High-Dose Flu Vaccine Enhances Elderly Immunity: Study in JCI Insights

In a groundbreaking study published in JCI Insights, researchers have discovered significant benefits of high-dose influenza vaccination. This study, titled “Boosting effect of high-dose influenza vaccination on innate immunity among elderly: a randomized-control trial,” highlights how high-dose vaccines enhance immune responses compared to standard doses.

Background and Objectives

Previously, the high-dose quadrivalent influenza vaccine (QIV-HD) showed superior efficacy in preventing influenza illness compared to the standard-dose quadrivalent influenza vaccine (QIV-SD) in elderly populations. However, the underlying mechanisms remained unclear. This Phase-IV randomized control trial aimed to clarify these mechanisms by examining early innate immune responses in individuals over 65.

Study Design

The study included 59 elderly participants. They were randomly assigned to receive either the QIV-HD or QIV-SD. Researchers assessed:

  • Systemic innate cells and gene signatures at Day 0 and Day 1 post-vaccination.
  • Hemagglutinin inhibition antibody (HIA) titers at Day 0 and Day 21.

Key Discoveries

Firstly, the QIV-HD triggered a more robust humoral response. This response was marked by significantly higher antibody titers and seroconversion rates compared to the QIV-SD. Moreover, at Day 1 post-vaccination, QIV-HD recipients showed a significant reduction in innate cells, such as conventional dendritic cells and natural killer cells. This reduction correlated with increased HIA titers at Day 21.

Additionally, blood transcriptomic analysis revealed a greater amplitude of gene expression in the QIV-HD group. These genes were related to innate immune response, interferons, and antigen processing and presentation. These findings strongly correlated with the observed humoral responses.

Comparative Insights

Interestingly, a comparative analysis with data from young adults vaccinated with the standard-dose influenza vaccine showed striking similarities. The gene expression patterns and biological pathways in young adults were similar to those in the elderly vaccinated with QIV-HD. This suggests that the high-dose vaccine may induce a more youthful immune response in the elderly.

Conclusion

In conclusion, the study found that the QIV-HD induces higher HIA titers and a youthful boost in innate gene expression. These findings underscore the potential of high-dose influenza vaccines in improving immune protection for the elderly, who are particularly vulnerable to influenza complications.

Collaborative Efforts

This study was a collaborative effort involving multiple institutions and researchers. At AltraBio, we played a crucial role in generating and analyzing the transcriptomic data. Our contributions helped in understanding the immune responses observed in this study.

Trial Registration

The trial is registered under EudraCT Number: 2021-004573-32.