Group sex and behavior change associated with the 2022 Mpox outbreak among men who have sex with men in Southern California

Background The Monkeypox (Mpox) outbreak disproportionately affected sexually active gay, bisexual, and other men who have sex with men. To understand community-level changes in sexual behavior, we surveyed individuals in a semi-urban area in Southern California. Methods Participants were recruited between October 2022 to April 2023, using palm cards, and geolocation-focused online advertisements on social media and dating apps. Eligible participants were male, ≥18 years, reported sex with men, residents of San Bernardino or Riverside counties, California, Human Immunodeficiency Virus (HIV)-negative, currently not taking pre-exposure prophylaxis (PrEP). Descriptive analyses were performed. Chi-square, Fisher’s exact, and Student’s T-tests examined the association between group sex behaviors and demographics. Results We enrolled 91 gay, bisexual, and other men who have sex with men with a median age of 35 years (range 18-70 years). Nearly half reported having participated in group sex in the past year. Overall, 48.9% of group sex participants reported changing their sexual behaviors to prevent Mpox transmission, with limiting the number of sex partners being the most reported prevention strategy (47.6%). To prevent Mpox infection, participants that engage in group sex reported limiting the number of sex partners (34.4%), using condoms for anal sex (16.7%), avoiding crowded social venues (14.3%), and asking partners about Mpox symptoms before sex (9.5%). Conclusion Survey participants reported modest sexual behavior changes in response to the Mpox outbreak. Group sex may increase the risk for Mpox, HIV, and other sexually transmitted infections; therefore, public health messages should include specific discussion of safer group sex practices in sexual health promotion.