mRNA vaccine

The idea seemed elegant but impractical: instead of injecting weakened viruses or viral proteins, inject the genetic instructions for the body to make those proteins itself. Cells would read the mRNA blueprint, produce the target antigen, and trigger an immune response—no pathogen required. Scientists had understood mRNA's role as cellular messenger since the 1960s, but naked mRNA degrades almost instantly when injected into tissue. For decades, mRNA vaccines remained a theoretical curiosity.

The adjacent possible assembled gradually. Katalin Karikó, a Hungarian-born researcher at the University of Pennsylvania, spent the 1990s and 2000s solving mRNA's fragility problem. Working with immunologist Drew Weissman, she discovered that modifying one nucleotide—replacing uridine with pseudouridine—dramatically reduced the immune system's inflammatory response to foreign mRNA, allowing it to survive long enough to be translated into protein. Their 2005 paper was largely ignored; funding agencies questioned why anyone would pursue such an unpromising approach.

Lipid nanoparticle technology provided the delivery mechanism. Developed through years of work on gene therapy, these fatty bubbles could protect mRNA and ferry it into cells. By 2010, companies like Moderna (founded by Derrick Rossi based partly on Karikó and Weissman's work) and BioNTech (founded by Ugur Sahin and Özlem Türeci) were betting on mRNA platforms. Neither had brought a vaccine to market. The technology remained unproven at scale.

Then COVID-19 arrived. On January 10, 2020, Chinese scientists published SARS-CoV-2's genome sequence. Within days, Moderna and BioNTech-Pfizer had designed vaccine candidates targeting the spike protein. What typically took years—developing, testing, manufacturing vaccines—compressed into months. The first mRNA vaccine doses were administered in December 2020, less than a year after the virus was sequenced. By late 2021, billions of doses had been delivered globally.

The pandemic proved mRNA's advantages: vaccines could be designed in days once a pathogen's sequence was known; manufacturing scaled faster than traditional methods; production didn't require growing actual viruses. The technology also demonstrated unprecedented efficacy—over 90% protection against symptomatic disease in trials. Karikó and Weissman received the 2023 Nobel Prize in Physiology or Medicine for their foundational work. By 2025, mRNA platforms were in development for influenza, HIV, cancer therapies, and autoimmune diseases. The pandemic had validated a technology that spent decades in the wilderness, revealing that its time had simply not yet come.