The association between human development index and COVID-19 vaccination coverage

The strategic deployment of COVID-19 vaccination is a cornerstone of the global pandemic response. However, equitable access to vaccines remains a critical challenge. This study was designed to investigate the association between COVID-19 vaccination coverage and the Human Development Index (HDI), and health system capacity at a global level. In this ecological study, data from 130 countries were analyzed. The dataset included the cumulative proportion of the COVID-19 fully vaccinated population, the HDI, its components (Life expectancy at birth, mean years of schooling, and Gross National Income (GNI) per capita), average routine vaccination coverage and universal health coverage (UHC), and World Bank income classifications. The associations between COVID-19 vaccination coverage, HDI, and its components were assessed using Spearman’s correlation coefficients and visualized with scatter plots Also, a multivariable linear regression model was done to control for confounders. A very strong positive correlation was observed between COVID-19 vaccination coverage and HDI ( r = 0.86, p < 0.001). Strong positive correlations were also found with the components of HDI: life expectancy at birth ( r = 0.84, p < 0.001), mean years of schooling ( r = 0.74, p < 0.001), and Gross National Income per capita ( r = 0.73, p < 0.001). When stratified by country income level, these correlations were most pronounced in lower-middle-income and upper-middle-income countries compared to low-income and high-income countries. In the multivariable model, HDI (β = 60.39, P = 0.003) and UHC (β = 0.91, P < 0.001) remained independent predictors, jointly explaining 76% of the between-country variation in COVID-19 vaccination coverage. HDI and UHC were strong independent predictors of COVID-19 vaccination coverage, indicating that equitable vaccine uptake depends on both socioeconomic development and health system capacity. Strengthening UHC, alongside long-term investments in education, health, and social development should be central to future pandemic preparedness and global vaccination strategies, particularly in low- and middle-income countries.