IFNG and COVID-19: Acute COVID-19 patients had a slightly higher rate of positive IFN-γ responses than IL-2 [61.9% (34/55) IFN-γ vs 56.4% (31/55) IL-2; and 65.4% (36/55) had at least a positive result for one of the two cytokines (p = 0.66)].