npj Vaccines (Jan 2025)

Antibody responses against influenza A decline with successive years of annual influenza vaccination

  • Sheena G. Sullivan,
  • Arseniy Khvorov,
  • Louise Carolan,
  • Leslie Dowson,
  • A. Jessica Hadiprodjo,
  • Stephany Sánchez-Ovando,
  • Yi Liu,
  • Vivian K. Y. Leung,
  • David Hodgson,
  • Christopher C. Blyth,
  • Marion Macnish,
  • Allen C. Cheng,
  • Michelle Haugenauer,
  • Julia Clark,
  • Sonia Dougherty,
  • Kristine Macartney,
  • Archana Koirala,
  • Ameneh Khatami,
  • Ajay Jadhav,
  • Helen Marshall,
  • Kathryn E. Riley,
  • Peter A. B. Wark,
  • Catherine Delahunty,
  • Kanta Subbarao,
  • Adam J. Kucharski,
  • Annette Fox

DOI
https://doi.org/10.1038/s41541-024-01057-x
Journal volume & issue
Vol. 10, no. 1
pp. 1 – 10

Abstract

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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.