Effectiveness of SMS Nudging to Increase Coverage of Influenza Vaccination Among the Elderly (InfluSMS)

August 6, 2024 updated by: Norwegian Institute of Public Health

InfluSMS: Effectiveness of SMS Nudging to Increase Coverage of Influenza Vaccination Among Elderly From the Majority Population, and Among Elderly From Immigrant Groups With Low Vaccination Coverage

The trial will investigate to what extent SMS reminders for influenza vaccination increases coverage of influenza vaccination among elderly from the majority population, and among elderly from immigrant groups with low vaccination coverage

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Background: The coverage of influenza vaccination among elderly in Norway is insufficient, especially in some immigrant groups. To improve public health, there is a need for an intervention that can increase influenza vaccination coverage. Further, interventions tailored to reduce potential barriers among immigrants can reduce health inequities.

Objective: InfluSMS aims to determine if SMS nudging increases vaccination coverage among those aged 65 or older (i) in Norway's general population; (ii) among immigrants born in Poland; (iii) among immigrants born in Ukraine; and to evaluate the impact of SMS nudging in Norwegian versus in the official language of the native country of immigrants born in Poland or Ukraine.

Methods: InfluSMS is a pragmatic randomized controlled trial conducted among people aged 65 or older residing in Norway. Influenza vaccination coverage is the main outcome, measured in control and intervention arms for each of the three populations listed above. In all three populations, the control arm is standard care, i.e., no individual reminder for influenza vaccination. All populations have an intervention arm that will receive an SMS nudge in the Norwegian language. In addition, the Polish and Ukrainian immigrant populations include a second intervention arm that will receive an SMS nudge in Polish or Ukrainian, respectively. Allocation to study arm is randomized, and the intervention will take place at the start of the 2025/2026 influenza season. All eligible individuals will be passively followed up through the National Immunisation Registry SYSVAK, from which individual influenza vaccination status three months after the SMS nudge will be extracted.

Results: Inclusion of participants will start in the third quarter of 2025, and the registry data will be available in the first quarter of 2026. Coverage rates of each strategy, and coverage differences between strategies will be presented.

Implications: SMS nudging could be integrated into the national influenza vaccination program if the trial shows it effectively increases influenza vaccination coverage among the elderly. Further, the trial will establish whether language is a barrier for influenza vaccination uptake among recent immigrant groups that have low influenza vaccination coverage, and to what extent this potential barrier can be diminished by SMS nudging in the official language of their native country.

Study Type

Interventional

Enrollment (Estimated)

1000000

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Aged 65+ (age at the end of 2025, i.e., born 1960 or earlier)
  • Resident in Norway and have a valid ID number on 1 September 2025
  • Have a registered mobile phone number

Exclusion Criteria:

  • Have received the 2025 influenza vaccine prior to the SMS nudge dispatch date
  • Have emigrated or died before SMS nudge dispatch date

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Control
Standard care: Influenza vaccination is generally recommended to all individuals aged 65 or older, but there is no systematic individual invitation/reminding/scheduling for vaccination by SMS or any other mode. The control arm is applicable to all three populations (general population, immigrants born in Poland, immigrants born in Ukraine)
Experimental: Norwegian SMS
Behavioral: Norwegian SMS
Individuals receive a SMS in Norwegian language at the start of the influenza season, to remind them they are recommended to get the influenza vaccine. This intervention arm is applicable to all three populations (general population, immigrants born in Poland, immigrants born in Ukraine)
Experimental: Polish/Ukrainian SMS
Behavioral: Polish/Ukrainian SMS
Individuals receive an SMS in the official language of their native country (i.e., Polish or Ukrainian) at the start of the influenza season, to remind them they are recommended to get the influenza vaccine. This intervention arm is only applicable to the two immigrant populations (immigrants born in Poland, immigrants born in Ukraine)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Influenza vaccination coverage (%)
Time Frame: Three months following the intervention, during the 2025/2026 influenza season
The percent uptake of the influenza vaccine in the population of interest
Three months following the intervention, during the 2025/2026 influenza season

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
COVID-19 vaccination coverage (%)
Time Frame: Three months following the intervention, during the 2025/2026 influenza season
The percent uptake of the COVID-19 vaccine in the population of interest
Three months following the intervention, during the 2025/2026 influenza season

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Norwegian Institute of Public Health

Collaborators

University of Oslo
University of Turku
University Hospital, Akershus
Finnish Institute for Health and Welfare

Investigators

  • Principal Investigator: Bo T Hansen, PhD, Norwegian Institute of Public Health

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2025

Primary Completion (Estimated)

January 1, 2026

Study Completion (Estimated)

July 1, 2026

Study Registration Dates

First Submitted

June 27, 2024

First Submitted That Met QC Criteria

June 27, 2024

First Posted (Actual)

July 5, 2024

Study Record Updates

Last Update Posted (Actual)

August 7, 2024

Last Update Submitted That Met QC Criteria

August 6, 2024

Last Verified

June 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 30052

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The project is not allowed to share the data. Data access requires legal permissions and applications for data must be directed to the registries involved

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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