NCT05542004

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

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 964,870 (actual)
• Sponsor: Tor Biering-Sørensen · Academic / Other
• Sex: All
• Age: 65 Years
• Healthy volunteers: Accepted

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 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.

Conditions

• Influenza
• Behavior and Behavior Mechanisms

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2022-09-16
• Primary completion: 2023-01-01
• Completion: 2023-05-31
• First posted: 2022-09-15
• Last updated: 2024-10-10

Locations

1 site across 1 country: Denmark