The Nobel Assembly at Karolinska Institutet, Stockholm, Sweden said the discoveries by Karikó and Weissman were critical for developing effective mRNA vaccines against COVID-19 during the pandemic that began in early 2020

https://www.firstpost.com/world/nobel-prize-in-medicine-2023-awarded-to-katalin-kariko-drew-weissman-for-pioneering-mrna-vaccine-to-fight-covid-19-13194442.html