Harvard Medical School Professor Kaelin Awarded Nobel Prize in Medicine


Harvard Medical School professor William G. Kaelin won the 2019 Nobel Prize in Medicine for his research discoveries on how cells use oxygen.

The prize was jointly awarded to Kaelin alongside Sir Peter J. Ratcliffe, a professor of medicine at Oxford University, and Gregg L. Semenza, a professor at Johns Hopkins School of Medicine.

The prize honored the professors’ research on “how cells sense and adapt to oxygen availability,” according to press release from the The Nobel Assembly at Karolinska Institutet.

“Thanks to the groundbreaking work of these Nobel Laureates, we know much more about how different oxygen levels regulate fundamental physiological processes,” the press release reads. “Oxygen sensing allows cells to adapt their metabolism to low oxygen levels: for example, in our muscles during intense exercise.”


Kaelin described receiving the prize as “thrilling” in an interview Monday.

“It’s of course thrilling when your colleagues, especially colleagues you admire, think that your work is worthy of any major scientific prize, let alone a Nobel Prize,” Kaelin said. “Obviously I’m on cloud nine that my colleagues around the world apparently thought this was a discovery that was Nobel Prize worthy, and I am thrilled to share it with my colleagues.”

Kaelin — who said that he was rejected from Harvard College, the Medical School, and a residency program before being hired by the Medical School — said that he heard about the news from a phone call from Stockholm at 4:40 a.m. Monday.

“I learned the news in the classical style, which is a very early phone call,” he said.

Kaelin said that while the prize was an honor, participating in the research itself was “the real prize.”

“On one level, the prize is participating in the discovery, being the first person to understand something that has never been truly understood before, seeing a mechanism that on occasion is actually beautiful or elegant. That’s the real prize in science,” Kaelin said.

Kaelin is the most recent Harvard faculty member to receive the award since Economics professor Oliver Hart won the Nobel Prize in Economics in 2016. Kaelin is the 17th Harvard faculty member to win the prize in physiology or medicine.

—Staff writer Alexis K. Bolner can be reached at


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