Despite their protective role in COVID-19 and other infectious diseases (such as influenza or parasitic infection), eosinophils and Th2 cytokines (especially IL-4 and IL-13) were repeatedly reported in the pathogenesis of idiopathic pulmonary fibrosis [23] and in other lung diseases, suggesting a possible role in the aberrant wound healing process. Here, IL4 is linked to COVID-19.