In elderly subjects, no differences were observed in the frequency of AIM-positive CD8+ T cells after stimulation with RBD variants compared with the negative control (Figure 6A), while a significantly increased frequency of AIM-positive CD8+ T cells was observed after stimulation with the ancestral wild-type RBD variant compared with the negative control in the COVID-19-naïve group (Figure 6B). This evidence concerns the gene CD8A and COVID-19.