The trillions of microorganisms that live in your gut may play a role in how you handle COVID-19, according to a new study. Likewise, intestinal bacteria it can also help explain the persistent symptoms of the coronavirus infection, known as “COVID long”.
It is becoming more and more known that the intestinal microbiome – the army of bacteria, archaea and fungi that live in the digestive tract – plays a key role in the body’s immune system. On a new study, researchers at the Chinese University of Hong Kong found that people who become seriously ill and hospitalized with COVID-19 have a different bacterial composition in their intestines compared to healthy people, suggesting a A person’s intestinal microbiome can affect the immune system’s response to COVID-19 infection.
The researchers collected 100 stool samples from hospital patients with COVID-19 and compared them to samples taken from 78 people before the COVID-19 pandemic. The team found that their microbiome was very different. Perhaps more significantly, people hospitalized with COVID-19 had far less of the bacterial species that are known to influence the immune system’s response, such as Bifidobacterium adolescentis, Faecalibacterium prausnitziiand Eubacterium rectale. In fact, the levels of these bacteria were related to the severity of the patients’ illness. COVID-19 patients also had noticeably higher numbers Ruminococcus gnavus, Ruminococcus torques, and Bacteroides dorei.
Low levels of the bacteria linked to the immune system have also been found in COVID-19 patients up to 30 days after having eliminated the virus from their bodies. The researchers argue that this microbial imbalance may help answer why so many people who are sick with COVID-19 seem to suffer from “Long COVID,” namely, fatigue, joint pain and other hidden symptoms long after your recovery.
This study was just an observational study and, although it found a convincing connection, it cannot firmly establish a cause. It is impossible to say with certainty, for example, whether people who were hospitalized with COVID-19 had a less diverse microbiome due to other factors, such as smoking.
However, another study released this week also looked at the broader question of how intestinal microbes are linked to disease. As part of the largest in-depth nutritional study in the world, scientists at King’s College London have identified a number of “good” bacteria species that are associated with a lower risk of certain diseases and “bad” species linked to an increased risk of disease. As reported in the newspaper Nature Medicine, the results even suggest that the microbiome has a greater association with disease biomarkers than other factors, such as genetics.
“We were surprised to see groups so large and clear of what we informally call ‘good’ and ‘bad’ microbes emerging from our analysis. It is also exciting to see that microbiologists know so little about many of these microbes that they are not even named yet, “Dr. Nicola Segata, author of the study, professor and principal investigator at the Computational Metagenomics Laboratory at the University of Trento in Italy, said in a statement.
Scientists are just beginning to understand how bacteria in our gut can help and disrupt our immune system, but it is becoming increasingly clear that human health is intrinsically linked to these microorganisms, especially with regard to COVID-19.
For more information on COVID-19, check out the IFLScience COVID-19 hub, where you can track the current status of the pandemic, the progress of vaccine development and more information about the disease.