We discuss the relationship between expertise, expert authority, and trust in the case of vaccine research and policy, with a particular focus on COVID-19 vaccines. We argue that expert authority is not merely an epistemic notion, but entails being trusted by the relevant public and is valuable if it is accompanied by expert trustworthiness. Trustworthiness requires, among other things, being transparent, acknowledging uncertainty and expert disagreement (e.g., around vaccines’ effectiveness and safety), being willing to revise views in response to new (...) evidence, and being clear about the values that underpin expert recommendations. We explore how failure to acknowledge expert disagreement and uncertainty can undermine trust in vaccination and public health experts, using expert recommendations around COVID-19 vaccines as a case study. (shrink)