It is known that chymase activates transforming growth factor-β (TGF-β) and matrix metalloproteinase (MMP) 9, converting their precursors into active forms involved in inflammation and fibrosis of tissues, which leads to structural damage and remodeling of organs, as well as to increased coagulation, which may be important in the pathogenesis of COVID-19 [7, 11, 21–23, 25, 29, 30]. This evidence concerns the gene TGFB1 and COVID-19.