Characteristics of the Sexual Networks of Men Who Have Sex With Men in Montréal, Toronto, and Vancouver: Insights from Canada's 2022 Mpox Outbreak.

BACKGROUND: The 2022-2023 global mpox outbreak disproportionately affected gay, bisexual, and other men who have sex with men (GBM). We investigated differences in GBM's sexual partner distributions across Canada's 3 largest cities and over time, and how they shaped transmission. METHODS: The Engage Cohort Study (2017-2023) recruited GBM via respondent-driven sampling in Montréal, Toronto, and Vancouver (n = 2449). We compared reported sexual partner distributions across cities and periods: before COVID-19 (2017-2019), pandemic (2020-2021), and after lifting of restrictions (2021-2023). We used Bayesian regression and poststratification to model partner distributions. We estimated mpox's basic reproduction number (R0) using a risk-stratified compartmental model. RESULTS: Pre-COVID-19 pandemic distributions were comparable: fitted average partners (past 6 months) were 10.4 (95% credible interval: 9.4-11.5) in Montréal, 13.1 (11.3-15.1) in Toronto, and 10.7 (9.5-12.1) in Vancouver. Sexual activity decreased during the pandemic and increased after lifting of restrictions, but remained below prepandemic levels. Based on reported cases, we estimated R0 of 2.4 to 2.7 and similar cumulative incidences (0.7%-0.9%) across cities. CONCLUSIONS: Similar sexual partner distributions may explain comparable R0 and cumulative incidence across cities. With potential for further recovery in sexual activity, mpox vaccination and surveillance strategies should be maintained.

Human Immunodeficiency Virus Treatment Attitudes and Bacterial Sexually Transmitted Infections Among Gay and Bisexual Men.

BACKGROUNDS: Positive attitudes toward human immunodeficiency virus (HIV) treatment, such as reduced concern about HIV transmissibility, are associated with sexual behaviors that may increase the risk of bacterial sexually transmitted infections (STIs) among gay, bisexual, and other men who have sex with men (GBM). We examined associations between HIV treatment attitudes and bacterial STI diagnoses among GBM in Canada's three largest cities. METHODS: We fit a structural equation model between HIV treatment attitudes and bacterial STI diagnoses via sexual behaviors in the Engage study's baseline data. We estimated direct and indirect paths between scores on HIV treatment attitudes and STIs via number of male anal sex partners, condomless anal sex, and oral sex. We conducted sub-analyses with participants stratified by HIV serostatus. RESULTS: Among 2449 GBM recruited in 2017 to 2019, there was a direct association between HIV treatment attitudes and current STI diagnoses (ß = 0.13; 95% CI, 0.07-0.19; P < 0.001). The mediated model revealed a positive total indirect effect through 2 pathways: (1) engaging in condomless anal sex and (2) number of male anal sex partners and condomless anal sex. These 2 indirect pathways remained in the stratified mediation models for both HIV negative GBM and for GBM living with HIV. CONCLUSIONS: The association between HIV treatment attitudes and diagnosed STIs is mediated through a higher number of male anal sex partners and condomless anal sex. The results highlight the importance of providers educating patients when providing effective STI counseling, testing, and prevention for GBM about how accurate HIV treatment attitudes may inadvertently be associated with the bacterial STI epidemic.

HIV Treatment Optimism Moderates the Relationship between Sexual Risk Behavior and HIV Risk Perception among Urban HIV-negative Gay, Bisexual, and Other Men who have Sex With Men.

Using baseline data of the Engage Cohort Study, a Canadian study of sexually active gay, bisexual and other men who have sex with men (GBM), we evaluated the association between sexual behavior and risk perception among HIV-negative participants and whether HIV treatment optimism moderated this relationship. Participants were recruited by respondent-driven-sampling (RDS). We defined high-risk sexual behavior in the past six months as any condomless anal sex with a casual partner (i.e. not the participant's main partner) with either unknown HIV-status where neither used pre-exposure prophylaxis or with a partner living with HIV having detectable/unknown viral load. We assessed HIV treatment optimism-skepticism using a 12-item scale. RDS-II-weighted adjusted logistic regression models examined associations with risk perception measured by the question "How would you assess your current risk of getting HIV?" (response options were on a 6-point Likert-scale ranging from "very unlikely" to "very likely", dichotomized into "No Perceived Risk" (very unlikely/unlikely) and "Perceived Risk" (somewhat likely/likely/very likely/I think I already have HIV). Of 1961 participants, engagement in high-risk sexual behavior was reported by 155 (17.0%), 62 (12.4%), 128 (17.2%) of participants in Montréal, Toronto, and Vancouver, respectively. High-risk sexual behavior increased the odds of perceived HIV risk (pooled adjusted odds ratio = 2.9, 95%CI = 2.2-3.8). HIV treatment optimism-skepticism scores moderated the relationship: for GBM engaging in high-risk sexual behavior, higher HIV treatment optimism-skepticism scores increased perceived HIV risk. Promoting awareness around advances related to HIV prevention and treatment is important for appropriate risk assessment and for increased engagement in prevention interventions.

RESUMEN: Evaluamos la asociación entre el comportamiento sexual y la percepción de riesgo entre los participantes VIH negativos y si el optimismo sobre el tratamiento del VIH moderó esta asociación. Definimos comportamiento sexual de alto riesgo en los últimos seis meses como cualquier sexo anal sin condón con una pareja casual con un estado de VIH desconocido donde ninguno utilizó profilaxis previa a la exposición o con una pareja que vive con el VIH y que tiene una carga viral detectable/desconocida. Se evaluó el optimismo sobre el tratamiento del VIH mediante una escala de 12 ítems. Los modelos de regresión logística ajustados examinaron las asociaciones con la percepción del riesgo ("Riesgo no percibido" vs. "Riesgo percibido"). De 1961 participantes, 155 (17,0%), 62 (12,4%), 128 (17,2%) de los participantes en Montreal, Toronto y Vancouver, informaron comportamiento sexual de alto riesgo. El comportamiento sexual de alto riesgo se mostró asociado con riesgo percibido. El optimismo sobre el tratamiento modero la asociación. Promover la conciencia sobre los avances relacionados con la prevención y el tratamiento del VIH es importante para una evaluación adecuada de los riesgos y una mayor participación en las intervenciones de prevención.

Minority Stress, Psychological Distress, Sexual Compulsivity, and Avoidance-Based Motivations Associated with Methamphetamine Use Among Sexual Minority Men Living with HIV: Examining Direct and Indirect Associations Using Cross-Sectional Structural Equation Modeling.

OBJECTIVE: Sexual minority men (SMM) living with HIV report significantly greater methamphetamine use compared with heterosexual and HIV-negative peers. Greater use may be related to stressors (e.g., HIV-related stigma) faced by SMM living with HIV and subsequent psychological and behavioral sequelae. We tested an integrated theoretical model comprised of pathways between stigma, discrimination, childhood sexual abuse, psychological distress, sexual compulsivity, and cognitive escape in predicting methamphetamine use among SMM living with HIV. METHODS: Among 423 SMM living with HIV, we tested a structural equation model examining factors hypothesized to be directly and indirectly associated with methamphetamine use. Analyses were adjusted for demographic covariates and sampling bias. RESULTS: The model showed good fit (CFI = 0.96, RMSEA = 0.01). Heterosexist discrimination was associated with psychological distress (ß = 0.39, p < 0.001) and psychological distress was associated with sexual compulsivity (ß = 0.33, p < 0.001). Sexual compulsivity was associated with cognitive escape (ß = 0.31, p < 0.001), which was associated with methamphetamine use (ß = 0.51, p < 0.001). Psychological distress was associated with methamphetamine use via serial indirect effects of sexual compulsivity and cognitive escape (ß = 0.05, p < 0.05). CONCLUSIONS: Heterosexist discrimination contributed to psychological distress among SMM living with HIV. Psychological distress is linked to methamphetamine use via sexual compulsivity and cognitive avoidance. Interventions seeking to reduce the likelihood that SMM living with HIV use methamphetamine should include coping strategies specific to heterosexism and related psychological distress.

Exploring the dynamics of the 2022 mpox outbreak in Canada.

The 2022 mpox outbreak predominantly impacted gay, bisexual, and other men who have sex with men (gbMSM). Two models were developed to support situational awareness and management decisions in Canada. A compartmental model characterized epidemic drivers at national/provincial levels, while an agent-based model (ABM) assessed municipal-level impacts of vaccination. The models were parameterized and calibrated using empirical case and vaccination data between 2022 and 2023. The compartmental model explored: (1) the epidemic trajectory through community transmission, (2) the potential for transmission among non-gbMSM, and (3) impacts of vaccination and the proportion of gbMSM contributing to disease transmission. The ABM incorporated sexual-contact data and modeled: (1) effects of vaccine uptake on disease dynamics, and (2) impacts of case importation on outbreak resurgence. The calibrated, compartmental model followed the trajectory of the epidemic, which peaked in July 2022, and died out in December 2022. Most cases occurred among gbMSM, and epidemic trajectories were not consistent with sustained transmission among non-gbMSM. The ABM suggested that unprioritized vaccination strategies could increase the outbreak size by 47%, and that consistent importation (≥5 cases per 10 000) is necessary for outbreak resurgence. These models can inform time-sensitive situational awareness and policy decisions for similar future outbreaks.

Increased risk of subsequent chlamydia infection among women not tested at the anorectal anatomical location.

BACKGROUND: Universal anorectal testing for Chlamydia trachomatis (chlamydia) among women is not recommended in many countries, while anorectal chlamydia infections are common. Missed anorectal infections might cause sequelae at the genital site if autoinoculation from the anorectum is possible, but evidence is limited. This study investigates the association between potentially missed anorectal infections and subsequent genital chlamydia infections in women, using not being tested at the anorectal site as a proxy for having a potentially missed anorectal infection. METHODS: We included all women with a repeat chlamydia test within 1 year (with at least a genital test) from the Dutch sexual health centre surveillance between 2014 and 2019. Multilevel logistic regression analyses were used to identify determinants of genital chlamydia infection at the repeat test, with anorectal testing at the previous chlamydia test as the main determinant. RESULTS: A total of 40 217 women were included in the analyses, of whom 15.4% tested chlamydia-positive genitally at their second test. Not being tested anorectally at the first test was an independent risk factor for genital chlamydia infection at the repeat test (adjusted OR 1.24, 95% CI 1.15 to 1.33). This association was in the same range as most other significant risk factors in the model: low education level, no condom use, STI symptoms and previous STI diagnosis. Young age (<20 years) (2.67, 2.39-2.98) and those who received partner notification (3.11, 2.91-3.31) showed stronger associations. The findings were robust; correcting for interactions and a sensitivity analysis stratifying by chlamydia infection at first visit did not show significant differences in the adjusted OR of not being tested anorectally at first test. CONCLUSION: The results are suggestive of an autoinoculation process from the anorectal to the genital anatomical site in women. To enhance chlamydia control, future studies on the role of extragenital testing and autoinoculation in chlamydia transmission are needed.

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.

Using an intersectionality-based approach to evaluate mental health services use among gay, bisexual and other men who have sex with men in Montreal, Toronto and Vancouver.

AIMS: To cope with homonegativity-generated stress, gay, bisexual and other men who have sex with men (GBM) use more mental health services (MHS) compared with heterosexual men. Most previous research on MHS among GBM uses data from largely white HIV-negative samples. Using an intersectionality-based approach, we evaluated the concomitant impact of racialization and HIV stigma on MHS use among GBM, through the mediating role of perceived discrimination (PD). METHODS: We used baseline data from 2371 GBM enrolled in the Engage cohort study, collected between 2017 and 2019, in Montreal, Toronto and Vancouver, using respondent-driven sampling. The exposure was GBM groups: Group 1 (n = 1376): white HIV-negative; Group 2 (n = 327): white living with HIV; Group 3 (n = 577): racialized as non-white HIV-negative; Group 4 (n = 91): racialized as non-white living with HIV. The mediator was interpersonal PD scores measured using the Everyday Discrimination Scale (5-item version). The outcome was MHS use (yes/no) in the prior 6 months. We fit a three-way decomposition of causal mediation effects utilizing the imputation method for natural effect models. We obtained odds ratios (ORs) for pure direct effect (PDE, unmediated effect), pure indirect effect (PIE, mediated effect), mediated interaction effect (MIE, effect due to interaction between the exposure and mediator) and total effect (TE, overall effect). Analyses controlled for age, chronic mental health condition, Canadian citizenship, being cisgender and city of enrolment. RESULTS: Mean PD scores were highest for racialized HIV-negative GBM (10.3, SD: 5.0) and lowest for white HIV-negative GBM (8.4, SD: 3.9). MHS use was highest in white GBM living with HIV (GBMHIV) (40.4%) and lowest in racialized HIV-negative GBM (26.9%). Compared with white HIV-negative GBM, white GBMHIV had higher TE (OR: 1.71; 95% CI: 1.27, 2.29) and PDE (OR: 1.68; 95% CI: 1.27, 2.24), and racialized HIV-negative GBM had higher PIE (OR: 1.09; 95% CI: 1.02, 1.17). Effects for racialized GBMHIV did not significantly differ from those of white HIV-negative GBM. MIEs across all groups were comparable. CONCLUSIONS: Higher MHS use was observed among white GBMHIV compared with white HIV-negative GBM. PD positively mediated MHS use only among racialized HIV-negative GBM. MHS may need to take into account the intersecting impact of homonegativity, racism and HIV stigma on the mental health of GBM.

Prevalence, Determinants, and Trends in the Experience and Perpetration of Intimate Partner Violence Among a Cohort of Gay, Bisexual, and Other Men Who Have Sex with Men in Montréal, Toronto, and Vancouver, Canada (2017-2022).

Purpose: Longitudinal data on the experience and perpetration of intimate partner violence (IPV) among gay, bisexual, and other men who have sex with men (GBM) are limited. We estimated the prevalence of past 6-month (P6M) physical and/or sexual IPV (hereafter IPV) experience and perpetration, identified their determinants, and assessed temporal trends, including the impact of the coronavirus disease (COVID)-19 pandemic. Methods: We used data from the Engage Cohort Study (2017-2022) of GBM recruited using respondent-driven sampling in Montréal, Toronto, and Vancouver. Adjusted prevalence ratios (aPRs) for determinants and self-reported P6M IPV were estimated using generalized estimating equations, accounting for attrition (inverse probability of censoring weights) and relevant covariates. Longitudinal trends of IPV were also assessed. Results: Between 2017 and 2022, 1455 partnered GBM (median age 32 years, 82% gay, and 71% White) had at least one follow-up visit. At baseline, 31% of participants experienced IPV in their lifetime and 17% reported ever perpetrating IPV. During follow-up, IPV experience was more common (6%, 95% confidence interval [CI]: 5%-7%) than perpetration (4%, 95% CI: 3%-5%). Factors associated with P6M IPV experience included prior IPV experience (aPR: 2.68, 95% CI: 1.76-4.08), lower education (aPR: 2.31, 95% CI: 1.32-4.04), and substance use (injection aPR: 5.05, 95% CI: 2.54-10.05, non-injection aPR: 1.68, 95% CI: 1.00-2.82). Similar factors were associated with IPV perpetration. IPV was stable over time; periods of COVID-19 restrictions were not associated with IPV changes in this cohort. Conclusion: Prevalence of IPV was high among GBM. Determinants related to marginalization were associated with an increased risk of IPV. Interventions should address these determinants to reduce IPV and improve health.

Problematic alcohol use among gay, bisexual, and other men who have sex with men in Canada: the role of proximal stressors and anxiety.

BACKGROUND: Gay, bisexual, and other men who have sex with men (GBM) report high rates of problematic alcohol use, anxiety, and depression. This may, in part, be due to stressors related to their sexual identity (i.e., minority stressors). However, few studies have examined both distal and proximal stressors, as well as the specific psychological mechanisms by which these stressors may be related to alcohol use outcomes, in a representative sample of GBM. We explored the relationship between distal and proximal stressors and alcohol use outcomes, as well as the role of anxiety and depression as potential mediators of these relationships. METHODS: We analyzed the baseline data of 2,449 GBM from Engage, a cohort study of sexually active GBM recruited using respondent-driven sampling (RDS) in Montreal, Toronto, and Vancouver from February 2017 to August 2019. Using structural equation modeling, we examined the associations between distal minority stressors (i.e., experiences of heterosexist harassment, rejection, and discrimination), proximal minority stressors (i.e., internalized homonegativity, concerns about acceptance, concealment, and lack of affirmation), anxiety and depression, and alcohol consumption and alcohol use problems. RDS-adjusted analyses controlled for age, income, sexual orientation, ethnicity, recruitment city, and HIV serostatus. RESULTS: There were positive direct associations between distal stress and proximal stress, anxiety, and depression, but not alcohol use outcomes. Proximal stress had a positive direct association with anxiety, depression, and alcohol use problems, but not alcohol consumption. Anxiety was positively associated with alcohol consumption and alcohol use problems. Depression was negatively associated with alcohol consumption but not alcohol use problems. Regarding indirect effects, distal stress was associated with alcohol use outcomes via proximal stress and anxiety, but not via depression. CONCLUSIONS: We found support for a minority stress model as it relates to alcohol use outcomes among GBM. Findings suggest that proximal minority stress and anxiety differentially impact the problematic alcohol use among GBM who experience heterosexist discrimination. Clinical providers should consider incorporating the treatment of proximal minority stressors and anxiety into existing alcohol interventions for GBM.

Mycoplasma genitalium infection among gay, bisexual and other men who have sex with men in Montréal, Canada.

Background: The bacteria Mycoplasma genitalium has been identified as a causative agent of urethritis in men, especially in gay, bisexual and other men who have sex with men (gbMSM). Canadian clinic-based data have identified a high prevalence of M. genitalium and resistance to antibiotic treatments. This article estimates the prevalence of M. genitalium infections among Montréal gbMSM, explores correlates for M. genitalium infection and estimates the prevalence of mutations associated with antimicrobial resistance (AMR). Methods: Engage Cohort Study is a multi-site longitudinal study on sexually active gbMSM, aged 16 years and older, recruited via respondent-driven sampling in Montréal, Toronto and Vancouver. Participants completed a questionnaire on behaviour and were tested for sexually transmitted and blood-borne infections at each visit. For this sub-study, Montréal participants with a follow-up visit that occurred between November 2018 and November 2019 were included. Results: A total of 2,064 samples were provided by 716 participants. Prevalence of M. genitalium infection was 5.7% at rectal and/or urethral sites, 4.0% at rectal site and 2.2% at urethral site. Correlates for M. genitalium infection were younger age and reporting six or more sexual partners in the past six months. Prevalence of macrolide resistance associated mutations (MRAM), quinolone resistance associated mutations (QRAM) and either MRAM or QRAM, was 82%, 29% and 85%, respectively. Conclusion: This first population-based study among gbMSM in Canada documents a high prevalence of urethral and rectal M. genitalium infection and high levels of AMR. Our results highlight the importance of access to testing and AMR detection when indicated.

External factors involved in the regulation of synthesis of an extracellular proteinase in Bacillus megaterium: effect of temperature.

We studied the effect of temperature on the production of an extracellular neutral metalloproteinase of Bacillus megaterium in a laboratory fermentor under constant aeration and pH. The optimal temperature for growth (35-38° C) was higher than that for the synthesis of proteinase during exponential growth (below 31° C). The critical biomass concentration at which the exponential growth terminated decreased with increase in cultivation temperature. The specific rate of proteinase synthesis decreased when the critical biomass concentration was achieved. The observed decrease in proteinase synthesis was related to the cultivation temperature. The temperature also influenced the level of mRNA coding for proteinase. We formulated a mathematical model of cultivation describing the dependence of growth and proteinase synthesis on dissolved oxygen and temperature. The parameters of the model were identified for temperature intervals from 21 to 41° C using a computer. The optimum temperature for the enzyme production was 21° C. The productivity (enzyme activity/time) was maximal at 24-28° C. When optimizing the temperature profile of cultivation, we designed a suboptimal solution represented by a linear temperature profile. We have found that under conditions of continuous decrease in temperature, the maximal production of the proteinase was achieved at a broad range of temperature (26-34° C) when the rate of temperature decrease was 0.2-0.8° C/h. The initial optimal temperature for the enzyme productivity was in the range of 32-34° C. The optimum temperature decrease was 0.8° C/h.