IL4 and COVID-19: On a different note, high IL-13 (although not as high as the rat IL-13 study discussed here) and IL-4 levels are noted in intensive care unit-admitted patients with coronavirus disease 2019 (COVID-19), but not in patients with a common cold, and IL-13 and IL-4 are included in COVID-19 cytokine storm cocktails in our studies (6).