Indeed, consistent with the generation of CIML NK cells, antigen‐independent in vitro responses to exogenous IL‐12 and IL‐18 were also elevated for up to 3 months after influenza vaccination in a UK study,13 but this response was detected for up to 6 months in African subjects.33 Enhancement of NK cell responses after influenza vaccination is therefore mediated by indirect mechanisms involving antigen‐specific cellular CD4+ and humoral responses combined with a shorter‐lived CIML component. This evidence concerns the gene CD4 and influenza.