Hungarian American Katalin Karikó and American Drew Weissman won the Nobel Prize for medicine on Monday for discoveries that helped create the mRNA vaccines to protect against COVID-19. Some five decades of public and private research laid the groundwork for the quick development of the lifesaving immunizations. Michael Mina, a former Harvard epidemiology professor and chief science officer at the telemedicine company EMed, explains how it works to The World’s Marco Werman.