It has been confirmed that the level of SARS-CoV-2-specific CD8+ T cells is closely related to disease outcome (Rydyznski Moderbacher et al., 2020), and in one study, even on the first day after the onset of symptoms, specific CD8+ T cells had begun to expand (these cells were not detected before infection) (Schulien et al., 2021). This evidence concerns the gene CD8A and infection.