Katalin Karikó: The Long Refusal to Quit
In 1985 a thirty-year-old Hungarian biochemist whose laboratory had just lost its funding sold the family car, changed the proceeds on the black market, and sewed roughly £900 into her two-year-old daughter's teddy bear because Hungary's currency controls allowed her to take out almost nothing. Then she flew to Philadelphia with her husband and the child. Thirty-eight years later, on 2 October 2023, she was told she had won the Nobel Prize in Physiology or Medicine. In between she was demoted, denied tenure, rejected by every major funder she approached, and turned down by *Nature* and *Science* for the paper that made the COVID-19 vaccines possible.
A House Without Running Water
Katalin Karikó was born on 17 January 1955 in Szolnok, Hungary, and raised in Kisújszállás in circumstances she has never romanticised or hidden. Her father János was a butcher, punished for his part in the Hungarian Revolution of 1956; her mother kept books. The family home had no running water, no refrigerator and no television. She took a B.Sc. in biology in 1978 and a doctorate in biochemistry in 1982, both from the University of Szeged, working under Jenő Tomasz, and stayed on at Hungary's Biological Research Centre until the money ran out in 1985.
The Teddy Bear
Robert J. Suhadolnik at Temple University offered her a research position, and the Karikós emigrated. The landing was rough. When she later accepted a post at Johns Hopkins without telling Suhadolnik, he reported her to the immigration authorities; she lost the Hopkins job and faced deportation proceedings. It was the first of many years in which her career survived on other people's tolerance rather than institutional support.
Penn, and the Demotion
In 1989 the cardiologist Elliot Barnathan hired her at the University of Pennsylvania to work on messenger RNA, and she submitted her first gene therapy grant application in 1990. The idea was straightforward and, at the time, unfashionable to the point of career suicide: instead of delivering a gene, deliver the message, a strand of mRNA instructing the body's own cells to manufacture a specific protein for a limited time. DNA-based gene therapy was where the field and the funding had gone. mRNA was regarded as too unstable and too inflammatory to be a therapeutic.
The grants were refused, over and over. In 1995 Penn demoted her. She never received tenure. She stayed anyway, kept alive by colleagues, among them the neurosurgeon David Langer, who found her bench space and problems to work on. She has said since, of the whole period, that she "dreamt about doing research, not getting an award."
A Chance Meeting at the Photocopier
In the late 1990s she fell into conversation with the immunologist Drew Weissman while both were queuing to photocopy papers. Weissman wanted a vaccine against HIV; Karikó had mRNA and no funding. They began working together in 1997, and immediately hit the wall that had defeated the field: injected synthetic mRNA provoked a violent inflammatory response. The body treated it as an invader.
Weissman's summary of the following decade was blunt: "We had to fight the entire way."
Pseudouridine
The answer, when it came, was chemical and precise. Naturally occurring mammalian mRNA carries chemically modified bases; mRNA synthesised in a laboratory does not. Karikó and Weissman found that dendritic cells use exactly that difference to identify foreign RNA and trigger the inflammatory cascade. When they swapped uridine for the modified base pseudouridine, the immune alarm went quiet. As the Nobel Committee later put it, the "inflammatory response was almost abolished" — and, as a bonus nobody had predicted, the mRNA produced substantially more protein, because the enzymes that shut down translation were no longer being activated.
*Nature* rejected the paper. *Science* rejected the paper. *Immunity* published it in August 2005, and the field largely ignored it. Follow-up work in 2008 showed pseudouridine improved mRNA stability, and in 2010 that it enhanced translation by inhibiting the enzyme PKR. Karikó and Weissman also worked on the lipid nanoparticles — protective droplets of fat — needed to get the molecule into cells intact.
She co-founded RNARx in 2006 to commercialise the patents. In 2013, hearing that Moderna had struck a deal with AstraZeneca on mRNA, she left Penn for BioNTech in Germany as a vice president, becoming senior vice president in 2019 and departing in 2022 to return to research.
Vindication at Scale
When SARS-CoV-2 arrived, both BioNTech-Pfizer and Moderna built their vaccines on nucleoside-modified mRNA. Efficacy exceeded ninety per cent. In the United States alone more than 655 million doses had been administered since December 2020 by the time the Nobel was announced. Penn's dean J. Larry Jameson stated the case plainly: "During the biggest public health crisis of our lifetimes, vaccine developers relied upon the discoveries by Dr. Weissman and Dr. Karikó, which saved innumerable lives." The Nobel citation named the contribution exactly: "for their discoveries concerning nucleoside base modifications that enabled" effective mRNA vaccines against COVID-19.
Why Katalin Is Called a Genius
The quality on display in Karikó's career is not spectacular reasoning speed or a sudden flash of insight. It is something the culture of science rewards badly and depends on entirely: correct judgement about which unfashionable problem is actually the important one, sustained for thirty years against unanimous institutional signals that she was wrong. Every funding committee, every promotions panel and every editor told her mRNA was a dead end. She was right and they were wrong, and the specific intellectual act that proved it — asking why natural mRNA carries modified bases when synthetic mRNA does not, and testing whether that difference is what the immune system is reading — was a question nobody else thought to ask, resolved with an elegance that made an entire therapeutic class possible.
Penn's president Liz Magill called Karikó and Weissman "brilliant researchers who represent the epitome of scientific inspiration and determination," and the second noun in that sentence is doing at least as much work as the first. The honest counter-case is worth stating. The Nobel was shared, and Weissman's immunological expertise was indispensable; neither of them could have done it alone. Karikó did not invent mRNA therapeutics as a concept, and the lipid nanoparticle delivery systems and the vaccine engineering that turned her insight into a product were the work of many hundreds of others at BioNTech, Pfizer and Moderna. What is uniquely hers is the identification of the obstacle everyone else had accepted as fundamental, and the decades of refusal to accept it. Genius here consists in stubbornness attached to a correct hypothesis, which is far rarer than stubbornness alone.
Legacy
Karikó is a professor at the University of Szeged and an adjunct professor of neurosurgery at Penn's Perelman School of Medicine, and was only the sixty-first woman to become a Nobel laureate. Before Stockholm she had won the Lasker-DeBakey Clinical Medical Research Award, the Breakthrough Prize, the Princess of Asturias Award, the Albany Medical Center Prize, the VinFuture Grand Prize and the 2022 Tang Prize, and had been named one of TIME's Heroes of the Year in 2021. She was inducted into the National Inventors Hall of Fame in 2023 and elected to the US National Academy of Sciences in May 2025. In April 2024 she gave more than $500,000 of her Nobel money to the University of Szeged. Her memoir *Breaking Through: My Life in Science* became Hungary's best-selling non-fiction book of 2023 and has been translated into nine languages. She is married to Béla Francia; their daughter Susan, the child whose teddy bear carried the family's savings out of Hungary, went on to win two Olympic gold medals in rowing.
Achievements
- Lasker-DeBakey Clinical Medical Research Award — 2021
- Nobel Prize in Physiology or Medicine — 2023
- Held posts at BioNTech, Biological Research Centre and Temple University
- Educated at Móricz Zsigmond Gimnázium és Közgazdasági Szakközépiskola and University of Szeged
- Fields of research: biochemistry and messenger RNA
