InfluenzaInfluSMSNCT06486766
Effectiveness of SMS Nudging to Increase Coverage of Influenza Vaccination Among the Elderly
A study testing Norwegian SMS and Polish/Ukrainian SMS in people with Influenza, run by Norwegian Institute of Public Health at 1 site in Norway.
Trial 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 Read more about this study
- Who is it for?
- Ages 65 years and older
- Conditions the study is for
- Influenza
- What is being tested?
- Norwegian SMS and Polish/Ukrainian SMS
- Type of treatment
- Vaccines, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 1,000,000 participants
- Where
- 1 siteNorway
- Study dates
- 14 Oct 2025to 14 Jan 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 65 years and older
- All sexes
- No healthy volunteers
- Older adult
Who may be able to join
- Aged 65+ (age at the end of 2025, i.e., born 1960 or earlier)
- Resident in Norway and have a valid ID number at the start of the 2025 influenza season
- Have a registered mobile phone number
Who cannot join
- Have received the 2025 influenza vaccine prior to the SMS nudge dispatch date
- Have emigrated or died before SMS nudge dispatch date
- Have opted out of electronic communication from public agencies
Trial locations and contacts
1 site in 1 country.
About this study
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
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
Read the 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 one month 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.
Protocol Amendment: The primary endpoint follow-up time for vaccination status was originally planned as 12 weeks after the SMS intervention at the start of the influenza season, based on the previous national policy of no reminders as standard care. However, this policy changed unexpectedly for the 2025/2026 season, as the national Adult Vaccination Programme began sending reminders to all unvaccinated older adults about four weeks after season start. Consequently, we shortened the primary endpoint follow-up to four weeks after the SMS reminders of the InfluSMS trial, and designated the 12-week follow-up as a secondary endpoint. This change was reported to ClinicalTrials.gov prior to trial initiation, on August 25, 2025.
- Conditions
- Influenza
- Being tested
- Norwegian SMS, Polish/Ukrainian SMS
- Keywords
- influenza vaccination, adult vaccination, coverage, uptake, behavioral nudging, vaccine hesitancy, undervaccination, migrant health
- Medical subject headings
- Influenza, Human, Vaccination Hesitancy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Norwegian SMSBehavioural
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)
Polish/Ukrainian SMSBehavioural
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)
| Study group | Role | What they receive |
|---|---|---|
| Control | No intervention | 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) |
| Norwegian SMS | Experimental | Not described Receives: Behavioral: Norwegian SMS |
| Polish/Ukrainian SMS | Experimental | Not described Receives: Behavioral: Polish/Ukrainian SMS |
What is being measured
The primary outcome is the main question the study is designed to answer.
Influenza vaccination coverage (%)
The percent uptake of the influenza vaccine in the population of interest
Measured: One month following the intervention, during the 2025/2026 influenza season
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jul 2024
- Study start14 Oct 2025
- Primary completion11 Nov 2025
- Study completion14 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for InfluenzaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- 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.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 1,000,000 participants (actual)
Sponsor and investigators
- Lead sponsor
- Norwegian Institute of Public Health
- Sponsor type
- Other government
- Collaborators
- University of Oslo, Finnish Institute for Health and Welfare, University of Turku, University Hospital, Akershus
- Responsible party
- Sponsor
- Investigators
- Bo T Hansen, PhD, Principal investigator, Norwegian Institute of Public Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06486766
- Sponsor's protocol ID
- 30052
- Acronym
- InfluSMS
- Status last verified
- Mar 2026
- First submitted
- 27 Jun 2024
- Last updated
- 5 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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
Publications
Hansen BT, Klungsoyr O, Labberton AS, Saaksvuori L, Rydland KM, Odeskaug LE, Wisloff T, Meijerink H. Effectiveness of Text Messaging Nudging to Increase Coverage of Influenza Vaccination Among Older Adults in Norway (InfluSMS Study): Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2025 Feb 25;14:e63938. doi: 10.2196/63938.
PubMed 39998878
Study at a glance
From the registry record, last updated by the sponsor on 5 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- 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
- ClinicalTrials.gov ID
- NCT06486766
- Acronym / sponsor ID
- InfluSMS / 30052
- Conditions
- Influenza
- Keywords
- influenza vaccination, adult vaccination, coverage, uptake, behavioral nudging, vaccine hesitancy, undervaccination, migrant health
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 1,000,000 participants (actual)
- Lead sponsor
- Norwegian Institute of Public HealthOther government
- Collaborators
- University of Oslo, Finnish Institute for Health and Welfare, University of Turku, University Hospital, Akershus
- Study start
- 14 Oct 2025 (actual)
- Primary completion
- 11 Nov 2025 (actual)
- Study completion
- 14 Jan 2026 (actual)
- First posted
- 5 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 one month 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.
Protocol Amendment: The primary endpoint follow-up time for vaccination status was originally planned as 12 weeks after the SMS intervention at the start of the influenza season, based on the previous national policy of no reminders as standard care. However, this policy changed unexpectedly for the 2025/2026 season, as the national Adult Vaccination Programme began sending reminders to all unvaccinated older adults about four weeks after season start. Consequently, we shortened the primary endpoint follow-up to four weeks after the SMS reminders of the InfluSMS trial, and designated the 12-week follow-up as a secondary endpoint. This change was reported to ClinicalTrials.gov prior to trial initiation, on August 25, 2025.
Study design
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- 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.
| Arm | Type | Receives |
|---|---|---|
| Control | No intervention | –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) |
| Norwegian SMS | Experimental | Behavioral: Norwegian SMS |
| Polish/Ukrainian SMS | Experimental | Behavioral: Polish/Ukrainian SMS |
Who may qualify
- Ages
- 65 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Older adult
Key inclusion criteria (3 listed)
- Aged 65+ (age at the end of 2025, i.e., born 1960 or earlier)
- Resident in Norway and have a valid ID number at the start of the 2025 influenza season
- Have a registered mobile phone number
Key exclusion criteria (3 listed)
- Have received the 2025 influenza vaccine prior to the SMS nudge dispatch date
- Have emigrated or died before SMS nudge dispatch date
- Have opted out of electronic communication from public agencies
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Norwegian SMSIndividuals 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) | Behavioural | Norwegian SMS |
| Polish/Ukrainian SMSIndividuals 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) | Behavioural | Polish/Ukrainian SMS |
Primary outcome
Influenza vaccination coverage (%)
Time frame: One month following the intervention, during the 2025/2026 influenza season
The percent uptake of the influenza vaccine in the population of interest
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Nov 2026.
- Background: PubMed 39998878Hansen BT, Klungsoyr O, Labberton AS, Saaksvuori L, Rydland KM, Odeskaug LE, Wisloff T, Meijerink H. Effectiveness of Text Messaging Nudging to Increase Coverage of Influenza Vaccination Among Older Adults in Norway (InfluSMS Study): Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2025 Feb 25;14:e63938. doi: 10.2196/63938.
- Individual participant dataSharing planned: No. 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
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Bo T Hansen, PhD principal investigator
Norwegian Institute of Public Health
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Norwegian SMS and Polish/Ukrainian SMS in people with Influenza, run by Norwegian Institute of Public Health at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Influenza vaccination coverage (%) (time frame: One month following the intervention, during the 2025/2026 influenza season). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06486766, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.