In this undated image provided by Penn Medicine, Katalin Karikó and Drew Weissman pose for a photo at the University of Pennsylvania in Philadelphia. (Peggy Peterson Photography/Penn Medicine via AP)In this undated image provided by Penn Medicine, Katalin Karikó and Drew Weissman pose for a photo at the University of Pennsylvania in Philadelphia. (Peggy Peterson Photography/Penn Medicine via AP)

Two scientists have won the Nobel Prize in Medicine for making molecule discoveries that helped create COVID-19 vaccines.

The Nobel Assembly at Sweden’s Karolinska Institute announced the winners Monday. They are Hungarian-American Katalin Kariko and American Drew Weissman.

Members of the assembly praised the two scientists for assisting in “the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times.”

Kariko and Weissman have long cooperated on research while working as professors at the University of Pennsylvania. The two centered on a technology called messenger RNA, or mRNA.

Technology companies such as Pfizer-BioNTech and Moderna used mRNA to create their COVID-19 vaccines. The vaccines were deployed around the world to fight the disease.

The Nobel organization said the two scientists had changed “our understanding of how mRNA interacts with our immune system.”

Vaccine makers usually add elements of an inactive or weakened virus to the shot mixture. But with mRNA vaccines, scientists instead create a genetic material to direct the human body to produce antibodies and recognize and destroy the virus.

Research on mRNA has gone on for about 30 years. But no mRNA vaccine was developed and approved for use on people until the COVID-19 pandemic. In early experiments, researchers discovered that injecting laboratory-grown mRNA into animals usually led to a body reaction that destroyed it.

But Kariko and Weissman found a way to make a small change, or modification, to the building blocks of RNA that permitted it to survive immune defenses in the body. Their discovery was seen as breaking a major barrier because it showed that mRNA technology could be used as a treatment in humans.

The 68-year-old Kariko is the 13th woman to win the Nobel Prize in medicine. She was a vice president at BioNTech, which partnered with Pfizer to make one of the COVID-19 vaccines. She and the 64-year-old Weissman met by chance in the 1990s at the University of Pennsylvania.

Kariko noted that her husband was first to pick up the early morning call about the news. She said she then watched the announcement to make sure it was true. “I was very much surprised. But I am very happy.”

In reaction to his prize, Weissman said, “The future is just so incredible. We’ve been thinking for years about everything that we could do with RNA, and now it’s here.”

The two researchers have cooperated for many years, with Kariko centering on RNA and Weissman studying related immunology. “We educated each other,” Kariko said.

The prize comes with an award of $1 million. An award ceremony for all the Nobel awards, except the Peace Prize, is set for December 10 in Stockholm. The Peace Prize ceremony will take place in Norway’s capital, Oslo.

Other Nobel announcements will be made this week. The prize in physics will be announced Tuesday. Chemistry will be announced Wednesday, while literature will be awarded on Thursday. The Nobel Peace Prize is set to be announced Friday.

I’m Bryan Lynn.

The Associated Press, Reuters and Agence France-Presse reported this story. Bryan Lynn adapted the reports for VOA Learning English.

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Words in This Story

unprecedented – adj. never having happened before

antibody – n. a substance produced in the body to fight disease

immune system – n. the cells and tissues in the body that fight against infection