According to an interesting observation supporting the hypothesis of reactivation of existing memory CD8 T cells, patients who recovered from SARS possess long-lasting memory T cells that are reactive to the N protein of SARS-CoV 17 years after the outbreak of SARS in 2003; these T cells displayed robust cross-reactivity to the N protein of SARS-CoV-2 [74]. The gene discussed is CD8A; the disease is severe acute respiratory syndrome.