High-dose trivalent influenza vaccine compared to standard dose vaccine in elderly adults: Safety, immunogenicity and relative efficacy during the 2009-2010 season

► The high-dose vaccine was safe and well tolerated (comparable to standard dose). ► The high-dose vaccine induced superior immune responses. ► Efficacy assessments presented are only exploratory (limited numbers/precision). ► All viruses typified were classified as A/California/7/2009 (vaccine unmatched).