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.
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).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
134,476
Participants will be individually randomized 1:1 to receive either QIV-HD or QIV-SD, one dose, the day of the inclusion in the trial
General Public Health Directorate of Galician Health Service
Santiago de Compostela, A Coruña, Spain
Occurrence of a hospitalization due to influenza or pneumonia
Time frame: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for any cardio-respiratory disease [composite endpoint]
Time frame: ≥14 days after vaccination and up to May 31 the following year
All-cause hospitalization
Time frame: ≥14 days after vaccination and up to May 31 the following year
All-cause mortality
Time frame: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for influenza
Time frame: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for pneumonia
Time frame: ≥14 days after vaccination and up to May 31 the following year
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