Doctors in London started seeing changes last month with the outbreak of new Coronovirus variants in Britain. In hospital critical care units, they were seeing more young people and women with severe cases of Kovid-19, a disease that previously provoked its worst symptoms in older patients and men on a larger scale.
The shift — now supported by statistical studies — is part of an urgent puzzle facing British public-health officials as they rush to understand a strain of the virus that is more contagious and, some studies indicate, earlier It can be fatal compared to versions of.
An early hypothesis, scientists say, is that one of the genetic mutations of the virus makes it better to invade large numbers of cells inside the body, which can lead to severe disease in those who are only mild in previous Kovid-19 variants Or there were no symptoms.
David Strain, a physician and instructor at the University of Exeter’s medical school who is also treating Kovid-19 patients, said preliminary research has a picture of a virus variant that is like a burglar that is better off and breaking down and penetration. To weak cells. In this case, not in the houses.
Dr. “We think that is why it is making people sick as well as more communicable,” said Strain.
Virologists suspect that this is a particular mutation known as N501Y on a new type of spike protein that has enhanced its ability to enter and infect human cells and move more efficiently through the human body .
Some doctors, such as Drs. Strain, thinks that behind the rise in young people and women – who have become ill at low rates for most of the epidemic – is ending up in hospital.
Doctors and scientists say that some things have not changed with the new variant. Once hospitalized, patients are more likely to survive as before and doctors cannot tell from the symptoms that the patient has.
In London, in the south-east and east of England, where the new version was first identified in a test sample from Sept 20, the average age of patients admitted to intensive care units fell from 61.4 years between September and September to the end of November. By 58.9. Years from 1 December to 21 January.
In the same period, the proportion of women admitted to the ICU increased from 30.1% to 35.1%. Data from the rest of the country show a similar pattern.
Through December, the proportion of 18- to 54-year-old children admitted to English hospitals with Kovid-19 had also begun, before a national lockout was made on 4 January.
Not all doctors are convinced that this is explained by mutations in the new version. Some believe that this behavior may be a matter of change, with more people, especially young people, mixing and becoming infected during the holiday season.
For example, Luke Allen, a local physician in Oxford, said he is treating more younger patients, but he is seeing more Kovid-19 patients in general, and the proportion of people appears to be similar to the first peak .
He attributes the increased number to the greater communicability of the new version and the increased socialization during the holidays. “This increases our chances of contact,” Dr. Alan said.
There is still much debate as to whether the new version is actually fatal, as some research suggests.
The new version, which has become the dominant version across the UK, is estimated to be 30% to 70% more infectious than earlier varieties. Last week, a government health advisory panel said that studies showed that there was a real possibility that it could be 30% to 40% fatal compared to the previous version.
Advisers say their findings are temporary. “While there is uncertainty, we cannot always wait for certainty,” said Peter Horby, chairman of the panel, the new and emerging Respiratory Virus Advisory Group, or Nervtag.
Julian Tang, a clinical virologist and professor of respiratory medicine at the University of Leicester, said more evidence was needed to prove that the new version was fatal, noting that social mixing was allowed during the winter months There was a huge jump in hospitalization rates.
“Viruses are generally more communicable and less deadly,” he said.
The proliferation of new variants has subjected the state-run healthcare to unprecedented stress, with a huge increase in the number of people hospitalized with Kovid-19 and an increase in the number of deaths in the UK. Kovid-19-related deaths in Britain are close to 100,000 since the onset of the epidemic.
So far, the disease caused by the variant does not appear to be any different from that instigated by its ancestors, but because the virus itself is able to move more easily to a patient’s system, it can overcome the body’s immune response. Is, doctors suspect.
“If you’re getting too strong a binding, you may need a lower infectious dose to get infected, which will increase the risk of transmission,” Dr. Hornby said. “Then, if it is able to spread between cells very quickly within the lungs, it can increase the rate of disease and the rate of inflammation that can progress faster than your body.”
To determine how deadly the new version was, scientists looked at data from about 850,000 cases of coronovirus tested in the community, where they knew which version of the virus each contained, killing 1,400 to 1,900 people. Had gone.
“You have to compare people who are similar to each other,” said John Edmonds, author of a study at the London School of Hygiene and Tropical Medicine.
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Researchers matched groups of people based on age, gender, and ethnicity, as well as income and where they lived, so as to minimize the effects that mortality could have on them.
Dr. Edmunds’ group found that if two identical people had coronavirus, the person with the new variant was about 30% more likely to die due to the disease. A group at Imperial College London found an equal probability of mortality with the new version compared to their ancestors. Researchers at the University of Exeter found a 91% increase in the risk of mortality from the new version, although this may be because the population that investigated it was large, Drs. Strain said.
Another study by Public Health England reported the likelihood of dying after infection with the new version was about 65% higher than the old version.
The results are preliminary and because only around 10% of all cases in the UK are known to be virus variants, it may not be representative of the population overall.
Write Joanna Sugden at [email protected] and Max Colchester at max.colchester @ wsj.com
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