Resumen

Although cisgender MSM (cis-MSM) and transgender women (TGW) suffer the highest burden due to the HIV epidemic in Latin America (LA), PrEP implementation is limited. ImPrEP was an implementation study to assess safety and feasibility of same-day PrEP initiation (daily-oral TDF/FTC) for cis-MSM and TGW vulnerable to HIV infection in Brazil, Peru and Mexico; results on factors associated with long-term PrEP engagement (LTPE) and HIV incidence are reported here. Eligible cis-MSM and TWG (HIV-negative, ?18 years- old, reporting 1+ risk criteria) were screened and enrolled on the same-day, receiving a 30-day PrEP supply. Follow-up visits were scheduled at week 4 after enrollment and quarterly thereafter. Main outcomes were LTPE (3+ follow-up visits within 52 weeks of enrollment) and HIV incidence. A multivariable model controlling for country, education, gender, substance use, STIs, and self-reported adherence is presented. From March 2018-June 2021, 9522 participants were enrolled (Brazil: 3928, Mexico: 3301, Peru: 2293), with 12348.92 person-years (PY) follow-up; follow-up time accrued for LTPE analysis affected by Covid-19 restrictions was shorter in Brazil than in Mexico and Peru. Overall, 26% were aged 18-24, 94.3% cis-MSM, 5.7% TGW, 73.2% non-white and 76.0% >secondary education; 92.8% reported condomless anal sex (CAS), 17.3% sex-work, 57.8% had >5 sex partners. Overall, 8.8% attended only the enrollment visit and 68.2% showed LTPE (Brazil:80.1%; Mexico:67.2%; Peru:45.0%). Participants aged 18-24 years (aOR 0.53[95%CI:0.46-0.62]), 10 sex partners (aOR 1.48[95%CI:1.28-1.70]), reporting receptive CAS (aOR 1.24[95%CI:1.12-1.39]), complete adherence at week-4 (aOR:3.11[95%CI:2.79-3.45]) and CAS with HIV+ partner (aOR:1.48[95%CI:1.28-1.71]) were more likely. HIV incidence was 0.84/100 PY (95% CI:0.69-1.02), higher in Peru, among TGW and 18-24 years-old participants. Same-day PrEP is feasible and safe among cis-MSM and TGW in LA. Overall LTPE was high; COVID-19 restrictive measures may partially explain the differences across countries. Social and structural levels of HIV risk need to be addressed for full PrEP benefits realization.