Katalin Karikó: the tenacious force behind the Covid vaccine

In 1997, the Hungarian biochemist Katalin Karikó met another struggling researcher, the American immunologist Drew Weissman, as they queued to photocopy scientific papers at the University of Pennsylvania. After commiserating about the lack of funding for their work, the two scientists found a common scientific interest — the genetic molecule RNA — and decided to collaborate.

This week, their partnership achieved the apex of scientific recognition. Karikó, 68, and Weissman, 64, jointly won the $1mn Nobel Prize in medicine for discoveries leading to the messenger RNA vaccines that stemmed the growing tide of coronavirus infections during the pandemic, saving many millions of lives and yielding sales worth $117bn for the manufacturers BioNTech/Pfizer and Moderna.

Over more than a decade of joint effort, the pair worked out how to manipulate mRNA, the molecule that translates genes into proteins, into a stable form that can be used in pharmaceutical and vaccine development.

But while both scientists endured years of professional struggle on the way to the huge acclaim that greeted the success of mRNA vaccines against Covid-19, Karikó had to overcome greater setbacks than Weissman.

In 2012, Weissman was promoted to full professor at Penn. The following year Karikó “was kicked out from Penn — forced to retire”, as she told the Nobel organisation after the prize was announced on Monday. The university told her that her work was not of faculty quality, she said in a 2020 interview.

Yet the scientist’s commitment to her work did not falter. “When I was terminated, I didn’t feel sorry for myself,” she said. “You have to focus all the energy on seeking out what’s next.”

Karikó travelled to Europe that same year, accompanying her daughter Susan Francia, a US Olympic rowing champion, to a competition. On the trip she visited BioNTech, then a little-known German company, where she met a group of mRNA enthusiasts. “This was the first time in my life that I didn’t have to explain that RNA is good, because all the people who were there were believers,” she said later. At the time, many members of the scientific community believed that RNA-based vaccines were not a feasible endeavour.

Uğur Şahin, BioNTech’s chief executive, immediately offered her a role as vice-president of research. She accepted, though her family stayed in Pennsylvania, resulting in almost a decade of intense transatlantic travel. In 2022, she moved back to the US while remaining an external consultant with the company.

Karikó, the daughter of a butcher, grew up on the plains of central Hungary. She was not born into wealth — her family lived in one room heated by a sawdust stove. But after an outstanding performance at school, she went on to study biology and biochemistry at the University of Szeged, obtaining a PhD in 1982.

After her lab lost its funding, Karikó emigrated to the US in 1985 with her engineer husband, Béla Francia, and their two-year-old daughter Susan. They successfully evaded currency export restrictions by sewing £900, obtained on the black market with funds from selling their car, into a teddy bear.

Once in America, Karikó worked as a postdoctoral researcher at Temple University before moving to Penn in 1989 to study mRNA. She continued her research through the 1990s, persisting despite grant rejections and Penn’s refusal to put her on the tenure track towards a secure academic position.

Collaboration with Weissman led in 2005 to what was seen in retrospect as a seminal paper in the history of mRNA research, though few colleagues recognised its significance at the time.

After being rejected by two leading journals, the study was published by Immunity. It showed how the molecular building blocks of mRNA could be tweaked so they would deliver protein building instructions to human cells without provoking destructive inflammation. This was an important breakthrough. An adverse immune system reaction to the injection was previously regarded as a serious barrier to the technology.

Eventually, the tide turned in favour of the mRNA approach pioneered by the duo, in time for the rapid production of Covid vaccines in 2020 — though not in time to save Karikó’s academic career. Today she has a position as an adjunct professor at Penn, and the university’s leadership lavished praise on her when she attended Nobel celebrations there.

Researchers in Karikó’s field are full of admiration for her generosity and persistence. “Her lifetime dedication to science . . . is remarkable,” says Zoltán Kis, an mRNA expert at the University of Sheffield. “She . . . can be quite critical and direct with others but the trouble she takes to help younger researchers is impressive.”

“She gives us a lesson in keeping going when you know you are right,” says John Tregoning, professor of vaccine immunology at Imperial College London.

In her Nobel interview, Karikó told female researchers: “You don’t have to choose between having a family [and science] . . . Your child will watch you and [follow] the example you present.”

But Karikó’s most frequently repeated message for scientists is about enjoying their work, regardless of any difficulties they may encounter. As the fizz flowed at Penn’s Nobel party, she told her colleagues: “I wish all of you to persevere . . . and have fun. Do great things and don’t give up that easily.”

clive.cookson@ft.com