- Sex work and transactional sex (SWTS), as well as Chemsex, the intentional use of specific substances aiming to enhance sexual experiences among men who have sex with men (MSM), are associated with high-risk sexual behaviors including unprotected sex and injection drug use and are consequently associated to worse health outcomes, such as higher rates of several sexually transmitted infections (STIs). The main objective of this project was to investigate the prevalence of SWTS among chemsex users and analyze the factors influencing their health outcomes. We conducted an online survey in three European German-speaking countries, and the recruitment took place between March and December 2023 and was performed by convenience sampling, such as placing advertisements and flyering in public places. Eligible participants were MSM aged 18 years old or older who had been sexually active in the past 12 months. There were 399 sexually active MSM included and categorized into three sub-groups: 129Sex work and transactional sex (SWTS), as well as Chemsex, the intentional use of specific substances aiming to enhance sexual experiences among men who have sex with men (MSM), are associated with high-risk sexual behaviors including unprotected sex and injection drug use and are consequently associated to worse health outcomes, such as higher rates of several sexually transmitted infections (STIs). The main objective of this project was to investigate the prevalence of SWTS among chemsex users and analyze the factors influencing their health outcomes. We conducted an online survey in three European German-speaking countries, and the recruitment took place between March and December 2023 and was performed by convenience sampling, such as placing advertisements and flyering in public places. Eligible participants were MSM aged 18 years old or older who had been sexually active in the past 12 months. There were 399 sexually active MSM included and categorized into three sub-groups: 129 MSM engaging in chemsex (MSM-CX), 128 MSM engaging in sexualized substance use with non-chemsex substances (MSM-SSU), and 142 MSM not engaging in sexualized substance use (MSM-NSU). MSM-CX reported significantly higher rates of SWTS compared to both MSM-SSU (p = .032) and MSM-NSU (p < .001). Chemsex and SWTS were both individually associated with a higher prevalence of HIV (p < .001 and p = .042, respectively) and multiple STIs (p < .001 and p = .023, respectively), MSM-CX engaging in SWTS were younger (p = .006), had more sexual partners (p = .029), and reported significantly higher rates of use and sexualized use of several substances. However, among MSM-CX, SWTS were not significantly linked to higher rates on HIV (p = .702) or multiple STIs (p = .380). Our findings have shown that participants involved in chemsex and participants involved in SWTS face overall poorer health outcomes when compared with controls. The results underscore the need for targeted prevention and intervention measures that address these specific needs and risks of MSM-CX and SWTS. There is an urgent need for more representative studies as well as longitudinal studies on chemsex.…

