CD69 and COVID-19: Similar to total CD4+ and CD8+ T cells, CD8+ MAIT cells in severe COVID-19 displayed significantly heightened activation for many of the measured markers, including HLA-DR (p=0.049 between severe and HD), CD38+ (p=0.048 between severe and HD), and CD69 (p=0.04 between severe and recovered) in severe COVID-19 (Fig. 5D and Fig. S4H), but not for PD-1 or Ki-67 as a cohort.