Rising rates of recent PrEP exposure among MSM newly diagnosed with HIV: antiviral resistance patterns and treatment outcomes

INTRODUCTION: Pre-exposure 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: 52/1030 (5%) individuals reported recent PrEP exposure at HIV diagnosis; 98% were MSM, median age 34 years (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. 33/52 (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). M184 V 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 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 M184 V mutation harboured in those newly diagnosed with HIV and reporting recent PrEP exposure