Mapping national and subnational zero-dose prevalence and multidimensional inequities across 77 countries

Zero-dose children remain a marker of populations unreached by routine immunisation, but national averages can obscure substantial subnational and multidimensional inequities. We analysed the most recent Demographic and Health Surveys and Multiple Indicator Cluster Surveys conducted between 2015 and 2024, including 170,553 children aged 12-23 months from 77 countries and 1,571 first-level administrative areas. Zero-dose prevalence ranged from 0.22% to 37.21% nationally, and 33 subnational areas had prevalence of at least 50%. Using the Vaccine Economics Research for Sustainability and Equity (VERSE) framework, we found that zero-dose children were consistently concentrated among multidimensionally disadvantaged groups, although the magnitude and drivers of inequity varied across countries. Maternal education, household wealth, geographic region, residence and health insurance were context-specific contributors. Combining burden, subnational distribution and multidimensional inequity can help identify where zero-dose children are concentrated and which barriers should be prioritised to advance equitable immunisation.