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Completed

NCT Number: NCT06030726

Nationwide Utilization of Danish Government Electronic Letter System for Confirming the Effectiveness of Behavioral Nudges in Increasing InFLUenza Vaccine Uptake Among Older Adults

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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Key information

Conditions

Influenza Behavior Behavior and Behavior Mechanisms Infections Influenza, Human Orthomyxoviridae Infections RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

65 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte

Hellerup, Capital Region, 2900, Denmark

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age >=65 years at January 15, 2024 (eligible for free-of-charge influenza vaccination in the Danish public health system)
  • Access to the official, mandatory Danish electronic mailbox system

Exclusion criteria

  • Persons living in nursing homes (approximated as any person living at an address with >=6 inhabitants aged 80 years and above)
  • Known to have already scheduled influenza vaccination appointment

Treatment and study plan

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.

Primary outcomes

  1. Number of participants who received an influenza vaccine

    Time frame: Up to 3 months

Secondary outcomes

  1. Time from intervention delivery to influenza vaccination

    Time frame: Up to 3 months

Other outcomes

  1. Number of participants with laboratory-confirmed influenza

    Time frame: Up to 8 months

  2. Number of participants with a hospitalization for influenza or pneumonia

    Time frame: Up to 8 months

  3. Number of participants with a hospitalization for any respiratory disease

    Time frame: Up to 8 months

  4. Number of participants with a hospitalization for any cardio-respiratory disease

    Time frame: Up to 8 months

  5. Number of participants with a hospitalization for any cardiovascular disease

    Time frame: Up to 8 months

  6. Number of participants with any hospitalization

    Time frame: Up to 8 months

  7. Total number of hospitalizations (first and recurrent)

    Time frame: Up to 8 months

  8. All-cause mortality

    Time frame: Up to 8 months

  9. Composite of incident heart failure, heart failure hospitalization, or cardiovascular death

    Time frame: Up to 8 months

  10. Composite of myocardial infarction, stroke, or cardiovascular death

    Time frame: Up to 8 months

  11. Composite of myocardial infarction, coronary revascularization, stroke, or cardiovascular death

    Time frame: Up to 8 months

  12. Number of participants with incident heart failure or heart failure hospitalization

    Time frame: Up to 8 months

  13. Total number of heart failure events (incident heart failure and first and recurrent heart failure hospitalizations)

    Time frame: Up to 8 months

  14. Cardiovascular death

    Time frame: Up to 8 months

  15. Number of participants with myocardial infarction

    Time frame: Up to 8 months

  16. Number of participants with coronary revascularization

    Time frame: Up to 8 months

  17. Number of participants with stroke

    Time frame: Up to 8 months

  18. Number of participants with incident atrial fibrillation or atrial fibrillation hospitalization

    Time frame: Up to 8 months

  19. Number of contacts to general practitioner (excluding vaccination visit)

    Time frame: Up to 8 months

  20. Number of participants with laboratory-confirmed COVID-19

    Time frame: Up to 8 months

  21. Number of participants with a hospitalization for COVID-19

    Time frame: Up to 8 months

  22. Number of participants who received a COVID-19 vaccine

    Time frame: Up to 3 months

  23. Number of participants who filled a prescription for any guideline-directed medical therapy for heart failure

    Time frame: Up to 8 months

  24. Total number of filled prescriptions for guideline-directed medical therapy for heart failure

    Time frame: Up to 8 months

  25. 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

Sponsors and collaborators

Lead sponsor

Tor Biering-Sørensen

Other

Registry information

Acronym: NUDGE-FLU-2

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Sep 11, 2023
Registry last updated
Oct 10, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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