There are fears Omicron is less susceptible to vaccines than the other variants seen so far, and a third injection will be needed to increase protection. Professor Van-Tam said the Omicron

variant, which he described as the "new kid on the block", was concerning. He told a Downing Street press conference that the number of mutations present in the Omicron variant

"makes us worry about a possible effect on vaccine effectiveness". As well as the change in booster rollout, on Saturday, Boris Johnson announced fresh Covid restrictions,

including the reintroduction of face masks in shops and public transport. The Prime Minister said that he was "confident" that this year's Christmas will be "considerably