Katalin Karikó and the Long Road to Being Right

On a cold morning in 1985, a young Hungarian scientist boarded a plane bound for the United States with her husband and their two-year-old daughter. The family carried no suitcases worth mentioning. Their car had already been sold. Their remaining cash, roughly nine hundred pounds, was hidden inside their child’s teddy bear, sewn carefully into the lining. Hungary was still communist then, and currency controls made honesty impractical. The scientist was thirty years old. Her name was Katalin Karikó. She believed, with a quiet and unyielding certainty, that a fragile molecule most scientists had given up on could one day change medicine.

That molecule was messenger RNA.

To understand why this belief mattered, it helps to know what messenger RNA is, and why betting a career on it looked, for a long time, like professional self-sabotage. Inside every human cell sits DNA, a vast instruction manual that never leaves its secure vault. Messenger RNA (Ribonucleic Acid), known as mRNA, is the courier. It carries short-lived copies of those instructions from DNA to the cell’s protein factories, where the body actually builds things. Whether it’s muscles, enzymes, antibodies, hormones, all of them begin as information carried by mRNA.

The molecule is essential, but fleeting. It degrades quickly. For decades, scientists viewed it as too unstable to be useful and too difficult to control. The dominant approach to medicine focused on introducing finished products into the body, proteins, weakened viruses, chemical compounds. The idea that you could instead give the body a temporary set of instructions and let it make what it needed itself felt, to many, naive. It was very difficult to make the body build what we want, so let’s just get them ready and send them into the body, that’s the uncomplicated explanation.

Karikó did not see it that way.

She grew up in Kisújszállás, a small Hungarian town without running water or a refrigerator. Her father was a butcher. Her mother worked as a bookkeeper. There was no television in the house. What there was, was time. She read. She studied. She learned early that biology was not mystical, but mechanical, governed by rules that could be understood if one was patient enough.

At the University of Szeged, she trained as a biochemist and earned her doctorate in 1982. Hungary offered limited prospects for ambitious scientists, and fewer still for those working in unfashionable fields. When her research funding collapsed in 1985, she looked west. Temple University in Philadelphia offered a postdoctoral position. The salary was modest. The future was uncertain. She took it anyway.

America did not greet her ideas warmly.

At Temple, Karikó continued working on RNA. She believed that if cells could be instructed safely, medicine could move from replacing what was broken to teaching the body how to repair itself. But the experiments were unforgiving. Injected mRNA often triggered violent immune reactions. The body treated it like an invader. Because of previous failed attempts, grants were rejected and reviewers called the work impractical. RNA, they insisted, was a dead end.

The setbacks multiplied. After accepting an offer from Johns Hopkins without informing her supervisor, she was reported to immigration authorities and nearly deported. The job fell apart. Her reputation suffered. She eventually found her way to the University of Pennsylvania, where she hoped stability might give her ideas room to breathe.

Instead, the pressure intensified.

By the mid-1990s, Penn made its position clear. She could abandon mRNA (a specific type of RNA crucial for protein synthesis) and pivot to safer, better-funded areas, or she could accept a demotion and leave the tenure track. Around the same time, she was diagnosed with cancer. Her husband who had traveled to Hungary was trapped by visa delays. The promise of academic life, prestige, security, recognition, dissolved quietly.

She chose to stay with mRNA and accepted the demotion.

Her salary dropped below that of her own technician. Over the years that followed, she would be demoted again and again. Four times in total. She kept working. She kept submitting grant proposals that were routinely rejected. She kept running experiments in borrowed lab space. I don’t think what sustained her was optimism. It had to be stubborn conviction. She believed the molecule itself was not the problem. She believed the way scientists were making it was.

In 1997, that belief found an unexpected ally.

At a photocopier, she met Drew Weissman, an immunologist newly arrived at Penn, struggling to develop an HIV vaccine. Weissman needed a way to stimulate the immune system without triggering destructive inflammation. Karikó told him she could produce any mRNA he wanted. He listened.

They began to collaborate, largely ignored, poorly funded, working at the margins of institutional interest. Together, they realized that synthetic mRNA being introduced into the body was setting off immune alarms because it lacked subtle chemical modifications present in natural RNA. The immune system was not rejecting the idea of instruction, it was reacting to how unnatural the message looked.

In 2005, they published their breakthrough. By replacing one building block in synthetic mRNA with a naturally occurring variant, they could prevent the immune system from overreacting. The molecule became both usable and safe. The solution was elegant, almost disappointingly simple in hindsight.

The world barely noticed.

Their paper was rejected by the most prestigious journals. When it was finally published, it attracted little attention. They expected funding t follow, but it did not. Stuff like that was career-changing, but they received none of that. For most of the scientific establishment, mRNA remained a curiosity, not a platform.

Years passed.

By 2013, the University of Pennsylvania declined to reinstate Karikó to a senior position. She was fifty-eight. American universities did not come calling. Instead, she accepted a role at a small German biotech company called BioNTech, where mRNA research continued quietly, without fanfare.

Then a virus arrived that did not respect timelines.

In early 2020, SARS-CoV-2, the specific virus that causes COVID-19, spread across the world with extraordinary speed. Governments needed vaccines in months, not years. Traditional vaccine methods could not move fast enough. Attention turned, suddenly and urgently, to mRNA. The technology offered something unprecedented. Once the genetic sequence of the virus was known, scientists could design an mRNA instruction telling human cells to produce a harmless piece of it, training the immune system without exposing the body to the virus itself. Again, the logic was: Instead of building from scratch and sending into the body, which would take years, why not just tell the body what to do?

Decades of ignored research became operational overnight.

Clinical trials followed. Results arrived in late 2020. The vaccines were highly effective. They were safe. They could be manufactured quickly. Millions of lives were saved.

When Karikó learned the trials had succeeded, she celebrated quietly. She locked herself in a room and ate an entire box of chocolate-covered peanuts.

In October 2023, the Nobel Committee awarded Karikó and Weissman the Nobel Prize in Physiology or Medicine. She had never been a tenured professor. She had been demoted repeatedly. Her work had been licensed and profited from by institutions that once discouraged it.

When asked how she endured decades of rejection, she said she felt successful because she had worked on something she believed was true. Recognition, she implied, was incidental.

Today, mRNA technology is being explored for cancer treatments, rare genetic diseases, and conditions that once seemed beyond reach.

Karikó now holds a professorship at the University of Szeged. She donated her Nobel Prize money to support scientific education in Hungary. She speaks without triumph, framing research not as heroism but as persistence.

For decades, mRNA looked like an idea that would never arrive. It survived not because institutions believed in it, but because one scientist refused to stop asking the same question in different ways.