Gastrointestinal distress is now a known symptom of COVID-19. This indicates that the gut may be an additional place where the virus can thrive, and a site where it can be treated. By observing whether there are changes in the gut microbial communities of hospitalized patients during the course of a COVID-19 infection, researchers hope to learn the role of gut bacteria in infection and how to fight it.

To explore this question, researchers at The Chinese University of Hong Kong conducted a small pilot study of 36 individuals: 15 with COVID-19, 6 with pneumonia, and 15 healthy participants. Those with COVID-19 not only had significantly different gut microbial makeups compared to the healthy participants and those with pneumonia, they also found that a person with COVID-19 who had been on antibiotics tended to move even further from a “healthy” gut microbe profile than those patients with the virus but who hadn’t been on antibiotics.

The researchers also identified types of bacteria that were notably more and less abundant in patients with severe COVID compared to those with a milder form of the disease, indicating that some bacteria may play a protective role against the development of COVID-19, while others may allow the virus to make us sicker.

Learning more about how the human gut microbiome interacts with respiratory diseases might open up new ways to predict who is at risk for severe COVID-19 infection, and may even indicate how to treat it.