The emergence of the Covid-19 Omicron variant means booster jabs should be given sooner, a Norfolk virus expert has said.

And Prof Paul Hunter, from the University of East Anglia's School of Medicine, backed the government's decision to make mask wearing in shops and on public transport compulsory again from Tuesday.

Eastern Daily Press: Prof Paul Hunter.Prof Paul Hunter. (Image: UEA)

An announcement is also expected on whether boosters should be given to more people - and more quickly.

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The Joint Committee on Vaccination and Immunisation is looking at whether boosters can be extended down from the over-40s to the over-18s.

The experts will also consider whether second doses should be offered to 12 to 15-year-olds, and whether the current six-month wait before a booster jab could be reduced.

Health secretary Sajid Javid said he expects to receive new advice "imminently" and Prof Hunter said he believed the wait should be cut.

He said: "Personally, I think they should bring it down to five months. Any boosters they can do will provide people with extra protection. The booster does give a pretty impressive boost to antibodies."

On the reintroduction of compulsory mask wearing in shops and on public transport, Prof Hunter said: "As the prime minister said at the press conference, it is not going to stop the transmission of this variant, but it may slow it a bit until we get a handle on what to do with it."

Two cases have been identified in England - in Nottingham and Essex. Both are linked to travel to south Africa, where the variant was first identified.

Prof Hunter said: "All the signs are that it will spread and it probably is already."

But he said: "The emerging consensus among people who understand this stuff is that it probably isn't going to be a disaster.

"It will undoubtedly cause problems, but the anecdotal information coming out of south Africa is that it is not causing serious illness.

"It is possible that is because those people have previously been infected, so have some immunity.

"But at, the moment, these are early days and we do not have the evidence to know quite what we are dealing with."