This episode covers the 2023 Nobel Prize in Physiology or Medicine, which was awarded to Katalin Karikó and Drew Weissman. The Nobel Assembly at the Karolinska Institute chose to give Karikó and Weissman the award “for their discoveries concerning nucleoside base modifications that enabled the development of effective mRNA vaccines against COVID-19”. Topics include the different historical vaccine design platforms, the development of modified mRNA and ionizable lipid nanoparticles for mRNA vaccines, and the rapid roll out of the mRNA vaccines during the COVID-19 pandemic.