Online HIV prevention intervention on condomless sex among men who have sex with men: a web-based randomized controlled trial

BACKGROUND: Given the widespread use of the Internet among men who have sex with men (MSM) and high risk of Internet-facilitated sexual behaviors, Internet-based interventions to reduce sexual risk are urgently needed. METHODS: We recruited 1,100 participants from online and randomly assigned to two groups. One group received online HIV intervention services. Online HIV intervention was developed through mix-method formative research, measures included scenarios experiencing intervention and HIV information dissemination. Self-reported condomless anal sex with a male in the past three months was measured to evaluate the intervention effect. RESULT: Of the 1,100 participants, the majority were aged between 21 and 30 years old (62%), had a college degree or higher (80%), were single (88%), and self-identified as homosexual (78%). The estimated risk difference of condomless sex with a male in the past three months between groups was 9.3% (95% confidence interval (CI): 1.1, 17.5%). Using multiple imputations intention-to-treat, the estimated risk difference was 8.9% (95%CI: 1.2, 16.6%). Modification effects were found between intervention and characteristics including: educational attainment (p = 0.012), marital status (p = 0.005) and awareness of AIDS-related knowledge (p = 0.010). CONCLUSION: Internet appears to be a promising approach to disseminate HIV prevention amongst MSM. Interactive online intervention appeals to MSM and poses a great potential for reducing HIV risky behavior. TRIAL REGISTRATION: ChiCTR1800014260 (retrospectively registered 2 Jan, 2018). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12879-019-4251-5) contains supplementary material, which is available to authorized users.