MAINZ, Germany—On a Friday in late January, Ugur Sahin received an email with bad news: A new study of a deadly new coronavirus in China suggested it was more infectious than previously believed. The outbreak, he believed, had the potential to grow into a pandemic.
The following Monday, the German scientist and chief executive of biotech firm BioNTech SE summoned his board to announce that the company, which had been developing next-generation cancer treatments, would start work on a Covid-19 vaccine. Human trials would need…
