IL10 and infection: Faecalibacterium prausnitzii produces short chain fatty acids (SCFAs) which play an important role in neuro-immunoendocrine regulation and are key sources for intestinal epithelial cells to improve the gut barrier function37 Besides, SCFAs activate signaling cascade by cell surface G-protein coupled receptors that control immune functions and inflammatory side effects.1F. prausnitzii, which produces butyrate and IL-10 in the gut leads to a negative relation with COVID-19 severity and protects the host from the infection.12,32