The story illuminates the way that many scientific discoveries become life-changing innovations: with decades of dead ends, rejections and battles over potential profits, but also generosity, curiosity and dogged persistence against scepticism and doubt. “It’s a long series of steps,” says Paul Krieg, a developmental biologist at the University of Arizona in Tucson, who made his own contribution in the mid-1980s, “and you never know what’s going to be useful”.

Hundreds of scientists had worked on mRNA vaccines for decades before the coronavirus pandemic brought a breakthrough.