DSEN Abstract
Comparative effectiveness of influenza vaccines in elderly persons

What is the current situation?

Influenza-related complications disproportionally affect seniors, thus effective influenza vaccination strategies are crucial. This is particularly important in the post-COVID era. As more influenza vaccine formulations become available, there is a great need for comparative studies that allow regulators to make evidence-based decisions regarding influenza vaccination, especially in seniors.

Summary

  • Influenza-related complications can lead to hospitalizations and death in seniors
  • Influenza vaccine immunogenicity (antibody response) is lower in seniors vs. those younger
  • Determining the most effective vaccine in seniors could potentially lower hospitalization risks for influenza and/or pneumonia
  • We compared hospitalizations and ER visits for influenza and/or pneumonia in seniors
  • We selected 6 study periods covering 6 influenza seasons from MarketScan Medicare data (USA, 2011-2018)
  • High-dose trivalent vaccines were associated with lower risk of hospitalization/ER visits for flu and pneumonia, compared to standard-dose trivalent and quadrivalent vaccines

Authors: Marina Amaral de Avila Machado, Cristiano S. Moura, Michal Abrahamowicz, Brian J. Ward, Louise Pilote

For more information, please contact:
sasha.bernatsky@mcgill.ca

What was the aim of the study?

Our aim was to determine which available influenza vaccines are most effective for adults 65+.

How was the study conducted?

We used MarketScan Medicare Supplemental data (2011-2018) that contain longitudinal information on inpatient and outpatient medical services, including vaccination, hospital stays and emergency room (ER) visits. We compared the effectiveness of standard-dose (SD) trivalent, high-dose (HD) trivalent, SD quadrivalent, and adjuvanted trivalent influenza vaccines in adults aged 65+ in the United States over six influenza seasons (2012/2013–2017/2018).

Primary outcomes:

  1. hospitalization or ER visit with a diagnosis of influenza
  2. hospitalization or ER visit with a diagnosis of pneumonia (a complication of influenza)

What did the study find?

  • Seniors vaccinated with an HD-trivalent influenza vaccine were less likely to visit the ER or be hospitalized for influenza and/or pneumonia than those receiving SD-formulations.
  • We were unable to demonstrate clear differences comparing the adjuvanted trivalent to the other vaccines.

Our findings provide real-world evidence that, in seniors, HD-trivalent vaccination is associated with fewer ER visits and/or hospitalizations for influenza and/or pneumonia.

Link to publication

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