Stéphane Bancel told Financial Times 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’.”

The new COVID-19 variant was first detected in southern Africa, which has led to a surge in infections in South Africa.

The World Health Organisation (WHO) has declared the recently-detected B.1.1.529 strain of COVID-19 as a variant of concern and named it as Omicron.

"Based on the evidence presented indicative of a detrimental change in Covid-19 epidemiology... the WHO has designated B.1.1.529 as a variant of concern (VOC), named Omicron," the UN health agency said in a statement.

This puts Omicron into the most-troubling category of COVID-19 variants besides the globally-dominant Delta.

The variant has also been detected in the United Kingdom, Botswana, Hong Kong, Israel and Belgium.