RESUMO
OBJECTIVE: To understand the factors associated with the practice of chemsex among MSM in Brazil, especially during the Mpox health crisis, and to design effective prevention and intervention strategies specifically for this population. DESIGN: A cross-sectional and analytical study using an electronic survey, conducted from September to December 2022, during the peak of the Mpox outbreak in Brazil. SAMPLE: A total of 1452 MSM aged 18 and older. MEASUREMENTS: Data were collected via the REDCap platform through a survey with 46 questions. These addressed demographic data, sexual affiliations, practices, experiences with Mpox, healthcare service usage, and stigma or fear related to Mpox. RESULTS: The prevalence of chemsex was 19.42% (n = 282). Multivariate Poisson modeling indicated a high incidence of chemsex among those diagnosed with Mpox and those involved in high-risk behaviors. The practice of chemsex was six times higher among those diagnosed with Mpox (95% CI: 4.73-9.10). MSM who engage in bugchasing had a prevalence twice that of the main outcome (95% CI: 1.31-3.16). CONCLUSION: There is a significant need for targeted interventions for MSM in Brazil, especially given the Mpox outbreak. This study highlights the strong relationships between chemsex, experiences with Mpox, and various sexual behaviors, underscoring the importance of effective public health initiatives.