LAUSR

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