Stéphane Bancel said the high number of Omicron mutations on the spike protein, which the virus uses to infect human cells, and the rapid spread of the variant in South Africa suggested that the current crop of vaccines may need to be modified next year.

“There is no world, I think, where [the effectiveness] is the same level . . . we had with [the] Delta [variant],” Bancel told the Financial Times in an interview at the company’s headquarters in Cambridge, Massachusetts.

He added: “I think it’s going to be a material drop. I just don’t know how much because we need to wait for the data. But all the scientists I’ve talked to . . . are like, ‘This is not going to be good’.”