Published reports provide evidence that prominent pre-­existing influenza-specific CD8+ or CD4+ memory T cell pools are associated with more rapid recovery from experimentally mild H3N2 or naturally occurring H1N1-2009 influenza virus infection, as manifested by milder disease symptoms, shorter illness time, diminished viral shedding, and less transmission (100, 101, 112, 113). This evidence concerns the gene CD8A and influenza.