It remains to be seen whether similar, non-antigen specific virtual memory CD8 EM T-cells are involved, particularly given that these homologous (repeated dosing) vaccine-induced responses did not appear to be sex-specific and the second dose was given only 3–4 weeks after the first (compared to the months between mild COVID-19 and influenza vaccination in our study). The gene discussed is CD8A; the disease is COVID-19.