NCT05542004

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 investigate whether digital behavioral nudges delivered via the official, mandatory Danish electronic letter system can increase influenza vaccine uptake among eligible influenza vaccination candidates.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
964,870

participants targeted

Target at P75+ for not_applicable

Timeline
Completed

Started Sep 2022

Shorter than P25 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

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, 2021

Completed
1 year until next milestone

First Posted

Study publicly available on registry

September 15, 2022

Completed
1 day until next milestone

Study Start

First participant enrolled

September 16, 2022

Completed
4 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

January 1, 2023

Completed
5 months until next milestone

Study Completion

Last participant's last visit for all outcomes

May 31, 2023

Completed
Last Updated

October 10, 2024

Status Verified

October 1, 2024

Enrollment Period

4 months

First QC Date

August 31, 2021

Last Update Submit

October 8, 2024

Conditions

InfluenzaBehavior and Behavior Mechanisms

Keywords

InfluenzaVaccinationNudgingBehavioral Science

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 (16)

  • Number of participants with laboratory-confirmed influenza

    Up to 8 months

  • Number of participants with a hospitalization with influenza or pneumonia

    Up to 8 months

  • Number of participants with any hospitalization

    Up to 8 months

  • +13 more other outcomes

Study Arms (10)

Control

NO INTERVENTION

No letter

Standard Letter

EXPERIMENTAL

This group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement

Behavioral: Behavioral Economic Principles

Priming & Hot State Activation - 1 reminder

EXPERIMENTAL

The standard letter sent out two times instead of once

Behavioral: Behavioral Economic Principles

Depersonalized Letter

EXPERIMENTAL

The standard letter without the recipient's name

Behavioral: Behavioral Economic Principles

Gain-Framing/Context

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Loss-Framing/Context

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Collective Goal

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Active Choice/Implementation Intention Prompt

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Cardiovascular Gain Frame

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Expert Authority

EXPERIMENTAL

Text added to the standard letter employing the specified behavioral economic principle

Behavioral: Behavioral Economic Principles

Interventions

Behavioral Economic PrinciplesBEHAVIORAL

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.

Active Choice/Implementation Intention PromptCardiovascular Gain FrameCollective GoalDepersonalized LetterExpert AuthorityGain-Framing/ContextLoss-Framing/ContextPriming & Hot State Activation - 1 reminderStandard Letter

Eligibility Criteria

Age65 Years+
Sexall
Healthy VolunteersYes
Age GroupsOlder Adult (65+)

You may qualify if:

  • Age \>=65 years at January 15, 2023 (eligible for free influenza vaccination in the official Danish vaccination program)
  • Access to the official, mandatory Danish electronic mailbox system

You may not qualify if:

  • \) Persons living in nursing homes

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

Location

Related Publications (7)

  • Bhatt 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: 39550717DERIVED

  • Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Modin D, Claggett BL, Dueger EL, Samson S, Loiacono MM, Harris RC, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Krause TG, Biering-Sorensen T. Clinical Outcomes With Electronic Nudges to Increase Influenza Vaccination : A Prespecified Analysis of a Nationwide, Pragmatic, Registry-Based, Randomized Implementation Trial. Ann Intern Med. 2024 Apr;177(4):476-483. doi: 10.7326/M23-2638. Epub 2024 Mar 19.

    PMID: 38498876DERIVED

  • Lassen MCH, Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Modin D, Claggett BL, Dueger EL, Samson SI, Loiacono MM, Fralick M, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Krause TG, Biering-Sorensen T. Electronically Delivered Nudges to Increase Influenza Vaccination Uptake in Older Adults With Diabetes: A Secondary Analysis of the NUDGE-FLU Trial. JAMA Netw Open. 2023 Dec 1;6(12):e2347630. doi: 10.1001/jamanetworkopen.2023.47630.

    PMID: 38117499DERIVED

  • Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Modin D, Claggett BL, Dueger EL, Samson S, Loiacono MM, Harris RC, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Valentiner-Branth P, Krause TG, Biering-Sorensen T. Electronic nudges to increase influenza vaccination uptake among patients with heart failure: A pre-specified analysis of the NUDGE-FLU trial. Eur J Heart Fail. 2023 Aug;25(8):1450-1458. doi: 10.1002/ejhf.2913. Epub 2023 Jun 4.

    PMID: 37211967DERIVED

  • Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Modin D, Claggett BL, Dueger EL, Samson SI, Loiacono MM, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Martel CJ, Valentiner-Branth P, Krause TG, Biering-Sorensen T. Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trial. Lancet. 2023 Apr 1;401(10382):1103-1114. doi: 10.1016/S0140-6736(23)00349-5. Epub 2023 Mar 5.

    PMID: 36889332DERIVED

  • Modin D, Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Claggett BL, Dueger EL, Samson SI, Loiacono MM, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Jean-Marie Martel C, Valentiner-Branth P, Krause TG, Biering-Sorensen T. Effect of Electronic Nudges on Influenza Vaccination Rate in Older Adults With Cardiovascular Disease: Prespecified Analysis of the NUDGE-FLU Trial. Circulation. 2023 May 2;147(18):1345-1354. doi: 10.1161/CIRCULATIONAHA.123.064270. Epub 2023 Mar 5.

    PMID: 36871213DERIVED

  • Johansen ND, Vaduganathan M, Bhatt AS, Lee SG, Modin D, Claggett BL, Dueger EL, Samson S, Loiacono MM, Kober L, Solomon SD, Sivapalan P, Jensen JUS, Valentiner-Branth P, Krause TG, Biering-Sorensen T. Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake (NUDGE-FLU): Study protocol for a nationwide randomized implementation trial. Am Heart J. 2023 Jun;260:58-71. doi: 10.1016/j.ahj.2023.02.009. Epub 2023 Feb 17.

    PMID: 36801265DERIVED

MeSH Terms

Conditions

Influenza, HumanBehavior

Condition Hierarchy (Ancestors)

Respiratory Tract InfectionsInfectionsOrthomyxoviridae InfectionsRNA Virus InfectionsVirus DiseasesRespiratory Tract Diseases

Study Officials

  • Tor Biering-Sørensen, MD, PhD, MPH

    Research Director

    PRINCIPAL INVESTIGATOR

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, PhD, MPH

Study Record Dates

First Submitted

August 31, 2021

First Posted

September 15, 2022

Study Start

September 16, 2022

Primary Completion

January 1, 2023

Study Completion

May 31, 2023

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.

Locations

DK(1)