Patterns of Chemsex Substance Use and Its Association with HIV Transmission Risk Among Men Who Have Sex with Men in Thailand: A Latent Class Analysis.

Sexualized substance use or "chemsex" may contribute to the HIV epidemic among men who have sex with men (MSM) in Thailand. Specific patterns of chemsex use may be associated with different HIV/STI transmission risks. We examined typologies and correlates of sexualized substance use among a sample of high-risk MSM (n = 532) who had attended a private sex party or circuit party in the past three years using latent class analysis. Multinomial regression was used to adjust for variables associated with the 3-class latent class model. We identified a 3-class model as the best fitting model, which included: (1) "negligible sexualized substance users" (36.7%), who had never engaged in chemsex in the past six months; (2) "sexualized substance users" (13.9%), who had a high level of sexualized alcohol use and a wide range of other substances before or during sex in the past six months; and (3) "exclusive chemsex users" (49.4%), who predominantly used crystal methamphetamine, amyl nitrite, and erectile dysfunctional drugs before or during sex in the past six months. Compared to negligible sexualized substance users, exclusive chemsex users were more likely to be HIV-positive, more likely to have six or more sexual partners in the past six months, less likely to have condom use at last anal intercourse, and more likely to have provided sex work. Relative to negligible sexualized substance users, sexualized substance users reported more frequent online sex-seeking behaviors. These subgroups of Thai MSM have unique substance use patterns and HIV-related risk profiles, underscoring the importance of targeted HIV prevention strategies.

Intention and preference to use long-acting injectable PrEP among MSM in the Netherlands: a diffusion of innovation approach.

Long-acting injectable pre-exposure prophylaxis (LAI-PrEP) is efficacious in preventing HIV among men-who-have-sex-with-men (MSM) and will be soon available in Europe. This study investigated the intention and preference to use LAI-PrEP among MSM in the Netherlands by employing a diffusion of innovation approach. This study had a cross-sectional design nested within a cohort study established in 2017 to understand oral PrEP use among MSM. 309 MSM completed the survey on their awareness, interest, intention, and preference for LAI-PrEP in June 2022. Among them, 83% showed high/very-high interest in, and 63% showed high/very-high intention to use LAI-PrEP. A repeated innovator effect from the early adopters to LAI-PrEP was not observed. Early adopters did not show increased intention to use LAI-PrEP compared to other MSM subgroups, but neither did PrEP-naïve nor PrEP-discontinued MSM. However, among the 218 current oral PrEP users, suboptimal adherence was associated with preference for LAI-PrEP but not with intention to use it. In conclusion, our findings indicated that an effective, available, and affordable LAI-PrEP would be welcomed in the Netherlands, but that its introduction may not significantly expand PrEP coverage. However, the introduction of LAI-PrEP in the Netherlands could prove beneficial to MSM with suboptimal adherence to oral PrEP.

Beyond community engagement: perspectives on the meaningful involvement of people with HIV and affected communities (MIPA) in HIV cure research in The Netherlands.

BACKGROUND: Meaningful involvement of people with HIV and affected communities in HIV cure research is essential to ensuring that cure research efforts are conducted transparently, socially justly, and ethically. This study set out to investigate how people with HIV and affected communities are involved in cure research in the Netherlands and explore what can be done to optimize involvement and engagement. METHODS: Eighty-five semi-structured online, telephone, and face-to-face interviews were conducted with people with HIV (N = 30), key populations (N = 35), and key informants (KI; N = 20) in the field of HIV. The interviews were analyzed using reflexive thematic analysis. RESULTS: Awareness of the meaningful involvement of people with HIV (MIPA) efforts was low among people with HIV and key populations, which contrasted with KI, who exhibited greater awareness. People with HIV and KI emphasized the importance of MIPA in ensuring the representation of lived experiences in HIV cure research and fostering trust between communities and researchers. Practical implementations of MIPA were unclear, ultimately resulting in difficulties defining MIPA beyond clinical trial participation. People with HIV and key populations also doubted their skills and self-efficacy to make meaningful contributions when confronted with involvement beyond participating in research and clinical trials. CONCLUSIONS: MIPA is crucial for improving the quality, transparency, and ethical conduct of HIV cure research. It emphasizes the need for increased awareness and funding, standardized guidelines to ensure meaningful involvement, and combat tokenism and misconceptions.

Socio-economic inequities in mental health problems and wellbeing among women working in the apparel and floriculture sectors: testing the mediating role of psychological capital, social support and tangible assets.

BACKGROUND: It is still unknown whether the mechanisms proposed by the Reserve Capacity Model (RCM) explaining socio-economic health and wellbeing inequities in high income countries can be applied to low-income countries. This study investigates whether different reserve capacities (intra-, inter-personal, and tangible) can explain the association between relative socio-economic position (SEP) and wellbeing outcome measures among Ethiopian women working in Foreign Direct Investment (FDI). METHOD: Using a cross-sectional design, we collected quantitative survey data among 2,515 women working in the apparel and floriculture sectors in Ethiopia, measuring GHQ-12 mental health problems, multi-dimensional wellbeing, relative SEP, psychological capital (PsyCap), social support (emotional and financial social support network), and tangible assets (e.g., owning mobile phone, having access to toilet facilities). We used cluster-adjusted structural equation modelling to test whether PsyCap, social support, and/or tangible assets mediate the association between relative SEP (IV) and GHQ-12 mental health problems and multi-dimensional wellbeing (DVs). RESULTS: PsyCap and the size of the financial support network significantly mediate the socio-economic gradient in both wellbeing outcomes. The size of the emotional social support network shows no association with multi-dimensional wellbeing and shows an unexpected negative association with GHQ-12 mental health problems scores, including a significant mediation effect. Tangible assets show no association with the wellbeing outcome measures and do not mediate socio-economic mental health problems and wellbeing inequities. CONCLUSIONS: The RCM can be applied in low-income countries, although in unexpected ways. Similar to findings from high-income countries, PsyCap and size of the financial social support network show significant mediation effects in explaining mental health problems and wellbeing inequities in Ethiopia. These reserves could therefore serve as a buffer for socio-economic inequities in mental health and wellbeing and can therefore assist in decreasing these inequities for women working in FDI sectors in Ethiopia.

Scenarios of future mpox outbreaks among men who have sex with men: a modelling study based on cross-sectional seroprevalence data from the Netherlands, 2022.

BackgroundFollowing the 2022-2023 mpox outbreak, crucial knowledge gaps exist regarding orthopoxvirus-specific immunity in risk groups and its impact on future outbreaks.AimWe combined cross-sectional seroprevalence studies in two cities in the Netherlands with mathematical modelling to evaluate scenarios of future mpox outbreaks among men who have sex with men (MSM).MethodsSerum samples were obtained from 1,065 MSM attending Centres for Sexual Health (CSH) in Rotterdam or Amsterdam following the peak of the Dutch mpox outbreak and the introduction of vaccination. For MSM visiting the Rotterdam CSH, sera were linked to epidemiological and vaccination data. An in-house developed ELISA was used to detect vaccinia virus (VACV)-specific IgG. These observations were combined with published data on serial interval and vaccine effectiveness to inform a stochastic transmission model that estimates the risk of future mpox outbreaks.ResultsThe seroprevalence of VACV-specific antibodies was 45.4% and 47.1% in Rotterdam and Amsterdam, respectively. Transmission modelling showed that the impact of risk group vaccination on the original outbreak was likely small. However, assuming different scenarios, the number of mpox cases in a future outbreak would be markedly reduced because of vaccination. Simultaneously, the current level of immunity alone may not prevent future outbreaks. Maintaining a short time-to-diagnosis is a key component of any strategy to prevent new outbreaks.ConclusionOur findings indicate a reduced likelihood of large future mpox outbreaks among MSM in the Netherlands under current conditions, but emphasise the importance of maintaining population immunity, diagnostic capacities and disease awareness.

Engagement of HIV-negative MSM and partners of people with HIV in HIV cure (research): exploring the influence of perceived severity, susceptibility, benefits, and concerns.

As the prospect of an HIV cure is gaining prominence, engaging key populations affected by an HIV cure becomes essential. This study examined the engagement of HIV-negative men who have sex with men (MSM) and/or partners of people with HIV (PHIV) in the Netherlands. Interviews were conducted with 19 MSM not in relationships with a partner with HIV and 16 partners of PHIV and were thematically analyzed. Perspectives on the importance of an HIV cure were shaped by the perceived severity of HIV and the level of susceptibility to the virus. Despite concerns about potential new HIV infections and treatment intensity, most participants believed that an HIV cure could reduce HIV burden. Both HIV eradication and HIV suppression were regarded as acceptable outcomes. Engagement was demonstrated through actions like accessing information, participating in research, and showing support for partners or community members involved in HIV cure research. In conclusion, we found that most participants were engaged due to their heightened perception of HIV's severity. However, this engagement tended to remain passive due to their perceived low susceptibility to HIV, resulting in a scenario where the perceived importance of an HIV cure is high, while personal relevance remains low.

Determinants of HIV Testing Among Migrant Men Who Have Sex With Men from Sub-Saharan Africa and Other Regions Residing in 10 European Countries.

Migrant men who have sex with men (mMSM) from sub-Saharan Africa (SSA) and other regions outside Europe are highly vulnerable to HIV. However, research on the determinants of HIV testing among mMSM from SSA, and how these differ across the categories of mMSM living in Europe, is limited. Using data from the European MSM Internet Survey (EMIS-2017), we assessed HIV testing prevalence and recency in mMSM from SSA and other mMSM residing in ten European countries, as well as the determinants of HIV testing across different mMSM categories with logistic regression analyses. Ever-testing for HIV was slightly higher in mMSM from SSA (83%) compared to other mMSM categories (75-80%), except for mMSM from Latin America and Caribbean region (84%). Overall, 20% of mMSM had never tested. In multivariable analysis, higher age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.01-1.10), higher HIV knowledge (AOR 1.45, 95%-CI 1.11-1.90), and residence in smaller settlements (AOR 0.45, 95%-CI 0.21-0.96) were significantly associated with ever testing for HIV in mMSM from SSA. Comparing mMSM from SSA to mMSM from other regions, we found varying significant similarities (higher age, residence in smaller settlements and HIV knowledge) and differences (lower educational attainment, not identifying as gay, being a student, and limited disclosure of homosexual attraction) in the determinants of ever-testing for HIV. Community-specific interventions addressing identified sociodemographic and behavioral determinants to increase HIV testing uptake in the different mMSM categories and better data for further research are warranted.

Partying in Thailand: Never Testing Among Men Who Have Sex With Men Who Attend Sexualized (Drug) Parties.

BACKGROUND: Human immunodeficiency virus (HIV) testing for Thai men who have sex with men (MSM) is suboptimal, which undermines their linkage to care and subsequent HIV preexposure prophylaxis (PrEP) uptake. METHODS: We analyzed a cross-sectional survey conducted in 2021 among Thai MSM who attended any private sex parties or circuit parties in the past 3 years ("sexualized parties"). RESULTS: Of the 424 men included in our analysis, 47.6% had been recently tested for HIV in the past 1 year, 30.2% had not recently been tested, and 22.2% had never been tested. In our multivariable analysis, relative to participants who had recently tested for HIV, those who have never tested were more likely to have lower education or to live outside of Bangkok, and to have attended both circuit and private sex parties (vs. private sex party only) but were less likely to report any sexually transmitted infection diagnosis or to have heard of PrEP. Participants who had an HIV test more than a year ago were more likely to have attended both circuit and private sex parties (vs. private sex parties only) but were less likely to have any sexually transmitted infection diagnosis, meet sexual partners online, or have heard of PrEP. Rates of condomless anal sex and willingness to use PrEP were similar across groups. CONCLUSIONS: Despite the high rates of sexual risk-taking, sexualized party attendees reported suboptimal HIV testing uptake. The joint promotion of HIV testing and PrEP is warranted-especially on-premise HIV testing at circuit parties and outreach at online platforms to reach sexualized party attendees.

Brief Report: Determinants of Potential Sexual Activity Reduction in the Face of the Mpox Epidemic.

BACKGROUND: The current mpox epidemic is most prevalent among men-who-have-sex-with-men (MSM). Vaccination programs are being rolled-out to curb the epidemic. Behavioural measures have been called for as well, for example, by the WHO and national public health authorities to reduce the number of sexual partners and sexual activity. We investigated intentions and determinants among Dutch MSM to follow such behavioural measures. METHODS: Early in July 2022, in the context of a dynamic ongoing epidemic, 394 MSM answered an online questionnaire investigating concepts such as perceived mpox risk, vaccination and behavioural change intentions and collecting socio-demographic and sexual behaviour information. RESULTS: The overall intentions to reduce number of partners and sexual activity were high, but only a minority had developed definite intentions. Determinant analysis revealed that dating/open relationship status was a positive predictor; vaccination intentions did not predict sexual behaviour change; those not on PrEP were more likely to change their sexual behaviour. Mpox infection concern was the main predictor for behaviour change intentions. CONCLUSIONS: Our results show that behavioural measures to avoid an mpox infection are present in majority of participants in our survey, but high intentions are held by a minority. Taking the historic complexity of behavioural change pleas among MSM into account sensitive, additional public health measures are necessary to reach and to inform MSM about potential benefits of sexual behaviour change.

Mpox stigma among men who have sex with men in the Netherlands: Underlying beliefs and comparisons across other commonly stigmatized infections.

People with or at risk for mpox are likely to be stigmatized because of analogies to other sexually transmitted infections. Stigma is driven by beliefs about the perceived severity of the condition and perceived responsibility for acquiring the condition, both in broader society and individual responsibility. We explored these beliefs and compared them across mpox, human immunodeficiency virus (HIV), syphilis, gonorrhoea, and chlamydia in an online survey, conducted in July 2022, with 394 men-who-have-sex-with-men in the Netherlands. We compared mean scores between infections using repeated measures analysis of variance and conducted hierarchical regression analyses to identify determinants of both mpox perceived responsibility endpoints. Results showed that participants expected that mpox would be seen as a "gay disease" and will be used to blame gay men. Compared to other infections, mpox was considered less severe than HIV, but more severe than syphilis, gonorrhoea, and chlamydia. Perceived responsibility was comparable across infections, but, for each infection, participants perceived attributed responsibility to be higher in society than individual responsibility. Both perceived responsibility endpoints were highly correlated with each other and with other stigma beliefs. These results provide insight on the underlying determinants of mpox stigma and demonstrate that anticipated mpox stigma is present in the Netherlands.

MSM with HIV: Improving prevalence and risk estimates by a Bayesian small area estimation modelling approach for public health service areas in the Netherlands.

Despite close monitoring of HIV infections amongst MSM (MSMHIV), the true prevalence can be masked for areas with small population density or lack of data. This study investigated the feasibility of small area estimation with a Bayesian approach to improve HIV surveillance. Data from EMIS-2017 (Dutch subsample, n = 3,459) and the Dutch survey SMS-2018 (n = 5,653) were utilized. We applied a frequentist calculation to compare the observed relative risk of MSMHIV per Public Health Services (GGD) region in the Netherlands and a Bayesian spatial analysis and ecological regression to quantify how spatial heterogeneity in HIV amongst MSM is related to determinants while accounting for spatial dependence to obtain more robust estimates. Both estimations converged and confirmed that the prevalence is heterogenous across the Netherlands with some GGD regions having a higher-than-average risk. Our Bayesian spatial analysis to assess the risk of MSMHIV was able to close data gaps and provide more robust prevalence and risk estimations.

The Importance of Social Engagement in the Development of an HIV Cure: A Systematic Review of Stakeholder Perspectives.

As research into the development of an HIV cure gains prominence, assessing the perspectives of stakeholders becomes imperative. It empowers stakeholders to determine priorities and influence research processes. We conducted a systematic review of the empirical literature on stakeholder perspectives. PubMed, Embase, Web of Science, and Scopus were searched for empirical, peer-reviewed articles, published before September 2022. Our analysis of 78 papers showed that stakeholders could be divided into three categories: people with HIV, key populations, and professionals. Following thematic synthesis, two main themes were distinguished: stakeholders' perspectives on HIV cure research and stakeholders' perspectives on HIV cure. Research on perspectives on HIV cure research showed that stakeholders' hypothetical willingness to participate (WTP) in HIV cure research was relatively high, while actual WTP was found to be lower. Studies also identified associated (individual) characteristics of hypothetical WTP, as well as facilitators and barriers to hypothetical participation. Additionally, we reported research on experiences of actual HIV cure research participation. Our analysis of stakeholder perceptions of HIV cure showed that most stakeholders preferred a cure that could eliminate HIV and outlined positive associated impacts. Furthermore, we observed that most included studies were conducted among PWHIV, and in the Global North. To empower stakeholders, we recommend that future research include an even greater diversity of stakeholders and incorporate theories of behavior to further explore how stakeholders decide to meaningfully engage in every stage of HIV cure research.

Spatio-temporal changes in pre-exposure prophylaxis uptake among MSM in mainland France between 2016 and 2021: a Bayesian small area approach with MSM population estimation.

INTRODUCTION: In France, oral pre-exposure prophylaxis (PrEP) for HIV prevention has been publicly available since 2016, mainly targeting at men who have sex with men (MSM). Reliable and robust estimations of the actual PrEP uptake among MSM on a localized level can provide additional insights to identify and better reach marginalized MSM within current HIV prevention service provision. This study used national pharmaco-epidemiology surveillance data and regional MSM population estimations to model the spatio-temporal distribution of PrEP uptake among MSM in France 2016-2021 to identify marginalized MSM at risk for HIV and increase their PrEP uptake. METHODS: We first applied Bayesian spatial analyses with survey-surveillance-based HIV incidence data as a spatial proxy to estimate the size of (1) regional HIV-negative MSM populations and (2) MSM who could be eligible for PrEP use according to French PrEP guidelines. We then applied Bayesian spatio-temporal ecological regression modelling to estimate the regional prevalence and relative probability of the overall- and new-PrEP uptake from 2016 to 2021 across France. RESULTS: HIV-negative and PrEP-eligible MSM populations vary regionally across France. Île-de-France was estimated to have the highest MSM density compared to other French regions. According to the final spatio-temporal model, the relative probability of overall PrEP uptake was heterogeneous across France but remained stable over time. Urban areas have higher-than-average probabilities of PrEP uptake. The prevalence of PrEP use increased steadily (ranging from 8.8% [95% credible interval 8.5%;9.0%] in Nouvelle-Aquitaine to 38.2% [36.5%;39.9%] in Centre-Val-de-Loire in 2021). CONCLUSIONS: Our results show that using Bayesian spatial analysis as a novel methodology to estimate the localized HIV-negative MSM population is feasible and applicable. Spatio-temporal models showed that despite the increasing prevalence of PrEP use in all regions, geographical disparities and inequalities of PrEP uptake continued to exist over time. We identified regions that would benefit from greater tailoring and delivery efforts. Based on our findings, public health policies and HIV prevention strategies could be adjusted to better combat HIV infections and to accelerate ending the HIV epidemic.

Barriers and Facilitators to HIV Treatment Adherence in Indonesia: Perspectives of People Living with HIV and HIV Service Providers.

HIV treatment adherence in Indonesia is a major challenge. Although previous studies have demonstrated several barriers and facilitators to adherence, studies providing a comprehensive analysis from both PLHIV and HIV service providers' perspectives are limited, especially in Indonesia. In this qualitative study with 30 people living with HIV on treatment (PLHIV-OT) and 20 HIV service providers (HSPs), we explored, via online interviews, the barriers and facilitators to antiretroviral therapy (ART) adherence using a socioecological approach. Both PLHIV-OT and HSPs reported stigma as a major barrier at each socioecological level, including public stigma at the societal level, stigma in healthcare settings, and self-stigma at the intrapersonal level. Stigma reduction must therefore be prioritized. PLHIV-OT and HSPs also reported support from significant others and HSPs as the foremost facilitators to ART adherence. The enablement of support networks is thus an important key to improved ART adherence. Overall, the societal level and health system barriers to ART adherence should be addressed in order to remove barriers and enhance the facilitators at the subordinate socioecological levels.

Association of internalised homonegativity with partner notification after diagnosis of syphilis or gonorrhoea among men having sex with men in 49 countries across four continents.

BACKGROUND: Partner notification (PN) after a sexually transmitted infection (STI) diagnosis is being promoted as a means to interrupt transmission chains. We investigated whether Internalised Homonegativity (IH) is associated with PN among men having sex with men (MSM). METHODS: PN, defined as notifying at least one partner after diagnosis of syphilis and gonorrhoea, was queried in two internet-based self-completion surveys conducted between Oct 2017 and May 2018 in 68 countries in Europe, Latin America, Canada, and the Philippines. IH is defined by a man's level of agreement or disagreement with negative social beliefs about male homosexuality. Covariates included in a multivariate regression model with a random intercept at country level were age, HIV diagnosis, partnership status, sexual self-efficacy, HIV serostatus communication during last sex with a non-steady partner, place where this partner was met, and PN-related socio-historical background of the country of residence. We grouped countries in three areas: North- and Central-Western European countries plus Canada, former socialist countries, and Latin-American/Mediterranean countries plus the Philippines. In each of the three areas individuals were assigned to 4 subgroups based on IH quartiles and PN rates were determined for each subgroup. RESULTS: PN rates were calculated for 49 countries (excluding countries with less than 10 diagnoses). Mean proportions of MSM notifying their partners were 68.1% and 72.9% after syphilis and gonorrhoea diagnoses, respectively. PN rates were lower in Latin American countries and the Philippines compared to European countries. Within Europe, a North-South divide with lower PN rates in Mediterranean countries was observed. In each of the three regions we mostly observed a stepwise increase of PN rates with decreasing IH. Regression analysis showed lower IH scores associated with higher PN rates. Higher perceived self-efficacy, living in a partnership, and HIV status communication were positively associated with PN. Men who had met their last partner in a gay social venue were more likely to have notified their partners of a syphilis diagnosis compared to men who had met this partner online. Men with diagnosed HIV were less likely to report PN. CONCLUSIONS: We could demonstrate that IH was associated with PN among MSM across all countries included in our analysis. Reducing cultural homophobia and ensuring inclusive policies may contribute to STI prevention and control.

Chemsex and chemsex associated substance use among men who have sex with men in Asia: A systematic review and meta-analysis.

BACKGROUND: The prevalence of chemsex has been reported by multiple systematic reviews among men who have sex with men (MSM) focussing predominantly on the Global North. An Asian perspective with meta-analytical evidence is missing. This meta-analysis summarised the prevalence of substance use associated with chemsex, and chemsex activity among MSM and MSM sub-populations in Asia, as well as the likelihood for chemsex among MSM living with or without HIV. METHODS: We utilized PubMed, Web of Science and medRxiv to search for literature describing chemsex and its associated substance use among MSM and MSM sub-populations in Asia from January 1, 2010 to November 1, 2021 to conduct three meta-analyses with both frequentist and Bayesian approaches. RESULTS: We identified 219 studies and included 23 in the meta-analysis. Based on the frequentist models, methamphetamine was the default substance associated with chemsex among MSM in Asia (prevalence = 0.16, 95 %CI:0.09-0.22), followed by GHB/GBL (prevalence = 0.15, 95 %CI:0.03-0.27) and ketamine (prevalence = 0.08, 95 %CI:0.04-0.12), but hardly any cocaine (prevalence = 0.01, 95 %CI:0.00-0.03). Compared to a general MSM population (prevalence = 0.19, 95 %CI:0.15-0.23), MSM engaging in transactional sex showed a higher prevalence of chemsex (MSM sex work clients [prevalence = 0.28, 95 %CI:0.11-0.45]; MSM sex worker [prevalence = 0.28, 95 %CI:0.17-0.26]). MSM living with HIV also showed higher odds of chemsex activity (OR = 3.35, 95 %CI:1.57-7.10), compared to MSM living without HIV. Both meta-analytic models converged, indicating robust evidence. CONCLUSIONS: Our meta-analyses showed that chemsex is not uncommon among MSM, and MSM engaging in transactional sex in Asia. We confirmed that MSM living with HIV have a higher likelihood of engaging in chemsex, too. Chemsex prevention and management strategies in Asia should be adjusted accordingly.

Sexually transmitted infection prevention behaviours: health impact, prevalence, correlates, and interventions.

Sexually transmitted infections (STIs) remain a major public health threat, disproportionately affecting young people, and men who have sex with men. In this narrative review of the current state of behavioural science research on STI prevention, we consider the definition, health impacts, correlates and determinants, and interventions to promote STI prevention behaviour. Research on STI prevention behaviour has extended from a focus on abstinence, partner reduction and condom use, to also include novel preventive behaviours, notably treatment-as-prevention, pre-exposure prophylaxis (i.e., the preventive use of medicines by uninfected people), and vaccination for some STIs. Social-cognitive factors specified by, for instance the theory of planned behaviour, are critical proximal determinants of STI prevention behaviours, and related interventions can effectively promote STI prevention behaviours. Social-ecological perspectives highlight that individual-level determinants are embedded in more distal environmental influences, with social stigma especially affecting STI prevention behaviours and requiring effective intervention. Further to providing a major domain of application, STI prevention also poses critical challenges and opportunities for health psychology theory and research. We identify a need for health behaviour theory that addresses the processes linking multiple levels of influence on behaviour and provides practical guidance for multi-level behaviour change interventions adapted to specific contexts.

Latin American Internet Survey for Men who have Sex with Men (LAMIS-2018): Design, methods and implementation.

Despite men-who-have-sex-with-men (MSM) from Latin America (LA) are still a vulnerable population for known health-related conditions and social problems, availability of comparable data across LA countries for assessment and monitoring purposes is limited. The objective of this article is to present the study design and the questionnaire of LAMIS-2018 (Latin America MSM Internet Survey), its recruitment strategy, rates and sources by country, and the lessons learned from its implementation. LAMIS-2018 was a cross-sectional, internet-based survey targeting MSM living in 18 LA countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela) that gathered data about sexual behaviors, HIV/STI and viral hepatitis knowledge, prophylactic use of antiretrovirals, psychosocial health, and access to sexual health services. The survey went online for four months and was available in three languages (Spanish, Portuguese, and Dutch). Promotion was carried out using dating apps, websites, social networks, and by community-based and academic organizations of each participating country directly in gay venues and in their own premises. Overall, 64,655 MSM participated in LAMIS-2018. Dating apps and websites were the most important recruitment source in most countries, except for Honduras, Nicaragua, and Suriname, where community-based organizations recruited most of the participants. Beyond the LAMIS-2018 implementation description, we highlight the feasibility of such a study in this context, based on the collaboration between community-based and academic organizations to obtain a large sample of MSM in the region. LAMIS-2018 data will contribute to identify determinants of risk behaviors and prevention needs of vulnerable MSM populations in each country of the region.