Rising rates of recent preexposure prophylaxis exposure among men having sex with men newly diagnosed with HIV: antiviral resistance patterns and treatment outcomes

Introduction: Preexposure prophylaxis (PrEP) is contributing to achieve a reduction in HIV diagnoses in men having sex with men (MSM). Albeit infrequent, HIV infections in the context of recent PrEP exposure represent a clinical challenge. Methods: Data on recent PrEP use and possible reasons leading to HIV infection were analysed in individuals newly diagnosed with HIV at 56 Dean Street clinic in 2016-2020. Demographics, immune-virological parameters, genotypic resistance test results and treatment management in this group were compared with those not reporting recent PrEP exposure using Mann-Whitney U test and Fisher's exact test. Results: Fifty-two of 1030 (5%) individuals reported recent PrEP exposure at HIV diagnosis; 98% were MSM, median age 34 years (interquartile range [IQR] 28-42), 65% of white ethnicity, 65% non-UK-born. 35% reported PrEP intake the day before testing HIV positive, 46% reported sub-optimal PrEP adherence since their last negative HIV test result. Thirty-three of 52 (63%) were self-sourcing PrEP and 9/52 (17%) reported issues with its supply. Recent PrEP use was associated to lower HIV viral load and higher CD4(+) cell count at baseline than in counterparts non-recently exposed to PrEP (P < 0.01). M184V mutation was harboured more commonly in the recent PrEP use group (30% vs. 1%, P < 0.01). The proportion of individuals recently exposed to PrEP among those diagnosed with HIV rose sharply, reaching 21% in the first semester of 2020. Viral suppression was achieved by all patients intensified from PrEP to antiretroviral treatment (ART) who remained in care at week 24. Discussion: Rapid PrEP intensification to ART allowed to achieve high rates of HIV viral suppression despite significant rates of M184V mutation harboured in those newly diagnosed with HIV and reporting recent PrEP exposure.