Use of gay app and the associated HIV/syphilis risk among non-commercial men who have sex with men in Shenzhen, China: a serial cross-sectional study

Objectives Geosocial networking application specific to men who have sex with men (MSM) (gay app) has revolutionised the social networking of MSM globally, much concern was raised over its linkage to HIV/syphilis risk. This study sought to examine the association between use of gay app and sexual behaviours and HIV/syphilis risk among Chinese MSM. Methods Eligible MSM were recruited through combined offline methods from 2015 to 2017 in Shenzhen, China, with data collected including demographics, sexual behaviours, app use, recreational drug use and HIV testing. All participants are required to sign a written informed consent and take a confidential HIV and syphilis testing. Results The prevalence of app use among non-commercial MSM (NcMSM) has rapidly increased from 12.5% in 2015 to 52.6% in 2017. The primary four apps used were Blued (97.2%), Aloha (18.4%), Jack'd (14.1) and Zank (14.1%). After controlling for confounders, HIV prevalence was still significantly lower among app users than non-app users (adjusted odds ratios [AOR]: 0.77, 95% CI 0.61 to 0.97), yet the lower prevalence of syphilis was not significant (AOR: 0.97, 95% CI 0.76 to 1.23). App-using NcMSM were more likely to be younger, unmarried, self-identified as homosexuality and having higher education level and income than non-app-using NcMSM. App-using NcMSM had higher rate of consistent condom use and HIV testing, higher level of knowledge on HIV/AIDS prevention and condom use; however, they were more likely to have multiple sexual partners, practice receptive role in anal sex and use recreational drug. Conclusions App-using NcMSM are more likely to have sexual risk behaviours as well as risk-reduction behaviours such as consistent condom use and HIV testing. Scaled-up and innovative venue-based HIV interventions are warranted for these high-risk MSM frequent social venues with less condom use and fewer HIV tests. Meanwhile, gay app should alternatively serve as an intervention and education platform for the MSM hard-to-reach via venue-based approaches.