The microbiota would play a role in the degree of severity of Covid-19

Each individual’s microbiota is unique. Inherited from our parents and modified by our diet and lifestyle, the microbiota serves as an internal protective barrier for the digestive system. It is for this reason that it is essential to maintain a resistant microbiota, in order to counter certain diseases. According to researchers from the University of Hong Kong (China), the composition of the gut microbiota at the time of SARS-CoV-2 infection may affect whether a person has long-lasting Covid. . Study results were published in the journal gut.

The composition of the microbiota in question

The gut microbiota plays an important role in health. The gut is home to trillions of microorganisms and over a thousand species of bacteria. Inseparable from the immune system, their presence in the intestine helps to digest food and also to reduce the risk of developing certain diseases. However, among all this flora, certain bacteria can contribute to the development of certain types of cancer, promote obesity and even have an effect on mental health.

The balance of the microbiota is fragile and changing, which can lead to complications. This phenomenon, called dysbiosis, can occur as a result of taking antibiotics or eating a diet of highly processed foods. Dysbiosis can contribute to the development of health problems.

To understand the involvement of the microbiota in the severity of Covid-19, researchers took blood and stool samples from 100 patients who tested positive for SARS-CoV-2 between February and May 2020 in two hospitals. from Hong Kong. They compared the data collected with samples obtained from 78 participants before the start of the pandemic. By observing the samples, the researchers noticed that patients with Covid-19 had a higher number of certain bacteria, in particular Ruminococcus gnavus, a bacterium associated with inflammatory bowel disease. In addition, their samples had a lower number of Bifidobacterium adolescentis, Faecalibacterium prausnitzii and Eubacterium rectum, species which, as the authors explain, have a “immunomodulatory potential”.

Large amounts of cytokine

Additionally, researchers have found elevated levels of cytokines in people with the coronavirus. These cytokines are important for cell communication because the immune system produces them in response to viral infection. However, when they are present in large numbers and become aggressive towards the pathogen, they trigger a violent inflammatory response in the immune system: this is the cytokine storm or cytokine shock. This violent response of the immune system is capable of creating deep tissue damage in the organs, particularly in the lungs, which can lead to death. Numerous studies have shown that Covid-19 tends to trigger cytokine storms, which explains a large part of the deaths.

“Associations between gut microbiota composition, cytokine levels and inflammatory markers in patients with Covid-19 suggest that the gut microbiota is involved in the magnitude of Covid-19 severity, possibly by modulation of host immune responses, note the researchers in their conclusion.

In light of these observations, the researchers also urge caution with prescribing antibiotics, as this could create dysbiosis that can weaken the immune system and amplify the devastating effects of a potential cytokine storm. . “Antibiotics are unlikely to be associated with improved patient outcomes assuming no bacterial co-infections but, on the contrary, they may exacerbate and prolong gut microbiota dysbiosis in patients with Covid-19.”

Currently, more than 93 million people have contracted Covid-19 and nearly two million of them have died. In France, more than 2.8 million people have been infected and 69,313 have died from Covid-19 according to Public Health France.