GREAT NEWS! University Of Oxford Study Shows That Even Mild SARS-CoV-2 Infections Can Result In Brain Changes And Cognitive Decline!
A new study by researchers lead by Professor Dr Gwenaëlle Douaud from the Wellcome Centre for Integrative Neuroimaging (WIN) at University of Oxford-UK has found that even mild SARS-CoV-2 infections can result in brain changes and cognitive decline! This is great news considering that many moronic doctors and ‘experts’ had commented that the extremely transmissible Omicron variants including the BA.2 variant that was spreading globally at a very exponential phase was claimed to be only mild!
Numerous past studies had showed strong evidence for brain-related abnormalities in COVID-19 but to date, it remains unclear as to whether the brain pathological impact of SARS-CoV-2 infections can be detected in milder cases.
The study team investigated brain changes in 785 UK Biobank participants (aged 51–81) imaged twice, including 401 cases who tested positive for infection with SARS-CoV-2 between their two scans, with 141 days on average separating their diagnosis and second scan, and 384 controls.
The availability of pre-infection imaging data reduces the likelihood of pre-existing risk factors being misinterpreted as disease effects.
The study findings shocking revealed significant longitudinal effects when comparing the two groups, including: (i) greater reduction in grey matter thickness and tissue-contrast in the orbitofrontal cortex and parahippocampal gyrus, (ii) greater changes in markers of tissue damage in regions functionally-connected to the primary olfactory cortex, and (iii) greater reduction in global brain size.
Importantly, the infected participants also showed on average larger cognitive decline between the two timepoints.
These imaging and cognitive longitudinal effects were still seen after excluding the 15 cases who had been hospitalized. These mainly limbic brain imaging results may be the in vivo hallmarks of a degenerative spread of the disease via olfactory pathways, of neuroinflammatory events, or of the loss of sensory input due to anosmia. Whether this deleterious impact can be partially reversed, or whether these effects will persist in the long term, remains to be investigated with additional follow up.
The study findings were published in the peer reviewed journal: Nature
the study findings showed that many middle-aged and older adults who'd been sick with COVID showed signs of tissue shrinkage in brain areas related to the sense of smell. They also tended to have more trouble completing complex mental tasks, when compared to individuals with no history of COVID-19…an effect that was most striking among the oldest adults.
These study findings strengthen evidence that even mild COVID-19 may cause detectable deficits in the brain.
Importantly, because the study team had access to brain scans taken from individuals both before and after they'd been infected. That helps distinguish brain changes associated with COVID-19 from any abnormalities that may have already been there.
Professor Douaud told Thailand Medical News
, "We still cannot be sure with
100% certainty that there is a causal effect of the infection but we can disentangle the effects that we observe from differences that may have pre-existed in the brain of the participants before they became infected with SARS-CoV-2."
However, there are still key questions such as what caused the brain changes? And what, precisely, do they mean?
Previous studies have estimated that up to 30% of individuals with COVID-19 develop "long-haul" symptoms that plague them well after they've beaten the infection. The list includes fatigue, headaches, shortness of breath, dulled sense of smell and taste, and problems with memory and concentration that have been dubbed "brain fog." However newer studies are emerging that up to between 68 to 87 percent of all those infected with the SARS-CoV-2 virus will ultimately develop one or more long term health and medical conditions.
Scientists still do not know what causes "long COVID," or why it can strike after a mild infection. One theory pins the blame on overactivation of the immune system, leading to widespread inflammation in the body.
Others attribute it to viral persistence and some to prions present in the virus genome.
A leading neurologist at the University of California-San Francisco, Dr Joanna Hellmuth who is also studying post-COVID symptoms said it's not clear what may have caused the brain changes seen in this study.
However, Dr Hellmuth said the fact that tissue shrinkage occurred in smell-related areas points to one possibility: lack of sensory input. Particularly during the pandemic's early waves, COVID-19 commonly caused individuals to lose their sense of smell.
Dr Hellmuth said, "The findings may indicate the degenerative spread of Covid-19, either via smelling pathways, inflammation of the nervous system or a lack of sensory input owing to a loss of smell."
Professor Dr Maurice Curtis, a neuroscientist from the University of Auckland said the shrinkage or loss of brain volume shown in the study was "significant" ie exceeding a six per cent difference on average.
He said, "Furthermore, those who demonstrated this shrinkage, performed significantly worse on executive function, visual searching and mental flexibility tests. We know that loss of the sense of smell very early on in Covid-19 is a key sign of infection and some people never get their sense of smell back. The smell pathway and the memory pathway in the brain are connected and these are the same pathways affected in some dementias, including Alzheimer's disease."
Professor Curtis also pointed out the study authors' conclusion that Covid-19 caused the shrinkage - whereas being infected with the seasonal flu didn't result in such an effect.
He added, "This study demonstrates that there is a long-term consequence to getting COVID-19 and it highlights the importance of taking all measures possible to reduce COVID-19's impact on the body and especially the brain."
The study findings also caused alarm among many researchers that people with mild COVID-19 could face the prospect of brain "degeneration."
Neurology expert, Dr Indranil Basak from the Otago University's Neurodegenerative and Lysosomal Diseases Laboratory, said the study findings were "very interesting, but worrying as well".
He himself is exploring what happened to our brains at a molecular and cellular level when it was exposed to the virus.
He added, "The results from our experiments will help us understand what is happening inside the cells, which could be leading to the changes in the brain that are highlighted in this study.”
He further added, "Our preliminary data shows some infection in brain cells, including neurons. However, we still don't know if the virus can enter these cells after crossing the blood-brain barrier, or if the symptoms we're seeing inside the cells are because of some other reason."
For instance, he said, they'd observed an immune response that occurred when the virus was infecting our bodies, which could be causing secondary effects that affected the brain cells as well.
Dr Basak said, "There are definitely several cases where patients infected with the virus started getting neurological symptoms like dizziness, disturbed consciousness, headache, loss of smell and taste, seizure, encephalitis and there have been links with Parkinson's disease. From this research and our own, it is clear there is an effect on the brain from COVID-19 infection, and this could lead to some Long COVID effects. We still don't know how to treat this, because no one has looked at it yet. But we do know that the virus directly, or indirectly, can affect the human brain."
The research included 785 British adults aged 51 to 81. All had undergone brain scans before the pandemic, as part of a research project called the UK Biobank. They came back for a second scan during the pandemic.
In that group, 401 contracted COVID-19 at some point between the two brain scans, while 384 did not.
Nearly all who fell ill ie 96% had a milder case. The second scan was taken an average of 4.5 months after their illness.
The study findings showed that on the average the COVID group showed greater tissue loss in specific brain areas related to smell, plus a bigger reduction in overall brain size.
The effect amounted to an extra 0.2% to 2% tissue loss, the study team found.
Dr Douaud agreed that a lack of sensory input might explain the changes in smell-related brain areas. But, she said, her team did not know whether participants had, in fact, lost their sense of smell. Hence, they could not look for correlations between those symptoms and brain changes.
The study team was however able to look at participants' performance on some standard tests of mental sharpness. And again, the COVID-19 group showed a greater decline, on average.
Interestingly, the divide was most clear among the oldest adults. Individuals in their 70s who'd had COVID worsened by 30%, on average. That compared with 5% among their COVID-free peers.
Also, there was some evidence that performance decline correlated with shrinkage in a brain structure involved in thinking and other mental skills.
It is not known yet as to whether the brain changes associated with COVID-19 resolve over time.
Professor Douaud said, "The best way to find out would be to scan these participants again in one or two years' time.”
The study team noted that the study was one of the largest to date on SARS-CoV-2 effects on the human brain.
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