COVID and Autoimmune Disease

Some individuals infected by SARS-CoV-2 experience brain damage.  Although it sounds like science fiction, “COVID brain fog” describes a very real condition in which infected patients experience memory loss, strokes, and other nervous system lesions.  How can this happen?

In an article published last week in Nature, Michael Marshall, a free-lance science journalist from the U.K., describes the current areas of research into the causes of this condition.  One possible mechanism is autoimmune disease.

The immune system’s job is to protect the body from agents of disease (“pathogens”) without damaging the body’s own cells.  Like the military guarding the border of a sovereign nation, the constituents of the immune system carry lethal weapons meant to destroy an invading enemy.  But what if the military can’t tell the difference between friend and foe?  Those lethal weapons might be unleashed on its own people, and the citizens of that nation would be at risk of harm from their own government.  Let’s say for example that the U.S. learned all its enemies wear red hats.  If the army was ordered to seek and destroy anyone wearing a red hat, many innocent Americans unwittingly wearing red hats could be killed in an effect to stamp out a threat to our nation.  

The immune system works by learning something about the pathogens that threaten the body—not the color hats they wear, but the shape and composition of molecules on the invaders.  When the shape and composition of those molecules are similar enough to the shape and composition of molecules on the cells in our own body, the immune system can’t tell the difference, and it attacks us.  That’s autoimmune disease.

Autoimmune disease is highly individualized.  Although we lump these diseases into categories ranging from lupus to rheumatoid arthritis, each person with an autoimmune disease has a disease that’s uniquely his or her own.  There’s a lot of overlap, but no two individuals have exactly the same disease manifestations.  

There are many examples of autoimmune disease targeting specific organs.  Hashimoto’s thyroiditis is a disease in which the immune system targets the thyroid gland.  In Crohn’s disease the immune system targets the cells of the gastrointestinal tract.  Multiple sclerosis is an autoimmune disease of the central nervous system.   COVID brain fog may also be, at least in part, an autoimmune disease of the central nervous system in which an immune system primed to destroy SARS-CoV-2 causes collateral damage to the brain.

If that’s the case, we have yet another reason to avoid COVID-19.  But we may also want to avoid stimulating the immune system to fight SARS-CoV-2, which is precisely the goal of a COVID vaccination.  We know that everyone who has had COVID-19 develops antibodies to the viral spike protein.  We also know that everyone who has received a COVID vaccine develops antibodies to the same viral spike protein.  What if these are the autoantibodies associated with COVID brain fog?

Although there is no proof this is the case, there is evidence suggesting that the idea is plausible.  Last week, we learned that vaccines may cause myocarditis and pericarditis, essentially an autoimmune disease affecting the heart.  VITT, a condition in which vaccination causes blood clots, is also immune mediated.  We must consider the possibility that stimulation of immunity against viral spike proteins causes autoimmune disease in some vaccine recipients.

As we connect more dots, an image emerges from the haze of the pandemic.  As the picture becomes clearer, will we have the courage to believe what we see?