Copyright © 2026 VPM, all rights reserved.
PBS is a 501(c)(3) not-for-profit organization.
VPM News Morning Edition
NEXT UP: 9:00 AM

Thanks to our sponsors – Become a Sponsor

Nobel Prize goes to scientists who made mRNA COVID vaccines possible

Secretary-General of the Nobel Assembly Thomas Perlmann speaks in front of a picture of Katalin Karikó and Drew Weissman, winners of the 2023 Nobel Prize in Physiology or Medicine, at the Karolinska Institute in Stockholm on Monday.
JONATHAN NACKSTRAND / AFP via Getty Images
Secretary-General of the Nobel Assembly Thomas Perlmann speaks in front of a picture of Katalin Karikó and Drew Weissman, winners of the 2023 Nobel Prize in Physiology or Medicine, at the Karolinska Institute in Stockholm on Monday.

A biochemist born in Hungary and an American immunologist have won the 2023 Nobel Prize for Physiology or Medicine for research that led to the development of the two most important COVID-19 vaccines.

Katalin Karikó and Drew Weissman met at copy machine at the University of Pennsylvania in Philadelphia and collaborated for decades to try to find ways to use genetic material called messenger RNA, or mRNA, to make vaccines.

The scientists discovered that modifying a chemical building block of mRNA kept the immune system from destroying the material and enabled it to instead stimulate protection against viruses. They published a seminal paper describing their work in 2005.

When the pandemic erupted, the vaccines developed by Moderna and Pfizer-BioNTech used the pair’s techniques to create highly safe and effective vaccines in record time.

“MRNA vaccines, together with other COVID-19 vaccines, have been administered over 13 billion times,” Rickard Sandberg, a Nobel committee member said Monday in announcing the award. “Together they have saved millions of lives, prevented severe COVID-19, reduced the overall disease burden and enabled societies to open up again.”

The advance also spurred interest in using mRNA technology to find out diseases, ranging from the flu to possibly cancer, the committee said.

The committee members said they hope the award might help overcome some of hesitancy that has plagued efforts to get more people to get vaccinated against COVID and save even more lives.

The pair’s discovery “fundamentally changed our understanding of how mRNA interacts with our immune system,” the panel that awarded the prize said. In addition, the work “contributed to the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times.”

Speaking to reporters at the University of Pennsylvania Monday, Weissman, 64, said the pair had to overcome many obstacles.

“We couldn’t get funding. We couldn’t get publications. We couldn’t get people to notice RNA as something interesting. And pretty much everybody gave up on it,” Weissman said. “But Kati (Karikó) lit the match and we spent the rest of our 20 plus years working together figuring out how to get it to work.”

Karikó, 68, had to overcome big challenges. For years, she went from one low-paying research job to another and even slept in her office at times. She says she was forced to retire from Penn and then commuted to work at BioNTech. But said she never gave up. And her mother never gave up hope she’d eventually win a Nobel.

“My mom, who passed away two years ago at age 89, every fall she was listening and she said to me, ‘You know, you might get this year.’ And I said, ‘Mom, I couldn’t even get a grant,’ ” Karikó said in a 2020 interview with NPR.

The first prize in the category was awarded in 1901. Of the 227 people whose work has been recognized with the prize, Karikó is only the 13th woman among them.

Copyright 2025 NPR

Scott Hensley edits stories about health, biomedical research and pharmaceuticals for NPR's Science desk. During the COVID-19 pandemic, he has led the desk's reporting on the development of vaccines against the coronavirus.

Hensley has worked on award-winning investigations in collaboration with journalistic partners.

He was the lead NPR editor on an investigation with the Center for Public Integrity in 2018 that exposed drug industry influence on the choices of preferred medicines by Medicaid programs. The work won the 2019 Gerald Loeb Award for audio reporting.

In 2017, Hensley was the lead NPR editor on an investigation with Kaiser Health News that showed how the pharmaceutical industry exploits government incentives intended to encourage the development of treatments for rare diseases. The stories won the 2019 digital award from the National Institute for Health Care Management.

Hensley has been editing in his current role since 2019. He joined NPR in 2009 to launch Shots, a blog that expanded to become a digital destination for NPR health coverage.

Before NPR, Hensley was a reporter and editor at The Wall Street Journal. He was the founding editor of The Wall Street Journal Health Blog, which focused on the intersection of health and business. As a reporter, he covered the drug industry and the Human Genome Project.

Hensley served on the board of the Association of Health Care Journalists from 2012 to 2020.

He has a bachelor's degree in natural sciences from Johns Hopkins University and a master's in journalism from Columbia University.

Before becoming a journalist, Hensley worked in the medical device industry. He remains, now and forever, a lover of Dobermans, lacrosse and Callinectes sapidus.

Related Stories