1. Antibody responses against influenza A decline with successive years of annual influenza vaccination.
- Author
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Sullivan, Sheena, Khvorov, Arseniy, Carolan, Louise, Dowson, Leslie, Hadiprodjo, A, Sánchez-Ovando, Stephany, Liu, Yi, Leung, Vivian, Hodgson, David, Blyth, Christopher, Macnish, Marion, Cheng, Allen, Haugenauer, Michelle, Clark, Julia, Dougherty, Sonia, Macartney, Kristine, Koirala, Archana, Khatami, Ameneh, Jadhav, Ajay, Marshall, Helen, Riley, Kathryn, Wark, Peter, Delahunty, Catherine, Subbarao, Kanta, Kucharski, Adam, and Fox, Annette
- Abstract
Influenza vaccine effectiveness and immunogenicity can be compromised with repeated vaccination. We assessed immunological markers in a cohort of healthcare workers (HCW) from six public hospitals around Australia during 2020-2021. Sera were collected pre-vaccination and ~14 and ~180 days post-vaccination and assessed in haemagglutination inhibition assay against egg-grown vaccine and equivalent cell-grown viruses. Responses to vaccination were compared by the number of prior vaccinations. Baseline sera were available for 595 HCW in 2020 and 1031 in 2021. 5% had not been vaccinated during five years prior to enrolment and 55% had been vaccinated every year. Post-vaccination titres for all vaccine antigens were lowest among HCW vaccinated in all 5-prior years and highest among HCW with 0 or 1 prior vaccinations, even after adjustment. This was observed for both influenza A subtypes and was dependent on pre-vaccination titre. Expanded cohorts are needed to better understand how this translates to vaccine effectiveness.
- Published
- 2025