Mapping Risk and Opportunity: A Space-Based Affiliation Network Analysis of Physical and Virtual Spaces Among High Risk Men

Background: Social and sexual networks, particularly the spaces where men who have sex with men (MSM) meet and interact, play a crucial role in shaping HIV risk and prevention behaviors. However, few studies have leveraged venue-level data to optimize the reach of targeted interventions in China. Methods: We conducted a venue-based social network analysis among 301 MSM recruited through online platforms and time-location sampling in a major metropolitan area. Participants identified social spaces they frequented, including both physical venues and digital platforms. We characterized these spaces based on HIV risk behaviors, STI prevalence, and preexposure prophylaxis–related indicators, and applied centrality and Key Player analyses to identify high-impact spaces for intervention reach. Results: MSM reported visiting an average of 2.9 spaces, with high prevalence of condomless anal sex (81.7%) and hazardous drinking (42.2%). We identified 23 key venues, including 6 newly nominated by participants. Blued and WeChat emerged as the most influential spaces, collectively connecting 91.4% of MSM and 100% of other social spaces. Risk levels varied widely across venues, with certain spaces exhibiting elevated rates of HIV and syphilis. Importantly, participants reached through key venues showed significantly higher PrEP awareness and willingness. Conclusion: Strategic engagement of high-centrality venues, especially popular virtual platforms, can substantially enhance the coverage and equity of HIV prevention efforts among MSM. Venue-level network analysis is a valuable tool to prioritize and tailor public health interventions.