Method: A randomized, modified double blind, multicenter study (NCT03282240) was conducted in 2670 healthy subjects in the United States, who were randomly assigned to receive IIV4-HD, a licensed IIV3-HD, or an IIV3-HD with the alternate B influenza strain. Using the hemagglutinin inhibition (HAI) assay at baseline and 28 days after vaccination, post-vaccination geometric mean titers and seroconversion rates were measured. Safety data were collected through six months post-vaccination.
Result: IIV4-HD was non-inferior to the licensed IIV3-HD and the investigational IIV3-HD (containing the alternate B strain) for all 4 influenza strains as assessed by HAI GMTs and seroconversion rates. Moreover, IIV4-HD induced a superior immune response (HAI GMTs and seroconversion rates) compared to the immune response induced by the IIV3-HD that does not contain the corresponding B strain. Reactogenicity profiles were comparable across all study groups. Most unsolicited adverse events were of Grade 1 or Grade 2 intensity. One serious adverse event considered related by the Investigator was reported in the IIV4-HD group.
Conclusion: Vaccination of adults 65 years of age and older with IIV4-HD was found to be non-inferior to two IIV3-HD vaccines with a similar safety profile. The addition of a second B lineage strain does not adversely affect the safety or immunogenicity profile of IIV4-HD compared with IIV3-HD.
L. J. Chang,
H. Janosczyk, Sanofi Pasteur: Employee , Salary .
V. Landolfi, Sanofi Pasteur: Employee , Salary .
H. K. Talbot, Sanofi Pasteur: Investigator , Research grant . Gilead: Investigator , Research grant . MedImmune: Investigator , Research grant . Vaxinnate: Safety Board , none . Seqirus: Safety Board , none .
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