(P257) Sexual Network Characteristics and Partnership Types among Men Who Have Sex With Men Diagnosed With Syphilis, Gonorrhea, and/or Chlamydia in Lima, Peru

Background: Sexual networks are known to structure STI transmission among men who have sex with men (MSM). Less is understood about how partnership types within these networks contribute to risk of transmission for different STIs.



Methods: We analyzed data from 810 MSM screened May-December 2022 for a partner management intervention in Lima, Peru. Participants were tested for HIV, syphilis, gonorrhea (GC) and chlamydia (CT). Syphilis diagnoses included review of treatment history and prior RPR titers. Participants completed surveys on their demographics, sexual identity/role, HIV status, partnership types, and sexual network from the prior 3 months. Chi-square and Wilcoxon Rank-Sum tests compared participants without STI to those diagnosed with 1) syphilis, 2) GC/CT, and 3) syphilis and GC/CT co-infection.



Results: 40.5% (n=328/810) of participants were diagnosed with an STI (syphilis: 15.2%, GC/CT: 15.6%, co-infection: 9.8%). Half of all participants were living with HIV, of whom 9.4% were newly diagnosed. A greater proportion of participants with syphilis and co-infection were known to be living with HIV (72.0%, p< 0.001; 66.0%, p< 0.001) compared to those with GC/CT (51.0%) or no STI (42.0%). All STI groups were more likely to report more single-encounter casual partners and endorse their sexual role as pasivo (receptive) or moderno (versatile) (46.0%, p=0.005; 48.0%, p=0.023) and their partner as activo (insertive) (64.0%, p=< 0.001) compared to those without STI (36.0%). Participants with GC/CT were younger, more frequently met casual partners online (77.0% vs. 62.0%, p=0.006), and less frequently drank alcohol prior to sex with casual partners (19.0% vs. 32.0%, p=0.012) than men without an STI. Compared to those without an STI, participants with co-infection reported more anonymous partners per visit to sex-on-premises venues (median (IQR)= 3 (2-6), p=0.002).



Conclusions: Peruvian MSM diagnosed with an STI reported more casual partners and more often endorsed moderno or pasivo roles with activo partners. Younger age, contacting partners online, and less frequent alcohol use were associated with higher prevalence of GC/CT. Syphilis and co-infection were more common among participants living with HIV with larger sexual networks of casual and anonymous partners. These findings demonstrate how partnership types differentially assign STI risk and suggest possible interventions.