🇭🇺Katalin
Karikó

In 1985, Katalin Karikó packed her entire savings — converted into $1,200 hidden in a stuffed bear — into two suitcases, took her two-year-old daughter, and left Hungary for the United States. She had accepted a postdoctoral position at Temple University in Philadelphia, and she had one idea that she believed could change medicine: that synthetic messenger RNA could be used to instruct the body's own cells to produce any protein it needed, turning each patient into their own pharmaceutical factory. The immigration officer at the airport asked what she was bringing into the country. "Everything I have," she said. It was almost literally true. It was also, though neither she nor anyone else could have known it, one of the most consequential smuggled assets in the history of modern biology.

Karikó had grown up in a small town in eastern Hungary, the daughter of a butcher, in a house without running water or a refrigerator. She studied biochemistry at the University of Szeged and earned her PhD from the University of Debrecen in 1982. She became fascinated by RNA — the molecular messenger that carries genetic instructions from DNA to the ribosome, where proteins are made — and specifically by the idea that synthetic mRNA could be used therapeutically. The concept was elegant: rather than giving a patient a protein drug, you give them the instructions to make it themselves. But in the 1980s and 1990s, mRNA was considered too unstable and too immunogenic to be practically useful. The scientific community was largely uninterested.

At the University of Pennsylvania, where she moved in 1989, Karikó found herself unable to secure grant funding for her mRNA research. Grant committees viewed it as speculative and unpromising. In 1995 — after a decade at Penn — the university demoted her from her faculty position, cutting her salary and her status simultaneously. She refused to leave. She kept working on mRNA at the bench, with fewer resources and less institutional support than almost any researcher at a major American university. Around this time, at a copy machine in a Penn hallway, she met Drew Weissman, an immunologist who was interested in HIV vaccines. They began talking. Within a few years, they were collaborating.

The breakthrough came in 2005. Karikó and Weissman discovered that the reason synthetic mRNA triggered a violent immune response — the obstacle that had made it clinically useless — was a specific chemical feature of the nucleosides, the building blocks of RNA. When they substituted modified nucleosides for the naturally occurring ones, the immune alarm was silenced: the mRNA could enter cells, produce protein, and not provoke an inflammatory catastrophe. They published the finding in the journal Immunity. The paper attracted modest attention. No drug company called. The university licensed the patents for a relatively small sum and did not expect much to come of them.

What came of them was the mRNA COVID-19 vaccines. The Pfizer-BioNTech and Moderna vaccines, developed at extraordinary speed in 2020, were built directly on Karikó and Weissman's modified nucleoside technology. Without that 2005 paper — ignored for more than a decade — neither vaccine would have been possible. The vaccines were administered more than 13 billion times. Karikó, who had left Penn for BioNTech in 2013 and risen to senior vice president, watched from inside the company as the technology she had believed in for forty years saved an estimated 20 million lives in its first year of deployment. In 2023, she and Weissman received the Nobel Prize in Physiology or Medicine. She was sixty-eight years old. She had been waiting — and working — for this moment since 1985.