Characterizing subgroups of sexual behaviors among men who have sex with men eligible for, but not using, PrEP in the Netherlands.

This study identified subgroups of sexual behaviors associated with increased STI/HIV risk among those eligible for but not using pre-exposure prophylaxis (PrEP) in order to improve PrEP uptake and prioritization in the context of restricted capacity. We used data from sexual health centers (SHCs) in the Netherlands, including all visits of eligible but non-PrEP using men who have sex with men (MSM), men who have sex with men and women (MSMW) and transgender persons between July 2019 (start of the Dutch national PrEP pilot (NPP)) and June 2021. Using latent class analysis (LCA), we identified classes of sexual behaviors (number of partners, chemsex, group sex and sex work) and explored whether these classes were associated with STI diagnosis and sociodemographics. Across 45,582 visits of 14,588 eligible non-PrEP using individuals, the best fitting LCA model contained three classes of sexual behaviors. Classes were distinguished by seldomly reported sexual behaviors (class 1; 53.5%, n = 24,383), the highest proportions of ≥6 partners and group sex (class 2; 29.8%, n = 13,596), and the highest proportions of chemsex and sex work (class 3; 16.7% of visits, n = 7,603). Visits in classes 2 and 3 (vs. class 1) were significantly more often with individuals who were diagnosed with an STI, older (≥36 vs. ≤35 years), MSMW (vs. MSM), and visiting an urban (vs. non-urban) SHC; while these visits were significantly less often with individuals from an STI/HIV endemic area. The percentage of visits at which an STI was diagnosed was 17.07% (n = 4,163) in class 1, 19.53% (n = 2,655) in class 2 and 25.25% (n = 1,920) in class 3. The highest risk of STI, and thereby HIV, was in those engaging in specific subgroups of sexual behavior characterized by frequently reporting multiple partners, group sex, sex work or chemsex. PrEP uptake should be encouraged and prioritized for these individuals.