Strategies for enhancing vaccine uptake among children under two years of age in low and middle-income countries (LMICs):A scoping review

Introduction Over 14.5 million infants remain unvaccinated globally, predominantly in low- and middle-income countries (LMICs), where health system gaps and inequities impede progress toward the Immunisation Agenda 2030. Objective This scoping review synthesised health system strengthening strategies aligned with the WHO Health Systems Framework to enhance vaccine uptake among children under two years of age in LMICs. Methods Following the PRISMA-ScR guidelines, six databases were searched until January 2025. Results Of 2897 records, 53 studies met the inclusion criteria: 54.7% from lower-middle-income and 41.5% from low-income countries, with 81.1% being community-based interventions. The mean intervention duration was 39.3 months (SD = 62.1). Health information systems (83.0%), leadership and governance (79.2%), and service delivery (60.4%) were the most frequently targeted, while the health workforce was the least addressed (35.8%). The key strategies included data monitoring (88.7%), coverage tracking (86.8%), and data-driven decision-making (86.8%). Community-centred, data-informed interventions improved service accessibility (67.9%) and quality (41.5%). Conclusion Multiple interventions addressing multiple WHO building blocks have demonstrated better outcomes. Strengthening workforce capacity, adopting an integrated health system approach, and addressing financing barriers are essential for achieving the Global Immunisation Agenda 2030.