Background Social apps provided important channels for people to communicate with each other. However, social network apps use also created a unique chance for casual partner seeking. This study aimed to know the situation of the using of social apps for partner seeking purpose among men who attend STDsclinics (MSCs) and to describe sexual behaviors among users.

Methods We conducted a cross-sectional study amongMSCs recruited from 9 cities in Guangdong, China from March to August in 2018. Data on socio-demographics, sexual behaviors and social app use for sex-seekingwere collected. Multivariable logistic regression models were used to identify the factors associated withpartner seeking through social apps.

Results A total of 1954 participants were recruited, with a mean age of 39.9 (SD: 13.9). Overall, 228 (11.7%) ever used a mobile app for partner-seeking. Among people seeking partner through social apps, 36.6% have one more partners, 14.0% met their partnersin-person within 24 hours, and 33.8% engaged incondomless intercourse with the last partner found through social apps. Only 27.2% of them negotiated about condom use before meeting in-person, and 12.3% asked for HIV status of the last partner before meeting in-person. Sex-seeking appsuse was positively associated with having casual partners in the last three months (aOR=3.5, 95%CI 2.6–4.7), everhaving anal sex with men (aOR=21.5, 95%CI 10.6–43.6), and not receiving HIV prevention services (aOR=7.9, 95%CI 5.6–11.3). Condomless intercourse with the last partner was positively associated with having more than three partners from app (aOR=5.0, 95%CI 1.9–13.2) and negotiating about condom use with the partner before meeting in-person (aOR=2.2, 95%CI 1.2–4.4).

Conclusion Social apps use has become an important sex-seekingroute among Chinese MSCs, which may facilitate the transmission of STDs. Social apps-based interventions are urgently needed.

Disclosure No significant relationships.