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OpenTrials
Completed

NCT Number: NCT05542004

Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake

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.

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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 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.

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, 2023 (eligible for free influenza vaccination in the official Danish vaccination program)
  • Access to the official, mandatory Danish electronic mailbox system

Exclusion criteria

  • Persons living in nursing homes

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 with influenza or pneumonia

    Time frame: Up to 8 months

  3. Number of participants with any hospitalization

    Time frame: Up to 8 months

  4. All-cause mortality

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

  9. Cardiovascular death

    Time frame: Up to 8 months

  10. Number of participants with myocardial infarction

    Time frame: Up to 8 months

  11. Number of participants with coronary revascularization

    Time frame: Up to 8 months

  12. Number of participants with stroke

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

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

    Time frame: Up to 8 months

  15. Number of participants with a hospitalization due to COVID-19

    Time frame: Up to 8 months

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

    Time frame: Up to 3 months

Sponsors and collaborators

Lead sponsor

Tor Biering-Sørensen

Other

Collaborators

  • Sanofi Pasteur, a Sanofi Company
  • Statens Serum Institut

Registry information

Acronym: NUDGE-FLU

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Sep 15, 2022
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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