Katalin Karikó

Based on Wikipedia: Katalin Karikó

The Scientist Who Refused to Quit

In 1985, a young Hungarian biochemist named Katalin Karikó stuffed nine hundred British pounds into her daughter's teddy bear. The money came from selling the family car on the black market—the only way to convert Hungarian currency into something usable in the West. She was leaving behind everything familiar to chase a molecule that almost no one believed in.

Four decades later, that molecule would help end a pandemic.

Karikó's story is one of the great scientific underdog tales of our time. She spent decades being demoted, defunded, and dismissed by the academic establishment. She watched colleagues abandon messenger RNA research because the grant money had dried up. She endured a supervisor who tried to have her deported when she sought a better position. And through all of it, she kept working on an idea that the scientific mainstream had written off as a dead end.

When the COVID-19 vaccines from Pfizer-BioNTech and Moderna proved more than ninety percent effective—an almost unheard-of success rate—they were built on the foundation Karikó had laid. In 2023, she received the Nobel Prize in Physiology or Medicine.

A Childhood Without Running Water

Katalin Karikó was born in 1955 in Szolnok, Hungary, and grew up in the small town of Kisújszállás. Her childhood home had no running water, no refrigerator, and no television. Her father János worked as a butcher. Her mother kept the books.

This was Communist Hungary, and her father had made a dangerous mistake: he had participated in the 1956 uprising against Soviet rule. The revolt was crushed by Russian tanks, and those who had joined it faced consequences that rippled through their families for years.

But young Katalin found an escape in science. By eighth grade, she had achieved top national rankings in biology competitions. A 2024 retrospective by the University of Szeged credits these early academic competitions with nurturing the passion that would eventually change the course of medicine.

She earned her bachelor's degree in biology in 1978 and her doctorate in biochemistry in 1982, both from the University of Szeged. She stayed on as a postdoctoral researcher at the Institute of Biochemistry, part of Hungary's Biological Research Centre.

There is a shadow over these years. From 1978 to 1985, Karikó was listed as an intelligence asset by the Hungarian secret police. She has said she was blackmailed into this arrangement out of fear for her career and her father. She maintains that she never actually provided information or acted as an agent. It is a reminder of the impossible choices that authoritarian regimes force upon ordinary people trying to live their lives.

The Teddy Bear Escape

In 1985, her lab lost its funding. This is the mundane way that scientific careers often end—not with a dramatic failure, but with a budget line that disappears.

Karikó started looking abroad. Robert Suhadolnik at Temple University in Philadelphia offered her a research position. She accepted, but leaving Hungary was not simple. Currency controls meant she could not legally take money out of the country. So she sold the family car, exchanged the currency on the black market, and hid the proceeds in her two-year-old daughter's teddy bear.

She arrived in America with her husband Béla Francia, her daughter, and that stuffed animal full of contraband cash.

Early Promise and Betrayal

At Temple, Karikó worked on double-stranded RNA, a molecule that was showing promise as a treatment for AIDS and other diseases. The research was considered cutting-edge. Scientists knew that this type of RNA could trigger the production of interferons—proteins that help the body fight viruses and cancer—even if they did not fully understand how.

But in 1988, Karikó made a decision that would nearly destroy her career. She accepted a job offer from Johns Hopkins University without first informing her supervisor Suhadolnik.

What happened next is documented in Gregory Zuckerman's book A Shot to Save the World. Suhadolnik told Karikó that if she went to Johns Hopkins, he would have her deported. Then he followed through, reporting her to immigration authorities and claiming she was in the country illegally.

While Karikó fought the deportation order—successfully—Johns Hopkins withdrew the job offer. Suhadolnik continued to badmouth her to other institutions, making it nearly impossible for her to find a new position. She was rescued by a researcher at Bethesda Naval Hospital who, as it happened, had his own difficult history with Suhadolnik.

Years later, Karikó confirmed that the incident happened as Zuckerman described it. But she added something remarkable: she remained grateful to Suhadolnik for giving her the opportunity to come to America in the first place. When she returned to Temple to give a lecture, she thanked him for what she had learned in his lab.

This capacity for grace under pressure—for separating the science from the scientist, the opportunity from the obstacle—would become one of her defining characteristics.

The University That Demoted Her

In 1989, Karikó joined the University of Pennsylvania to work with cardiologist Elliot Barnathan on messenger RNA.

To understand why this was a risky bet, you need to know what messenger RNA is and why it seemed so unpromising in the 1990s.

Messenger RNA, or mRNA, is essentially a set of instructions. Your DNA contains the master blueprints for every protein your body can make. But DNA lives in the nucleus of your cells, locked away like architectural plans in a vault. When your body needs to build a specific protein, it creates a temporary copy of the relevant instructions—that copy is mRNA. The mRNA travels out of the nucleus to the cell's protein-making machinery, delivers its message, and then gets destroyed.

Karikó saw an opportunity here. What if you could inject synthetic mRNA into the body? You could essentially hijack the cell's protein factories, giving them new instructions. Want the body to produce a specific therapeutic protein? Just write the mRNA code for it and inject it. Want to train the immune system to recognize a virus? Inject mRNA that tells cells to produce a harmless piece of that virus, so the immune system can learn to fight the real thing.

In 1990, Karikó submitted her first grant application proposing mRNA-based gene therapy. It was rejected. So was the next one. And the next.

The scientific establishment had decided that mRNA was a dead end. The molecule was fragile, difficult to work with, and—most problematically—it triggered dangerous inflammatory reactions when injected into living tissue. Researchers, biotech companies, and pharmaceutical giants all moved on to other approaches.

Karikó did not move on.

By 1995, her grant rejections had accumulated to the point where the University of Pennsylvania demoted her. She was initially on track to become a full professor. Instead, she lost her position on the tenure track entirely. The university was sending a clear message: stop working on mRNA, or leave.

She stayed. She kept working.

The Partnership That Changed Everything

In 1997, Karikó was standing at a photocopier when she met Drew Weissman, an immunologist who had just arrived at Penn. They started talking. Then they started collaborating.

Weissman brought funding—crucial for keeping Karikó's research alive—and expertise in immunology. Karikó brought her deep knowledge of RNA biochemistry and her relentless determination. Together, they began tackling the problems that had stalled mRNA research, solving them one at a time.

The central problem was inflammation. When you inject synthetic mRNA into the body, the immune system treats it as an invader and attacks. This made therapeutic mRNA essentially unusable—the cure was as dangerous as the disease.

Karikó noticed something strange during one of her experiments. She was using transfer RNA, a different type of RNA, as a control. Surprisingly, the transfer RNA did not trigger the same inflammatory response as her synthetic messenger RNA. Both were RNA. Both were being introduced into the body. Why was one treated as a threat and the other ignored?

The answer turned out to be subtle modifications in the molecular structure. Natural RNA in the body contains slight chemical variations—tiny alterations to the building blocks that make up the molecule. Synthetic mRNA lacked these modifications. The immune system had evolved to recognize unmodified RNA as a sign of viral infection.

In a series of landmark studies beginning in 2005, Karikó and Weissman showed that by making one specific modification—replacing a building block called uridine with a closely related molecule called pseudouridine—they could create mRNA that slipped past the immune system's defenses.

They had found the key.

Rejection by the Journals That Mattered

When Karikó and Weissman submitted their findings to Nature and Science—the two most prestigious scientific journals in the world—both rejected the paper.

This was not unusual. Major journals reject most submissions. But it meant that the discovery would not receive the attention and validation that a Nature or Science publication provides. Their work was eventually published in the journal Immunity, which is respected but lacks the same reach.

The researchers also tackled another challenge: delivery. Even with the immune problem solved, mRNA is a delicate molecule that breaks down quickly in the body. It needs protection to reach its target cells. Karikó and Weissman developed a technique using lipid nanoparticles—essentially tiny bubbles of fat that encapsulate the mRNA and carry it safely through the bloodstream.

If you have received an mRNA vaccine, you have experienced this technology directly. The injection contains mRNA wrapped in lipid nanoparticles. The fat bubbles protect the genetic instructions until they can enter your cells and deliver their message.

The University Sells the Rights

In 2006, Karikó and Weissman founded a small company called RNARx to commercialize their discoveries. They received patents in 2006 and 2013 for using modified nucleosides to reduce immune reactions to mRNA.

Then the University of Pennsylvania sold the intellectual property license to Gary Dahl, who ran a lab supply company that eventually became Cellscript. Weeks later, Flagship Pioneering—the venture capital firm backing a startup called Moderna—contacted Karikó trying to license the patent. She had to tell them it was no longer available.

The irony is bitter. Penn had demoted Karikó, defunded her research, and refused to support her work. Then the university sold the rights to her discoveries for what turned out to be a tiny fraction of their eventual value.

In early 2013, Karikó learned that Moderna had signed a two-hundred-forty-million-dollar deal with AstraZeneca to develop mRNA therapeutics. She realized that she would never get the chance to apply her expertise at Penn. So she left.

BioNTech and the Pandemic

Karikó joined BioNTech, a small German biotechnology company, as vice president. She was promoted to senior vice president in 2019.

BioNTech had licensed Karikó and Weissman's technology, as had Moderna. Both companies were working to develop mRNA-based treatments for cancer and other diseases. Then, in late 2019, reports emerged from Wuhan, China, of a mysterious respiratory illness.

By January 2020, scientists had sequenced the genome of the novel coronavirus. BioNTech's co-founder Uğur Şahin immediately began designing an mRNA vaccine. The sequence coding for the virus's spike protein—the key that the virus uses to enter human cells—was inserted into modified mRNA, wrapped in lipid nanoparticles, and prepared for testing.

The development speed was unprecedented. Traditional vaccines take years or even decades to develop. The mRNA vaccines were designed in days, tested in months, and authorized for emergency use before the end of 2020. The Pfizer-BioNTech vaccine demonstrated ninety-five percent efficacy. Moderna's showed ninety-four percent.

These numbers were remarkable. Most vaccines are considered successful if they achieve fifty to sixty percent efficacy. The mRNA vaccines were in a different category entirely.

The technology that Karikó had pursued for decades, that had cost her promotions and funding and professional respect, was suddenly the most important tool in the fight against a global pandemic.

Recognition After Decades of Doubt

The awards came in a flood. The Lasker-DeBakey Clinical Medical Research Award. Time Magazine's Hero of the Year 2021. The Tang Prize in Biopharmaceutical Science. The Novo Nordisk Prize. The VinFuture Grand Prize.

And then, on October 2, 2023, the Nobel Prize in Physiology or Medicine.

Karikó and Weissman shared the prize for their work on mRNA technology. During Nobel Week, a journalist asked Karikó about her feelings. "I dreamt about doing research," she said, "not getting an award." It was a characteristically direct response from a scientist who had spent most of her career being ignored by the establishment.

She donated more than half a million dollars of her Nobel Prize money to the University of Szeged, her alma mater in Hungary. In 2023, she became a professor there, bringing her journey full circle.

The Daughter in the Teddy Bear Story

Remember the two-year-old daughter who came to America with nine hundred pounds hidden in her teddy bear? Her name is Susan Francia, and she became a two-time Olympic gold medalist in rowing.

Susan won gold in the women's eight at the 2008 Beijing Olympics and the 2012 London Olympics. She is married to architect Ryan Amos. Their son—Karikó's grandson—was born in February 2021, just as the vaccines his grandmother helped create were being distributed worldwide.

The coincidence of timing feels almost too perfect for fiction.

The Broader Implications

Karikó's work extends far beyond COVID-19 vaccines. The ability to deliver therapeutic mRNA safely into the body opens possibilities that scientists are only beginning to explore.

Cancer treatment is one promising area. Tumors often display abnormal proteins on their surface. An mRNA vaccine could theoretically instruct the immune system to recognize and attack those specific proteins—a personalized cancer treatment tailored to each patient's tumor.

Cardiovascular disease is another frontier. Researchers are investigating whether mRNA can be used to promote the growth of new blood vessels in damaged heart tissue or to repair genetic defects that cause heart problems.

There are potential applications in treating metabolic diseases, in regenerating damaged tissues, even in creating pluripotent stem cells—the blank-slate cells that can develop into any type of tissue.

In 2023, Karikó was inducted into the National Inventors Hall of Fame. In 2024, Time magazine named her one of the hundred most influential people in health. In 2025, she was elected to the United States National Academy of Sciences.

She has received more than one hundred thirty international awards.

What Persistence Looks Like

Drew Weissman, reflecting on their collaboration, once described Karikó's exceptional qualities: "Kate was really just unbelievable. She was always incredibly inquisitive. She read voraciously. She would always know the latest technology or the latest paper, even if it was in a totally different area, and she'd put two and two together and say, 'Well why don't we do this?' Or, 'Why don't we try this formulation?'"

Weissman also noted: "We had to fight the entire way."

That fight lasted decades. Karikó was demoted in 1995 and never received tenure at Penn. She was never granted the security and recognition that the academic system is supposed to provide to researchers doing important work. The institution that should have supported her instead actively discouraged her research.

When she finally left Penn in 2013 to join BioNTech, the university lost the opportunity to be at the center of one of the most important medical breakthroughs of the twenty-first century. They had the researcher. They had the technology. They chose to let both go.

In November 2024, Karikó returned to Temple University—the institution where her troubles in America began—and delivered a public lecture about her Nobel Prize experience. She encouraged students to pursue research with persistence and enthusiasm.

In May 2025, she delivered the prestigious Mendel Lecture at the European Society of Human Genetics Annual Meeting, discussing clinical applications of mRNA therapeutics and the collaborative efforts that enabled rapid COVID-19 vaccine development.

Her autobiography, Breaking Through: My Life in Science, was published in October 2023, just days after the Nobel announcement. It became the best-selling non-fiction book in Hungary that year and has been translated into nine languages.

Two children's books have been written about her. One is called Never Give Up.

It is an apt title for a life spent proving that sometimes the scientific establishment is wrong, and sometimes the person standing alone at the photocopier has the idea that will save millions of lives.