It had been known for months that the Kent variant was far more infectious than the original strain, thanks to mutations on its spike protein which make it easier to bind to human cells.
Professor Peter Horby, a senior SAGE expert who reviewed the data, said today the mutations which make it more transmissible could also be behind its increased lethality.
He said: ‘If you’re getting much stronger binding… the virus is able to spread between cells quicker and that may increase rate of disease and rate of inflammation.’
But Professor Horby added that there was ‘no evidence’ the Kent strain is resistant to vaccines or even current Covid treatments.
Eight separate analyses comparing death rates between the two dominant Covid strains currently circulating through England concluded the Kent one was more deadly.
Professor John Edmunds, a chief scientist behind one of the eight studies, said that although the finding was ‘concerning’, the proportion of infected people who die from the disease could still be lower than in the spring because medics have more approved medicines in their arsenal and doctors have got better at treating the virus.
The Kent coronavirus variant may be deadlier than the original strain because it multiplies faster inside the lungs, SAGE scientists Peter Horby (left) and John Edmunds (right) warned today
A mutation on the Kent variant’s spike protein — which protrudes from the coronavirus and hijacks human cells — is thought to make it better at infecting people. This so-called N501Y mutation could also be what is making the variant more deadly than older versions, according to Professor Horby
The Kent variant was first picked up in the South East in late September and has quickly gone on to become the dominant strain in the UK.
It is responsible for the winter wave of infections and hospital admissions that plunged England into its third national lockdown.
What do we know about the Kent variant?
Name: B.1.1.7, formerly VUI-202012/01
Where did it come from? The variant was first found in Kent and can be traced back to September 2020. Scientists noticed that it was spreading in November and it was revealed to the public in December.
What makes it new? The variant, which is a version of the SARS-CoV-2 coronavirus that causes Covid-19, has a series of mutations that change the shape of the spike protein on its outside. The main one is known as N501Y. This appears to make it better able to stick to the cells inside the body and makes it more likely to cause infection and faster to spread.
How did that happen? Viruses, particularly ones spreading so fast and in such huge numbers, mutate all the time. To reproduce they basically force living cells to copy and paste the viral genetic code, and this can contain errors that lead to slightly different versions of the virus. Often these mutations make no difference but, if they make the virus stronger, they can stick around for further generations and become the norm.
What can we do about it? Nothing much. People who catch the virus won’t know which type they have, and it will still cause the same symptoms and illness. Officials can try to contain it by locking down the areas where it is most prevalent, but if it is stronger than other versions of the virus it will eventually spread everywhere and become dominant as long as people continue to travel.
Will our vaccines still work? Yes, it’s very likely they will. Scientists on SAGE are fairly sure the mutations the Kent variant carries do not significantly affect how well the immune system can handle it. People who have a vaccine modelled on an older version of the virus, or who have been infected with Covid-19 before, are likely to be immune to it. This is because the main mutations are only on one part of the spike protein, whereas the immune system is able to target various other parts of the virus.
UK studies have shown the variant is between 50 and 70 per cent more infectious than the original strain.
A mutation on the variant’s spike protein — which protrudes from the coronavirus and hijacks human cells — is thought to make it better at infecting people.
This so-called N501Y mutation could also be what is making the variant more deadly than older versions, according to Professor Horby.
He said: ‘The N501Y change increases its strength of binding to cells. If you’re getting much stronger binding you may need much lower dose to get infected.
‘If it’s able to spread between cells quicker that may increase the rate of disease and the rate of inflammation.
‘But there is no evidence this virus [variant] would in any way behaves different to treatments currently being used. Those treatments are not related to the virus but instead related to the host response.’
There are only a handful of drugs which have been scientifically proven to treat Covid and reduce death rates, including the cheap steroid Dexamethasone and the anti-inflammatory drugs tocilizumab and sarilumab.
All of the approved treatments focus on reducing the body’s sometimes fatal overreaction to Covid.
In some people – particularly the elderly and those with underlying health conditions – their immune systems go haywire while trying to clear Covid-19 in the body.
The deadly complication sees immune molecules start to attack healthy tissue as well, including vital organs such as the heart and lungs.
Professor Edmunds said today that although the Kent variant is more deadly than regular Covid, the overall Covid death rate could be lower than in spring.
Numerous studies have shown the ICU mortality rate for Covid patients has dropped by about a third now compared to the peak in April.
The survival chances are thought to be higher now than at the beginning of the Covid pandemic because of the emergence of new treatments.
Doctors are also more reluctant to put Covid sufferers on ventilators than they were in spring, after it became clear the machines made some patients worse.
Number 10 was accused of scaremongering on Friday when Boris Johnson and his chief scientists announced the terrifying development that the Kent strain was more deadly without providing much supporting evidence.
Members of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), a subcommittee of SAGE, compiled 10 different studies looking into the lethality of the new strain.
Eight found the variant was more deadly than previous strains, which led to the group concluding there was a ‘realistic possibility’.
But the findings from the studies varied wildly and had wide confidence intervals, which led to accusations that No10 was premature in announcing the development.
Chief Scientific adviser Sir Patrick Vallance even admitted during the press conference evidence the strain is more deadly is still ‘weak’.
Responding to those criticisms, Professor Edmunds said today: ‘I think it’s pretty solid [the evidence] and if we had not said something about it, you’d be criticising the Government for not saying something about it and sweeping it under the carpet.’
Asked about what Kent strain’s increased deadliness means for lockdown, Professor Graham Medley, another SAGE member, said the new analysis was ‘concerning’ but doesn’t mean we need to do anything hugely different.
‘The situation is we’ve got about 100,000 infections a day and that is very serious. Additional mortality from new variant is concerning but it doesn’t change the effect of 100,000 [cases] ,that’s the main cause of the deaths.
‘If we want to reduce number of deaths we have to reduce incidence. Reduction of cases is the critical thing.’
WHAT DO STUDIES SUBMITTED TO SAGE ON THE KENT STRAIN’S LETHALITY SHOW?
IMPERIAL COLLEGE LONDON (1)
IMPERIAL COLLEGE LONDON (2)
LONDON SCHOOL OF HYGIENE & TROPICAL MEDICINE (1)
LONDON SCHOOL OF HYGIENE & TROPICAL MEDICINE (2)
UNIVERSITY OF EXETER
COVID-19 CLINICAL INFORMATION NETWORK
PUBLIC HEALTH ENGLAND (1)
PUBLIC HEALTH ENGLAND (2)
PUBLIC HEALTH ENGLAND (3)
PUBLIC HEALTH ENGLAND (4)
HOW MUCH MORE DEADLY?
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