Randomized, Double‐Blind Controlled Phase 3 Trial Comparing the Immunogenicity of High‐Dose and Standard‐Dose Influenza Vaccine in Adults 65 Years of Age and Older

TLDR

Influenza morbidity and mortality have remained unchanged over the past decade despite higher vaccination rates. The study aimed to determine whether a high‑dose trivalent influenza vaccine improves immunogenicity compared with the standard dose in adults 65 and older. A multicenter, randomized, double‑blind controlled trial enrolled 2575 participants receiving the 60‑µg high‑dose vaccine and 1262 receiving the 15‑µg standard dose. High‑dose vaccination produced significantly higher seroconversion rates, higher hemagglutination inhibition titers, and superior or non‑inferior responses for all strains, with only mild increased local reactions, indicating improved protection for older adults.

Abstract

Influenza-associated morbidity and mortality has not decreased in the last decade, despite increased receipt of vaccine. To improve the immunogenicity of influenza vaccine, a high-dose (HD) trivalent, inactivated influenza vaccine was developed.A multicenter, randomized, double-blind controlled study was conducted to compare HD vaccine (which contains 60 microg of hemagglutinin per strain) with the licensed standard-dose (SD) vaccine (which contains 15 microg of hemagglutinin per strain) in adults > or = 65 years of age.HD vaccine was administered to 2575 subjects, and SD vaccine was administered to 1262 subjects. There was a statistically significant increase in the rates of seroconversion and mean hemagglutination inhibition titers at day 28 after vaccination among those who received HD vaccine, compared with those who received SD vaccine. Mean postvaccination titers for individuals who received HD vaccine were 116 for H1N1, 609 for H3N2, and 69 for B strain; for those who received SD vaccine, mean postvaccination titers were as 67 for H1N1, 333 for H3N2, and 52 for B strain. The HD vaccine met superiority criteria for both A strains, and the responses for B strain met non-inferiority criteria. Seroprotection rates were also higher for those who received HD vaccine than for those who received SD vaccine vaccine, for all strains. Local reactions were more frequent in individuals who received HD vaccine, but the reactions were mild to moderate.There was a statistically significant increase in the level of antibody response induced by HD influenza vaccine, compared with that induced by SD vaccine, without an attendant increase in the rate or severity of clinically relevant adverse reactions. These results suggest that the high-dose vaccine may provide improved protective benefits for older adults.ClinicalTrials.gov identifier: NCT00391053 .