TLR9 and influenza: [31, 32, 33, 34] Flagellin has been shown to elicit Th1 and Th2 immune responses,[35, 36, 37] and combining flagellin into H1 influenza vaccine formulations enhances antibody and T cell responses.[35, 36, 38] In the majority of studies, flagellin is solubly co‐administered with antigen; however, an alternative strategy genetically incorporates flagellin with a recombinant virus expressing influenza antigen.[35, 36, 37] The Th1‐skewing TLR9 agonist, CpG 1826, is the second adjuvant conjugated to our current E2 NP vaccine formulations in this study.