The new strain of coronavirus identified in England is up to 70 per cent more transmissible, prime minister Boris Johnson has said, as the government announced further restrictions to curb the rapid spread of the mutated virus.
Scientists have confirmed that the variant is passed more easily between people than the previously dominant strain, raising concerns that NHS services could be overwhelmed over the Christmas period if the spread of the virus is not slowed.
According to government analysis, more than 60 per cent of new cases in London are currently linked to the new strain. It accounts for 59 per cent of cases in the east and 48 per cent in the southeast.
This has led to a recent jump in hospitalisations across all three regions, professor Chris Whitty, the government’s chief medical officer, said during a Downing Street briefing on Saturday.
If allowed to go unchecked, the new variant of the virus could increase the country’s R rate, which is estimated to be between 1.1 and 1.2, by 0.4 per cent.
Sir Patrick Vallance, the government's chief scientific adviser, said: “It’s taken off, it’s moving fast and it’s leading inevitably to a sharp increase in hospitalisations."
The government has insisted the variant does not cause a more serious disease and is unlikely to affect the nationwide rollout of Covid-19 vaccines.
The current tier 3 restrictions, which affect 38 million people in the country, are not enough to halt the spread of the new strain, Mr Johnson said on Saturday.
In response, a new set of tier 4 measures, including a “stay at home” order, are to be implemented across the capital and large swathes of southeast England from Sunday.
People will be advised not to enter tier 4 areas, while residents must not stay overnight away from home. People are still able to travel to work, if required.
Gyms, hairdressers and non-essential shops in the new severe level of restrictions will be ordered to close their doors just days before Christmas.
Similar to previous lockdowns, exemptions will apply for those in bubbles and people who need to travel for education, childcare purposes and unlimited amounts of exercise. Individuals will able to meet with one other person in a public space outside in tier 4 areas.
In areas of the country not affected by new measures, the planned relaxation of rules from 23-27 December, will be scrapped. Instead, people will only be able to form bubbles for a single day, on Christmas Day.
Mr Johnson said: “I know how disappointing this will be. But we have said throughout this pandemic that we must and we will be guided by the science.
“When the virus changes its method of attack we must change our method of defence ... there is no alternative.”
Sir Patrick said analysis showed that the new coronavirus strain contains 23 different genetic changes, many associated with the so-called “spike” protein – the part of the virus which is responsible for binding to human cells.
These variations are now thought to make it easier for the virus to infect people. Sir Patrick said it was a “concern” how the new version looks, which is suspected to have first emerged in London or Kent around September.
However, he said that there was no evidence that the new variant “causes more trouble” and would make people sicker.
Sir Patrick added there were "theoretical reasons" to suggest that it may alter an immune response, but said 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. “We need to keep vigilant about this.”
The government said the new variant was also likely to be present in other countries beyond England.
"We think it may be in other countries as well," Sir Patrick said. "It may have started here, we don't know for sure."
Separately, Professor Whitty said people considering leaving tier 4 areas now should unpack their bag and stay at home.
“My short answer would be 'please unpack it at this stage',” he said. “If they were to go with this new variant, unwittingly, to an area that has a low prevalence and starts this being seeded even more outside the high prevalence areas that would be a significant risk to the area they went to.
“That is the reason we are really keen that people do not go from these areas.”
He indicated that tier 3 and tier 2 restrictions had proven ineffective at controlling the new variant.
Scientists said the new interventions were “essential” to combat the “very concerning” strain.
“The variant has a number of concerning mutations that mean we should control transmission through social restrictions whilst we work to learn more about the impact of these mutations on how the virus behaves,” said Ravindra Gupta, a professor of clinical microbiology at the University of Cambridge.
He called for a targeted regional rollout of the vaccine to help control the spread of the virus.
Dr Jeffrey Barrett, director of the Covid Genomics Initiative at the Wellcome Sanger Institute, said the new strain was “unlike anything we have seen so far in the pandemic.
“The new restrictions announced today are an entirely justified response to the rapidly developing situation,” he added.
Daniel Altmann, a professor of Immunology at Imperial College London, has meanwhile said that the immune response induced by the Covid-19 jabs “would be unchanged by the mutations – so the vaccines will still work.”
The UK has notified the World Health Organisation over the new strain of coronavirus, with scientists continuing to assess the latest mutation.
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