Intanza 15 microg intradermal seasonal influenza vaccine: in older adults (aged >or=60 years).

Intradermal seasonal influenza vaccine delivered by a microneedle injection system (Intanza) contains inactivated split virion antigens from influenza type A (H1N1 and H3N2) and B strains as recommended annually by the WHO and the EU for the prevention of seasonal influenza. In randomized, comparator-controlled, phase III trials in elderly volunteers, Intanza 15 microg elicited a strong immune response against influenza virus. In a pivotal trial, seroprotection rates with Intanza 15 microg were significantly greater than with the intramuscular comparator vaccine Vaxigrip (primary endpoint). A strong immune response was also observed with Intanza 15 microg following second and third annual vaccinations in consecutive seasons in terms of seroprotective antibody titres for all three strains (H1N1, H3N2 and B). In another phase III trial, Intanza 15 microg was as immunogenic as the intramuscular, adjuvanted vaccine Fluad, with noninferiority established in terms of ratios of geometric mean titres against H1N1 and B strains using the haemagglutinin inhibition method and against all three strains using the single radial haemolysis method. Intanza 15 microg was generally well tolerated in clinical trials in the elderly, with the most common adverse events observed being solicited injection-site reactions. The majority of solicited injection-site reactions were mild and spontaneously resolved within 1-3 days of onset; transient, visible injection-site reactions with the intradermal route of injection are not surprising as the vaccine is injected close to the skin surface.