BackgroundVaccine equity has been a major concern during the COVID-19 pandemic. According to the principle of vaccine equity, donor countries should apply the criterion of needs to make decisions about vaccine donation instead of considering recipient countries’ economic status. We examine whether people follow the same criterion or consider other factors to decide which country to donate vaccines and how many vaccines should be delivered.MethodsWe conducted online surveys with the design of conjoint experiment in the United States and Taiwan in 2021. 1,532 American citizens and 1,587 Taiwanese citizens were interviewed. The respondents were broadly quota-matched to their respective demographic proportions on the dimensions of age, gender, and education. We estimated the average marginal component effects (AMCEs) of the conjoint attributes by using the OLS regression models with standard errors clustered at the respondent level.Results15,320 and 15,870 decisions on vaccine donation generated by conjoint experiment respectively in the United States and Taiwan were included in the analysis. Both American and Taiwanese people tend to donate vaccines to countries that suffer severe consequences of COVID-19 and democracies compared to authoritarian countries. However, they are less willing to donate vaccines to those with higher levels of capability in response to COVID-19. Taiwanese people tend to donate vaccines to countries having formal diplomatic relations with Taiwan (AMCE 13.4%, 95% CI 11.8%-15.1%). Nonetheless, American people would rather donate vaccines to countries without formal diplomatic relations with the United States (AMCE − 4.0%, 95% CI -5.6%--2.4%).ConclusionsThe findings reveal that politics plays a significant role in people’s decisions about vaccine donation. Under electoral pressure, political leaders must think about how to respond to the public’s preferences over vaccine donation to achieve vaccine equity and address the global health crisis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12992-023-00940-x.