Recruitment
HIV or syphilis
RECRUITMENT
We recruited participants by partnering with seven local MSM community-based organizations (CBOs) across seven provinces located in different parts of China. All men living with HIV were recruited in-person through MSM-led clinics, and HIV-negative men were recruited in a 50:50 ratio (half online and half offline) through CBOs. All study sites followed the same research procedure. For the offline recruitment, trained CBO staff at each clinic provided information about the study to men seeking HIV or syphilis testing services, verified the HIV status of those interested in potentially enrolling in the study, and then issued them a link to access an online survey. For the online recruitment of HIV-negative men, an invitation to join the study was posted on the WeChat Official Account of each CBO (WeChat, a popular Chinese messaging app) and was also sent via QQ (a messaging platform) by each CBO. Online recruitment was restricted to people living in the province by verifying their IP address, and all participants were required to upload their HIV-negative testing reports during the eligibility screening procedure.All participants who clicked the link were directed to a survey website hosted by Sojump (Changsha Haoxing Information Technology Co., Ltd., China) to give consent and complete eligibility screening. Eligible participants completed a baseline survey and were required to provide contact information, including a cell phone number or a WeChat account to receive text messages, a shipping address for participants who applied for kits, and a preferred name. Participants were provided compensation of US$3 for their time completing the baseline survey.