InfluenzaNUDGE-FLUNCT05542004
Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake
A study testing Behavioral Economic Principles in people with Influenza and Behavior and Behavior Mechanisms, run by Tor Biering-Sørensen at 1 site in Denmark.
Trial 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. Read more about this study
- Who is it for?
- Ages 65 years and olderHealthy volunteers can take part
- Conditions the study is for
- Influenza, Behavior and Behavior Mechanisms
- What is being tested?
- Behavioral Economic Principles
- Type of treatment
- Vaccines, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 964,870 participants
- Where
- 1 siteDenmark
- Study dates
- 16 Sep 2022to 31 May 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 65 years and older
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- 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
Who cannot join
- 1) Persons living in nursing homes
Trial locations and contacts
1 site in 1 country.
Denmark1 site
Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte
Hellerup, Capital Region, 2900
About this study
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.
Read the detailed description
The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons identified as eligible for free-of-charge influenza vaccination in the Danish health system aged 18 years and above. Subjects will be identified through Danish nationwide health registries using codes from the International Classification of Diseases, 10th revision (ICD-10) and the Anatomical Therapeutic Chemical (ATC) classification system. Individuals will be randomized to 1 of 10 arms (1 control arm and 9 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. The study will be performed in collaboration with the Danish Health Data Authority and Statens Serum Institut.
- Conditions
- Influenza, Behavior and Behavior Mechanisms
- Being tested
- Behavioral Economic Principles
- Keywords
- Influenza, Vaccination, Nudging, Behavioral Science
- Medical subject headings
- Influenza, Human, Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Behavioral Economic PrinciplesBehavioural
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.
| Study group | Role | What they receive |
|---|---|---|
| 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 Receives: Behavioral: Behavioral Economic Principles |
| Priming & Hot State Activation - 1 reminder | Experimental | The standard letter sent out two times instead of once Receives: Behavioral: Behavioral Economic Principles |
| Depersonalized Letter | Experimental | The standard letter without the recipient's name Receives: Behavioral: Behavioral Economic Principles |
| Gain-Framing/Context | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
| Loss-Framing/Context | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
| Collective Goal | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
| Active Choice/Implementation Intention Prompt | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
| Cardiovascular Gain Frame | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
| Expert Authority | Experimental | Text added to the standard letter employing the specified behavioral economic principle Receives: Behavioral: Behavioral Economic Principles |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of participants who received an influenza vaccine
Measured: Up to 3 months
Secondary outcomes (1)
Time from intervention delivery to influenza vaccination
Measured: Up to 3 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2022
- Study start16 Sep 2022
- Primary completion1 Jan 2023
- Study completion31 May 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for InfluenzaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 964,870 participants (actual)
Sponsor and investigators
- Lead sponsor
- Tor Biering-Sørensen
- Sponsor type
- University, hospital or other
- Collaborators
- Statens Serum Institut, Sanofi Pasteur, a Sanofi Company
- Responsible party
- Sponsor-investigator, Tor Biering-Sørensen, Herlev and Gentofte Hospital
- Investigators
- Tor Biering-Sørensen, MD, PhD, MPH, Principal investigator, Research Director
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05542004
- Sponsor's protocol ID
- FLU00180
- Acronym
- NUDGE-FLU
- Status last verified
- Oct 2024
- First submitted
- 31 Aug 2021
- Last updated
- 10 Oct 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Publications
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.
PubMed 39550717Johansen 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.
PubMed 38498876Lassen 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.
PubMed 38117499Johansen 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.
PubMed 37211967Johansen 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.
PubMed 36889332Modin 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.
PubMed 36871213Johansen 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.
PubMed 36801265
Study at a glance
From the registry record, last updated by the sponsor on 10 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake
- ClinicalTrials.gov ID
- NCT05542004
- Acronym / sponsor ID
- NUDGE-FLU / FLU00180
- Conditions
- Influenza, Behavior and Behavior Mechanisms
- Keywords
- Influenza, Vaccination, Nudging, Behavioral Science
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 964,870 participants (actual)
- Lead sponsor
- Tor Biering-SørensenUniversity, hospital or other
- Collaborators
- Statens Serum Institut, Sanofi Pasteur, a Sanofi Company
- Study start
- 16 Sep 2022 (actual)
- Primary completion
- 1 Jan 2023 (actual)
- Study completion
- 31 May 2023 (actual)
- First posted
- 15 Sep 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons identified as eligible for free-of-charge influenza vaccination in the Danish health system aged 18 years and above. Subjects will be identified through Danish nationwide health registries using codes from the International Classification of Diseases, 10th revision (ICD-10) and the Anatomical Therapeutic Chemical (ATC) classification system. Individuals will be randomized to 1 of 10 arms (1 control arm and 9 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. The study will be performed in collaboration with the Danish Health Data Authority and Statens Serum Institut.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 10
| Arm | Type | Receives |
|---|---|---|
| Control | No intervention | –No letter |
| Standard Letter | Experimental | Behavioral: Behavioral Economic PrinciplesThis group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement |
| Priming & Hot State Activation - 1 reminder | Experimental | Behavioral: Behavioral Economic PrinciplesThe standard letter sent out two times instead of once |
| Depersonalized Letter | Experimental | Behavioral: Behavioral Economic PrinciplesThe standard letter without the recipient's name |
| Gain-Framing/Context | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
| Loss-Framing/Context | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
| Collective Goal | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
| Active Choice/Implementation Intention Prompt | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
| Cardiovascular Gain Frame | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
| Expert Authority | Experimental | Behavioral: Behavioral Economic PrinciplesText added to the standard letter employing the specified behavioral economic principle |
Who may qualify
- Ages
- 65 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (2 listed)
- 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
Key exclusion criteria (1 listed)
- 1) Persons living in nursing homes
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Behavioral Economic PrinciplesThe 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. | Behavioural | Active Choice/Implementation Intention Prompt, Cardiovascular Gain Frame, Collective Goal, Depersonalized Letter, Expert Authority, Gain-Framing/Context, Loss-Framing/Context, Priming & Hot State Activation - 1 reminder, Standard Letter |
Primary outcome
Number of participants who received an influenza vaccine
Time frame: Up to 3 months
1 secondary outcome
Time from intervention delivery to influenza vaccination
Time frame: Up to 3 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Oct 2024.
- Derived from this study: PubMed 39550717Bhatt 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.
- Derived from this study: PubMed 38498876Johansen 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.
- Derived from this study: PubMed 38117499Lassen 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.
- Derived from this study: PubMed 37211967Johansen 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.
- Derived from this study: PubMed 36889332Johansen 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.
- Derived from this study: PubMed 36871213Modin 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.
- Derived from this study: PubMed 36801265Johansen 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.
- Individual participant dataSharing planned: Yes. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Tor Biering-Sørensen, MD, PhD, MPH principal investigator
Research Director
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Behavioral Economic Principles in people with Influenza and Behavior and Behavior Mechanisms, run by Tor Biering-Sørensen at 1 site in Denmark.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 10 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants who received an influenza vaccine (time frame: Up to 3 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05542004, which also lists 7 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Oct 2024.