The Nobel Prize in Physiology or Medicine for 2023 has been awarded to Katalin Karikó and Drew Weissman for their discoveries concerning nucleoside base modifications that enabled the development of effective mRNA vaccines against COVID-19. Their research, which began in the 1990s, focused on how different RNA types interact with the immune system and led to a breakthrough in understanding how cells recognize and respond to mRNA. This understanding was crucial for the development of mRNA vaccines, which have saved millions of lives and prevented severe disease in many more. The award recognizes the significance of their work in addressing one of the biggest health crises of our time.