The presence of conserved CD8+ T cell peptides in the viral protein sequences of the 1918 influenza virus (Quiñones-Parra et al., 2014) and the ability the of the 2009 H1N1 pandemic influenza virus to recall influenza virus-specific CD8+ T cells, cross-reacting with the 1918 H1N1 influenza virus (Gras et al., 2010) suggest that pre-existing CD8+ T cells should have been protective against severe infection with the 1918 H1N1 influenza virus, especially in the case of young adults. This evidence concerns the gene CD8A and infection.