The major vaccines against SARS-CoV-2 have been developed at a speed unprecedented in human history. For some people, this raises concerns around their safety. This two-part episode proposes a critical framework to allow laypeople to satisfy themselves of the answers to those questions. What do we know so far? What do we not know? What are the various types of evidence and how do we weigh them appropriately to determine if the risks outweigh the benefits? Part One addresses the merits, unpacking the science that underpins the vaccines. Part Two addresses procedure: the processes that both regulators and we as healthcare consumers employ to assess safety.