A Pragmatic Randomized Trial to Evaluate the Effectiveness of High-Dose Quadrivalent Influenza Vaccine vs. Standard-Dose Quadrivalent Influenza Vaccine in Older Adults

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE4

Total Enrollment

332438 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-09-22

Study Completion Date

2025-08-31

Brief Summary

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The purpose of this pragmatic randomized trial is to evaluate the relative vaccine effectiveness of high-dose quadrivalent influenza vaccine (QIV-HD) vs. standard-dose quadrivalent influenza vaccine (QIV-SD) in older adults. Participants will be randomized 1:1 to either QIV-HD or QIV-SD.

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Detailed Description

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The study is a pragmatic, registry-based, open-label, active-controlled, individually randomized trial. The Danish nationwide administrative health registries will be used for data collection including baseline information, follow-up data, and safety monitoring. The study aims to randomize 339,700 participants over 3 influenza seasons. In each season, participants will be individually randomized 1:1 to receive either QIV-HD or QIV-SD. During the 2023/2024 and 2024/2025 seasons, up to 12,000 participants will be enrolled in a sub-cohort where participants are asked to perform home self-swabs and answer symptom questionnaires in case of influenza-like illness to enable further assessment of the impact of QIV-HD vs. QIV-SD on patient-reported outcomes among individuals with influenza-like illness and laboratory-confirmed influenza.

Conditions

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Influenza

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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High-Dose Quadrivalent Influenza Vaccine

QIV-HD single injection at Day 0

Group Type EXPERIMENTAL

High-Dose Quadrivalent Influenza Vaccine

Intervention Type BIOLOGICAL

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

Standard-Dose Quadrivalent Influenza Vaccine

QIV-SD single injection at Day 0

Group Type ACTIVE_COMPARATOR

Standard-Dose Quadrivalent Influenza Vaccine

Intervention Type BIOLOGICAL

Any standard-dose quadrivalent influenza vaccine administered in the Danish governmental influenza vaccine program may be used.

Interventions

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High-Dose Quadrivalent Influenza Vaccine

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

Intervention Type BIOLOGICAL

Standard-Dose Quadrivalent Influenza Vaccine

Any standard-dose quadrivalent influenza vaccine administered in the Danish governmental influenza vaccine program may be used.

Intervention Type BIOLOGICAL

Other Intervention Names

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QIV-HD QIV-SD

Eligibility Criteria

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Inclusion Criteria

* Age 65 years and above (this inclusion criterion will be modified according to the Danish government's official recommendations for the 2022/2023 and 2023/2024 influenza seasons)
* Informed consent form has been signed and dated

Minimum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes