UK scientists are "more concerned" that the South African and Brazilian Covid-19 may be less susceptible to vaccines.
Chief Scientific Adviser Sir Patrick Vallance has made the warning at today's Downing Street press conference, saying the variants which had emerged in South Africa and Brazil may be less susceptible to the vaccines that have been developed.
Sir Patrick told the Downing Street press conference: "We know less about how much more transmissible they are.
"We are more concerned that they have certain features that they might be less susceptible to vaccines.
"They are definitely of more concern than the one in the UK at the moment, and we need to keep looking at it and studying it very carefully."
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Sir Patrick said 44 people in the UK have the South African variant of coronavirus, according to figures from PHE, with a maximum estimate of 71 having the variant.
"It's important to recognise that there's no evidence that the South African or Brazilian variants have transmission advantages over what is already here, so they won't be expected to spread more quickly or take over," he added.
"They may actually have less, we don't know."
The Prime Minister told the press conference: "We've been informed today that in addition to spreading more quickly it also now appears that there is some evidence that the new variant, the variant that was first identified in London and the South East, may be associated with a higher degree of mortality."
Sir Patrick also moved to downplay concerns raised in Israel that a single dose of the Pfizer vaccine may not be as effective as previously thought.
He told the media briefing: "In terms of the Israeli data, I think that was information from one of the organisations that organises health in Israel, I think there are four, and it was preliminary data that came out on the numbers.
"I think the Israeli health ministry has said they're not entirely sure those are the final data and they're expecting the effects to increase so I think it's very preliminary.
"These are preliminary information from a subset of people, they haven't followed people for long enough. We had a discussion with the Israeli advisers yesterday and they are expecting to get more information over the next few weeks.
"And I think we are going to have to monitor this very carefully, we're going to have to keep looking at data and understanding the performance of vaccines in the real world."
The UK's "awful" death rate will stay "high for a little while" before declining, regardless of the impact of the new variant, warned the chief scientific adviser.
"The death rate is awful and it's going to stay, I'm afraid, high for a little while before it starts coming down, that was always what was predicted from the shape of this," he said.
"I think the information about the new variant doesn't change that."
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