COVID-19 and Your Microbiome

“In a war against bugs the medical doctors are the soldiers”. Dr. Sabine Hazan

Novel coronavirus, officially known as COVID-19, has now been declared a global pandemic.  Originating in bats in the city of Wuhan, China, the virus attacks the lungs, causing fevers, coughing, and shortness of breath.  However, as the virus has also been found to lodge in the small intestine, other symptoms including nausea, vomiting, and diarrhea have also been reported, as well as headaches, fatigue, and chills.  These symptoms can worsen to the degree that oxygen support and even ventilation are required.  Diagnostic testing is done via a technique called real time PCR, also known as qPCR.  This test is very sensitive, meaning that it picks up on positive results.  It’s also very specific, meaning that it doesn’t find other viruses and indicate positive for COVID-19.  There is currently no FDA approved treatment or cure, although there are numerous clinical trials being conducted to test whether existing medications might be effective in treating the virus.  In one study, in a little less than half of patients with COVID-19, there was a decrease of T cells (T lymphocytes).  T cells play many important roles in the immune response, and as such are essential to human health.


Young, healthy people are at a lower risk for developing serious illness.  Those at elevated risk include the elderly, and people with chronic illness.  Of particular concern are older adults with heart disease, lung disease, or diabetes.  Other high-risk populations include patients taking immunosuppressive medications like prednisone, patients with autoimmune diseases, cancer patients on chemotherapy, patients with HIV or hepatitis, patients with liver or kidney disease, and patients with lung disease such as asthma or COPD.


Scientists worldwide have been working around the clock to understand the virus, and how to combat it.  Part of that study includes discovering the structure of the virus.  This allows scientists to see potential targets for treatment.  One such target is the ACE2 receptor binding domain (RBD), which is what allows the virus to adhere to its objective, in this case, human lungs.  This domain is found on the spikes that give the coronavirus it’s name.  The binding between COVID-19 and ACE2 is a potential place to direct treatments.  The authors of the above study suggested that antibodies and small molecules should be developed to do precisely that.


While ACE2 is present in the lungs, allowing people to get pneumonia, it is also present in the intestines, kidneys, and testis.  The significance of this is that the virus could be shed in stool, and thus be transmitted via the fecal oral route.  It also suggests that the gut microbiome of patients with COVID-19 could be detrimentally impacted by the virus.  Although only a small percentage of patients have GI symptoms, the prevalence of ACE2 in the GI tract suggest that this could be a reservoir of the virus, which would have a dramatic impact on the population of microbes already present there.


Future studies should include sequencing of the microbiome of patients following successful treatment for COVID-19, to determine the nature of imbalance, or dysbiosis, caused by the virus.  Only then can appropriate treatment measures for this imbalance be established.

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