UK Coronavirus variant studied for increased risk for younger people

An early hypothesis, scientists say, is that one of the virus’s genetic mutations makes it better to enter a greater number of cells in the body, leading to serious illness in people treated with previous Covid-19 variants only. mild or no symptoms. .

David Strain, a physician and instructor at the University of Exeter School of Medicine who also treats Covid-19 patients, said the initial study paints a picture of a virus variant that resembles a burglar that has gotten better and is invading vulnerable cells. in this case no houses.

“We think that’s why it makes people both sicker and more transmissible,” said Dr. Strain.

Virologists suspect that it is a particular mutation known as N501Y on the new variant’s spike protein that has increased the ability to invade and infect human cells and move more efficiently through the human body.

Some doctors, such as Dr. Strain, believe this is the cause of the increase in younger people and women – who were less likely to get sick for most of the pandemic – who end up in the hospital.

Some things, doctors and scientists say, don’t seem to have changed with the new variant. Once admitted to the hospital, patients seem to have the same survival rate as before and doctors cannot tell from the symptoms which variant a patient has.

In London, the South East and East of England, where the new variant was first identified in a September 20 test sample, the mean age of patients admitted to intensive care units decreased from 61.4 years between September and the end of November up to 58.9 years. year from December 1 to January 21.

The proportion of women admitted to IC has risen from 30.1% to 35.1% over the same period. Data from the rest of the country shows a similar pattern.

Through December, the proportion of 18- to 54-year-olds admitted to UK hospitals with Covid-19 also started to rise, before a national lockdown was imposed on January 4.

Not all doctors are convinced that this is explained by mutations in the new variant. Some think it could also be a matter of behavioral changes, with more people, especially younger ones, mixing during the holiday season and becoming infected.

For example, Luke Allen, a local doctor in Oxford, said he treats more younger patients, but sees more Covid-19 patients overall, and the ratio between people appears to be the same as in the first peak.

He attributes the increased numbers to the greater portability of the new variant and the increased fun during the holidays. “That increases the likelihood of contacting us,” said Dr. Allen.

There is still much debate as to whether the new variant is indeed more deadly, as some studies suggest.

The new variety, which has become the dominant version in the UK, is estimated to be 30% to 70% more contagious than previous varieties. Last week, a government health advisory panel said studies suggest there was a realistic possibility that it could also be 30% to 40% more deadly than the previous variant.

The advisers say their conclusions are preliminary. “While there is uncertainty, we cannot always wait for certainty,” said Peter Horby, chair of the panel, the New and Emerging Respiratory Virus Threats Advisory Group of 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 variant was more deadly, as social mixing was allowed during the winter months, significantly accelerating hospital admissions.

Viruses generally mutate to be more transmissible and less deadly, he said.

The spread of the new variant coincided with a massive increase in the number of people hospitalized with Covid-19 and an increase in the number of people who died of the disease in the UK, putting the state-run health service under unprecedented pressure. Covid-19-related deaths in the UK are nearly 100,000 since the start of the pandemic.

The disease caused by the variant seems no different so far from that caused by its ancestors, but because the virus itself can move more easily through a patient’s system, it can outpace the body’s immune response, doctors suspect.

“If you get a much stronger binding, you may need a lower infectious dose to get infected, which would increase the risk of transmission,” said Dr. Horby. “Then if it has been able to spread much faster between cells in the lungs, it can increase the disease rate and the rate of inflammation, which can then get worse than your body can respond to.”

To determine whether the new variant was more deadly, scientists looked at data from about 850,000 cases of the coronavirus tested in the community where they knew which variant of the virus each person had, including between 1,400 and 1,900 people who died.

“You have to compare people who are as similar as possible,” said John Edmunds, an author of one of the studies from the London School of Hygiene & Tropical Medicine.

The researchers compared groups of people based on age, gender and ethnicity, as well as income and place of residence, to reduce the effect of pressure on hospitals on mortality rates.

Dr. Edmunds found that if two similar people had the coronavirus, the one who had the new variant was about 30% more likely to have died from the disease that causes it. A group from Imperial College London found a similar mortality risk with the new variant compared to its ancestor. Researchers at the University of Exeter found a 91% increase in the risk of death from the new variant, although that could be because the population studied is older, Dr. Strain.

Another study from Public Health England stated that the risk of death after infection with the new variant was about 65% higher than with the old version.

The results are preliminary and because the virus variant is known in only about 10% of all cases in the UK, it may not be representative of the population as a whole.

Write to Joanna Sugden at [email protected] and Max Colchester at [email protected]