P569 Seroadaptive behaviors influenced by partner-level and environmental-level factors among IPREX participants

Background Seroadaptive behaviors to decrease risk of HIV acquisition and transmission is based on the knowledge of one’s own serostatus and that of one’s sexual partners. Partner-level and environmental-level attributes may affect seroadaptation practices. We characterized seroadaptive behaviors among iPrEX participants. Methods Men who have sex with men (MSM) and transgender women (TGW) were recruited from eleven study sites in the US, Peru, Brazil, Ecuador, Thailand and South Africa. Partnership-level data were collected at the screening visit for the 3 most recent sexual partners. Participants who reported knowing their partner was HIV-negative or did not have receptive anal intercourse were considered to be practicing seroadaptive behaviors. Results Of the 2,095 iPrEX participants, 1,271 (61%) reported seroadaptive behaviors with all partners, 544 (26%) with some partners and 280 (13%) did not practice seroadaptation with any partners. Participants in steady relationships (aOR=1.45; p=0.005), who felt closer to their partner (aOR=1.08; p=0.013) and from US (aOR=3.33; p Conclusion Seroadaptive behaviors were more commonly observed among iPrEX participants with partners they felt closer and more committed to. Seroadaptive behaviors were also more common among participants from study sites in North and South America compared to Africa and Asia. These geographic differences may reflect greater access to HIV testing in these areas, thereby facilitating awareness of HIV status and enabling engagement in seroadaptation practices. TGW have fewer options than MSM to be classified as practicing seroadaptive behaviors since most engage in receptive sexual positioning. Our findings suggest that seroadaptive practices are influenced by the level of commitment to and emotional intimacy with partners. Disclosure No significant relationships.