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Completed

NCT Number: NCT05048589

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

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.

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Key information

Conditions

Influenza Infections Influenza, Human Orthomyxoviridae Infections RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

65 year–79 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Cardiovascular Non-Invasive Imaging Research Laboratory, Department of Cardiology, Herlev and Gentofte Hospital, Hellerup, Denmark

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About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 65-79 years
  • Informed consent form has been signed and dated

Exclusion criteria

  • Allergy/hypersensitivity towards the influenza vaccines used in this study

Treatment and study plan

Standard-Dose Quadrivalent Influenza Vaccine

Drug

For the control arm, the standard-dose quadrivalent influenza vaccines Influvactetra® and Vaxigriptetra will be used.

Other names: QIV-SD

High-Dose Quadrivalent Influenza Vaccine

Drug

For the control arm, the high-dose quadrivalent influenza vaccine Efluelda®/Fluzone® High-Dose Quadrivalent will be used.

Other names: QIV-HD

Primary outcomes

  1. Number of persons contacted by recruitment letter

    Time frame: Up to 8 months

  2. Number of participants included and randomized to QIV-HD or QIV-SD

    Time frame: Up to 8 months

  3. Agreement between randomization assignment and actual received vaccine

    Time frame: Up to 8 months

  4. Balance between groups in terms of number of subjects in each arm and baseline characteristics

    Time frame: Up to 8 months

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

Sponsors and collaborators

Lead sponsor

Tor Biering-Sørensen

Other

Collaborators

  • Sanofi Pasteur, a Sanofi Company

Registry information

Acronym: DANFLU-1

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Sep 17, 2021
Registry last updated
Aug 23, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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