Katalin Kariko and Drew Weissman win Nobel Prize in Medicine

Kariko and Weissman have been working together on mRNA vaccines for more than 20 years. The Nobel Prize in Physiology or Medicine honors their contribution to the rapid development of COVID-19 immunizations.
| Photo Credit: Peggy Peterson Photography/Penn Medicine

The Nobel Prize in Medicine 2023 has gone to Katalin Kariko and Drew Weissman for their work that enabled the development of effective mRNA vaccines against COVID-19.

Through their findings on how mRNA interacts with our immune system Hungary’s Kariko and US’ Weissman “contributed to the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times”, the Nobel jury in Stockholm said.

It is the second year in a row that the Nobel Prize for Medicine has been awarded to researchers who have been tackling questions regarding the novel coronavirus pandemic. In 2022, the award went to Swedish scientist Svante Paabo whose discoveries concerning Neanderthal DNA provided key insights into the human immune system, including vulnerability to severe COVID-19.

The 13th woman to win in the prize’s history

The Nobel committee contacted both Kariko and Weissman by phone prior to the public announcement. Kariko was reportedly “overwhelmed” on receiving the news, while Weissman was “enormously grateful”.

The Nobel Prize is considered the most prestigious award in the fields in which it is conferred. The prize money this year was increased by 1 million to 11 million kronor (just over $1 million) due to the Swedish currency having significantly depreciated this year.

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The Nobel Prize in Physiology or Medicine has been awarded 114 times since the inaugural one in 1901. There have been 227 recipients including this year’s winners, but Kariko is only the 13th woman to receive the accolade.

How mRNA research contributed to faster vaccine development

In human cells, genetic information encoded in DNA is transferred to messenger RNA (mRNA), which is used as a template for protein production. mRNA vaccines work by triggering the production of proteins that stimulate the formation of virus-blocking antibodies in our cells.

In the 1980s researchers were able to produce mRNA “in vitro”, that is, without having to first create large-scale cell cultures in a resource-intensive process. The resulting in vitro mRNA, however, was highly unstable and triggered the immune system, leading to inflammatory responses in the body.

Kariko and Weissman found out that mRNA with chemically modified bases did not lead to inflammatory reactions. Subsequent to publishing their discovery in 2005, they also found that using mRNA with altered bases significantly increased protein production.

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Kariko and Weissman’s discoveries would turn out to be invaluable during the COVID-19 pandemic; in part thanks to their research findings, two base-modified mRNA vaccines were developed at record speed.

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The duo has been working as a team at the University of Pennsylvania in the US for more than 20 years and have won numerous awards for their work contributing to the development of mRNA vaccines, including the Lasker-DeBakey Clinical Medical Research Award, the Breakthrough Prize, the Princess of Asturias Award, the Albany Medical Center Prize in Medicine and Biomedical Research, the VinFuture Grand Prize, and the Tang Prize in Biopharmaceutical Science.

In December 2020 they received their COVID-19 shots together. On that occasion, Kariko expressed her happiness about their contribution to the development of the crucial vaccines.

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“I always wanted to do something to help patients,” Kariko said. “I wasn’t thinking about a vaccine or infectious disease; I was always thinking about developing mRNA for therapeutics. I’m hopeful, now that there is so much interest and excitement for this research, that it will be possible to develop and test this mRNA vaccine technology for prevention and treatment of other diseases too.”

Since then mRNA research has progressed significantly. In spring 2023 scientists in the US published the results from the trial of a new mRNA vaccine designed to prevent the return of pancreatic cancer in patients who have previously battled the disease. For the study published in the journal Nature, the researchers used customised mRNA vaccines to treat 16 pancreatic cancer patients who had previously had their tumors surgically removed. By the end of the 18-month trial period, half of the patients had not relapsed. For a cancer that usually returns within a few months of surgery, this represents a significant advance.

Weissman, who was not involved in the study, told DW at the time that he “[knew] they were looking at a bunch of different types of cancer” and that he was “surprised that pancreatic was one it worked so well in”.

Making her mother proud

After the announcement, Kariko told broadcaster Swedish Radio that her mother would always listen to the Nobel Prize announcements. “She listened when I was not even a professor, like 10 years ago,” Kariko told the station. “She always listened, saying: ‘Maybe your name will be said.’ I was just laughing because I never [got] a grant and never had a team.”

Kariko’s mother has since passed away, but the researcher speculated that she might be “listening from above.” Weissman received the good news from Kariko, because the Nobel Prize committee didn’t have his phone number. “We weren’t sure if somebody was playing a prank on us,” remarked Weissman to Swedish Radio.