Study Design, Setting, and Participants
This study was a 2-arm cluster randomized controlled trial; the trial protocol provides more details [Participants were eligible if they were born biologically male, were aged 18 years or older, currently lived in and planned to remain living in 1 of the 11 cities for the 12 months after enrollment, were HIV seronegative or had unknown serum status, had anal sex with a man in the past 12 months, had not been tested for HIV in the past 3 months, and provided informed consent. Participants were recruited by sending a link to the questionnaire to potential participants through Blued (a popular social app among Chinese MSM) and community-based organizations (CBOs) in each city. Additionally, eligible participants were invited to recommend at most 5 MSM in their city to participate in this study from their social networks.