IFNG and COVID-19: Therefore, patients from the categories “mild” and “hospitalized” were grouped together to the group “moderate,” whereas the patients with “severe” and “fatal” COVID-19 were consolidated to the group “serious.” We observed a significant decline of spots increment in the IFN-γ ELISpot assay comparing the “serious” group (N = 21, median = 9.5, and IQR = 6.8–19.3) to the “moderate” group (N = 161, median = 14.0, IQR = 8.5–32.8, p = 0.04, Figure 1A).