Recently, to study the relationship between gut microbiota metabolomics and the pathogenesis and severity of COVID-19, Zhang et al. (2022) also found that impaired synthesis of SCFA and L-isoleucine in the gut microbiome of patients with COVID-19, which is also associated with increased disease severity and inflammatory markers such as CRP and CXCL-10, increased urea synthesis as well. This evidence concerns the gene CXCL10 and COVID-19.