A phase 1, open-label, randomized study to compare the immunogenicity and safety of different administration routes and doses of virosomal influenza vaccine in elderly

Intradermal delivery significantly improved influenza vaccine immunogenicity compared with intramuscular delivery. Triple dose (45 μg) virosomal vaccine did not demonstrate any benefit on vaccine's immunogenicity over 15 μg commercial presentation. All treatments were generally safe and well-tolerated.