 2017 and 2019, sexually active GBM aged 16 years or more in Montréal, Toronto and Vancouver were recruited via respondent-driven sampling (RDS). Participation included testing for HIV and sexually transmitted and blood-borne infections, and completion of a questionnaire. We examined PrEP access using a health care services model and fit RDS-adjusted logistic regressions to determine correlates of not using PrEP among those for whom PrEP was clinically recommended and who were aware of the intervention.

RESULTS

A total of 2449 GBM were recruited, of whom 2008 were HIV-negative or HIV-unknown; 1159 (511 in Montréal, 247 in Toronto and 401 in Vancouver) met clinical recommendations for PrEP. Of the 1159, 1100 were aware of PrEP (RDS-adjusted proportion: Montréal 84.6%, Toronto 94.2%, Vancouver 92.7%), 678 had felt the need for PrEP in the previous 6 months (RDS-adjusted proportion: Montréal 39.2%, Toronto 56.1%, Vancouver 49.0%), 406 had tried to access PrEP in the previous 6 months (RDS-adjusted proportion: Montréal 20.6%, Toronto 33.2%, Vancouver 29.6%) and 319 had used PrEP in the previous 6 months (RDS-adjusted proportion: Montréal 14.5%, Toronto 21.6%, Vancouver 21.8%). Not using PrEP was associated with several factors, including not feeling at high enough risk, viewing PrEP as not completely effective, not having a primary care provider and lacking medication insurance.

INTERPRETATION

Although half of GBM met clinical recommendations for PrEP, less than a quarter of them reported use. Despite high levels of awareness, a programmatic response that addresses PrEP-related perceptions and health care system barriers is needed to scale up PrEP access among GBM in Canada.

Characteristics of the HIV cascade of care and unsuppressed viral load among gay, bisexual and other men who have sex with men living with HIV across Canada's three largest cities

INTRODUCTION

Treatment as prevention strategies have been variously applied across provinces in Canada. We estimated HIV care cascade indicators and correlates of unsuppressed viral load (VL) among gay, bisexual and other men who have sex with men (GBM) recruited in Vancouver, Toronto and Montreal.

METHODS

Sexually active GBM, aged ≥16 years, were recruited through respondent-driven sampling (RDS) from February 2017 to August 2019. Participants completed a Computer-Assisted Self-Interview and tests for HIV and other sexually transmitted infections (STIs). We conducted bivariate analyses comparing RDS-adjusted proportions across cities. We used multivariable logistic regression to examine factors associated with having a measured VL ≥ 200 copies/mL with data pooled from all three cities.

RESULTS

We recruited 1179 participants in Montreal, 517 in Toronto and 753 in Vancouver. The RDS-adjusted HIV prevalence was 14.2% (95% CI 11.1 to 17.2) in Montreal, 22.1% (95% CI 12.4 to 31.8) in Toronto and 20.4% (95% CI 14.5 to 26.3) in Vancouver (p < 0.001). Of participants with confirmed HIV infection, 3.3% were previously undiagnosed in Montreal, 3.2% undiagnosed in Toronto and 0.2% in Vancouver (p = 0.154). In Montreal, 87.6% of GBM living with HIV were receiving antiretroviral therapy (ART) and 10.6% had an unsuppressed VL; in Toronto, 82.6% were receiving ART and 4.0% were unsuppressed; in Vancouver, 88.5% were receiving ART and 2.6 % were unsuppressed (p < 0.001 and 0.009 respectively). Multivariable modelling demonstrated that participants in Vancouver (adjusted odds ratio [AOR]=0.23; 95% CI 0.06 to 0.82), but not Toronto (AOR = 0.27; 95% CI 0.07 to 1.03), had lower odds of unsuppressed VL, compared to Montreal, as did older participants (AOR 0.93 per year; 95% CI 0.89 to 0.97), those at high-risk for hazardous drinking (AOR = 0.19; 95% CI 0.05 to 0.70), those with a primary care provider (AOR = 0.11; 95% CI 0.02 to 0.57), and those ever diagnosed with other STIs (AOR = 0.12; 95% CI 0.04 to 0.32).

CONCLUSIONS

GBM living in Montreal, Toronto and Vancouver are highly engaged in HIV testing and treatment and all three cities have largely achieved the 90-90-90 targets for GBM. Nevertheless, we identified disparities which can be used to identify GBM who may require additional interventions, in particular younger men and those who are without a regular primary care provider.

Combination HIV Prevention Strategies Among Montreal Gay, Bisexual, and Other Men Who Have Sex with Men in the PrEP Era: A Latent Class Analysis

Pre-exposure prophylaxis (PrEP) became publicly available in Quebec for gay, bisexual and other men who have sex with men (GBM) in 2013. We used baseline data from Engage, a cohort of GBM recruited by respondent-driven sampling, to examine patterns of combination HIV prevention use among Montreal GBM since PrEP became available. Latent class analysis, stratified by HIV status, was used to categorize GBM by self-reported use of biomedical and behavioural prevention strategies. Correlates of resulting classes were identified using multinomial logistic regression. Among HIV-negative/unknown GBM (n = 968), we identified four classes: low use of prevention (32%), condoms (40%), seroadaptive behaviour (21%), and biomedical (including PrEP; 7%). Those using prevention (condoms, seroadaptive behaviour, and biomedical) had a higher number of anal sex partners and were more likely to report a recent sexually transmitted infection diagnosis. GBM using biomedical prevention also had a higher level of formal education. Among GBM living with HIV (n = 200), we identified three classes: mainly antiretroviral treatment (ART) with viral suppression (53%), ART with viral suppression and condoms (19%), and ART with viral suppression and seroadaptive behaviour (18%). Again, the number of anal sex partners was higher among those using condoms and seroadaptive behaviours. Our findings show antiretroviral-based prevention, either alone or in combination with other strategies, is clearly a component of the HIV prevention landscape for GBM in Montreal. Nevertheless, PrEP uptake remains low, and there is a need to promote its availability more widely.

Population-Level Sexual Mixing According to HIV Status and Preexposure Prophylaxis Use Among Men Who Have Sex With Men in Montreal, Canada: Implications for HIV Prevention

Using cross-sectional survey data (Engage, 2017–2018) from 1,137 men who have sex with men, ≥16 years old, in Montreal, we compared observed human immunodeficiency virus (HIV) seroconcordance in previous-6-months’ sexual partnerships with what would have been observed by chance if zero individuals serosorted. Of 5 recent partnerships where both individuals were HIV-negative, we compared observed concordance in preexposure prophylaxis (PrEP) use with the counterfactual if zero individuals selected partners based on PrEP use. We estimated the concordance by chance using a balancing-partnerships approach assuming proportionate mixing. HIV-positive respondents had a higher proportion of HIV-positive partners (66.4%, 95% confidence interval (CI): 64.0, 68.6) than by chance (23.9%, 95% CI: 23.1, 24.7). HIV-negative respondents (both on and not on PrEP) had higher proportions of HIV-negative partners (82.9% (95% CI: 81.1, 84.7) and 90.7% (95% CI: 89.6, 91.7), respectively) compared with by chance (76.1%, 95% CI: 75.3, 76.9); however, those on PrEP had a higher proportion of HIV-positive partners than those not on PrEP (17.1% (95% CI: 15.3, 18.9) vs. 9.3% (95% CI: 8.3, 10.4). Those on PrEP also had a higher proportion of partners on PrEP among their HIV-negative partners (50.6%, 95% CI: 42.5, 58.8) than by chance (28.5%, 95% CI: 27.5, 29.4). The relationship between PrEP and sexual-mixing patterns demonstrated by less population-level serosorting among those on PrEP and PrEP-matching warrants consideration during PrEP roll-out.