Imbalance In Gut Microbiome Could Worsen Severity Of Covid-19
Research suggests that an imbalance of the microbes in the gut may increase the chance of developing more severe Covid-19 and could also put people at risk of the post viral syndrome known as ‘long Covid’.
We now know that the type and amounts of microbes found in the gut – our gut microbiome — can play an important role in our ability to fight off a range of diseases including infections, autoimmune diseases, and cancer. It even plays a role in our susceptibility to mental illnesses.
Since the pandemic began, there has been a significant variation in the response people have when they become infected with the SARS-CoV-2 virus. Most people only have mild, or moderate symptoms, but some (around 14%) have severe symptoms requiring hospital admission.
While some factors, such as age, gender, ethnicity and presence of other medical conditions, are known to influence a person’s risk for experiencing more severe Covid-19, there are still severe cases that seem hard to explain.
One thing that distinguishes severe Covid-19 patients who are hospitalized from those who have a milder case of the disease is an overreaction of their immune systems to infection with SARS-CoV-2. Essentially, the body has a reaction to the infection that varies in its severity, but is similar to someone going into anaphylactic shock after having a severe allergic reaction to something.
This reaction, known as a cytokine storm, is responsible for many of the symptoms seen in severe Covid-19 patients such as breathing difficulties and damage to different organs in the body due to excessive inflammation.
the gut are thought to have a protective effect on the immune system. Professor Siew Chien Ng from The Chinese University of Hong Kong is an expert on the microbiome. She and her colleagues decided to test the theory that having an unhealthy gut microbiome could increase the severity of Covid-19 symptoms.
They tested fecal samples from 100 patients with confirmed Covid-19 and symptoms ranging from mild to critical to analyze the number and types of microbes in their guts. They then compared these with samples taken from 78 people without Covid-19 who participated in a microbiome study before the pandemic began.
This showed that there was a distinct difference in gut microbial content between those with Covid-19 and those without. Patients with more severe disease also had a greater imbalance in their gut microbiome compared with those who only had mild symptoms.
“They lack certain good bacteria known to regulate our immune defense,” says Ng. “As a result, they have elevated inflammatory cytokines and other blood markers of tissue damage leading to serious outcomes.”
After taking account of factors that might influence the makeup of the gut microbiome such as antibiotic use and age, lower numbers of two types of bacteria — Faecalibacterium prausnitzii and Bifidobacterium bifidum – were significantly associated with more severe Covid-19 symptoms.
The researchers also took blood samples from the people in the study and found that levels of inflammatory proteins in the blood went up as levels of these beneficial bacteria went down.
