Barriers to and facilitators of the implementation of Community Health Worker programmes in high-income countries: a systematic review

BACKGROUND: Global interest in Community Health Workers (CHWs) is rising as health systems seek to address persistent health inequities and the social determinants of health. However, in high-income countries (HICs), CHW implementation remains fragmented. This systematic review synthesises evidence on the factors that act as barriers and facilitators to the implementation and integration of CHW programmes across HIC primary healthcare settings. METHODS: We searched MEDLINE, Scopus, PsycINFO, and CINAHL for studies published between January 2001 and August 2025. Inclusion focused on qualitative, quantitative, and mixed-methods papers regarding CHW implementation in HICs. Methodological quality was appraised using the Mixed Methods Appraisal Tool (MMAT). Data were synthesised using a 'Best Fit' Framework Synthesis and confidence in the findings was assessed via GRADE-CERQual. RESULTS: Seventy-two papers were included (US n = 64; UK n = 4; Australia n = 3; Belgium n = 1), primarily comprising qualitative and mixed methods designs. Key facilitators included leadership buy-in, the presence of implementation champions, and established community partnerships that enabled resource sharing. Prominent barriers included precarious, short-term funding models that prioritised quantitative outputs over relational labour; hierarchical medical power dynamics; and disconnected IT systems that necessitated redundant data entry. The COVID-19 pandemic acted as a catalyst, elevating the CHW role within public health infrastructure while simultaneously exposing digital divides and structural fragility. GRADE-CERQual ratings indicated high confidence in findings regarding funding sustainability, training, and integration. CONCLUSIONS: The evidence synthesised in this review reveals a fundamental misalignment within current health services: while CHWs are valued for their unique relational capacity, they remain systemically undermined by transactional health system designs. Achieving sustainability requires a strategic shift toward long-term, flexible funding models and the workforce development of supportive infrastructure, including reflective supervision and standardised training. Integration must move beyond short-term, project-based initiatives toward a resilient and permanent public health workforce capable of addressing structural health inequities. TRIAL REGISTRATION: PROSPERO: CRD42022310789.