The inclusion of flagellin into immunogens can serve as a potential adjuvant.53-57 There is experience where flagellin has been safe and effective as an adjuvant in pre-clinical animal studies.53–57 It also has been effective when used for immunizations of both younger and older persons in clinical trials for influenza vaccines.53–57 There is a robust literature which describes studies of the mechanisms whereby this TLR5 ligand functions as an adjuvant.53-57. This evidence concerns the gene TLR5 and influenza.