Association of gross domestic product with equitable access to childhood vaccines in 195 countries: a systematic review and meta-analysis.

Introduction: Gross domestic product (GDP) has been shown to affect government spending on various budget heads including healthcare and the purchase and distribution of vaccines. This vulnerable situation has been exacerbated by the COVID-19 pandemic which disrupted and exposed the fragile nature of equitable access to vaccines for childhood immunisation globally. A systematic review and meta-analysis to assess the association of country income status and GDP with vaccination coverage of vaccines for childhood immunisation and other major infectious diseases around the globe will inform global and national policy on equity in living standards and vaccine uptake. This study was carried out to identify factors influenced by GDP that affect access, distribution, and uptake of childhood vaccines around the world using a systematic review and meta-analysis approach.

Methods: Data were extracted for the burden of major infectious diseases of childhood immunisation programmes, factors affecting access to vaccines, vaccine procurement platforms, vaccination coverage and percentage of GDP used for the procurement of vaccines. Factors influencing the global vaccination coverage rate were also assessed. The protocol was registered on PROSPERO (ID: CRD42022350418) and carried out using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results: Data from 195 countries showed that the following infectious diseases had the highest burden; human papillomavirus (HPV), measles, Ebola and yellow fever. Low-income and some lower-middle-income countries (LMICs) used COVAX and UNICEF for vaccine procurement while high-income countries (HICs) preferred national and regional public tenders. Global vaccination coverage for tuberculosis, diphtheria/tetanus/pertussis, hepatitis B, Haemophilus influenzae type b, measles, polio, meningitis and HPV had a significantly higher coverage than COVID-19. Being an HIC and having coverage data collected from 1985 to 2015 as the most current data were associated with high vaccination coverage. The percentage of GDP spent on vaccine procurement did not influence vaccination coverage.

Conclusion: Low-income countries and LMICs should prioritise vaccine research and improve on development capacity. Countries worldwide should share data on vaccine expenditure, vaccination coverage, and the development and introduction of new vaccines and technologies to facilitate equitable vaccine access.