Immunogenicity and safety of a quadrivalent high-dose inactivated influenza vaccine compared with a standard-dose quadrivalent influenza vaccine in healthy people aged 60 years or older: a randomized Phase III trial.

A quadrivalent high-dose inactivated influenza vaccine (IIV4-HD) is licensed for adults ≥65 y of age based on immunogenicity and efficacy studies. However, IIV4-HD has not been evaluated in adults aged 60-64 y. This study compared immunogenicity and safety of IIV4-HD with a standard-dose quadrivalent influenza vaccine (IIV4-SD) in adults aged ≥60 y.