Can the molecule behind the Pfizer and Moderna jabs revolutionise medicine? When Dr Katalin Kariko first started her research of mRNA, she had a difficult time convincing peers to take her discoveries seriously. But fifteen years later, her work paved the way for the rapid development of many coronavirus vaccines. Though mRNA had been rarely rested on humans before the pandemic, the vaccines that use its technology work incredibly well, with a considerably higher efficacy rate than rival inoculations. Here, David Crow reveals why supporters of molecular technology claim it could tackle thousands of other illnesses — from cancer to cystic fibrosis. However, other specialists believe that it will be decades before it is fit for purpose and that the risks of failure are high.