Covid new strain symptoms: Bacteria in your gut could affect the severity of your symptoms

Blood samples revealed this microbial imbalance was also linked to higher levels of cytokines, small molecules which are a natural part of the immune response but can cause damage if not properly regulated.

A hallmark of severe COVID-19 is the immune system going haywire following coronavirus infection and, in severe cases, attacking healthy cells and tissues.

The study was observational and is unable to say if COVID-19 changes the gut microbiome, or a weakened microbiome leads to more severe infection.

However, a separate study by South Korean researchers, published in Mbio, although only a review, indicates the latter option is the most likely.