The scientists concluded that an imbalance in the type and number of bacteria can influence the severity of the coronavirus. And here the immune response that the body is able to give is of great importance; it is also associated with the severity of the disease. The variety of bacteria in the gut is called the microbiome. An imbalance in its composition can cause long-term inflammatory symptoms in coronavirus.
Based on the observations of these phenomena, the scientists identified a new type of disease, which was named "long-term COVID". This is primarily a viral disease, but new evidence suggests that the gut is involved and its condition is of key importance.
It is the largest immunological organ and contains microbes that form immune responses. Between February and May last year, the experts analyzed blood and stool samples, as well as all medical records obtained during the observation of 100 patients in the hospital, who had confirmed COVID-19.
Among the participants in the experiment were 78 people without a diagnosis, who agreed to take part in the study of the microbiome. Disease severity was defined as mild in the absence of evidence of pneumonia. The average grade was assigned if pneumonia with fever was found. And the severe degree was assigned to those patients who required mechanical ventilation.
Analysis of collected samples showed that the composition of the gut microbiome was significantly different in patients with and without coronavirus. Diagnosed patients had more bacteria such as Ruminococcus gnavus, Ruminococcus torques, and Bacteroides dorei than people without infection.
These are bacteria that form the immune response. Their numbers remained low in samples that were collected 30 days after the first collection, when infected patients actually cleared their bodies of the virus.
The microbial imbalance was linked to increased levels of inflammatory cytokines and markers of tissue damage in the blood. That is, the gut microbiome has the ability to influence the immune system's response to the COVID-19 infection and potentially influence disease severity and outcome.