The influence of social and sexual networks in the spread of HIV and syphilis among men who have sex with men in Shanghai, China

Objectives: To analyze characteristics of social and sexual networks and their role as risk factors for HIV and syphilis among men who have sex with men (MSM) in Shanghai, China. Design: A cross-sectional study. Methods: We recruited 477 participants using a snowball sampling method. We administered a face-to-face questionnaire and provided testing and counseling for HIV and syphilis. Results: The prevalences of HIV and markers for syphilis were 1.47% (95% confidence interval [CI]: 0.59 to 3.01) and 13.47% (95% CI: 10.53 to 16.88), respectively. The independent factors associated with lower risk for syphilis infection were having a contact network, overlap of social and sexual networks, meeting other MSM at the gym or through the Internet, having 3 to 5 lifetime male anal sex partners, and having a female stead), sex partner. A larger male sexual network size, having been married, being more knowledgeable about HIV, having 6 or more lifetime male anal sex partners, and having steady male or female sex partners were independently associated with having unprotected anal or vaginal intercourse. Conclusions: Significant associations were found between network characteristics and syphilis infection and unprotected sex. Network-based interventions should be developed to reduce this HIV risk among MSM in China.