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Updated: Aug 6, 2025

An Optimized Hemagglutination Inhibition HI Assay to Quantify Influenza-specific Antibody Titers
Published on: December 1, 2017
Humoral and Cellular Immunity Induced by Adjuvanted and Standard Trivalent Influenza Vaccine in Older Nursing Home
Carson L Smith1, Beth Bednarchik2, Htin Aung3
1Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
Background:
Despite wide use of adjuvanted influenza vaccine in nursing home residents (NHR), little immunogenicity data exist for this population.
Methods:
We collected blood from NHR (n = 85) living in nursing homes participating in a cluster randomized clinical trial comparing MF59-adjuvanted trivalent inactivated influenza vaccine (aTIV) with nonadjuvanted vaccine (TIV) (parent trial, NCT02882100). NHR received either vaccine during the 2016-2017 influenza season. We assessed cellular and humoral immunity using flow cytometry and hemagglutinin inhibition, antineuraminidase (enzyme-linked lectin assay), and microneutralization assays.
Results:
Both vaccines were similarly immunogenic and induced antigen-specific antibodies and T cells, but aTIV specifically induced significantly larger 28 days after vaccination (D28) titers against A/H3N2 neuraminidase than TIV.
Conclusions:
NHRs respond immunologically to TIV and aTIV. From these data, the larger aTIV-induced antineuraminidase response at D28 may help explain the increased clinical protection observed in the parent clinical trial for aTIV over TIV in NHR during the A/H3N2-dominant 2016-2017 influenza season. Additionally, a decline back to prevaccination titers at 6 months after vaccination emphasizes the importance of annual vaccination against influenza.
Clinical Trials Registration:
NCT02882100.
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