A new study, released Monday, shows that even a mild infection with COVID-19 can cause “deep” cellular effects in the brain with a long-term impact on memory and executive function.
A preprint study from authors at Stanford, Yale, and Mount Sinai in New York, which has not been published or peer-reviewed, found that people with COVID can often experience neurological effects similar to those who undergo cancer treatment — a case you know Known as cancer therapy-related cognitive impairment (CRCI) or “chemo brain”.
“The results presented here illustrate striking similarities between the neurophysiology after cancer treatment and after SARS-CoV-2 infection, and illustrate cellular deficiencies that may contribute to the persistence of neurological symptoms after mild SARS-CoV-2 infection,” the authors wrote.
Symptoms of Covid-19 disease and the brain
Using injured mice as a model, the researchers found a “sharp drop” in new neurons being generated in the hippocampus region of the brain just a week after the injury, and determined that the condition persisted for at least seven weeks. (The generation of neurons in that area of the brain is thought to support healthy memory function.)
Researchers examined brain tissue from people who died in early 2020 and had COVID at the time of death; They found “severely elevated” signs of inflammation in the brain, even in those who were mildly or asymptomatically ill.
In addition, they studied people with “prolonged COVID” in two groups, those with cognitive effects and those without — most of whom only had mild infections and were not admitted to the hospital. The authors reported that subjects with cognitive effects had elevated levels of an inflammation-related protein in their plasma.
Symptoms of Omicron COVID-19
In their discussion, the researchers summarized, “Taken together, the results presented here confirm the multicellular abnormality deep in the brain caused by SARS-CoV-2 mild respiratory infection.”
Much of the data in the study comes from early in the pandemic, and scientists say it remains unclear what the long-term effect of the omicron variant, for example, will have on people.
They noted that “the incidence and severity of post-COVID-19 cognitive impairment caused by newer SARS-CoV-2 variants such as the Omicron variant, or as a result of penetration of infection in vaccinated individuals, remains to be determined.”
The study adds to a growing body of evidence about what some call the “COVID brain” or “COVID haze,” which scientists are still trying to fully understand — in particular, how long it may last in those who have recovered.
More and more evidence is emerging that COVID-19 can have disturbing effects on the brain, informally referred to as “brain fog,” and doctors are concerned that people are suffering from it without knowing it is linked to COVID. Rana Novini reports from NBC New York.