Kay Nietfeld/picture-alliance/dpa/AP Images

The Nobel Committee has awarded the 2020 Nobel Prize in Physiology or Medicine for the discovery of the hepatitis C virus, one of the most common causes of liver cancer. The prize was given to Harvey Alter of the U.S. National Institutes of Health (NIH), Michael Houghton of the University of Alberta, Edmonton, and Charles Rice of Rockefeller University.

The hepatitis C virus is transmitted via blood. While most people quickly clear an infection, some develop chronic inflammation of the liver that quietly destroys the organ over years or decades, ultimately leading to cirrhosis and cancer. Patients often end up needing liver transplantation—or dying.

Half a century ago, doctors knew that recipients of blood transfusions were at higher risk of liver disease, and in 1967, Baruch Blumberg, also at NIH, discovered the hepatitis B virus, which won him one half of the 1976 Nobel Prize in Physiology or Medicine. But hepatitis B did not explain all of the cases of hepatitis seen in patients who had a blood transfusion. This year’s Nobel laureates did work over 3 decades to identify the hepatitis C virus, show it was responsible for most of the unexplained cases of hepatitis in blood transfusions, and make it possible to screen blood donations for the virus.

In the 1970s, Alter and his colleagues studied hepatitis in transfusion recipients and showed that even though screens for the hepatitis B virus could reduce the  number of  cases, many remained. Hepatitis A, a virus which is transmitted via water or food, wasn’t the explanation either. In 1978, Alter showed that plasma from patients with unexplained hepatitis could cause disease when transferred to chimpanzees, indicating it was caused by an infectious agent. Additional studies suggested it was a virus.

In 1989, Houghton, then working at the pharmaceutical company Chiron, along with colleagues cloned the virus for the first time and named it the hepatitis C virus in a paper in Science. The team then developed a blood test and showed it could identify samples suspected of transmitting the unexplained cases of hepatitis. This allowed blood donations around the world to be screened, which dramatically reduced the number of newly infected people. Before these discoveries, “it was like Russian roulette to receive a blood transfusion,” says Nils-Göran Larsson, a member of the Nobel Committee. (Transmission though the blood supply is now nearly eliminated.)

Rice, then working at Washington University in St. Louis, showed in a 1997 paper, also published in Science, that the new virus was highly varied, with many clones that did not cause disease. He went on to show, however, that an active version of the virus—alone—could cause infection and liver disease.

The pioneering work of this year’s laureates is a landmark achievement in our ongoing battle against virus infections.

Gunilla Karlsson Hedestam, Nobel Committee

Eventually, the trio’s discoveries also led to treatments that can now cure about 95% of hepatitis C patients. “These developments saved millions of lives worldwide,” Nobel Committee member Gunilla Karlsson Hedestam said today. “The pioneering work of this year’s laureates is a landmark achievement in our ongoing battle against virus infections.”

Yet about 71 million people worldwide are still suffering from a chronic infection with the virus today. The World Health Organization estimates that about 400,000 people died of hepatitis C in 2016, mostly from cirrhosis and cancer. Egypt, long one of the worst affected countries in the world, with up to 15% of people affected in some regions, has led the way on combatting the virus, treating millions of people with new drugs in recent years and conducting a countrywide screening campaign to find undiagnosed cases.

With reporting by Kai Kupferschmid and John Travis.

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