Characteristics and rates of infection by HIV in people receiving non-occupational post-exposure prophylaxis (nPEP) against HIV

Introduction/objectives: The use of non-occupational post-exposure prophylaxis (nPEP) emerges as a strategic intervention to reduce HIV infection risk following sexual encounters in our setting. Notwithstanding, there is a scarcity of contemporary data regarding adherence to this treatment, its effectiveness and tolerance. Our study aims to delve into these factors among individuals who have resorted to nPEP after high-risk sexual encounters.

Methods: We conducted a retrospective observational study of cases administered nPEP for HIV from 1 January 2018 to 31 December 2021 at a tertiary hospital in Madrid. The study included all adults over 18 years who sought care at the emergency department of the Fundación Jiménez Díaz Hospital following a risky sexual encounter and were subsequently recommended HIV nPEP treatment.

Results: 878 individuals received nPEP for HIV and underwent initial serological tests. Of these, 621 had comprehensive follow-ups. The prescribed regimen for all was raltegravir (RAL) 1200 mg combined with tenofovir/emtricitabine (TDF/FTC) 245/200 mg daily for 28 days. The study revealed a 1.1% rate (n=10) of previously undetected infection and a 0.16% (n=1) failure rate of nPEP. Regarding regimen tolerability, 5.6% (n=35) experienced symptoms linked to the treatment, yet none necessitated discontinuation of the regimen. On the contrary, six per cent (n=53) reported symptoms consistent with an STI during one of the medical visits; specifically, 4.4% had urethritis, and 1.6% had proctitis.

Conclusion: nPEP with RAL/TDF/FTC demonstrates high efficacy and safety, contingent on proper adherence. There is an observed increase in STI prevalence in this cohort, with nearly half of the participants not engaging in appropriate follow-up after initiating nPEP.