William Kaelin Wins Nobel Prize in Physiology or Medicine

Kaelin is the forty-ninth Harvard faculty member to win the Nobel. 

William G. Kaelin pictured in his home in Boston shortly after receiving the call from Sweden

William G. Kaelin

Photograph by Stephanie Mitchell/HPAC

William Kaelin, Farber professor of medicine, has won the Nobel Prize in physiology or medicine, the Nobel Foundation announced this morning. He shares the prize with Sir Peter J. Ratcliffe, of the University of Oxford, and Gregg Semenza ’78, of Johns Hopkins University, for their research on how cells adapt to changing oxygen levels. 

The team “discovered how cells can sense and adapt to changing oxygen availability. They identified molecular machinery that regulates the activity of genes in response to varying levels of oxygen,” according to an announcement from the Nobel Assembly at Karolinska Institutet. “The seminal discoveries by this year’s Nobel Laureates revealed the mechanism for one of life’s most essential adaptive processes. They established the basis for our understanding of how oxygen levels affect cellular metabolism and physiological function. Their discoveries have also paved the way for promising new strategies to fight anemia, cancer and many other diseases.”

Kaelin is the forty-ninth Harvard faculty member to win a Nobel Prize. His most recent predecessor, economics professor Oliver Hart won the 2016 Nobel Prize in economic sciences for his advances in contract theory.

Kaelin’s fellow winner Gregg L. Semenza ’78 is Armstrong professor of medicine at the Johns Hopkins University School of Medicine. A Hopkins press release notes that his research paves the way for the development of drugs that could kill cancer cells by cutting off the supply of oxygen a tumor needs to grow, and could also lead to medicines allowing tissues affected by conditions such as arterial disease to survive on low oxygen.

You might also like

Harvard Faculty Group Proposes Limits on A Grades

The grade inflation measure requires a full faculty vote, expected in the spring.

Harvard Students, Alumni to Compete at the 2026 Olympics

Six Crimson athletes are headed to the XXV Winter Games in Milano Cortina. 

FAS Announces New Endowment for Ph.D. Candidates

A $50 million gift from alumni donors aims to protect research opportunities amid political uncertainty

Most popular

Harvard’s Epstein Probe Widened

The University investigates ties to donors, following revelations in newly released files.

U.S. Military to Sever Some Academic Ties with Harvard, Hegseth Says

The defense department will discontinue graduate-level professional programs for active-duty service members.

Harvard’s Hasty Pudding Toasts, Roasts Michael Keaton

The Batman actor was “encouraged as hell” by the students around him during the 2026 Man of the Year festivities.

Explore More From Current Issue

Black and white photo of a large mushroom cloud rising above the horizon.

Open Book: A New Nuclear Age

Harvard historian Serhii Plokhy’s latest book looks at the rising danger of a new arms race.

A football player kicking a ball while another teammate holds it on the field.

A Near-Perfect Football Season Ends in Disappointment

A loss to Villanova derails Harvard in the playoffs. 

A busy hallway with diverse people carrying items, engaging in conversation and activities.

Yesterday’s News

A co-ed experiment that changed dorm life forever