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Covid can cause regions of the brain to SHRINK

A Covid infection can triple the rate of brain degeneration in middle-aged and older people, a world-first study suggests.

University of Oxford researchers looked at brain scans of more than 400 people between the ages of 51 and 81 before and after they had the disease. 

Results showed that in olfactory-related regions, responsible for smell, their brain volume shrunk by an average of 0.7 per cent compared to a control group who did not get Covid. 

A middle-aged person would normally expect to lose about 0.2 per cent volume in that area per year, while an older person could expect to see a 0.3 per cent decrease.

On average, Covid patients involved in the study had four months between their two scans — suggesting the virus significantly speeds up the rate of degeneration.   

Survivors also took longer to complete cognitive tests and achieved poorer scores compared to their peers.

To check that the declines in brain matter and cognition could not have been replicated by any respiratory illness, the researchers carried out an analysis of the brains of pneumonia patients and found no similar changes.

The study may help explain why many people continue to suffer brain fog and other neurological issues months after clearing a Covid infection. 

Brain's gradually reduce in size as we age, with reductions beginning in the 30s and 40s. The above graph shows falls 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 that did not get the disease (blue line)

Brain’s gradually reduce in size as we age, with reductions beginning in the 30s and 40s. The above graph shows falls 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 that did not get the disease (blue line)

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

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

Scientists from the University of Oxford examined the brains of 785 participants aged 51-81 who had received MRI scans both before and during the pandemic. (Stock image)

Scientists from the University of Oxford examined the brains of 785 participants aged 51-81 who had received MRI scans both before and during the pandemic. (Stock image)

Oxford scientists said the reduction in brain volume was more pronounced among older people and the 15 patients who were hospitalised with the disease.

But declines were still evident in patients who had mild to moderate Covid or were asymptomatic.  

Scientists find 16 ‘Covid genes’ raising your risk of falling critically ill 

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

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

One genetic variant was found to be slower at signalling to the immune system that cells are under attack from the virus.

Having just one of the genes could be the difference between getting a cough or being admitted to intensive care, according to the biggest study of its kind.

As part of the Government-funded research, experts at 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 studies have found different genes could predispose certain people to becoming severely ill with Covid.

But the scientists hope the latest finding will help identify new drugs and treatments in the future. Their earlier work has already helped lead to the discovery that arthritis drug baricitinib could treat certain patients at risk of severe disease

Professor Gewnaelle Douaud, a neuroscientist who led the study, said: ‘Despite the infection being mild in 96 per cent of our participants, we saw a greater loss of grey matter volume, and greater tissue damage in the infected participants.

‘All these negative effects were more marked at older ages.’

But she noted that the brain ‘is plastic, which means it can re-organise and heal itself to some extent, even in older people.’ 

Reductions in brain matter were observed in areas of the brain including the parahippocampal gyrus — a key region for smell – and in the cerebellum — responsible for balance and coordination.

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 a Covid infection. 

Human brains naturally shrink as people age, with the first reductions normally observed in the 30s and 40s.   

The study was based on participants in the UK Biobank database.

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

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

‘However, I find the significant association between the imaging findings and the cognitive tests highly compelling.’

She added: ‘These sorts of changes are seen after many forms of disease onslaught, and even that of healthy ageing.

‘The key difference shown here is that they appear to be happening faster than with ageing alone.’ 

On the other hand, Professor Alan Carson, a neuropsychiatrist at Edinburgh University 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 by the alarming use of language in the report with terms such as “neurodegenerative”.’

He suggested the area of the brain linked to smell may have been reduced because of reduced signals from cells in the nose — which the virus infects.

Nearly 30million people in England had dodged Covid 

Almost 30million people in England have managed to avoid Covid since the pandemic began, No10’s scientific advisers believe amid warning signs that the outbreak is growing again.

Cambridge University scientists tasked with tracking the pandemic suspect only 51.8 per cent of the population has caught the virus in the last two years.

Experts told MailOnline they were ‘not particularly concerned’ by the fact that half of the country have not been exposed to the virus. 

It ‘doesn’t mean the rest are susceptible’, according to Dr Thomas Woolley, a mathematical biologist at Cardiff University.

Officials estimate that 98 per cent of people in England have antibodies against Covid thanks to high vaccination rates and the combination of jabs and natural immunity has shown to provide the strongest protection.

Long Covid is a poorly understood condition that leaves survivors with lingering symptoms more than three months after clearing the initial infection. 

It has been linked to a wide range of symptoms, including extreme tiredness, breathing difficulties, a loss of smell, and problems concentrating.  

An estimated 1.5million people in the UK — or 2.4 per cent of the population — are currently suffering from long Covid, according to the Office for National Statistics (ONS). 

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

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

One genetic variant was found to be slower at signalling to the immune system that cells were under attack from the virus.  

Having just one of the genes could be the difference between getting a cough or being admitted to intensive care, according to the biggest study of its kind.

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

The study did not break down the risk of becoming severely ill per gene, or which Britons might be more at risk then others based on their heritage.

However, they said some genes were linked to a doubling of the risk of severe illness from Covid.  

This is not the first time studies have found different genes could predispose certain people to becoming severely ill with Covid.

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

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