November 30th, 2020

Our immune response is usually commensurate with the strength of the attacking pathogen and the location of attack.

Our systemic response to COVID is very person specific based on the current 9 month data set. Assuming that we are not one of the rare people with an innate immune genetic defect that allows the pathogen to overwhelm us, we all fall into the category of immune response based on pathogen tissue penetration, growth and survival in the early illness. The more deeply the virus penetrates into protected tissue layers the more vigorously the immune system will respond out of pathogenic fear.

The immune story is very clear for me at this point. If we are prepared to receive the virus immunologically, then we will see it and rapidly contain it leaving us marginally infected and irritated with a mild immune response localized to the location of attack, the respiratory tract. On the other hand, if we are poorly kept from a health perspective having diseases like obesity, heart disease, high blood pressure and diabetes mellitus, then the virus will likely hijack our own baseline inflammatory pathology to replicate rapidly, overwhelm the local immune response and become systemic. Then, unfortunately, survival is based on the medical system's ability to respond in a reasonable timeframe to the inflammatory nightmare that follows the immune response. To date, the medicines employed at this stage are improving death rates, but not long hauler disease.

This post COVID immunopathology is likely the genesis of the long hauler phenomenon. The virus had a robust attack, we responded in kind immunologically with vigor and the resulting hyper inflammation caused tissue damage leading to autoimmune responses, cellular/organ dysfunction and chronic symptomatology that we see as chronic fatigue, shortness of breath and heart damage. The autopsy of the immunopathology of the long haulers is still underway. We can look backward at SARS1 for a road map. See the article by Gu. et. al. for a glimpse.

This article set yet again reaffirms the reality that we need to get our collective act together immunologically to prevent these risks. We must as a society tackle obesity and the behaviors that lead to chronic diseases of lifestyle.

Dr. M

Marshall Nature
Iwasaki Nature Immunology
Gu American J of Pathology