Hungarian scientist Katalin Kariko and US colleague Drew Weissman, who met in line for a photocopier before making mRNA molecule discoveries that paved the way for Covid-19 vaccines, won the 2023 Nobel Prize for Medicine on Monday.
“The laureates contributed to the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times,” the Swedish award-giving body said in the latest accolade for the pair.
The prize, among the most prestigious in the scientific world, was selected by the Nobel Assembly of Sweden’s Karolinska Institute medical university and comes with 11 million Swedish crowns (about $1m) to share between them.
Kariko, a former senior vice president and head of RNA protein replacement at German biotech firm BioNTech, is a professor at the University of Szeged in Hungary and an adjunct professor at the University of Pennsylvania (UPenn).

“We are not working for any kind of reward,” Kariko, who struggled for years to find grants for her research, said in remarks alongside Weissman at UPenn’s Philadelphia campus, a few hours after she was awoken by the call from Stockholm. “The importance was to have a product which is helpful.”
Co-winner Weissman, a professor in vaccine research also at UPenn, said it was a “lifetime dream” to win and recalled working intensely with Kariko for more than 20 years, including middle-of-the-night emails as they both suffered disturbed sleep.
In 2005, Kariko and Weissman developed so-called nucleoside base modifications, which stop the immune system from launching an inflammatory attack against lab-made mRNA, previously seen as a major hurdle against any therapeutic use of the technology.
“We couldn’t get people to notice RNA as something interesting,” Weissman said on Monday. “Pretty much everybody gave up on it.”
Mass use BioNTech said in June that about 1.5 billion people across the world had received its mRNA shot, co-developed with Pfizer. It was the most widely used shot in the West.
Having grown up in a village in a house without running water or a refrigerator, Kariko got a biochemistry doctorate in Szeged before she and her husband sold their Soviet-made Lada car, sewed some cash into their daughter’s teddy bear and went to the US on a one-way ticket.
The daughter, Susan Francia, became a US national rower and Olympic gold winner.
At UPenn, Kariko tried to turn mRNA into a treatment tool throughout the 1990s but struggled to win grants because work on DNA and gene therapy captured most of the scientific community’s attention at the time.
Kariko has said she endured ridicule from university colleagues for her dogged pursuit and her failure to secure research grants led to UPenn demoting her from a full-time professor track in 1995.