HMS Professor Kaelin wins Nobel in Physiology or Medicine

William Kaelin recognized for work on how cells adapt to oxygen availability

William Kaelin in his home
Stephanie Mitchell/Harvard University

William G. Kaelin Jr., the Sidney Farber Professor of Medicine at Harvard Medical School and Dana-Farber Cancer Institute and senior physician in medicine at Brigham and Women's Hospital, has won the 2019 Nobel Prize in Physiology or Medicine, the Royal Swedish Academy of Sciences announced on Oct. 7.

Kaelin shares the award with Peter J. Ratcliffe of the University of Oxford and the Francis Crick Institute and Gregg L. Semenza of the Johns Hopkins University School of Medicine, who were cited for the discovery of the molecular pathway used by all multicellular organisms to sense and adapt to changes in oxygen, a process essential for survival.

Kaelin is now the 16th researcher to share in a Nobel Prize for work done while at Harvard Medical School.

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Kaelin said he was awakened by a phone call at 4:50 a.m. and answered, still foggy with sleep. When he saw a long international number, he thought he might have a busy day ahead.

“My heart started racing, I was overwhelmed,” he said of his reaction to hearing the news.

Kaelin said his first call was to his daughter, Kathryn, in law school at Oxford, and then to his son, William "Tripp" Kaelin III, a graduate student at Harvard.

"I've known Bill for a number of years now, and he is the consummate physician-scientist. He is fiercely dedicated to rigor and excellence both in the laboratory and in the clinic. Bill Kaelin is the finest that medicine has to offer, and it is a privilege to be able to offer my congratulations to Bill, Peter and Gregg," said HMS Dean George Q. Daley at a morning news conference at Dana-Farber, attended by Kaelin, Laurie Glimcher, Dana-Farber president and CEO, and Elizabeth Nabel, president of Brigham Health.

At the news conference, Kaelin said he was accepting the Nobel partly on behalf of his late wife, Carolyn Kaelin, who was an HMS assistant professor of surgery and a breast cancer surgeon at Dana-Farber and Brigham and Women's.

"She was a pioneering breast surgeon, and she was my best friend and hero and partner in everything I did. And to be honest, there were a couple years after I lost her that I thought, 'Please, not a prize,' because it would just be too bittersweet and it would be too crushing to receive such a wonderful recognition without Carolyn," said Kaelin. "But I’m at a point now where I’d like to think she’s smiling down and nodding and saying, ‘I told you this was going to happen.’"

Harvard’s William Kaelin wins Nobel Prize in physiology or medicine