The new variant of Covid-19 could drive the R number up by as much as 0.4, prime minister Boris Johnson has revealed.
He told a Downing Street press conference that it is behind a rapid escalation of cases in London and the south east.
He said there was "no evidence" it was any more severe strain or could cause more mortality but it "does spread more easily".
"It could increase the R number by as much as 0.4," he said. "It could be 70% more transmissable."
What do we know about the new variant?
Chief Scientific Adviser Sir Patrick Vallance said the variant was displaying 23 different changes to the original Covid-19 virus, many of them specifically linked to the proteins.
He added: “This is an unusually large number of variants, it’s also got variants in areas of the virus that are known to be associated with how the virus binds to cells and enters cells.
“So there are some changes which cause concern in terms of how the virus looks.”
He posed three questions:
1: Does the new variant transmit more readily? The new variant was first identified in September in London and Kent, said Sir Patrick. By November, 28% of all Covid cases were traced to the new variant - but by the week beginning December 9, that figure had risen to 60%. "It moves fast and has become the dominant variant," he said. "This new variant not only moves fast - but it is beating all the other variants."2. Does it make people sicker? Sir Patrick said that based on research so far, the new variant does not appear to cause more severe reactions or lead to more hospitalisations.
3. Does it alter the immune response caused by vaccines? Again, said Sir Patrick, based on what is known right now, the variant does not appear alter the response of the vaccine - ie make it less effective. He said there were “theoretical reasons” to suggest that it may alter an immune response though there was no evidence for this. “Our working assumption from all the scientists is that the vaccine response should be adequate for this virus,” he told the Downing Street press conference. However, he added: “We need to keep vigilant about this.”
Sir Patrick said it was not known where the variant originated - it may have started in England - but may also be in other parts of the world.
Focusing on NHS data for the south-east and east of England and London, Sir Patrick said hospital admissions per day from September to now had gradually increased, with a “very sharp increase” during December.
“This virus has taken off, it’s moving fast and it’s leading inevitably to a sharp increase in hospital admissions,” he said.
How widespread is the new variant?
Screening tests suggested that in the South East 43% of the virus was now the new variant, in the East of England it is 59% and in London 62%.
“Those have gone up very, very fast over the last few weeks,” Chief Medical Office Prof Christ Whitty told the Downing Street news conference.
“This has really gone incredibly quickly. They are much lower in other areas of the country.”
The number of people in hospitals was also increasing in areas where the new variant was more prevalent.
“In the areas where this is very, very common you are seeing rates of increase of maybe 36% in the East of England, 34% in London and 28% in the South East.
“These are the areas which have actually had significant numbers of this new variant.”
How worried should we be about the new variant?
Professor Chris Whitty said that while the new strain of coronavirus will make things much worse, if the vaccine works against it there was room for optimism.
He added: “I think this is a situation which is going to make things a lot worse, there are some really optimistic things if you look once we get the vaccine out, assuming the vaccine works against this which I think at the moment is the working assumption.”
Prof Whitty added: “If we can take it down from a doubling time of every seven days, which it is in many areas, which is really fast, and pull it right out even if we don’t manage to get it all the way down, and we hope we will, at least then we are not going to have this sky-rocketing number, we are not going to have the numbers spreading out across the country.
“And that will give us a chance to get the vaccine out and protect the most vulnerable people so that if it does then escape what we have is the barrier of the vaccine to help protect them.”
What has Britain done about the discovery of the new variant?
The chief medical officer for England Professor Chris Whitty earlier said the UK had now informed the World Health Organisation that it had concluded the mutant strain could spread more quickly.
It has been named VUI-202012/01, the first variant under investigation in December.“As announced on Monday, the UK has identified a new variant of Covid-19 through Public Health England’s genomic surveillance,” he said in a statement.
“As a result of the rapid spread of the new variant, preliminary modelling data and rapidly rising incidence rates in the South East, the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) now consider that the new strain can spread more quickly.
“We have alerted the World Health Organisation and are continuing to analyse the available data to improve our understanding.
“There is no current evidence to suggest the new strain causes a higher mortality rate or that it affects vaccines and treatments although urgent work is under way to confirm this.
“Given this latest development it is now more vital than ever that the public continue to take action in their area to reduce transmission.”
Is it the first novel strain detected in the UK?
A number of variants have been detected using sequencing studies in the UK.
A specific variant (the D614G variant) has previously been detected in western Europe and North America, which is believed to spread more easily but not cause greater illness.
But it is thought this is the first strain that will be investigated in such detail by PHE.
What are the scientists doing now?
Scientists will be growing the new strain in the lab to see how it responds.
This includes looking at whether it produces the same antibody response, how it reacts to the vaccine, and modelling the new strain.
It could take up to two weeks for this process to be complete.
COG-UK is carrying out random sequencing of positive samples across the UK to compile a sequencing coverage report, which is sent to each of the four public health agencies each week.
It said random sampling is important to capture regional coverage.