Assessment of enhanced influenza vaccination finds that FluAd conveys an advantage in mice and older adults.

Objectives: Enhanced inactivated influenza vaccines (eIIV) aim to increase immunogenicity and protection compared with the widely used standard IIV (S-IIV).

Methods: We tested four vaccines in parallel, FluZone high dose, FluBlok and FluAd versus S-IIV in a randomised controlled trial of older adults and in a mouse infection model to assess immunogenicity, protection from lethal challenge and mechanisms of action.

Results: In older adults, FluAd vaccination stimulated a superior antibody profile, including H3-HA antibodies that were elevated for up to 1 year after vaccination, higher avidity H3HA IgG and larger HA stem IgG responses.