Incidence and Clinical, Virological, and Resistance Characteristics of HIV Infections Among pre-Exposure Prophylaxis Users in Spain (SCOPE Study): A Multicentre Prospective and Retrospective Cohort Study.

BACKGROUND

Implemented in Spain in 2019, pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention strategy that reached an estimated 28,800 users by 2024. We aimed to address HIV incidence and characteristics in PrEP users.

METHODS

Ambispective observational cohort study conducted across 12 centers in Spain. Data from adults diagnosed with HIV who had used oral PrEP within six months prior to seroconversion were collected from August 2024 to March 2025. Main outcomes were HIV incidence among PrEP users, and clinical, virological, and drug resistance characteristics at diagnosis for all cases, as well as 12-month follow-up data for retrospective cases.

FINDINGS: Until March 2025, 53 seroconversions occurred among 19,884 PrEP users, yielding an incidence of 0.06 cases per 100 person-years (95% CI: 0.01-0.15). Most individuals were cisgender men who have sex with men (91%), median age of 32 years [IQR:27-37], and from Latin America (31/52; 60%) or Spain (17/52; 33%). Chemsex was reported by 24 (45%), and 49% had a concomitant sexually-transmitted infection. Daily emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) was the most frequent regimen (36/50; 72%). PrEP interruptions occurred in 71% (32/45) and 42% (15/36) had suboptimal adherence. Time on PrEP at diagnosis was 8 months [IQR:3-19] and time from last negative to first positive HIV test 3.6 months [IQR:2.7-9.3]. Baseline median viral load (VL) was 14,917 copies/mL [IQR:825-221,000]. Resistance testing was successful in 90% of individuals (44/49), with nucleos(t)ide reverse transcriptase inhibitor-related substitutions detected in 41% (18/44), mainly M184V/I. Thirty-five retrospective cases completed 1-year follow-up, with VL suppression of 87% (20/23) at 12 months.

INTERPRETATION: PrEP interruptions and/or poor adherence were very prevalent. Most cases were migrants and chemsex use was frequent. Resistance substitutions were frequently found. Despite overall low HIV incidence, some subgroups of PrEP users require additional interventions to prevent HIV.

FUNDING: ISCIII (PI23/00355).