Inequities and trends of polio immunisation among children aged 12-23 months in Ethiopia: a multilevel analysis of Ethiopian demographic and health survey.

Introduction: Despite Ethiopia's policy intention to provide recommended vaccination services to underprivileged populations, inequity in polio immunisation persists.

Objective: This study examined inequity and trends in polio immunisation and determinant factors among children aged 12-23 months in Ethiopia between 2000 and 2019.

Methods: Cross-sectional data from 2000, 2005, 2011, 2016 and 2019 Ethiopian demographic and health surveys were analysed with the updated version of the WHO's Health Equity Assessment Toolkit software. Six standard equity measures: equity gaps, equity ratios, population attributable risk, population attributable fraction, slope index of inequality and relative index of inequality were used. Datasets were analysed and disaggregated by the five equality stratifiers: economic status, education, place of residence, sex of the child and regions. Multilevel logistic regression analysis was used to identify determinant factors.

Results: Polio immunisation coverage was increased from 34.5% (2000) to 60.0% (2019). The wealth index-related inequity, in coverage of polio immunisation between quintiles 5 and 1, was 20 percentage points for most surveys. The population attributable risk and population attributable fraction measure in 2011 indicate that the national polio immunisation coverage in that year could have been improved by nearly 36 and 81 percentage points, respectively, if absolute and relative wealth-driven inequity, respectively, had been avoided. The absolute difference between Addis Ababa and Afar Region was 74 percentage points in 2000 and 60 percentage points in 2019. In multilevel analysis result, individual-level factors like wealth index, maternal education antenatal care and place of delivery showed statistical significance.

Conclusion: Although polio immunisation coverage gradually increased over time, in the 20-year survey periods, still 40% of children remained unvaccinated. Inequities in coverage by wealth, educational status, urban-rural residence and administrative regions persisted. Increasing service coverage and improving equitable access to immunisations services may narrow the existing inequity gaps.