IFNG and COVID-19: We then found that IL-10 at 5 ng/ml significantly downregulates spike-induced IFN-γ response in spike-responders of COVID-19 patients (14/29) [1.82 (0.30-3.468) vs 0.11 (0.37-0.75), p=0.0004] identified based on a cut-off previously defined (24) (Figure 3A).