Factors influencing PrEP adoption in sexual health clinics within Ontario's public health system: a qualitative study using the Consolidated Framework for Implementation Research (CFIR).

Introduction: HIV pre-exposure prophylaxis (PrEP) utilization in Ontario is concentrated in two large urban centers, resulting in geographic and structural inequities in access. Little is known about adoption in Public Health Sexual Health Clinics (PHSHCs) or the implementation factors influencing uneven uptake. This study aimed to: (1) assess the extent of PrEP adoption in PHSHCs; (2) identify barriers and facilitators affecting implementation; and (3) explore factors supporting successful and equitable PrEP implementation. Methods: Semi-structured interviews were conducted with 18 staff and managers across 12 PHSHCs. The Consolidated Framework for Implementation Research (CFIR) guided data collection and analysis, while the Health Equity Implementation Framework (HEIF) was applied to examine structural, organizational, and socio-cultural influences on PrEP access. Clinics were categorized into five adoption categories using the diffusion of innovations model. A content analysis was done to identify common facilitators, barriers, and equity-relevant factors distinguishing clinics at different adoption categories. Results: PrEP adoption varied widely across clinics. Two were innovators, providing on-site PrEP; three were early adopters with formal referral pathways; four were early majority, relying on informal referrals; and five lacked established services. Facilitators included strong PrEP knowledge and beliefs, inter-organizational partnerships, and supportive organizational cultures. Key barriers were post-COVID-19 service recovery constraints, limited external prescribers, insufficient medication funding, constrained internal capacity, and social individual-level barriers. Differences between advanced and less advanced adopters reflected perceived relative advantage of PrEP within PHSHC mandates, workflow integration complexity, and the presence of a supportive learning climate. Equity-focused analysis highlighted obstacles affecting clients experiencing socioeconomic disadvantage, rurality, stigma, and limited healthcare navigation capacity. Conclusion: This study highlights that inequities in PrEP access across Ontario PHSHCs are shaped not only by clinic readiness but also by broader structural and organizational conditions. These findings advance understanding of PrEP adoption outside large urban centers, identifying barriers and strategies to expand services and enhance implementation readiness. Using the CFIR and HEIF, we delineated factors to support adoption in early-stage PHSHCs while learning from those with successful integration. Addressing these factors will be critical to expanding equitable access to PrEP and advancing HIV prevention goals.