The strain, named Omicron and designated a “variant of concern” by the World Health Organization (WHO), reached Belgium after being discovered in South Africa.
The WHO has warned that preliminary evidence suggests the variant has an increased risk of reinfection and may spread faster than other strains.
A number of pharmaceutical companies have said they are working to adapt their vaccines in light of the emergence of Omicron.
Health Secretary Sajid Javid said there was “huge international concern” over the strain after banning flights from South Africa, Botswana, Lesotho, Eswatini, Zimbabwe and Namibia to limit its spread.
Mr Javid told MPs the variant could be more transmissible, make existing vaccines less effective and hamper one of the UK’s Covid treatments, Ronapreve.
Ministers were facing calls to go further to prevent a wave of the new variant from arriving in Britain as a Delta wave is underway, with Belgium becoming the first EU country to announce a case.
Professor John Edmunds, who advises the government on the Scientific Advisory Group for Emergencies (Sage), warned that this could create a “very, very, very difficult situation.”
The EU, US and Canada all followed Britain’s decision to impose travel restrictions on visitors to southern Africa before the WHO added the strain, also known as of B.1.1.529, to its highest category for variants of concern.
WHO experts have said there is early evidence suggesting that Omicron has an “increased risk of reinfection” and its rapid spread in South Africa suggests it has a “growth advantage”.
Novavax said it “has already started the development of a novel advanced recombinant protein based on the known genetic sequence of B.1.1.529 and will be ready to start testing and manufacturing in the coming weeks.”
Moderna said: “Since the start of 2021, Moderna has put forward a comprehensive strategy to anticipate the new variants of concern.
“This strategy includes three levels of response if the currently authorized booster dose of 50 µg (micrograms) mRNA-1273 is insufficient to enhance the waning immunity against the Omicron variant.”
Pfizer and BioNTech said that in the event of a variant that could escape the effects of the vaccines, the company expects “to be able to develop and produce a bespoke vaccine against that variant in approximately 100 days, subject to l ‘regulatory approval’.
AstraZeneca said it has “developed, in close collaboration with the University of Oxford, a vaccine platform that allows us to respond quickly to new variants that may emerge” and “is already researching places where the variant has been identified”.
The company is also testing its combined antibody drug against the new variant and hopes that it “will retain its effectiveness because it includes two potent antibodies with different and complementary activities against the virus.”
Professor Sir Andrew Pollard, director of the Oxford Vaccine Group, expressed cautious optimism that existing vaccines might be effective in preventing serious illnesses caused by the Omicron variant.
He told BBC Radio 4’s Today show that most of the mutations are in similar regions seen in other variants so far, adding: “This tells you that despite these mutations existing in other variants , vaccines continued to prevent serious illness over time via Alpha, Beta, Gamma, and Delta.
“At least from a speculative point of view, we have some optimism that the vaccine should still work against a new variant for severe disease, but we really have to wait several weeks for that to be confirmed.
“It is extremely unlikely that a restart of a pandemic in a vaccinated population as we saw last year will occur.”
Professor Pollard said a new vaccine to fight Omicron could start “very quickly” if needed.
“The processes of developing a new vaccine are getting more and more well oiled, so if that is necessary, it is something that could be moved very quickly.”
No cases of the new strain have been detected in the UK, but its arrival in Belgium – after being discovered in Botswana, Hong Kong and Israel – has heightened concerns.
Marc Van Ranst, a virologist at the Rega Institute in Belgium, said a sample was confirmed to be variant in a traveler who returned from Egypt on November 11 before showing symptoms for the first time 11 days later.
The six African countries were added to the UK travel red list on Thursday evening and passengers arriving in the UK from these countries from 4 a.m. on Sunday will be required to book and pay for an approved hotel quarantine by the government for 10 days.
Downing Street urged anyone who has recently arrived from these countries to get tested.
Mr Javid said discussions were underway on the prospect of adding more countries to the red list, telling the Commons that the government “will not hesitate to act if we need to”.
Boris Johnson had a telephone interview with South African President Cyril Ramaphosa on Friday afternoon after Foreign Minister Naledi Pandor said the flight ban “appeared to have been rushed”.
The Prime Minister “commended South Africa’s rapid genomic sequencing” and its “leadership in transparent sharing of scientific data,” Downing Street said.
“They discussed the challenges posed globally by the new variant of Covid-19 and ways to work together to address it and reopen international travel,” a statement read.
Professor Edmunds said the new strain “is of huge concern” and “all data suggests” that it would be able to evade current immunity.
“We are concerned that it will to a large extent,” he told BBC Radio 4’s PM program.
Professor Edmunds urged ministers to consider extending travel restrictions and to prepare a plan to deal with Omicron because “at some point we will have this variant here in the UK”.
Professor Calum Semple, another Sage adviser, told BBC Breakfast: ‘If you can slow the entry of the virus into the country because you are timed for the recall campaign to get ahead of it, and that (then ) lets scientists see if there is anything to worry about, which it does not appear to be.
“The virus will come here by hook or by crook, eventually it will come here because people are asymptomatic, but that doesn’t mean we shouldn’t try to slow it down. “
He said he was an advocate for masks and hand washing and said: “I feel particularly uncomfortable in public transport. I am pro-mask in shops and public transport. We still have high levels of coronavirus but the vaccines work. “
Professor Semple encouraged people to get vaccinated against the coronavirus.
Professor Brendan Wren, of the London School of Hygiene and Tropical Medicine, said people should “stay calm and not overreact”, adding that scientists can “easily modify vaccines to respond to new variants” .
Optimistically in the Daily Mail, he wrote: “In the arms race against the virus, humanity is winning – and we are well prepared. This is not the last time that another variant will see the light of day.
“In the meantime, it is essential to remember to remain calm and not to overreact.”
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