Clinical evaluation of a novel microneedle device for intradermal delivery of an influenza vaccine: are all delivery methods the same?

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 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 3 μg 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 15 μg 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.