Air travel from Europe should be suspended to all countries where the new COVID variant has been detected, the European Commission president said.
Ursula von der Leyen also said vaccine producers are obliged under their contracts to adapt their jabs as soon as a new variant emerges.
She called for the new travel measures after the first European case of the B.1.1.529 variant first detected in South Africa was identified in Belgium.
“It is now important that all of us in Europe act very swiftly, decisively and united,” she said.
All air travel to these countries should be suspended until we have a clearer understanding about the danger posed by this new variant.”
The Commission president said those arriving from regions where the variant has been detected should be party to “strict quarantine rules”.
She said the EU was “taking it very seriously” and warned the variant could spread “worldwide in months”.
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It “could lead to the emergence and spread of even more concerning variants”,” she added.
Marc Van Ranst, who works with the Rega Institute in Belgium, said a sample confirmed as the new variant was from a traveller who returned to Belgium from Egypt on 11 November and they started to show symptoms on 22 November.
Since midday on Friday, flights from six southern African nations – South Africa, Namibia, Lesotho, Botswana, Eswatini and Zimbabwe – have been suspended until 4pm on Sunday.
After that, new arrivals of UK and Irish residents into the UK from those countries will be required to quarantine in hotels after they were placed on the red list on Thursday night.
Non UK and Ireland residents will not be allowed in from those countries.
UK Health Secretary Sajid Javid said experience has shown “we must move quickly and at the earliest possible moment”.
He said there are concerns the variant may be more transmissible, make vaccines less effective and may affect one of the UK’s COVID treatments, Ronapreve.
Mr Javid told the Commons it was “highly likely” the variant had already spread from southern Africa to other countries.