HD vs SD Quadrivalent Influenza Vaccine in Adults Aged 65 to 79 Years in Galicia

Last updated: August 4, 2025
Sponsor: Federico Martinón Torres
Overall Status: Completed

Phase

4

Condition

Influenza

Treatment

Influenza vaccine

Clinical Study ID

NCT06141655
GALFLU
  • Ages 65-79
  • All Genders
  • Accepts Healthy Volunteers

Study Summary

This pragmatic randomized trial is designed to evaluate the relative vaccine effectiveness of QIV-HD vs. QIV-SD in reducing the risk of hospitalization for influenza or pneumonia in adults 65-79 years of age in Galicia during 2023/2024 and 2024/2025 seasons.

Eligibility Criteria

Inclusion

Inclusion Criteria:

  1. Age 65-79 years residing in the community (only individuals who are noteligible to receive QIV-HD as part of the standard of care)
  1. Informed consent form has been signed and dated

Exclusion

Exclusion Criteria:

  • There are no specific exclusion criteria for this study

Study Design

Total Participants: 134476
Treatment Group(s): 1
Primary Treatment: Influenza vaccine
Phase: 4
Study Start date:
October 26, 2023
Estimated Completion Date:
May 31, 2025

Study Description

The study is a pragmatic, registry-based, open-label, active-controlled, individually randomized trial using the infrastructure of the Regional Vaccination Program of Galicia for patient recruitment, inclusion, randomization, and vaccine administration and the Galician health registries for data collection including baseline information, follow-up data and safety monitoring. Participants will have the opportunity of receiving all the information for the trial prior to the vaccination appointment. Informed consent will be obtained during the vaccination appointment by the study team prior to their vaccine administration. The participation in the study is voluntary, and only individuals who accept signing the informed consent will be recruited. Participants may withdraw from the study at any point.

The study aims to randomize at least 114.011 participants over 2 influenza seasons (2023/2024 and 2024/2025) with approximately 57,000 participants per season (pending any further potential sample size adjustments following interim analysis).

Connect with a study center

  • General Public Health Directorate of Galician Health Service

    Santiago de Compostela, A Coruña
    Spain

    Site Not Available

Map preview placeholder

Not the study for you?

Let us help you find the best match. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.