I saw a summary of this research a couple of weeks ago and felt it was so important I put it on my page in an abbreviated form.
Now that I have the full report from Oxford University I can write about it in more detail.
Covid affects major organs in the body in ways we never even dreamed of.
One of them turns out to be the brain.
And this latest research finds it doesn’t even have to be a serious infection to inflict damage.
It looks as if the areas of the brain to do with smell are worst hit by shrinkage but the virus can spread throughout the nervous system.
We don’t know as yet if these effects persist or are reversible.
Most of the past studies showing Covid-19 may cause brain-related abnormalities are in hospital patients with severe disease.
The effects of mild Covid were unknown until now.
Professor Gwenaëlle Douaud and colleagues from Oxford University investigated changes in the brains of 785 participants from UK Biobank, a large-scale biomedical database and research resource.
Participants aged 51-81 underwent two brain scans, on average 38 months apart, as well as cognitive tests.
A total of 401 participants tested positive for Covid between their two scans, of whom 15 were hospitalised.
The remaining 384 individuals, who didn’t get infected acted as controls.
About 4.5 months following infection, the researchers noted a greater reduction in grey matter thickness in the regions of the brain associated with smell (the orbitofrontal cortex and parahippocampal gyrus) and a reduction in the size of the whole brain.
On average, the participants who were infected with Covid also showed greater cognitive decline between their two scans, associated with the shrinkage of a specific part of the cerebellum (hindbrain) which is linked to cognition.
Professor Stephen Smith, senior author on the study, commented: “Another strength of this study is that it investigated the same people at two different times.
“Importantly here, the first scan of UK Biobank participants was obtained before they became infected with SARS-CoV-2, with the second scan after infection.
“The fact that we have the pre-infection scan helps us distinguish brain changes related to the infection from differences that may have pre-existed in their brains.”
This before and after tracking makes this study unique.
We therefore may have found the blueprint for the degenerative spread of Covid-19 related to the sense of smell, inflammation or immune response of the nervous system.
That’s incredible news.