Brain scans show even a mild covid case can shrink your brain – as many of us are finding out.

National Geographic takes a broad look at neurological studies done at labs around the world that show that even the “mild flu” version of COVID-19 can cause brain fog, memory loss, and physical changes to your brain equal to a decade of aging, including literally shrinking your brain:

The United States remains the world’s worst affected country by cases and numbers of deaths. Of the roughly 80 million Americans who’ve gotten COVID-19 so far, about one of every four survivors suffers from impaired cognition, commonly described as brain fog – a symptom mirrored in other parts of the world. While this isn’t a formal medical term, says Edward Shorter, a professor of psychiatry at University of Toronto, it has become an umbrella term for describing an array of symptoms such as confusion, word-finding difficulties, short-term memory loss, dizziness, or inability to concentrate.

Patients hospitalised with COVID-19 are almost three times more likely than those not hospitalised to have impaired cognition. But brain scans now show that even a mild case of COVID-19 can shrink part of the brain, causing physical changes equivalent to a decade of ageing.

“There is evidence of neurologic injury [after COVID-19] that is persistent,” says Ayush Batra, a neurologist at Northwestern University Feinberg School of Medicine. “We are seeing biological and biochemical evidence of it, we are seeing radiographic evidence of it, and most importantly, the patients are complaining of their symptoms. It is affecting their quality of life and day-to-day functioning.”

The 785 participants, between 51 and 81 years old, who had already been scanned before the start of the pandemic, were scanned on average three years apart as part of the U.K. Biobank project. Tests or medical records showed that 401 of these volunteers had become infected with SARS-CoV-2. Most had mild infections; only 15 of the 401 were hospitalised.

The results showed that four and half months after a mild COVID infection, patients had lost, on average, between 0.2 and 2 percent of brain volume and had thinner grey matter than healthy people. By comparison, older adults lose between 0.2 and 0.3 percent of their grey matter each year in the hippocampus, a region linked to memory.

In the region of the brain linked to smell, the COVID-19 patients had 0.7 percent more tissue damage compared to healthy people.

Because COVID-19 affects respiration, it can starve the brain of oxygen, as seen in autopsy data from Finland. In rare cases, COVID-19 can also damage the brain by causing encephalitis, a form of brain inflammation. More broadly, COVID-19 can elicit a severe immune response that triggers a storm of proteins called cytokines, which amplify inflammation throughout the body. Long-term inflammation has been shown to promote cognitive decline and neurodegenerative disease and so could be causing neurodegeneration among COVID-19 survivors.

COVID-19 also increases the risk for blood clots for up to six months, which can cause strokes that deprive the brain tissue of oxygen. One study found large stray bone marrow cells—responsible for the production of blood-clotting platelets—lodged in the brain capillaries of individuals who died from COVID-19 infection. These cells could cause strokes in COVID-19 patients and trigger some neurologic impairments.

Some scientists even fear that COVID-19 survivors could be at higher risk for Alzheimer’s disease, based on evidence for a protein called beta-amyloid in the brains of younger patients who died of COVID-19.

Studies are also accumulating that show direct evidence of the SARS-CoV-2 virus invading the brain.

At least one study shows that two-thirds of COVID-19 survivors seen at 59 hospitals in the U.S. were diagnosed with cognitive issues during a six-month follow-up. However, as the recent U.K.-based study shows, even mild cases can put people at risk, and tracking those patients will be a challenge if they don’t make the connection between mild COVID-19 and any neurological symptoms that pop up later.

There are more studies linked in the original article than you can shake a stick at – go there to chase down a lot of science.

I started my morning today reading about the very first Devo show. Now, I’m wondering about these effects not just on a personal level – I know a few folks with Long Covid and related issues – but a societal level. If there are 80 million covid sufferers in the U.S. and 2/3 of them experience some kind of neurological consequence, that’s around 53 million people who will be experiencing impaired senses, vertigo, fatigue, memory loss, aphasia, and all the rest of it. That’s more people than belong to the Republican (36 million) or Democratic (48 million) parties. That’d be a major social movement – except it’s not ideological, but neurological.