begun in that country, the question asked was “ _If an approved vaccine to prevent COVID-19 was to become available at no cost, would you agree to be vaccinated?_ ” In surveys that took place after the vaccine rollout had begun, the wording of the question was either “ _Are you planning to be vaccinated?_ ” or “ _When a vaccine to prevent COVID-19 is available to you, are you planning to be vaccinated?”_ In the sample, 47 countries offered three answer options (yes, not sure, and no), while the other six offered only two categories (yes and no). For this analysis, we combine the “no” and “not sure” answers to obtain the measure of vaccine hesitancy.

To obtain the respondent’s reason for vaccine hesitancy, survey respondents who answered “no” or “not sure” were asked “ _What is your (main) reason/concern for not wanting to be vaccinated / not being sure if you want to be vaccinated_ ?” The answer categories varied widely across surveys. To make these more comparable across countries, answers were remapped into the following nine most common categories (see Appendix Tables 2a and 2b for the original answer options in each survey and a mapping of how they were harmonized):

1. Safety, which includes concerns about side effects

2. Efficacy 3. Distrust of government, pharmaceutical industry, international community 4. Dislike of vaccines in general 5. Preference for natural immunity, which included perceiving self as low risk and already having had COVID-19 infection 6. Lack of knowledge or access, which included “I do not have enough information about the vaccine,” “too hard to get,” “health facility to far” and “I don’t have the time” 7. Religious reasons 8. Not eligible, which included “counter-indication,” “recent medical discharge, “have an underlying health condition and believe taking the vaccine will make it worse” 9. Other The surveys also differed across countries in terms of whether a single concern or multiple concerns were collected. To account for the difference in the number of response options, the results are presented separately.

# _2c. Contextual data_

Country-level contextual data were drawn from other sources. New COVID-19 cases per million, measured as a 7-day rolling average prior to the midpoint of the month household survey data was collected in each country, were obtained from Dong and colleagues (2022), and the Oxford Stringency Index was drawn from Hale et al. 2022. The latter is an index, ranging from 0–100, that indicates the degree to which various restrictions were put in place by governments to control the pandemic (for example, school closures and shelter-in-place requirements). Confidence in the press, the government, and the WHO was drawn from the World Values Survey Wave 7, fielded in 2017-2020, and aggregated up to the country level (Inglehart 2022). Excess deaths due to COVID-19 draw on WHO data (WHO 2022). Country geographic region and income group are based on the World Bank classifications.

# _2d. Analytical strategy_

Data from 53 countries was pooled into a single data set. First, we report point estimates and 95% confidence intervals for each country based on standard errors clustered at the state or province level within each country. We also report the simple average across all countries and stratified by: (i) World Bank region, (ii) World Bank country income group, (iii) urban vs. rural residence, (iv) gender of the 6