Smoking is linked to the exacerbation of respiratory infections, including COVID-19; it promotes inflammation by the excess production of TNF-α and transforming growth factor β (TGF-β), and diverse interleukins (IL) such as IL-1β, IL-12, IL-17, and IL-23 also have an impact on gene expression [62,79]. Here, TGFB1 is linked to COVID-19.