CD8A and COVID-19: Because we observed loss of CD8 naïve T cells and T effector memory cells in hospitalized aged COVID‐19 patients (Figure 2 b, d), we examined a publicly available single‐cell transcriptomic dataset of CD8 T cells from 25 severe/critical COVID‐19 patients (aged n = 12; younger n = 13) (Stephenson et al., 2021) in order to search for aging‐related molecular mechanisms in a cell type‐specific manner.