Boris Johnson has told ministers that the Omicron variant of coronavirus appears to be “more transmissible” than Delta.
The Prime Minister updated his Cabinet on the latest situation on Tuesday, as a scientist warned cases of the Omicron variant in the UK are soon expected to be higher than in some African countries on the travel red list.
The PM’s official spokesman said: “The Prime Minister said it was too early to draw conclusions on the characteristics of Omicron but early indications were that it is more transmissible than Delta.”
But the spokesman said there was no Cabinet debate on whether to introduce Plan B to control the virus this winter.
Mr Johnson later said “now is the time” for people to get a booster jab.
“The booster programme is the fastest in Europe, I think we have done more boosters than any comparable country,” he told reporters.
“That doesn’t mean it couldn’t go faster.”
He added: “I would certainly say to people that now is the time to get it and, of course, from Monday, we will be contracting the interval, so you go down to three months and that will lead to a big uptick in the programme as well.”
It comes as Tim Spector, professor of genetic epidemiology at King’s College London, said early data suggested cases of the coronavirus mutation are doubling every two days, putting it on course to overtake some of the 11 countries from where travellers to the UK are now required to quarantine, to try to stymie community transmission.
New rules came into force in the early hours of Tuesday, requiring all travellers to take a pre-departure test before heading to England. They will not be able to travel if they test positive.
Professor Spector told BBC Breakfast there was “very little point” in having travel restrictions if case numbers exceeded those in red list countries.
He said: “The official estimates are about 350-odd Omicron cases, and because the current testing is missing a lot of those, it’s probably at least 1,000 to 2,000 I would guess at the moment.
“And we are expecting this to be doubling about every two days at the moment, so if you do your maths – assume it’s 1,000 at the moment, and you think it’s going to be doubling every two days, you can see that those numbers are going to be pretty (high) certainly in about 10 days’ time.
“By that time we’ll probably have more cases than they will in some of those African countries.
“So I think these travel restrictions do perhaps have their place initially, when cases are really low here and really high in the other country, but when we reach that equilibrium, there’s very little point in having them, in my opinion.”
A total of 437 cases of Omicron had been confirmed across the UK as of Tuesday, 333 in England, 99 in Scotland and five in Wales.
Dr Jeffrey Barrett, director of the Covid-19 genomics initiative at the Wellcome Sanger Institute, said he thought Omicron would take over from Delta in the UK as the dominant variant of coronavirus “within a matter of weeks”.
He told BBC Radio 4’s Today programme: “I think we can now say that this variant is spreading faster in the UK than the Delta variant at the same time, and that’s something that I think was unclear until very recently.
“The fact that so far we have seen not very many severe cases of Omicron, maybe because it is infecting these individuals with some amount of immunity, and that’s good news that they aren’t having tonnes of severe disease, but I think it is too soon to assume that fundamentally Omicron is more mild than, say, Delta.”
Prof Spector added: “If early reports pan out – we don’t absolutely know this, we’ve got hardly any data in this country where we have high rates of vaccination – but if we assume that it is not more severe and possibly milder than Delta, but it’s much more transmissible.
“So it means that perhaps twice as many people are going to pass it on from when someone gets it in a crowd.
“That’s going to be good news for the individual because we have less cases going to hospital, and partly this is due to our high vaccination rates.
“But it also means that eventually you will get more deaths and problems, because nearly everyone is infected or reinfected.
“And so, this means that for the country as a whole, it could be worse news but better for the individual.
“So it’s absolutely no reason for complacency.”
Health Secretary Sajid Javid told MPs on Monday that none of the Omicron variant cases identified to date had resulted in hospital admission.
On Tuesday, Wales’ health minister Eluned Morgan said they were expecting a “significant wave” of Omicron to hit Wales, while Scotland’s First Minister Nicola Sturgeon predicted a “continued and potentially rapid rise in cases” of the variant in the days ahead.
Meanwhile, the UK has reported its highest weekly number of new cases of Covid-19 since January.
A total of 336,893 new cases have been reported in the past seven days, including 45,691 on Tuesday, Government figures show.
This is the highest number for a seven-day period since the week to January 16, when 339,956 were reported.
Weekly cases during the second wave of the virus peaked at 417,620, for the seven days to January 9.