Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease
1 other identifier
interventional
299,881
1 country
1
Brief Summary
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for not_applicable
Started Sep 2023
Shorter than P25 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
August 31, 2023
CompletedFirst Posted
Study publicly available on registry
September 11, 2023
CompletedStudy Start
First participant enrolled
September 24, 2023
CompletedPrimary Completion
Last participant's last visit for primary outcome
January 1, 2024
CompletedStudy Completion
Last participant's last visit for all outcomes
May 31, 2024
CompletedOctober 10, 2024
October 1, 2024
3 months
August 31, 2023
October 8, 2024
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Number of participants who received an influenza vaccine
Up to 3 months
Secondary Outcomes (1)
Time from intervention delivery to influenza vaccination
Up to 3 months
Other Outcomes (25)
Number of participants with laboratory-confirmed influenza
Up to 8 months
Number of participants with a hospitalization for influenza or pneumonia
Up to 8 months
Number of participants with a hospitalization for any respiratory disease
Up to 8 months
- +22 more other outcomes
Study Arms (7)
Usual Care
NO INTERVENTIONNo letter
Standard Letter
EXPERIMENTALThis group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement
Repeated Letter
EXPERIMENTALThe standard letter sent out two times instead of once
Cardiovascular Gain-Framing Letter
EXPERIMENTALText added to the standard letter highlighting potential cardiovascular benefits of influenza vaccination
Respiratory Gain-Framing Letter
EXPERIMENTALText added to the standard letter highlighting potential respiratory disease-related benefits of influenza vaccination
Implementation Intention Prompt Letter
EXPERIMENTALImplementation intention prompt added to the standard letter
Loss-Framing Letter
EXPERIMENTALText added to the standard letter highlighting potential risks of not receiving influenza vaccination
Interventions
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.
Eligibility Criteria
You may qualify if:
- Age 18-64 years
- 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:
- Chronic lung disease
- Chronic cardiovascular disease other than hypertension
- Type 1 or type 2 diabetes mellitus
- Congenital or acquired immunodeficiency
- Impaired breathing due to muscular weakness
- Chronic renal or hepatic insufficiency
- Other chronic conditions with an increased risk of severe influenza as determined by the treating physician
- Access to the official, mandatory Danish electronic mailbox system
You may not qualify if:
- None
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte
Hellerup, Capital Region, 2900, Denmark
Related Publications (4)
Lassen MCH, Johansen ND, Vaduganathan M, Bhatt AS, Modin D, Chatur S, Claggett BL, Janstrup KH, Larsen CS, Larsen L, Wiese L, Dalager-Pedersen M, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Krause TG, Biering-Sorensen T. Electronic Nudge Letters to Increase Influenza Vaccination Uptake in Younger and Middle-Aged Individuals With Diabetes. JACC Adv. 2024 Nov 13;3(12):101391. doi: 10.1016/j.jacadv.2024.101391. eCollection 2024 Dec.
PMID: 39606218DERIVEDBhatt AS, Johansen ND, Vaduganathan M, Modin D, Pareek M, Chatur S, Claggett BL, Janstrup KH, Larsen CS, Larsen L, Wiese L, Dalager-Pedersen M, Dueger EL, Samson S, Loiacono MM, Harris RC, Kober L, Solomon SD, Martel CJ, Sivapalan P, Jensen JUS, Biering-Sorensen T. Electronic Nudges and Influenza Vaccination Among Patients With a History of Myocardial Infarction: Insights From 3 Nationwide Randomized Clinical Trials. JAMA Cardiol. 2025 Jan 1;10(1):78-86. doi: 10.1001/jamacardio.2024.4648.
PMID: 39550717DERIVEDJohansen ND, Vaduganathan M, Bhatt AS, Modin D, Chatur S, Claggett BL, Janstrup KH, Larsen CS, Larsen L, Wiese L, Dalager-Pedersen M, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Krause TG, Biering-Sorensen T. Electronic Nudges to Increase Influenza Vaccination in Patients With Chronic Diseases: A Randomized Clinical Trial. JAMA. 2024 Dec 10;332(22):1900-1911. doi: 10.1001/jama.2024.21060.
PMID: 39392741DERIVEDJohansen ND, Vaduganathan M, Bhatt AS, Modin D, Chatur S, Claggett BL, Janstrup KH, Larsen CS, Larsen L, Wiese L, Dalager-Pedersen M, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Krause TG, Biering-Sorensen T. Rationale and design of NUDGE-FLU-CHRONIC and NUDGE-FLU-2: Two nationwide randomized trials of electronic nudges to increase influenza vaccination among patients with chronic diseases and older adults during the 2023/2024 influenza season. Am Heart J. 2024 Jun;272:23-36. doi: 10.1016/j.ahj.2024.03.003. Epub 2024 Mar 7.
PMID: 38460754DERIVED
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- 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 Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- NONE
- Purpose
- OTHER
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR INVESTIGATOR
- PI Title
- Professor, MD, MSc, MPH, PhD
Study Record Dates
First Submitted
August 31, 2023
First Posted
September 11, 2023
Study Start
September 24, 2023
Primary Completion
January 1, 2024
Study Completion
May 31, 2024
Last Updated
October 10, 2024
Record last verified: 2024-10
Data Sharing
- IPD Sharing
- Will share
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.