High blood levels of cytokines and chemokines have been detected in patients with COVID-19, including IL1-β, IL1RA, IL-2, IL-4, IL-6, IL-7, IL-8, IL-9, IL1-0, basic FGF2, GCSF, GMCSF, IFNγ, IP10, PDGFB, TNF-α, and VEGFA; all of these markers have been proposed as biomarkers of the severity and fatal outcome of COVID-19 [10,11,12]. Here, IL9 is linked to COVID-19.