Background: Pre exposure prophylaxis (PrEP) is recommended as part of combination prevention for individuals at high risk for HIV infection. Before initiating PrEP, individuals must test HIV negative to avoid including HIV positives, thereby preventing resistance, and assure adequate care. During early acute HIV infection (AHI), neither antibodies nor antigens can be detected by serologic tests, but virus is detectable with molecular methods. Therefore, some individuals with AHI may be enrolled in PrEP, as molecular methods are not included in conventional PrEP screenng. ┬┤ImPrEP┬┤ is a PrEP demonstration study to assess feasibility of daily oral PrEP provided to MSM and transgender people at risk for HIV in Brazil, Mexico and Peru.
Methods: Individuals with AHI were defined as those enrolling with a negative HIV rapid test (4thgeneration in Mexico and Peru, 3rd generation in Brazil) with detectable virus using molecular methods. At enrollment, all participants provide data related to potential factors for HIV acquisition (number of sexual partners, condomless anal sex, STIs, among others), use of post-exposure prophylaxis in the last year and signs or symptoms suggestive of AHI in the last 30 days. At enrollment, participants only receive 1 month of PrEP, to assure the exclusion of individuals with AHI.
Results: From January-December 2018, 3,433 individuals were enrolled, 2160 in Brazil, 702 in Mexico and 571 in Peru. Nine individuals with AHI were identified. The overall prevalence of AHI visit was 0.26%, of which 0.28% in Brazil, 0.35% in Peru and 0.14% in Mexico. All AHI cases had 2 or more HIV risk factors and 3/9 had used PEP in the last year. PrEP exposure was short (8 - 30 days). In Brazil, 5/6 started ART the day they stopped taking PrEP. In Peru and Mexico all the cases were referred to treatment and care facilities the day they stopped PrEP. Only one AHI case presented symptoms of potential acute infection at enrollment.
Conclusions: AHI is a rare event among ImPrEP participants, and initiation of PrEP the same day of screening is safe, only exposing those with AHI for a limited period, decreasing the theoretical risk of resistance.