Decomposition of wealth-related inequalities in childhood zero-dose vaccination : analysis of the 2016 Ethiopian demographic and health survey

Vaccination prevents 3.5-5 million deaths annually, yet inequities persist within low- and middle-income countries, including Ethiopia. Zero-dose children, those who have not received any routine vaccines, are often found in the poorest and most marginalized communities. In 2019, 16.3% of Ethiopian children aged 12-35 months were zerodose, highlighting persistent wealth-related disparities. The aim for the present study was to examine wealth-related inequalities in zero-dose status among Ethiopian children aged 12-23 months and identify key contributing factors. A secondary analysis of the 2016 Ethiopian Demographic and Health Survey was conducted, including 1,890 children aged 12-23 months. Zero-dose status was defined as not receiving the first dose of a diphtheria-, tetanus-, and pertussis-containing vaccine. Wealth-related inequality was measured using the Erreygers corrected concentration index (CnI), and contributing factors were assessed using Wagstaff decomposition analysis. Overall, 25.7% of children were zero-dose, with the highest prevalence among those whose mothers had no education, received no antenatal care (ANC), delivered at home, or lived in rural or pastoralist areas. The CnI (20.15; P <0.001) indicated that zero-dose children were disproportionately concentrated among poorer households. Low household wealth (36.5%) and a lack of ANC (33%) were the main contributors to inequality, followed by religion (22.3%), place of childbirth (10.2%), and maternal education (5.9%). Substantial wealth-based inequalities in zero-dose vaccination persist in Ethiopia. Expanding ANC coverage, prioritizing the poorest and most underserved populations through targeted outreach, and strengthening maternal education are essential to advancing immunization equity and achieving national and global immunization goals.