Feasibility of Randomizing Danish Citizens Aged 65-79 Years to High-Dose Quadrivalent Influenza Vaccine vs. Standard-Dose Quadrivalent Influenza Vaccine in a Pragmatic Registry-Based Setting

Overview

The purpose of the study is to assess the feasibility of identifying, recruiting and randomizing a large sample of Danish citizens aged 65-79 years to high-dose quadrivalent influenza vaccine or standard-dose quadrivalent influenza vaccine in the 2021/2022 influenza season in a registry-based setting using Danish nationwide registries for all data collection including baseline information and outcome assessment.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: May 31, 2022

Detailed Description

To evaluate the feasibility of recruiting and randomizing Danish citizens aged 65-79 years, we aim to randomize 40,000 citizens 1:1 to high-dose quadrivalent influenza vaccine or standard-dose quadrivalent influenza vaccine in a pragmatic, open-label, registry-based design using the infrastructure of Danske Lægers Vaccinations Service (DLVS), an organization responsible for numerous vaccination clinics in Denmark, for recruitment and randomization and Danish nationwide registries for data collection. Citizens will be recruited by DLVS and randomized and vaccinated at the DLVS clinics. All collection of data related to baseline information, outcomes, and safety monitoring will be performed by a central trial site utilizing information from Danish nationwide health registries. The findings of this pilot trial will indicate whether the conduction of a full-scale, adequately powered pragmatic RCT is feasible within the Danish registry-based framework.

Interventions

  • Drug: Standard-Dose Quadrivalent Influenza Vaccine
    • For the control arm, the standard-dose quadrivalent influenza vaccines Influvactetra® and Vaxigriptetra will be used.
  • Drug: High-Dose Quadrivalent Influenza Vaccine
    • For the control arm, the high-dose quadrivalent influenza vaccine Efluelda®/Fluzone® High-Dose Quadrivalent will be used.

Arms, Groups and Cohorts

  • Active Comparator: Standard-Dose Quadrivalent Influenza Vaccine
    • QIV-SD single injection at Day 0
  • Experimental: High-Dose Quadrivalent Influenza Vaccine
    • QIV-HD single injection at Day 0

Clinical Trial Outcome Measures

Primary Measures

  • Number of persons contacted by recruitment letter
    • Time Frame: Up to 8 months
  • Number of participants included and randomized to QIV-HD or QIV-SD
    • Time Frame: Up to 8 months
  • Agreement between randomization assignment and actual received vaccine
    • Time Frame: Up to 8 months
  • Balance between groups in terms of number of subjects in each arm and baseline characteristics
    • Time Frame: Up to 8 months
  • Comparison of baseline characteristics for the QIV-HD and QIV-SD groups to the overall Danish general population aged 65-79 years
    • Time Frame: Up to 8 months
  • Comparison of baseline characteristics for the QIV-HD and QIV-SD groups to the population aged 65-79 years in the DLVS database used for recruitment
    • Time Frame: Up to 8 months
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization for influenza and/or pneumonia
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with a primary (A) diagnosis code for influenza or pneumonia of at least 1 night duration
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization for respiratory disease
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with a primary (A) diagnosis code for respiratory disease of at least 1 night duration
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization for cardio-respiratory disease
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with a primary (A) diagnosis code for cardio-respiratory disease of at least 1 night duration
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization for cardiovascular disease
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with a primary (A) diagnosis code for cardiovascular disease of at least 1 night duration
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization from any cause
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with any diagnosis code of at least 1 night duration
  • Description of event rates and calculation of relative vaccine effectiveness for all-cause mortality
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • Death from any cause
  • Description of event rates and calculation of relative vaccine effectiveness for hospitalization for COVID-19
    • Time Frame: >= 14 days after vaccination up to 8 months post-vaccination
    • First hospitalization with a primary (A) diagnosis code for COVID-19 of at least 1 night duration

Participating in This Clinical Trial

Inclusion Criteria

1. Age 65-79 years 2. Informed consent form has been signed and dated Exclusion Criteria:

1. Allergy/hypersensitivity towards the influenza vaccines used in this study

Gender Eligibility: All

Minimum Age: 65 Years

Maximum Age: 79 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Tor Biering-Sørensen
  • Collaborator
    • Sanofi Pasteur, a Sanofi Company
  • Provider of Information About this Clinical Study
    • Sponsor-Investigator: Tor Biering-Sørensen, Research Director, MD, PhD, MPH – Herlev and Gentofte Hospital
  • Overall Official(s)
    • Tor Biering-Sørensen, MD, PhD, MPH, Study Chair, Research Director

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