Since the Alma Ata Declaration of 1978, countries have varied in their progress towards establishing and sustaining comprehensive primary health care (PHC) and realizing its associated vision of ‘Health for All’. International health emergencies such as the coronavirus-19 (COVID-19) pandemic underscore the importance of PHC in underpinning health equity, including via access to routine essential services and emergency responsiveness. This review synthesizes the current state of knowledge about PHC impacts, implementation enablers and barriers, and knowledge gaps across the three main PHC components as conceptualized in the 2018 Astana Framework. A scoping review design was adopted to summarize evidence from a diverse body of literature with a modification to accommodate four discrete phases of searching, screening and eligibility assessment: a database search in PubMed for PHC-related literature reviews and multi-country analyses (Phase 1); a website search for key global PHC synthesis reports (Phase 2); targeted searches for peer-reviewed literature relating to specific components of PHC (Phase 3) and searches for emerging insights relating to PHC in the COVID-19 context (Phase 4). Evidence from 96 included papers were analysed across deductive themes corresponding to the three main components of PHC. Findings affirm that investments in PHC improve equity and access, healthcare performance, accountability of health systems and health outcomes. Key enablers of PHC implementation include equity-informed financing models, health system and governance frameworks that differentiate multi-sectoral PHC from more discrete service-focussed primary care, and governance mechanisms that strengthen linkages between policymakers, civil society, non-governmental organizations, community-based organizations and private sector entities. Although knowledge about, and experience in, PHC implementation continues to grow, critical knowledge gaps are evident, particularly relating to country-level, context-specific governance, financing, workforce, accountability and service coordination mechanisms. An agenda to guide future country-specific PHC research is outlined…more