Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease

Sponsor

Tor Biering-Sørensen (Other)

Overall Status

Recruiting

CT.gov ID

NCT06030739

Collaborator

Statens Serum Institut (Other)

325,000

Enrollment

Location

Arms

8.5

Anticipated Duration (Months)

38193.8

Patients Per Site Per Month

Study Details

Study Description

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 whether digital behavioral nudges delivered via the official, mandatory Danish electronic letter system can increase influenza vaccine uptake among adults aged 18-64 years with chronic diseases.

Condition or Disease	Intervention/Treatment	Phase
Influenza Behavior and Behavior Mechanisms	Behavioral: Behavioral Economic Principles	N/A

Detailed Description

The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons aged 18-64 years identified as eligible for free-of-charge influenza vaccination due to a chronic condition. Subjects will be identified through Danish nationwide health registries using codes from the International Classification of Diseases, 10th revision (ICD-10). 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.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

325000 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

None (Open Label)

Primary Purpose:

Other

Official Title:

Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease

Anticipated Study Start Date :

Sep 15, 2023

Anticipated Primary Completion Date :

Jan 1, 2024

Anticipated Study Completion Date :

May 31, 2024

Arms and Interventions

Arm	Intervention/Treatment
No Intervention: Usual Care No letter
Experimental: Standard Letter This group will receive a standard letter on the benefits of influenza vaccination without behavioral economic enhancement	Behavioral: Behavioral Economic Principles 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.
Experimental: Repeated Letter The standard letter sent out two times instead of once	Behavioral: Behavioral Economic Principles 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.
Experimental: Cardiovascular Gain-Framing Letter Text added to the standard letter highlighting potential cardiovascular benefits of influenza vaccination	Behavioral: Behavioral Economic Principles 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.
Experimental: Respiratory Gain-Framing Letter Text added to the standard letter highlighting potential respiratory disease-related benefits of influenza vaccination	Behavioral: Behavioral Economic Principles 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.
Experimental: Implementation Intention Prompt Letter Implementation intention prompt added to the standard letter	Behavioral: Behavioral Economic Principles 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.
Experimental: Loss-Framing Letter Text added to the standard letter highlighting potential risks of not receiving influenza vaccination	Behavioral: Behavioral Economic Principles 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 Outcome Measures

Number of participants who received an influenza vaccine [Up to 3 months]

Secondary Outcome Measures

Time from intervention delivery to influenza vaccination [Up to 3 months]

Other Outcome Measures

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 Criteria

Criteria

Ages Eligible for Study:

18 Years to 64 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Age 18-64 years
Must be registered in the Danish nationwide registries as meeting at least one of the following eligibility criteria for free-of-charge influenza vaccination in the Danish public health system:
Chronic lung disease
Chronic cardiovascular disease other than hypertension
Type 1 or type 2 diabetes mellitus
Congenital or acquired immunodeficiency
Impaired breathing due to muscular weakness
Chronic renal or hepatic insufficiency
Other chronic conditions with an increased risk of severe influenza vaccination as determined by the treating physician
Access to the official, mandatory Danish electronic mailbox system

Exclusion Criteria:

None

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte	Hellerup	Hovedstaden	Denmark	2900

Sponsors and Collaborators

Tor Biering-Sørensen
Statens Serum Institut

Investigators

Principal Investigator: Tor Biering-Sørensen, MD, MSc, MPH, PhD, Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte