Abstract Body

Gay, bisexual, and other men who have sex with men (GBM) in Brazil remain disproportionally affected by HIV despite the availability of prevention and treatment. We sought to estimate the clinical benefits of increasing the uptake of publicly funded, daily, oral tenofovir/emtricitabine (TDF/FTC) for pre-exposure prophylaxis (PrEP).

We used the Cost-Effectiveness of Preventing AIDS Complications (CEPAC) model to assess the impact of increasing PrEP uptake to different levels (range 10-60%) across various timelines (within 1-4 years) in a cohort of adult (?18 years) GBM without HIV. We used local studies, national data, and the international literature to represent the HIV epidemic in three Brazilian cities: Rio de Janeiro (Southeast), Salvador (Northeast), and Manaus (North). Age-stratified HIV incidence rates were highest in Rio de Janeiro (4.3/100 person-year (PY), 2.5/100PY in Salvador and 1.4/100PY in Manaus); PrEP efficacy was 96%, and adherence was 74%. Outcomes included HIV infections, with and without PrEP, over 5 and 10 years. In sensitivity analyses, we examined how results varied with changes in adherence to PrEP (range 50-85%), drop-out rates (range 0-25%/year), and age at initiation of PrEP (21-33 years). We also estimated the PrEP uptake level needed to reach a 75% incidence reduction in 5 years.

We found that a PrEP intervention achieving 10% uptake among GBM within 60 months could avert 501 infections in Rio de Janeiro (Salvador: 161, Manaus: 119) by 5 years. An intervention achieving 60% uptake among GBM within 24 months would avert ~10-times as many infections (35.9% incidence reduction in Rio de Janeiro, 37.8% in Salvador, and 38.9% in Manaus). In sensitivity analyses, increasing PrEP adherence to 85% would increase the number of averted infections by 14%; decreasing adherence to 50% would reduce averted infections by 31%. If the cohort mean age decreased to 21 years at PrEP start, then averted infections increased by 42%, while including drop-out rate decreased the transmission impact of PrEP. To reach 75% incidence reduction in 5 years, a PrEP intervention would need to achieve 80% uptake among GBM over 36 months.

Increased oral PrEP uptake in Brazil would substantially decrease HIV transmission over the next 5 to10 years. PrEP uptake would need to be extremely high to achieve a proposed target of 75% incidence reduction within 5 years.