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.

Organisation of testing services, structural barriers and facilitators of routine HIV self-testing during sexually transmitted infection consultations: a qualitative study of patients and providers in Abidjan, Côte d'Ivoire.

BACKGROUND: Consultations for sexually transmitted infection (STI) provide an opportunity to offer HIV testing to both patients and their partners. This study describes the organisation of HIV self-testing (HIVST) distribution during STI consultations in Abidjan (Côte d'Ivoire) and analyse the perceived barriers and facilitators associated with the use and redistribution of HIVST kits by STI patients. MATERIALS AND METHODS: A qualitative study was conducted between March and August 2021 to investigate three services providing HIVST: an antenatal care clinic (ANC), a general health centre that also provided STI consultations, and a dedicated STI clinic. Data were collected through observations of medical consultations with STI patients (N = 98) and interviews with both health professionals involved in HIVST distribution (N = 18) and STI patients who received HIVST kits for their partners (N = 20). RESULTS: In the ANC clinic, HIV testing was routinely offered during the first prenatal visit. HIVST was commonly offered to women who had been diagnosed with an STI for their partner's use (27/29 observations). In the general health centre, two parallel pathways coexisted: before the consultation, a risk assessment tool was used to offer HIV testing to eligible patients and, after the consultation, patients who had been diagnosed with an STI were referred to a care assistant for HIVST. Due to this HIV testing patient flow, few offers of HIV testing and HIVST were made in this setting (3/16). At the dedicated STI clinic, an HIVST video was played in the waiting room. According to the health professionals interviewed, this video helped reduce the time required to offer HIVST after the consultation. Task-shifting was implemented there: patients were referred to a nurse for HIV testing, and HIVST was commonly offered to STI patients for their partners' use (28/53). When an HIVST was offered, it was generally accepted (54/58). Both health professionals and patients perceived HIVST positively despite experiencing a few difficulties with respect to offering HIVST to partners and structural barriers associated with the organisation of services. CONCLUSION: The organisation of patient flow and task-shifting influenced HIV testing and offers of HIVST kits. Proposing HIVST is more systematic when HIV testing is routinely offered to all patients. Successful integration requires improving the organisation of services, including task-shifting.

Regional and country-level trends in cervical cancer screening coverage in sub-Saharan Africa: A systematic analysis of population-based surveys (2000-2020).

BACKGROUND: Sub-Saharan Africa (SSA) has the highest cervical cancer (CC) burden globally-worsened by its HIV epidemics. In 2020, the World Health Organization (WHO) introduced a CC elimination strategy with goals for vaccination, screening, and treatment. To benchmark progress, we examined temporal trends in screening coverage, percent screened at least twice by the age of 45, screening coverage among women living with HIV (WLHIV), and pre-cancer treatment coverage in SSA. METHODS AND FINDINGS: We conducted a systematic analysis of cross-sectional population-based surveys. It included 52 surveys from 28 countries (2000 to 2020) with information on CC screening among women aged 25 to 49 years (N = 151,338 women). We estimated lifetime and past 3-year screening coverage by age, year, country, and HIV serostatus using a Bayesian multilevel model. Post-stratification and imputations were done to obtain aggregate national, regional, and SSA-level estimates. To measure re-screening by age 45, a life table model was developed. Finally, self-reported pre-cancer treatment coverage was pooled across surveys using a Bayesian meta-analysis. Overall, an estimated 14% (95% credible intervals [95% CrI]: 11% to 21%) of women aged 30 to 49 years had ever been screened for CC in 2020, with important regional and country-level differences. In Eastern and Western/Central Africa, regional screening coverages remained constant from 2000 to 2020 and WLHIV had greater odds of being screened compared to women without HIV. In Southern Africa, however, screening coverages increased and WLHIV had equal odds of screening. Notably this region was found to have higher screening coverage in comparison to other African regions. Rescreening rates were high among women who have already been screened; however, it was estimated that only 12% (95% CrI: 10% to 18%) of women had been screened twice or more by age 45 in 2020. Finally, treatment coverage among 4 countries with data was 84% (95% CrI: 70% to 95%). Limitations of our analyses include the paucity of data on screening modality and the few countries that had multiple surveys. CONCLUSION: Overall, CC screening coverage remains sub-optimal and did not improve much over the last 2 decades, outside of Southern Africa. Action is needed to increase screening coverage if CC elimination is to be achieved.

Global, regional, and national prevalence estimates of physical or sexual, or both, intimate partner violence against women in 2018.

BACKGROUND: Intimate partner violence against women is a global public health problem with many short-term and long-term effects on the physical and mental health of women and their children. The Sustainable Development Goals (SDGs) call for its elimination in target 5.2. To monitor governments' progress towards SDG target 5.2, this study aimed to provide global, regional, and country baseline estimates of physical or sexual, or both, violence against women by male intimate partners. METHODS: This study developed global, regional, and country estimates, based on data from the WHO Global Database on Prevalence of Violence Against Women. These data were identified through a systematic literature review searching MEDLINE, Global Health, Embase, Social Policy, and Web of Science, and comprehensive searches of national statistics and other websites. A country consultation process identified additional studies. Included studies were conducted between 2000 and 2018, representative at the national or sub-national level, included women aged 15 years or older, and used act-based measures of physical or sexual, or both, intimate partner violence. Non-population-based data, including administrative data, studies not generalisable to the whole population, studies with outcomes that only provided the combined prevalence of physical or sexual, or both, intimate partner violence with other forms of violence, and studies with insufficient data to allow extrapolation or imputation were excluded. We developed a Bayesian multilevel model to jointly estimate lifetime and past year intimate partner violence by age, year, and country. This framework adjusted for heterogeneous age groups and differences in outcome definition, and weighted surveys depending on whether they were nationally or sub-nationally representative. This study is registered with PROSPERO (number CRD42017054100). FINDINGS: The database comprises 366 eligible studies, capturing the responses of 2 million women. Data were obtained from 161 countries and areas, covering 90% of the global population of women and girls (15 years or older). Globally, 27% (uncertainty interval [UI] 23-31%) of ever-partnered women aged 15-49 years are estimated to have experienced physical or sexual, or both, intimate partner violence in their lifetime, with 13% (10-16%) experiencing it in the past year before they were surveyed. This violence starts early, affecting adolescent girls and young women, with 24% (UI 21-28%) of women aged 15-19 years and 26% (23-30%) of women aged 19-24 years having already experienced this violence at least once since the age of 15 years. Regional variations exist, with low-income countries reporting higher lifetime and, even more pronouncedly, higher past year prevalence compared with high-income countries. INTERPRETATION: These findings show that intimate partner violence against women was already highly prevalent across the globe before the COVID-19 pandemic. Governments are not on track to meet the SDG targets on the elimination of violence against women and girls, despite robust evidence that intimate partner violence can be prevented. There is an urgent need to invest in effective multisectoral interventions, strengthen the public health response to intimate partner violence, and ensure it is addressed in post-COVID-19 reconstruction efforts. FUNDING: UK Department for International Development through the UN Women-WHO Joint Programme on Strengthening Violence against Women Data, and UNDP-UN Population Fund-UNICEF-WHO-World Bank Special Programme of Research, Development, and Research Training in Human Reproduction, a cosponsored programme executed by WHO.

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.

The Association Between Heterosexual anal Intercourse and HIV Acquisition in Three Prospective Cohorts of Women.

The extent to which receptive anal intercourse (RAI) increases the HIV acquisition risk of women compared to receptive vaginal intercourse (RVI) is poorly understood. We evaluated RAI practice over time and its association with HIV incidence during three prospective HIV cohorts of women: RV217, MTN-003 (VOICE), and HVTN 907. At baseline, 16% (RV 217), 18% (VOICE) of women reported RAI in the past 3 months and 27% (HVTN 907) in the past 6 months, with RAI declining during follow-up by around 3-fold. HIV incidence in the three cohorts was positively associated with reporting RAI at baseline, albeit not always significantly. The adjusted hazard rate ratios for potential confounders (aHR) were 1.1 (95% Confidence interval: 0.8-1.5) for VOICE and 3.3 (1.6-6.8) for RV 217, whereas the ratio of cumulative HIV incidence by RAI practice was 1.9 (0.6-6.0) for HVTN 907. For VOICE, the estimated magnitude of association increased slightly when using a time-varying RAI exposure definition (aHR = 1.2; 0.9-1.6), and for women reporting RAI at every follow-up survey (aHR = 2.0 (1.3-3.1)), though not for women reporting higher RAI frequency (> 30% acts being RAI vs. no RAI in the past 3 months; aHR = 0.7 (0.4-1.1)). Findings indicated precise estimation of the RAI/HIV association, following multiple RVI/RAI exposures, is sensitive to RAI exposure definition, which remain imperfectly measured. Information on RAI practices, RAI/RVI frequency, and condom use should be more systematically and precisely recorded and reported in studies looking at sexual behaviors and HIV seroconversions; standardized measures would aid comparability across geographies and over time.

"I take it and give it to my partners who will give it to their partners": Secondary distribution of HIV self-tests by key populations in Côte d'Ivoire, Mali, and Senegal.

INTRODUCTION: HIV epidemics in Western and Central Africa (WCA) remain concentrated among key populations, who are often unaware of their status. HIV self-testing (HIVST) and its secondary distribution among key populations, and their partners and relatives, could reduce gaps in diagnosis coverage. We aimed to document and understand secondary HIVST distribution practices by men who have sex with men (MSM), female sex workers (FSW), people who use drugs (PWUD); and the use of HIVST by their networks in Côte d'Ivoire, Mali, and Senegal. METHODS: A qualitative study was conducted in 2021 involving (a) face-to-face interviews with MSM, FSW, and PWUD who received HIVST kits from peer educators (primary users) and (b) telephone interviews with people who received kits from primary contacts (secondary users). These individual interviews were audio-recorded, transcribed, and coded using Dedoose software. Thematic analysis was performed. RESULTS: A total of 89 participants, including 65 primary users and 24 secondary users were interviewed. Results showed that HIVST were effectively redistributed through peers and key populations networks. The main reported motivations for HIVST distribution included allowing others to access testing and protecting oneself by verifying the status of partners/clients. The main barrier to distribution was the fear of sexual partners' reactions. Findings suggest that members of key populations raised awareness of HIVST and referred those in need of HIVST to peer educators. One FSW reported physical abuse. Secondary users generally completed HIVST within two days of receiving the kit. The test was used half the times in the physical presence of another person, partly for psychological support need. Users who reported a reactive test sought confirmatory testing and were linked to care. Some participants mentioned difficulties in collecting the biological sample (2 participants) and interpreting the result (4 participants). CONCLUSION: The redistribution of HIVST was common among key populations, with minor negative attitudes. Users encountered few difficulties using the kits. Reactive test cases were generally confirmed. These secondary distribution practices support the deployment of HIVST to key populations, their partners, and other relatives. In similar WCA countries, members of key populations can assist in the distribution of HIVST, contributing to closing HIV diagnosis gaps.

Can HIV self-testing reach first-time testers? A telephone survey among self-test end users in Côte d'Ivoire, Mali, and Senegal.

BACKGROUND: Coverage of HIV testing remains sub-optimal in West Africa. Between 2019 and 2022, the ATLAS program distributed ~400 000 oral HIV self-tests (HIVST) in Côte d'Ivoire, Mali, and Senegal, prioritising female sex workers (FSW) and men having sex with men (MSM), and relying on secondary redistribution of HIVST to partners, peers and clients to reach individuals not tested through conventional testing. This study assesses the proportion of first-time testers among HIVST users and the associated factors. METHODS: A phone-based survey was implemented among HIVST users recruited using dedicated leaflets inviting them to anonymously call a free phone number. We collected socio-demographics, sexual behaviours, HIV testing history, HIVST use, and satisfaction with HIVST. We reported the proportion of first-time testers and computed associated factors using logistic regression. RESULTS: Between March and June 2021, 2 615 participants were recruited for 50 940 distributed HIVST (participation rate: 5.1%). Among participants, 30% received their HIVST kit through secondary distribution (from a friend, sexual partner, family member, or colleague). The proportion who had never tested for HIV before HIVST (first-time testers) was 41%. The main factors associated with being a first-time tester were sex, age group, education level, condom use, and secondary distribution. A higher proportion was observed among those aged 24 years or less (55% vs 32% for 25-34, aOR: 0.37 [95%CI: 0.30-0.44], and 26% for 35 years or more, aOR: 0.28 [0.21-0.37]); those less educated (48% for none/primary education vs 45% for secondary education, aOR: 0.60 [0.47-0.77], and 29% for higher education, aOR: 0.33 [0.25-0.44]). A lower proportion was observed among women (37% vs 43%, aOR: 0.49 [0.40-0.60]); those reporting always using a condom over the last year (36% vs 51% for those reporting never using them, aOR: 2.02 [1.59-2.56]); and those who received their HISVST kit through primary distribution (39% vs 46% for secondary distribution, aOR: 1.32 [1.08-1.60]). CONCLUSION: ATLAS HIVST strategy, including secondary distribution, successfully reached a significant proportion of first-time testers. HIVST has the potential to reach underserved populations and contribute to the expansion of HIV testing services in West Africa.

Seroprevalence and Risk Factors for Severe Acute Respiratory Syndrome Coronavirus 2 Among Incarcerated Adult Men in Quebec, Canada, 2021.

BACKGROUND: People in prison are at increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We examined the seroprevalence of SARS-CoV-2 and associated carceral risk factors among incarcerated adult men in Quebec, Canada. METHODS: We conducted a cross-sectional seroprevalence study in 2021 across 3 provincial prisons, representing 45% of Quebec's incarcerated male provincial population. The primary outcome was SARS-CoV-2 antibody seropositivity (Roche Elecsys serology test). Participants completed self-administered questionnaires on sociodemographic, clinical, and carceral characteristics. The association of carceral variables with SARS-CoV-2 seropositivity was examined using Poisson regression models with robust standard errors. Crude and adjusted prevalence ratios (aPR) with 95% confidence intervals (95% CIs) were calculated. RESULTS: Between 19 January 2021 and 15 September 2021, 246 of 1100 (22%) recruited individuals tested positive across 3 prisons (range, 15%-27%). Seropositivity increased with time spent in prison since March 2020 (aPR, 2.17; 95% CI, 1.53-3.07 for "all" vs "little time"), employment during incarceration (aPR, 1.64; 95% CI, 1.28-2.11 vs not), shared meal consumption during incarceration ("with cellmates": aPR, 1.46; 95% CI, 1.08-1.97 vs "alone"; "with sector": aPR, 1.34; 95% CI, 1.03-1.74 vs "alone"), and incarceration post-prison outbreak (aPR, 2.32; 95% CI, 1.69-3.18 vs "pre-outbreak"). CONCLUSIONS: The seroprevalence of SARS-CoV-2 among incarcerated individuals was high and varied among prisons. Several carceral factors were associated with seropositivity, underscoring the importance of decarceration and occupational safety measures, individual meal consumption, and enhanced infection prevention and control measures including vaccination during incarceration.

How Can Progress Toward Ending the Human Immunodeficiency Virus Epidemic in the United States Be Monitored?

The plan for Ending the HIV (human immunodeficiency virus) Epidemic (EHE) in the United States aims to reduce new infections by 75% by 2025 and by 90% by 2030. For EHE to be successful, it is important to accurately measure changes in numbers of new HIV infections after 5 and 10 years (to determine whether the EHE goals have been achieved) but also over shorter timescales (to monitor progress and intensify prevention efforts if required). In this viewpoint, we aim to demonstrate why the method used to monitor progress toward the EHE goals must be carefully considered. We briefly describe and discuss different methods to estimate numbers of new HIV infections based on longitudinal cohort studies, cross-sectional incidence surveys, and routine surveillance data. We particularly focus on identifying conditions under which unadjusted and adjusted estimates based on routine surveillance data can be used to estimate changes in new HIV infections.

Population sizes, HIV prevalence, and HIV prevention among men who paid for sex in sub-Saharan Africa (2000-2020): A meta-analysis of 87 population-based surveys.

BACKGROUND: Key populations, including sex workers, are at high risk of HIV acquisition and transmission. Men who pay for sex can contribute to HIV transmission through sexual relationships with both sex workers and their other partners. To characterize the population of men who pay for sex in sub-Saharan Africa (SSA), we analyzed population size, HIV prevalence, and use of HIV prevention and treatment. METHODS AND FINDINGS: We performed random-effects meta-analyses of population-based surveys conducted in SSA from 2000 to 2020 with information on paid sex by men. We extracted population size, lifetime number of sexual partners, condom use, HIV prevalence, HIV testing, antiretroviral (ARV) use, and viral load suppression (VLS) among sexually active men. We pooled by regions and time periods, and assessed time trends using meta-regressions. We included 87 surveys, totaling over 368,000 male respondents (15-54 years old), from 35 countries representing 95% of men in SSA. Eight percent (95% CI 6%-10%; number of surveys [Ns] = 87) of sexually active men reported ever paying for sex. Condom use at last paid sex increased over time and was 68% (95% CI 64%-71%; Ns = 61) in surveys conducted from 2010 onwards. Men who paid for sex had higher HIV prevalence (prevalence ratio [PR] = 1.50; 95% CI 1.31-1.72; Ns = 52) and were more likely to have ever tested for HIV (PR = 1.14; 95% CI 1.06-1.24; Ns = 81) than men who had not paid for sex. Men living with HIV who paid for sex had similar levels of lifetime HIV testing (PR = 0.96; 95% CI 0.88-1.05; Ns = 18), ARV use (PR = 1.01; 95% CI 0.86-1.18; Ns = 8), and VLS (PR = 1.00; 95% CI 0.86-1.17; Ns = 9) as those living with HIV who did not pay for sex. Study limitations include a reliance on self-report of sensitive behaviors and the small number of surveys with information on ARV use and VLS. CONCLUSIONS: Paying for sex is prevalent, and men who ever paid for sex were 50% more likely to be living with HIV compared to other men in these 35 countries. Further prevention efforts are needed for this vulnerable population, including improved access to HIV testing and condom use initiatives. Men who pay for sex should be recognized as a priority population for HIV prevention.

Chemsex and incidence of sexually transmitted infections among Canadian pre-exposure prophylaxis (PrEP) users in the l'Actuel PrEP Cohort (2013-2020).

OBJECTIVES: Use of illicit substances during sex (chemsex) may increase transmission of HIV and other STIs. Pre-exposure prophylaxis (PrEP) is highly effective at preventing HIV transmission, providing an important prevention tool for those who practise chemsex. However, it does not prevent acquisition of other STIs. We aim to examine the impact of chemsex on STI incidence among gay, bisexual and other men who have sex with men (gbMSM), and transgender women using PrEP in Montréal, Canada. METHODS: We linked baseline sociodemographic and behavioural data with follow-up STI testing from 2013 to 2020 among PrEP users in the l'Actuel PrEP Cohort (Canada). Focusing on the 24 months following PrEP initiation, we estimated the effect of chemsex reported at baseline on cumulative incidence of gonorrhoea and chlamydia using Kaplan-Meier curves and survival analyses. We investigated the role of polysubstance use and effect modification by sociodemographic factors. RESULTS: There were 2086 clients (2079 cisgender gbMSM, 3 transgender gbMSM, 4 transgender women) who initiated PrEP, contributing 1477 years of follow-up. There were no incident HIV infections among clients on PrEP. Controlling for sociodemographic confounders, clients reporting chemsex at baseline had a 32% higher hazard of gonorrhoea/chlamydia diagnosis (adjusted HR=1.32; 95% CI: 1.10 to 1.57), equivalent to a risk increase of 8.9 percentage points (95% CI: 8.5 to 9.4) at 12 months. The effect was greater for clients who reported polysubstance use (adjusted HR=1.51; 95% CI: 1.21 to 1.89). The strength of the effect of chemsex on STI incidence varied by age, education and income. CONCLUSION: Among PrEP users, chemsex at baseline was linked to increased incidence of gonorrhoea and chlamydia. This effect was stronger for people reporting multiple chemsex substances. The high STI incidence among gbMSM who report chemsex highlights the importance of PrEP for this population and the need for integrated services that address the complexities of sexualised substance use.

Geographic concentration of SARS-CoV-2 cases by social determinants of health in metropolitan areas in Canada: a cross-sectional study.

BACKGROUND: Understanding inequalities in SARS-CoV-2 transmission associated with the social determinants of health could help the development of effective mitigation strategies that are responsive to local transmission dynamics. This study aims to quantify social determinants of geographic concentration of SARS-CoV-2 cases across 16 census metropolitan areas (hereafter, cities) in 4 Canadian provinces, British Columbia, Manitoba, Ontario and Quebec. METHODS: We used surveillance data on confirmed SARS-CoV-2 cases and census data for social determinants at the level of the dissemination area (DA). We calculated Gini coefficients to determine the overall geographic heterogeneity of confirmed cases of SARS-CoV-2 in each city, and calculated Gini covariance coefficients to determine each city's heterogeneity by each social determinant (income, education, housing density and proportions of visible minorities, recent immigrants and essential workers). We visualized heterogeneity using Lorenz (concentration) curves. RESULTS: We observed geographic concentration of SARS-CoV-2 cases in cities, as half of the cumulative cases were concentrated in DAs containing 21%-35% of their population, with the greatest geographic heterogeneity in Ontario cities (Gini coefficients 0.32-0.47), followed by British Columbia (0.23-0.36), Manitoba (0.32) and Quebec (0.28-0.37). Cases were disproportionately concentrated in areas with lower income and educational attainment, and in areas with a higher proportion of visible minorities, recent immigrants, high-density housing and essential workers. Although a consistent feature across cities was concentration by the proportion of visible minorities, the magnitude of concentration by social determinant varied across cities. INTERPRETATION: Geographic concentration of SARS-CoV-2 cases was observed in all of the included cities, but the pattern by social determinants varied. Geographically prioritized allocation of resources and services should be tailored to the local drivers of inequalities in transmission in response to the resurgence of SARS-CoV-2.

A framework to model global, regional, and national estimates of intimate partner violence.

BACKGROUND: Accurate and reliable estimates of violence against women form the backbone of global and regional monitoring efforts to eliminate this human right violation and public health problem. Estimating the prevalence of intimate partner violence (IPV) is challenging due to variations in case definition and recall period, surveyed populations, partner definition, level of age disaggregation, and survey representativeness, among others. In this paper, we aim to develop a sound and flexible statistical modeling framework for global, regional, and national IPV statistics. METHODS: We modeled IPV within a Bayesian multilevel modeling framework, accounting for heterogeneity of age groups using age-standardization, and age patterns and time trends using splines functions. Survey comparability is achieved using adjustment factors which are estimated using exact matching and their uncertainty accounted for. Both in-sample and out-of-sample comparisons are used for model validation, including posterior predictive checks. Post-processing of models' outputs is performed to aggregate estimates at different geographic levels and age groups. RESULTS: A total of 307 unique studies conducted between 2000-2018, from 154 countries/areas, and totaling nearly 1.8 million unique women responses informed lifetime IPV. Past year IPV had a similar number of studies (n = 332), countries/areas represented (n = 159), and individual responses (n = 1.8 million). Roughly half of IPV observations required some adjustments. Posterior predictive checks suggest good model fit to data and out-of-sample comparisons provided reassuring results with small median prediction errors and appropriate coverage of predictions' intervals. CONCLUSIONS: The proposed modeling framework can pool both national and sub-national surveys, account for heterogeneous age groups and age trends, accommodate different surveyed populations, adjust for differences in survey instruments, and efficiently propagate uncertainty to model outputs. Describing this model to reproducible levels of detail enables the accurate interpretation and responsible use of estimates to inform effective violence against women prevention policy and programs, and global monitoring of elimination efforts as part of the Sustainable Development Goals.

Past dynamics of HIV transmission among men who have sex with men in Montréal, Canada: a mathematical modeling study.

BACKGROUND: Gay, bisexual, and other men who have sex with men (gbMSM) experience disproportionate risks of HIV acquisition and transmission. In 2017, Montréal became the first Canadian Fast-Track City, setting the 2030 goal of zero new HIV infections. To inform local elimination efforts, we estimate the evolving role of prevention and sexual behaviours on HIV transmission dynamics among gbMSM in Montréal between 1975 and 2019. METHODS: Data from local bio-behavioural surveys were analyzed to develop, parameterize, and calibrate an agent-based model of sexual HIV transmission. Partnership dynamics, HIV's natural history, and treatment and prevention strategies were considered. The model simulations were analyzed to estimate the fraction of HIV acquisitions and transmissions attributable to specific groups, with a focus on age, sexual partnering level, and gaps in the HIV care-continuum. RESULTS: The model-estimated HIV incidence peaked in 1985 (2.3 per 100 person years (PY); 90% CrI: 1.4-2.9 per 100 PY) and decreased to 0.1 per 100 PY (90% CrI: 0.04-0.3 per 100 PY) in 2019. Between 2000-2017, the majority of HIV acquisitions and transmissions occurred among men aged 25-44 years, and men aged 35-44 thereafter. The unmet prevention needs of men with > 10 annual anal sex partners contributed 90-93% of transmissions and 67-73% of acquisitions annually. The primary stage of HIV played an increasing role over time, contributing to 11-22% of annual transmissions over 2000-2019. In 2019, approximately 70% of transmission events occurred from men who had discontinued, or never initiated antiretroviral therapy. CONCLUSIONS: The evolving HIV landscape has contributed to the declining HIV incidence among gbMSM in Montréal. The shifting dynamics identified in this study highlight the need for continued population-level surveillance to identify gaps in the HIV care continuum and core groups on which to prioritize elimination efforts.

Longitudinal determinants of anal intercourse among women with, and without HIV in the United States.

BACKGROUND: Anal intercourse (AI) is not uncommon among U.S. women and, when condomless, confers a far greater likelihood of HIV transmission than condomless vaginal intercourse. We aim to identify determinants preceding AI, among women with, and women without HIV. METHODS: 3708 women living with (73%), and without HIV (27%) participating in the Women's Interagency HIV Study provided sexual behavior and other data at 6-monthly visits over a median of 9 years (1994-2014). We used generalized estimating equation models to examine sociodemographic, structural and behavioral determinants reported in the visit preceding (1) AI, and (2) condomless AI. RESULTS: AI was reported at least once over follow-up by 31% of women without, and 21% with HIV. AI was commonly condomless; reported at 76% and 51% of visits among women living without HIV, and with HIV, respectively. Women reporting AI were more likely to be younger (continuous variable, adjusted odds ratio (aOR) = 0.97, 95% confidence interval (CI):0.96-0.98), Hispanic (aOR = 1.88, CI:1.47-2.41) or White (aOR = 1.62, CI:1.15-2.30) compared to Black, and have at least high school education (aOR = 1.33, CI:1.08-1.65). AI was more likely following the reporting of either (aOR = 1.35, CI:1.10-1.62), or both (aOR = 1.77, CI:1.13-2.82) physical and sexual violence, excessive drinking (aOR = 1.27, CI:1.05-1.66) or any drug use (aOR = 1.34, CI:1.09-1.66), multiple male partners (aOR = 2.64, CI:2.23-3.11), exchange sex (aOR = 3.45, CI:2.53-4.71), one or more female sex partners (aOR = 1.32, CI:1.01-1.75), condomless vaginal intercourse (aOR = 1.80, CI:1.53-2.09), and high depressive symptoms (aOR = 1.23, CI:1.08-1.39). CONCLUSION: AI disproportionally follows periods of violence victimization, substance use, multiple sex partners and depression. Better prevention messaging and biomedical interventions that reduce acquisition or transmission risk are needed, but when AI occurs in the context of violence against women, as our findings indicate, focusing on gender-based violence reduction and immediate treatment to reduce HIV transmission risk is important.

Dengue, Severity Paradox, and Socioeconomic Distribution Among Afro-Colombians.

BACKGROUND: The clinical presentation of dengue ranges from self-limited mild illness to severe forms, including death. African ancestry is often described as protective against dengue severity. However, in the Latin American context, African ancestry has been associated with increased mortality. This "severity paradox" has been hypothesized as resulting from confounding or heterogeneity by socioeconomic status (SES). However, few systematic analyses have been conducted to investigate the presence and nature of the disparity paradox. METHODS: We fit Bayesian hierarchical spatiotemporal models using individual-level surveillance data from Cali, Colombia (2012-2017), to assess the overall morbidity and severity burden of notified dengue. We fitted overall and ethnic-specific models to assess the presence of heterogeneity by SES across and within ethnic groups (Afro-Colombian vs. non-Afro-Colombians), conducting sensitivity analyses to account for potential underreporting. RESULTS: Our study included 65,402 dengue cases and 13,732 (21%) hospitalizations. Overall notified dengue incidence rates did not vary across ethnic groups. Severity risk was higher among Afro-Colombians (risk ratio [RR] = 1.16; 95% Credible Interval [95% CrI] = 1.08, 1.24) but after accounting for underreporting by ethnicity this association was nearly null (RR = 1.02; 95% CrI = 0.97, 1.07). Subsidized health insurance and low-SES were associated with increased overall dengue rates and severity. CONCLUSION: The paradoxically increased severity among Afro-Colombians can be attributed to differential health-seeking behaviors and reporting among Afro-Colombians. Such differential reporting can be understood as a type of intersectionality between SES, insurance scheme, and ethnicity that requires a quantitative assessment in future studies.

Trends in hepatitis C virus seroprevalence and associated risk factors among men who have sex with men in Montréal: results from three cross-sectional studies (2005, 2009, 2018).

OBJECTIVES: To eliminate the hepatitis C virus (HCV) by 2030, Canada must adopt a microelimination approach targeting priority populations, including gay, bisexual and other men who have sex with men (MSM). Accurately describing HCV prevalence and risk factors locally is essential to design appropriate prevention and treatment interventions. We aimed to estimate temporal trends in HCV seroprevalence between 2005 and 2018 among Montréal MSM, and to identify socioeconomic, behavioural and biological factors associated with HCV exposure among this population. METHODS: We used data from three cross-sectional surveys conducted among Montréal MSM in 2005 (n=1795), 2009 (n=1258) and 2018 (n=1086). To ensure comparability of seroprevalence estimates across time, we standardised the 2005 and 2009 time-location samples to the 2018 respondent-driven sample. Time trends overall and stratified by HIV status, history of injection drug use (IDU) and age were examined. Modified Poisson regression analyses with generalised estimating equations were used to identify factors associated with HCV seropositivity pooling all surveys. RESULTS: Standardised HCV seroprevalence among all MSM remained stable from 7% (95% CI 3% to 10%) in 2005, to 8% (95% CI 1% to 9%) in 2009 and 8% (95% CI 4% to 11%) in 2018. This apparent stability hides diverging temporal trends in seroprevalence between age groups, with a decrease among MSM <30 years old and an increase among MSM aged ≥45 years old. Lifetime IDU was the strongest predictor of HCV seropositivity, and no association was found between HCV seroprevalence and sexual risk factors studied (condomless anal sex with men of serodiscordant/unknown HIV status, number of sexual partners, group sex). CONCLUSIONS: HCV seroprevalence remained stable among Montréal MSM between 2005 and 2018. Unlike other settings where HCV infection was strongly associated with sexual risk factors among MSM, IDU was the pre-eminent risk factor for HCV seropositivity. Understanding the intersection of IDU contexts, practices and populations is essential to prevent HCV transmission among MSM.

Under-Reporting of Known HIV-Positive Status Among People Living with HIV: A Systematic Review and Meta-analysis.

Monitoring progress towards the UNAIDS 'first 90' target requires accurate estimates of levels of diagnosis among people living with HIV (PLHIV), which is often estimated using self-report. We conducted a systematic review and meta-analysis quantifying under-reporting of known HIV-positive status using objective knowledge proxies. Databases were searched for studies providing self-reported and biological/clinical markers of prior knowledge of HIV-positive status among PLHIV. Random-effects models were used to derive pooled estimates of levels of under-reporting. Thirty-two estimates from 26 studies were included (41,465 PLHIV). The pooled proportion under-reporting known HIV-positive status was 20% (95% confidence interval 13-26%, I2 = 99%). In sub-group analysis, under-reporting was higher among men who have sex with men (32%, number of estimates [Ne] = 10) compared to the general population (9%, Ne = 10) and among Black (18%, Ne = 5) than non-Black (3%, Ne = 3) individuals. Supplementing self-reported data with biological/clinical proxies may improve the validity of the 'first 90' estimates.

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.