Inequality in COVID-19 vaccine acceptance and uptake: A repeated cross-sectional analysis of COVID vaccine acceptance and uptake in 13 countries.

Background COVID-19 vaccine hesitancy was a key barrier to ending the pandemic via mass immunisation. Objectives Assess magnitudes and differences in socioeconomic inequality in stated COVID-19 vaccine acceptance (hesitancy) and uptake. Methods Online surveys were conducted in 13 countries, collecting data from 15,337 and 18,189 respondents respectively. The investigation compares socioeconomic inequality in reported vaccine acceptance, measured in 2020-21 and subsequent uptake of vaccination in 2022. Inequalities are quantified using differences, ratios and the Erreygers adjusted concentration index. A regression decomposition approach is used to identify factors associated with inequality. Results Mean uptake levels were 87 %, while acceptance was lower at 77 %. The difference between the richest and the poorest quintile was as large as 23 percentage points in acceptance and 30 p.p. in uptake, both observed in France. Acceptance and uptake were pro-rich (regressive) in most countries. Nine countries reported pro-rich inequality in acceptance, and eight in uptake. Uptake was significantly less regressive than acceptance in Australia, China, India, and USA. Australia and Colombia were the only countries where vaccination uptake was pro-poor (progressive). Age, marital status and political ideology were correlated with socioeconomic inequalities in several countries in both waves, while gender and education were associated with acceptance, and health levels with uptake. Conclusion We found significant inequalities in vaccination acceptance and uptake across countries but inequality was generally lower in vaccine uptake than in acceptance. This suggests that inequalities can be reduced over time if adequate policies are in place to overcome hesitancy and reduce inequalities.