Clinical trial NCT06486766: Effectiveness of SMS Nudging to Increase Coverage of Influenza Vaccination Among the Elderly
Official title: 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
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Influenza
Keywords: influenza vaccination
adult vaccination
coverage
uptake
behavioral nudging
vaccine hesitancy
undervaccination
migrant health
Lead sponsor: Norwegian Institute of Public Health
Sponsor class: OTHER_GOV
Collaborators: name: University of Oslo
name: Finnish Institute for Health and Welfare
name: University of Turku
name: University Hospital, Akershus
First posted: 2024-07-05
Enrollment: 1000000
Sex: ALL
Minimum age (years): 65
Standard ages: OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The trial is conducted in three populations of elderly (aged 65 years or older) residing in Norway: (i) the general population; (ii) immigrants born in Poland; (iii) immigrants born in Ukraine. 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.
Primary purpose: HEALTH_SERVICES_RESEARCH

Brief summary: 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

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.

Eligibility criteria: 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

Primary outcomes:
measure: Influenza vaccination coverage (%)
timeFrame: Three months following the intervention, during the 2025/2026 influenza season
Secondary outcomes:
Other outcomes:
measure: COVID-19 vaccination coverage (%)
timeFrame: Three months following the intervention, during the 2025/2026 influenza season
Locations:
Study officials:
affiliation: Norwegian Institute of Public Health
name: Bo T Hansen, PhD
role: PRINCIPAL_INVESTIGATOR
References: