Covid can cause regions of the brain to shrink

A Covid infection can shrink parts of the brain and triple the rate of degeneration in middle-aged and elderly people, a first global study suggests.

Researchers at the University of Oxford examined the brain scans of more than 400 people between the ages of 51 and 81 before and after contracting the disease.

The results showed that in regions related to olfaction, responsible for smell, their brain volume decreased by an average of 0.7% compared to a control group that did not contract Covid.

A middle-aged person would normally expect to lose about 0.2% volume in this area in a year, while an older person might expect to see a 0.3% decrease.

On average, the Covid patients involved in the study had four-and-a-half months between their two scans – suggesting that the virus is dramatically accelerating the rate of degeneration.

Survivors also took longer to complete cognitive tests than their peers and had lower scores.

Brain size gradually decreases as we age, with reductions beginning in the 30s and 40s. The graph above shows drops in size in the left parahippocampal gyrus, an area of ​​the brain linked to smell. It reveals that it fell faster in people who tested positive for Covid (orange line) compared to those who did not contract the disease (blue line)

The graphs above show the changes in size of the brain (left) and cerebellum - which is related to movement - (right) between Covid patients (orange) and those who did not catch the virus (blue) .  This shows in both cases that those who had Covid saw a faster decline as they aged

The graphs above show the changes in size of the brain (left) and cerebellum – which is related to movement – (right) between Covid patients (orange) and those who did not catch the virus (blue) . This shows in both cases that those who had Covid saw a faster decline as they aged

Scientists from the University of Oxford examined the brains of 785 participants aged 51 to 81 who had undergone MRI scans before and during the pandemic.  (File image)

Scientists from the University of Oxford examined the brains of 785 participants aged 51 to 81 who had undergone MRI scans before and during the pandemic. (File image)

The scientists said the reduction was more pronounced in the elderly and in the 15 patients hospitalized with the disease.

But declines were still evident in patients who had mild to moderate Covid or who were asymptomatic – experienced no symptoms.

It’s unclear why Covid patients saw a greater reduction in brain size, but scientists said the findings may explain why some virus survivors have ‘long Covid’ symptoms such as brain fog that can persist for months after an infection.

Some scientists today called the results ‘convincing’, but others suggested they had found only ‘very modest’ reductions in brain size.

The study – published in the journal Nature – is believed to be the first in the world to investigate large-scale changes in the brain after Covid infection.

The human brain naturally shrinks as people age, with the first reductions normally seen in the 30s and 40s.

But this study found that people who caught Covid had a faster reduction in brain tissue than those who didn’t.

Scientists discover 16 ‘Covid genes’ increasing your risk of getting seriously ill

Scientists have discovered more than a dozen genetic oddities that may explain why some people are more vulnerable to severe Covid than others.

Up to 16 DNA changes have been found in patients critically ill with the virus, many of which are involved in blood clotting and inflammation.

A genetic variant has been found to be slower in signaling to the immune system that cells are under attack by the virus.

Having just one of the genes could mean the difference between having a cough or being admitted to intensive care, according to the largest study of its kind.

As part of the government-funded research, experts from the University of Edinburgh studied the genes of more than 57,000 people across the UK, including 9,000 Covid patients.

This is not the first time that studies have found that different genes could predispose some people to getting seriously ill with Covid.

But scientists hope the latest discovery will help identify new drugs and treatments in the future. Their previous work has already found that the arthritis drug baricitinib could treat some patients at risk for severe disease.

Professor Gewnaelle Douaud, neuroscientist who led the study, said: “Although the infection was mild in 96% of our participants, we found a greater loss of gray matter volume and greater tissue damage in infected participants.

“All of these negative effects were more marked at older ages.”

Reductions were seen in areas of the brain, including the parahippocampal gyrus – which is linked to smell.

There was also an additional 0.7% reduction in the cerebellum, which sits at the back of the brain and helps control muscle movement.

The scientists also compared brain changes in patients with pneumonia versus those without.

They found some changes, but not as large as between Covid and non-Covid patients.

The study was based on participants in the UK Biobank, a database including the genetic and health information of half a million British nationals.

Reacting to the research, Dr Rebecca Dewey, a neuroimaging expert at the University of Nottingham who was not involved in the study, said it was ‘compelling’.

“If the results were based on imaging data alone, I would say that we have much less reason to worry about this because the brain is so plastic that it is likely to compensate in the absence of conditions preventing this. .

“However, I find the significant association between imaging results and cognitive testing very compelling.”

She added: “These types of changes are seen after many forms of disease attacks, and even that of healthy aging.

“The main difference shown here is that they seem to happen faster than with aging alone.”

On the other hand, Professor Alan Carson, a neuropsychiatrist at the University of Edinburgh who was also not involved in the research, said the changes in brain size were “very modest”.

“Such changes can be caused by a simple change in mental experience,” he said.

“I am very concerned about the alarming use of language in the report with terms such as ‘neurodegenerative’.’

He suggested that the area of ​​the brain related to smell may have been reduced due to reduced signals from cells in the nose – which the virus infects.

Almost 30 million people in England had dodged Covid

Almost 30 million people in England have managed to avoid Covid since the start of the pandemic, scientific advisers to No 10 estimate amid warning signs that the epidemic is growing again.

Cambridge University scientists tasked with tracking the pandemic suspect that only 51.8% of the population has caught the virus in the past two years.

Experts told MailOnline they were ‘not particularly concerned’ that half the country has not been exposed to the virus.

This ‘does not mean that others are susceptible’, according to Dr Thomas Woolley, a mathematical biologist at Cardiff University.

Officials estimate that 98% of people in England have antibodies to Covid thanks to high vaccination rates and the combination of shots and natural immunity has been shown to offer the strongest protection.

Long Covid is defined as having persistent symptoms of the virus for more than a month after infection.

It is a poorly understood condition, with patients normally reporting extreme fatigue, difficulty breathing, loss of sense of smell and problems concentrating. But it has been linked to an array of other symptoms like joint pain, nausea, insomnia and depression.

An estimated 1.5million people in the UK – or 2.4% of the population – are currently suffering from long Covid.

For those who had the disease for more than 12 weeks, exhaustion was the most common condition, followed by shortness of breath, loss of smell and difficulty concentrating.

The latest research comes after scientists at the University of Edinburgh discovered more than a dozen genetic oddities that may explain why some people are more vulnerable to severe Covid than others.

Up to 16 DNA changes have been found in patients critically ill with the virus, many of which are involved in blood clotting and inflammation.

A genetic variant was found to be slower in signaling to the immune system that cells were under attack by the virus.

Having just one of the genes could mean the difference between having a cough or being admitted to intensive care, according to the largest study of its kind.

As part of the government-funded research, experts from the University of Edinburgh studied the genes of more than 57,000 people across the UK, including 9,000 Covid patients.

The study, partly funded by the Department of Health, did not break down the risk of becoming seriously ill by gene, or which Britons might be more at risk than others based on their heritage.

However, they said certain genes were linked to a doubling of the risk of severe Covid disease.

This is not the first time that studies have found that different genes could predispose some people to getting seriously ill with Covid.

But scientists hope the latest discovery will help identify new drugs and treatments in the future.

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