Top US infectious disease expert Anthony Fauci said there was still a danger of a surge in hospitalisation due to a large number of coronavirus cases even as early data suggests the Omicron Covid-19 variant is less severe.

"The only difficulty is that if you have so many cases, even if the rate of hospitalisation is lower with Omicron than it is with Delta, there is still the danger that you will have a surging of hospitalisations that might stress the healthcare system," Fauci said in an interview on Sunday with CNN.

The Omicron variant was estimated to be...