I will be eternally grateful to all the scientists who made the mRNA vaccines that have saved millions of lives during he COVID pandemic. Today two of them received the Nobel Prize for medicine: Two scientists won the Nobel Prize in medicine on Monday for discoveries that enabled the creation of mRNA vaccines against COVID-19 that were critical in slowing the pandemic — technology that’s also being studied to fight cancer and other diseases. Hungarian-American Katalin Karikó and American Drew Weissman were cited for contributing “to the unprecedented rate of vaccine development during one of the greatest threats to human health,” according to the panel that awarded the prize in Stockholm. The panel said the pair’s “groundbreaking findings … fundamentally changed our understanding of how mRNA interacts with our immune system.” Traditionally, making vaccines required growing viruses or pieces of viruses and then purifying them before next steps. The messenger RNA approach starts with a snippet of genetic code carrying instructions for making proteins. Pick the right virus protein to target, and the body turns into a mini vaccine factory. In early experiments with animals, simply injecting lab-grown mRNA triggered a reaction that usually destroyed it. Those early challenges caused many to lose faith in the approach: “Pretty much everybody gave up on it,” Weissman said. But Karikó, a professor at Szeged University in Hungary and an adjunct professor at the University of Pennsylvania, and Weissman, of the University of Pennsylvania, figured out a tiny modification to the building blocks of RNA that made…