It is also known that influenza vaccination does not induce a strong virus-specific CD8 T-cell immune response compared with natural infection, and although this comparison may be a disadvantage of inactivated influenza vaccines, it is beneficial for eliminating SARS-CoV-2 infection, as vaccinated persons will have more T-cell diversity compared with persons who were naturally infected with influenza [60,61]. This evidence concerns the gene CD8A and influenza.