IFNG and COVID-19: The spike-specific IFNγ-releasing cells were significantly lower in SARS-CoV-2 severe patients requiring hospitalization (8 [0; 26] s.f.c.×106), as compared to COVID-19 mild-moderate patients (135 [64; 159] s.f.c.×106; p<0.001) and healthy subjects (103 [50; 188] s.f.c.×106; p<0.001).