| Registry | NCT06030726, acronym NUDGE-FLU-2 |
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| Status | Completed |
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| Phase | Not applicable |
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| Study type | Interventional; randomized, parallel, masking: none, other |
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| Enrollment | 881373 (Actual) |
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| Sponsor | Tor Biering-Sørensen (Other) |
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| Conditions | Influenza, Behavior and Behavior Mechanisms |
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| Interventions | Behavioral Economic Principles (Behavioral) |
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| Dates | start 2023-09-14, primary completion 2024-01-01, completion 2024-05-31, first posted 2023-09-11, last updated 2024-10-10 |
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| Locations | 1 site in Denmark |
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Related Papers Related Patents Related Grants Related Experts
All trials for Influenza All trials for Behavior and Behavior Mechanisms All trials of Behavioral Economic Principles
-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. Conducted during the 2022/2023 influenza season, the first NUDGE-FLU trial demonstrated the effectiveness of two electronic behavioral nudging letter strategies in increasing influenza vaccination rates among older adults in Denmark - a letter highlighting potential cardiovascular benefits of vaccination and a standard informational letter sent at baseline and repeated at day 14. This present study will once again investigate whether digital behavioral nudges delivered via the official, mandatory Danish electronic letter system can increase influenza vaccine uptake among older adults including whether the effectiveness of previously successful strategies can be confirmed during a subsequent influenza season.
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+Detailed description
The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons aged >=65 years at January 15, 2024 - this age group is eligible for free-of-charge influenza vaccination in the official Danish vaccination program. Subjects will be identified through Danish nationwide health registries including the Danish Civil Registration System. 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.
+Arms and interventions
| Arm | Type | Interventions | Description |
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| Usual Care | No intervention | | No letter |
| Standard Letter | Experimental | Behavioral: Behavioral Economic Principles | This group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement |
| Repeated Letter | Experimental | Behavioral: Behavioral Economic Principles | The standard letter sent out two times instead of once |
| Cardiovascular Gain-Framing Letter | Experimental | Behavioral: Behavioral Economic Principles | Text added to the standard letter highlighting potential cardiovascular benefits of influenza vaccination |
| Respiratory Gain-Framing Letter | Experimental | Behavioral: Behavioral Economic Principles | Text added to the standard letter highlighting potential respiratory disease-related benefits of influenza vaccination |
| Implementation Intention Prompt Letter | Experimental | Behavioral: Behavioral Economic Principles | Implementation intention prompt added to the standard letter |
| Loss-Framing Letter | Experimental | Behavioral: Behavioral Economic Principles | Text added to the standard letter highlighting potential risks of not receiving influenza vaccination |
- Behavioral Economic Principles (Behavioral): 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.
+Outcome measures
Primary outcomes
- Number of participants who received an influenza vaccine [Up to 3 months]
Secondary outcomes
- Time from intervention delivery to influenza vaccination [Up to 3 months]
Other outcomes
- 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]
- Number of participants with a hospitalization for any cardio-respiratory disease [Up to 8 months]
- Number of participants with a hospitalization for any cardiovascular disease [Up to 8 months]
- Number of participants with any hospitalization [Up to 8 months]
- Total number of hospitalizations (first and recurrent) [Up to 8 months]
- All-cause mortality [Up to 8 months]
- Composite of incident heart failure, heart failure hospitalization, or cardiovascular death [Up to 8 months]
- Composite of myocardial infarction, stroke, or cardiovascular death [Up to 8 months]
- Composite of myocardial infarction, coronary revascularization, stroke, or cardiovascular death [Up to 8 months]
- Number of participants with incident heart failure or heart failure hospitalization [Up to 8 months]
- Total number of heart failure events (incident heart failure and first and recurrent heart failure hospitalizations) [Up to 8 months]
- Cardiovascular death [Up to 8 months]
- Number of participants with myocardial infarction [Up to 8 months]
- Number of participants with coronary revascularization [Up to 8 months]
- Number of participants with stroke [Up to 8 months]
- Number of participants with incident atrial fibrillation or atrial fibrillation hospitalization [Up to 8 months]
- Number of contacts to general practitioner (excluding vaccination visit) [Up to 8 months]
- Number of participants with laboratory-confirmed COVID-19 [Up to 8 months]
- Number of participants with a hospitalization for COVID-19 [Up to 8 months]
- Number of participants who received a COVID-19 vaccine [Up to 3 months]
- Number of participants who filled a prescription for any guideline-directed medical therapy for heart failure [Up to 8 months]
- Total number of filled prescriptions for guideline-directed medical therapy for heart failure [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 [Up to 8 months]
+Eligibility
Sex: All, ages: 65 Years to any, accepts healthy volunteers
Inclusion Criteria:
1. Age >=65 years at January 15, 2024 (eligible for free-of-charge influenza vaccination in the Danish public health system)
2. Access to the official, mandatory Danish electronic mailbox system
Exclusion Criteria:
1. Persons living in nursing homes (approximated as any person living at an address with >=6 inhabitants aged 80 years and above)
2. Known to have already scheduled influenza vaccination appointment
+Locations (1)
| Facility | City | Country | Status |
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| Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte | Hellerup, Capital Region | Denmark | |
+Publications
- Results publication: Reimer Jensen AM, Johansen ND, Wolff PS, Vaduganathan M, Bhatt AS, Modin D, Skaarup KG, Duus LS, Chatur S, Claggett BL, Janstrup KH, Hill JA, Van Spall HGC, 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 Immunosuppressed Adults Across the Age Spectrum: A Pooled Analysis of 2 Nationwide Randomized Trials. Clin Infect Dis. 2026 Sep 2;83(2):321-330. doi: 10.1093/cid/ciag219. PMID 41968745
- Results publication: 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 39550717
- Results publication: 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 nudges for sustained influenza vaccination uptake in older adults: the nationwide randomized NUDGE-FLU-2 trial. Nat Med. 2024 Nov;30(11):3142-3149. doi: 10.1038/s41591-024-03202-4. Epub 2024 Aug 30. PMID 39215149
- Results publication: 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. 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 38460754
+Investigators
- Tor Biering-Sørensen, MD, MSc, MPH, PhD, Principal investigator, Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte