Health Secretary Sajid Javid warned the new strain may be more infectious than Delta and vaccines may be less effective against it
The Health Secretary delivered an update to the Commons after the UK announced it was suspending flights from six southern African countries amid fears over the B.1.1.529 strain.
Transport Secretary Grant Shapps said the UK was “buying time” by adding South Africa, Botswana, Lesotho, Eswatini, Zimbabwe and Namibia to its travel red list, with arrivals ordered to stay in quarantine hotels from 4am on Sunday.
British health officials are scrambling to identify people who arrived in the UK in recent days from these countries.
Mr Javid told MPs: “We are concerned that this new variant may pose substantial risk to public health. The variant has an unusual large number of mutations.”
Early indications show the current vaccines “may be less effective against it” and it may be more transmissible, he said.
It may also impact the effectiveness of Ronapreve, a critical treatment for the virus in adults.
There are currently no cases of the new strain in the UK but Mr Javid said it was highly likely that it has begun to spread to other countries.
The Health Secretary said: “I must stress this a fast-moving situation and there remains a great deal of uncertainty.”
More countries could be added to the red list if the situation worsens, he told Parliament.
Mr Javid said: “We are going primarily by where the new variant has been detected at this point, and that’s been confirmed in two countries in southern Africa – South Africa and Botswana.
“We’ve included the four other countries I mentioned earlier in southern Africa as a precaution.”
He added: “We are keeping this under review and there’s very live discussions going on about whether we should and when we might add further countries, and we won’t hesitate to act if we need to do so.”
The Health Secretary went on: “This variant is a reminder for all of us that this pandemic is far from over.
“We must continue to act with caution and do all we can to keep this virus at bay, including once you’re eligible getting your booster shot.
“We’ve already given over 16 million booster shots. The booster jab was already important before we knew about this variant, but now it could not be more important.”
He urged people to go out and get their booster jabs to make sure their immunity levels are topped up, saying: “Make this your booster weekend”.
The Government is still resisting a move to Plan B measures – but Mr Javid warned that “if we need to go further, we will”.
Asked about Covid mitigations by Labour MP Rachel Maskell, Mr Javid said: “The Plan A, the policies that we put in place, they remain the policies that I think we need at this time.
“She won’t be surprised to know we do keep this under review and if we need to go further, we will.”
Earlier, UKHSA chief medical adviser Dr Susan Hopkins said it was possible that the new strain had already reached the UK and described it as the “most worrying” variant seen by scientists.
The new strain has been found in South Africa, Botswana, Hong Kong and Israel.