1. Immunogenicity of adjuvanted versus high-dose inactivated influenza vaccines in older adults: a randomized clinical trial
- Author
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Kenneth E. Schmader, Christine K. Liu, Brendan Flannery, Wes Rountree, Heidi Auerbach, Elizabeth D. Barnett, Elizabeth P. Schlaudecker, Christopher A. Todd, Marek Poniewierski, Mary A. Staat, Theresa Harrington, Rongxia Li, Karen R. Broder, and Emmanuel B. Walter
- Subjects
Influenza vaccine ,Immunogenicity ,Aged ,Adjuvanted influenza vaccine ,High dose influenza vaccine ,Immunologic diseases. Allergy ,RC581-607 ,Geriatrics ,RC952-954.6 - Abstract
Abstract Background Adjuvanted inactivated influenza vaccine (aIIV) and high-dose inactivated influenza vaccine (HD-IIV) are U.S.-licensed for adults aged ≥ 65 years. This study compared serum hemagglutination inhibition (HAI) antibody titers for the A(H3N2) and A(H1N1)pdm09 and B strains after trivalent aIIV3 and trivalent HD-IIV3 in an older adult population. Results The immunogenicity population included 342 participants who received aIIV3 and 338 participants who received HD-IIV3. The proportion of participants that seroconverted to A(H3N2) vaccine strains after allV3 (112 participants [32.8%]) was inferior to the proportion of participants that seroconverted after HD-IIV3 (130 participants [38.5%]) at day 29 after vaccination (difference, − 5.8%; 95%CI, − 12.9% to 1.4%). There were no significant differences between the vaccine groups in percent seroconversion to A(H1N1)pdm09 or B vaccine strains, in percent seropositivity for any of the strains, or in post-vaccination GMT for the A(H1N1)pdm09 strain. The GMTs for the post-vaccination A(H3N2) and B strains were higher after HD-IIV than after aIIV3. Conclusions Overall immune responses were similar after aIIV3 and HD-IIV3. For the primary outcome, the aIIV3 seroconversion rate for H3N2 did not meet noninferiority criteria compared with HD-IIV3, but the HD-IIV3 seroconversion rate was not statistically superior to the aIIV3 seroconversion rate. Trial registration ClinicalTrials.gov Identifier: NCT03183908.
- Published
- 2023
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