BRAIN EFFECTS OF COVID-19. A recent study from Oxford University confirmed that Covid-19 often does produce changes in the brain during and after infection. These changes may explain some of the symptoms of ‘Long Covid’.
The study compared MRI imaging before and after SARS-CoV-2 infection. Most of the infections studied were not associated with severe illness. Participants in the study who had experienced a Covid-19 infection had more grey matter loss and abnormalities in the area of the brain associated with smell (olfactory) functions, and more brain size shrinkage than participants who had not experienced an infection. Many people infected with CoVID report changes in their ability to smell during and after the infection. All of the 401 scans after Covid were carried out between February and May 2021 before vaccines were available. The infections would have included the original SARS-COV-2 strain but were probably mostly due to the Alpha variant.
The study also found greater decline in the ability to perform complex tasks in those infected, compared to a group of people who were not infected. These changes and those found on MRI may be reversible – let’s hope so. The effects were greater in the older participants.
Another study from Wuhan, China suggests that cognitive changes observed in some people with Covid may continue for at least a year, especially for those who have had a more severe disease.
Still another recent postmortem study examined the olfactory nerves and olfactory tracts in the brains of people who had died with or soon after Covid-19 infection. The findings of this study suggested damage to these olfactory structures was not due to direct infection by the virus but instead due to damage to microscopic blood vessels as part of an extreme immune response. My post last year (July 21) referred to a German study which suggested, from other evidence, that ‘Long Covid’ might be due to some form of inflammatory/autoimmune response.
https://jamanetwork.com/journals/jama/fullarticle/2790595