TGFB1 and pulmonary fibrosis: Additionally, for both RSV and SARS-CoV-2, we did not detect any changes in levels of some pulmonary fibrosis biomarkers, such as transforming growth factor beta (TGF-β), fibroblast growth factor (FGF), granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) (20).