The skin provides the largest immune barrier to infection and is a readily accessible site for vaccination, although intradermal (ID) injection can be challenging. The MicronJet? microneedle is a novel device that simply and consistently injects antigens very close to the skin´s dendritic cells. A dose-sparing ID injection study was conducted in 280 healthy adult volunteers using trivalent virosomal adjuvanted influenza vaccine. ID injection of 3μg using the MicronJet? was well tolerated and showed a statistically higher geometric mean fold rise than the same dose ID using a conventional needle (Mantoux technique) for the H1N1 and B strains or a 15μg intramuscular (IM) injection for the H3N2 strain. Thus, the immune response appears to partially depend on the delivery device and route of injection. The MicronJet? may allow dose-sparing, yet give a superior response in influenza vaccination and warrants further clinical evaluation.