Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease

October 8, 2024 updated by: Tor Biering-Sørensen
In randomized clinical trials and observational studies, influenza vaccination has been shown to be effective in reducing influenza-related illness, hospitalizations, cardiovascular events, and mortality in select populations. However, the real-world effectiveness of influenza vaccination is limited by its uptake. This study will investigate whether digital behavioral nudges delivered via the official, mandatory Danish electronic letter system can increase influenza vaccine uptake among adults aged 18-64 years with chronic diseases.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons aged 18-64 years identified as eligible for free-of-charge influenza vaccination due to a chronic condition. Subjects will be identified through Danish nationwide health registries using codes from the International Classification of Diseases, 10th revision (ICD-10). Individuals will be randomized to 1 of 7 arms (1 usual care arm and 6 intervention arms) with each testing different nudging strategies employing various behavioural economic principles. The interventions will be delivered through the official, mandatory Danish electronic letter system. All subject data will be retrieved from the Danish nationwide registries with the exception of information on intervention allocation. Endpoints will be retrieved at prespecified dates using prespecified search algorithms.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
299881

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Denmark
    • Hovedstaden
      • Hellerup, Hovedstaden, Denmark, 2900
        • Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age 18-64 years

  2. Must be registered in the Danish nationwide registries as meeting at least one of the following eligibility criteria for free-of-charge influenza vaccination in the Danish public health system:

    1. Chronic lung disease
    2. Chronic cardiovascular disease other than hypertension
    3. Type 1 or type 2 diabetes mellitus
    4. Congenital or acquired immunodeficiency
    5. Impaired breathing due to muscular weakness
    6. Chronic renal or hepatic insufficiency
    7. Other chronic conditions with an increased risk of severe influenza as determined by the treating physician
  3. Access to the official, mandatory Danish electronic mailbox system

Exclusion Criteria:

None

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Standard Letter
This group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.
No Intervention: Usual Care
No letter
Experimental: Repeated Letter
The standard letter sent out two times instead of once
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.
Experimental: Cardiovascular Gain-Framing Letter
Text added to the standard letter highlighting potential cardiovascular benefits of influenza vaccination
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.
Experimental: Respiratory Gain-Framing Letter
Text added to the standard letter highlighting potential respiratory disease-related benefits of influenza vaccination
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.
Experimental: Implementation Intention Prompt Letter
Implementation intention prompt added to the standard letter
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.
Experimental: Loss-Framing Letter
Text added to the standard letter highlighting potential risks of not receiving influenza vaccination
Behavioral: Behavioral Economic Principles
The control arm will receive no letter to reflect the background vaccination uptake. Intervention arms will test the effects of different letters developed using behavioral economic principles.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Number of participants who received an influenza vaccine
Time Frame: Up to 3 months
Up to 3 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Time from intervention delivery to influenza vaccination
Time Frame: Up to 3 months
Up to 3 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Time Frame
Number of participants with laboratory-confirmed influenza
Time Frame: Up to 8 months
Up to 8 months
Number of participants with any hospitalization
Time Frame: Up to 8 months
Up to 8 months
All-cause mortality
Time Frame: Up to 8 months
Up to 8 months
Composite of incident heart failure, heart failure hospitalization, or cardiovascular death
Time Frame: Up to 8 months
Up to 8 months
Composite of myocardial infarction, stroke, or cardiovascular death
Time Frame: Up to 8 months
Up to 8 months
Composite of myocardial infarction, coronary revascularization, stroke, or cardiovascular death
Time Frame: Up to 8 months
Up to 8 months
Number of participants with incident heart failure or heart failure hospitalization
Time Frame: Up to 8 months
Up to 8 months
Cardiovascular death
Time Frame: Up to 8 months
Up to 8 months
Number of participants with myocardial infarction
Time Frame: Up to 8 months
Up to 8 months
Number of participants with coronary revascularization
Time Frame: Up to 8 months
Up to 8 months
Number of participants with stroke
Time Frame: Up to 8 months
Up to 8 months
Number of contacts to general practitioner (excluding vaccination visit)
Time Frame: Up to 8 months
Up to 8 months
Number of participants with laboratory-confirmed COVID-19
Time Frame: Up to 8 months
Up to 8 months
Number of participants who received a COVID-19 vaccine
Time Frame: Up to 3 months
Up to 3 months
Number of participants with a hospitalization for influenza or pneumonia
Time Frame: Up to 8 months
Up to 8 months
Number of participants with a hospitalization for any respiratory disease
Time Frame: Up to 8 months
Up to 8 months
Number of participants with a hospitalization for any cardio-respiratory disease
Time Frame: Up to 8 months
Up to 8 months
Number of participants with a hospitalization for any cardiovascular disease
Time Frame: Up to 8 months
Up to 8 months
Total number of hospitalizations (first and recurrent)
Time Frame: Up to 8 months
Up to 8 months
Total number of heart failure events (incident heart failure and first and recurrent heart failure hospitalizations)
Time Frame: Up to 8 months
Up to 8 months
Number of participants with incident atrial fibrillation or atrial fibrillation hospitalization
Time Frame: Up to 8 months
Up to 8 months
Number of participants with a hospitalization for COVID-19
Time Frame: Up to 8 months
Up to 8 months
Number of participants who filled a prescription for any guideline-directed medical therapy for heart failure
Time Frame: Up to 8 months
Up to 8 months
Total number of filled prescriptions for guideline-directed medical therapy for heart failure
Time Frame: Up to 8 months
Up to 8 months
Number of participants who filled a prescription for a sodium-glucose cotransporter 2 inhibitor or glucagon-like peptide 1 receptor agonist
Time Frame: Up to 8 months
Up to 8 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tor Biering-Sørensen

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Statens Serum Institut

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Tor Biering-Sørensen, MD, MSc, MPH, PhD, Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 24, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 31, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 31, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 8, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 11, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 10, 2024

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 8, 2024

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • NUDGE-FLU-CHRONIC

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data will be collected from Danish administrative health registries, which are subject to Danish legislation and can only be made available to a third party under certain conditions. Please contact the sponsor-investigator in case of any inquiries.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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