Additionally, in our meta-analysis, the alterations of serum interleukin (IL-1β, IL-2, IL-4, IL-6, IL-8, and IL-10) levels in COVID-19 patients and healthy subjects were analyzed according to the following groups: (i) COVID-19 patients vs. healthy subjects, (ii) severe vs. nonsevere patients, (iii) survivor vs. nonsurvivor patients, and (iv) ICU vs. non-ICU patients. Here, IL4 is linked to COVID-19.