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Journal Article Ppublish 5 citations

PubMed: 39670611 DOI: 10.1093/infdis/jiae615

Estimating Standard-Dose and High-Dose Fluzone Vaccine Efficacies for Influenza A Based on Hemagglutination Inhibition Titers.

J Infect Dis 231(5):1336-1345

Authors: Savannah M Hammerton, W Zane Billings, Hayley Hemme, Ted M Ross, Ye Shen, Andreas Handel

Affiliations

  • Department of Epidemiology and Biostatistics, College of Public Health. Center for the Ecology of Infectious Diseases.
  • Department of Epidemiology and Biostatistics, College of Public Health.
  • Center for the Ecology of Infectious Diseases.
  • Center for Vaccines and Immunology, University of Georgia, Athens.
  • Florida Research and Innovation Center, Cleveland Clinic, Port St Lucie.

Abstract

BACKGROUND

The high-dose (HD) Fluzone influenza vaccine is recommended for individuals aged ≥65 years due to its improved antibody responses and vaccine efficacy (VE) over the standard-dose (SD) formulation. Since influenza vaccines are frequently reformulated, monitoring VE changes is crucial. Traditional efficacy trials are costly and time-consuming, but immunogenicity studies using hemagglutination inhibition (HAI) titers-a reliable correlate of protection-can be used to estimate VE more efficiently.

METHODS

We analyzed data from a human vaccine cohort who received either the SD or HD Fluzone split-inactivated influenza vaccine during influenza seasons 2013-2014 to 2021-2022. We used a previously developed statistical model to map pre- and postvaccination HAI titers to protection probabilities, and computed differences in VE of the HD vaccine in older (≥65 years) populations compared to SD vaccines in the same age group and in younger (<65 years) adults.

RESULTS

We found that the HD vaccine generally improved the estimated VE in older adults. We also found that HD recipients often had a lower estimated VE than younger SD recipients.

CONCLUSIONS

While HD vaccines lead to a small increase in estimated VE compared to SD in older adults, further increases in dose or other developments to improve VE should be considered.

MeSH

Vaccines, Influenza, Human, Influenza Vaccines, Communicable Diseases, Hemagglutination, Vaccine Efficacy

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