How does the vaccine approval procedure affect COVID-19 vaccination intentions?

People's willingness to vaccinate is critical to combating the COVID-19 pandemic. We devise a representative experiment to study how the design of the vaccine approval procedure affects trust in newly developed vaccines and consequently public attitudes towards vaccination. Compared to an , choosing the more thorough approval procedure increases vaccination intentions by 13 percentage points. The effects of the increased duration of the approval procedure are positive and significant only for . Treatment effects do not differ between relevant subgroups, such as respondents who had (did not have) COVID-19, or between vaccinated and unvaccinated respondents. Increased trust in the vaccine is the key mediator of treatment effects on vaccination intentions.