Measures
verbal abuse, syphilis, syphilis, HIV and other STIs, sexual behaviors
STIS, SYPHILIS, ADVERSE EVENTS
All eligible indexes completed a baseline questionnaire at enrollment, which included sociodemographic characteristics, sexual orientations disclosure, number of male sex partners, syphilis testing, HIV testing and other STIs testing, and their size of social network, like “How many MSMs have you known in your live?” Indexes were provided with 3 USD for completing the baseline survey. After uploading the syphilis test result, each alter received an online survey which collected questions on the relationship between the index and the alter, sociodemographic information, sexual behavior, the experience of receiving syphilis testing packages or links, testing history of syphilis, HIV and other STIs, and size of social network. At three-month follow-up, we invited all indexes to complete a brief online questionnaire that collected information on their experience of distributing syphilis testing packages or links, relationship between the indexes and the alters, reasons of unwillingness to distribute, history of syphilis, HIV and other STIs testing in the past three months; and sexual behaviors in the past three months. Potential adverse events such as forced testing, physical and/or verbal abuse, or causing mistrust from alters during the delivery procures were both asked from indexes and alters. Indexes were provided with 4 USD for completing the follow-up survey.