High-Risk Sexual Activities and Condom Use Patterns During Group Sex Among Men Who Have Sex With Men in Melbourne, Australia

Few studies have examined the types of sexual activities and condom use during group sex among men who have sex with men (MSM). This study aimed to examine sexual activities and condom use during group sex.A cross-sectional survey among MSM attending a sexual health clinic in Melbourne, Australia, between May 2019 and March 2020.Participants were asked whether they had engaged in group sex (sex involving more than 2 participants) within the past 3 months, the number of people involved, the sexual activities they engaged in, and their condom use during the most recent group sex.More than a quarter (26.8%, 287 of 1071) had engaged in group sex in the past 3 months, and the median number of people involved was 3 (interquartile range 3-4), including the participant. Fellatio was the most common activity in group sex (94.4%, 271 of 287), followed by kissing (85.7%, 246 of 287) and anal sex (79.8%, 229 of 287). The proportion of men who always used condoms and changed condoms between partners was 27.0% (48 of 178) for insertive and 32.3% (52 of 161) for receptive anal sex. Compared with men not taking pre-exposure prophylaxis (PrEP), men living with HIV (adjusted odds ratio [aOR]: 2.35; 95% confidence interval [CI]: 1.20 to 4.59) and men taking PrEP (aOR: 3.07; 95% CI: 2.21 to 4.26) had higher odds of engaging in group sex after adjusting for confounders.Two-thirds of MSM either did not use condoms or did not change condoms between partners during group sex, which may increase sexually transmitted infection transmission between partners.