COVID and your gut: How a healthy microbiome can reduce the severity of infection – and vice versa

The microbes in our gut provide essential signals for our immune responses across the body, including in the lungs.

A vast combination of microorganisms live in our gut, including bacteria, fungi and viruses. Collectively, we refer to this as the the microbiome.

Despite their tiny size, these microbes have significant effects on our health and wellbeing. In fact, the microbiome is often referred to as the “second brain” due to the extensive relationship it has with the body’s organs and systems.

One role in particular the microbes in our gut play is supporting immune function. They help to control local and systemic inflammation, the process by which the immune system protects us from harmful pathogens.

So it’s not entirely surprising that research has shown the make-up of bacteria in the gut may influence the severity of a COVID infection. At the same time, evidence is beginning to suggest a COVID infection could affect the balance of bacteria in the gut, which might go some way to explaining why some people have persistent symptoms after a COVID infection.

The microbes in our gut provide essential signals for our immune responses across the body, including in the lungs. A “healthy” gut microbiome comprises a broad range of bacteria, though is not identical in every person. Studies have previously shown that a healthy gut microbiome can improve the immune response to respiratory infections by regulating immune cells and messages.

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On the flip side, evidence shows a poorer composition of gut bacteria increases susceptibility to influenza infections in the lungs, and leads to reduced clearance of germs from the lungs in mice.