Kati Kariko Helped Shield the World From the Coronavirus

Collaborating with devoted colleagues, Dr. Kariko laid the groundwork for the mRNA vaccines turning the tide of the pandemic.

She grew up in Hungary, daughter of a butcher. She decided she wanted to be a scientist, although she had never met one. She moved to the United States in her 20s, but for decades never found a permanent position, instead clinging to the fringes of academia. Now Katalin Kariko, 66, known to colleagues as Kati, has emerged as one of the heroes of Covid-19 vaccine development. Her work, with her close collaborator, Dr. Drew Weissman of the University of Pennsylvania, laid the foundation for the stunningly successful vaccines made by Pfizer-BioNTech and Moderna. For her entire career, Dr. Kariko has focused on messenger RNA, or mRNA — the genetic script that carries DNA instructions to each cell’s protein-making machinery. She was convinced mRNA could be used to instruct cells to make their own medicines, including vaccines.