Presentation (CTI)

OBJECTIVES: Despite significant advances in vaccine development, achieving equitable access, particularly in low- and middle-income countries (LMICs), remains challenging. Here we aim to identify persistent systemic barriers to vaccine access, delivery and uptake in LMICs by synthesizing evidence across diseases, geographies and immunization programmes.
METHODS: A targeted literature review spanning 2016-2026 was conducted using PubMed, focusing on peer-reviewed systematic, scoping and narrative reviews of vaccination in LMICs. Included studies were screened for predefined barrier domains (economic, health-system capacity, policy/regulatory, supply, data gaps and sociopolitical factors), with findings analysed descriptively. Of 346 abstracts screened, 92 studies were included.
RESULTS: Most studies adopted a multiregional approach, commonly covering Africa, Latin America (LATAM) and Asia Pacific (APAC), and examined barriers across multiple vaccines; where analyses focused on individual vaccines, HPV and COVID-19 were most studied. The most frequently reported barriers were cost (60.9%), health infrastructure (58.7%) and supply (54.3%), followed by workforce (47.8%) and cold chain/storage (45.7%). Procurement, transport and policy barriers were reported less often (27-29%). Least frequently reported barriers included limited local epidemiological data (17.4%), vaccine nationalism (prioritizing vaccines for domestic use; 14.1%), lack of cost-effectiveness data (9.8%) and regulatory constraints (8.7%). When stratified, cost was the most frequently reported barrier for HPV, rotavirus and influenza; regionally, cold chain and workforce were the most prominent barriers in Africa and APAC, whereas barriers of cost and health infrastructure were most common in LATAM.
CONCLUSIONS: Barriers to vaccine access in LMICs can be driven by upstream systemic constraints, particularly financing, health-system capacity and supply-chain limitations. Expanding local vaccine production in LMICs may improve supply but can shift bottlenecks to technology transfer, manufacturing capacity and sustainable financing. Coordinated, regionally aligned strategies that integrate local manufacturing, technology sharing and health-system investment may improve equitable access, alongside greater emphasis on local data generation, regulatory strengthening and sociopolitical factors.