InfluenzaPhase 4NCT06141655
HD vs SD Quadrivalent Influenza Vaccine in Adults Aged 65 to 79 Years in Galicia
A Phase 4 study testing Influenza vaccine in people with Influenza, run by Federico Martinón Torres at 1 site in Spain.
Trial summary
This pragmatic randomized trial is designed to evaluate the relative vaccine effectiveness of QIV-HD vs. QIV-SD in reducing the risk of hospitalization for influenza or pneumonia in adults 65-79 years of age in Galicia during 2023/2024 and 2024/2025 seasons. Read more about this study
- Who is it for?
- Ages 65 to 79 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza
- What is being tested?
- Influenza vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 134,476 participants
- Where
- 1 siteSpain
- Study dates
- 26 Oct 2023to 31 May 2025
- Phase
- Phase 4
- 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 to 79 years
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- 1. Age 65-79 years residing in the community (only individuals who are not eligible to receive QIV-HD as part of the standard of care)
- 2. Informed consent form has been signed and dated
Who cannot join
- There are no specific exclusion criteria for this study
Trial locations and contacts
1 site in 1 country.
Spain1 site
General Public Health Directorate of Galician Health Service
Santiago de Compostela, A Coruña
About this study
Official title: Pragmatic Randomized Trial to Evaluate the Effectiveness of High-Dose Quadrivalent Influenza Vaccine vs. Standard-Dose Quadrivalent Influenza Vaccine in Adults Aged 65 to 79 Years in Galicia, Spain
This pragmatic randomized trial is designed to evaluate the relative vaccine effectiveness of QIV-HD vs. QIV-SD in reducing the risk of hospitalization for influenza or pneumonia in adults 65-79 years of age in Galicia during 2023/2024 and 2024/2025 seasons.
Read the detailed description
The study is a pragmatic, registry-based, open-label, active-controlled, individually randomized trial using the infrastructure of the Regional Vaccination Program of Galicia for patient recruitment, inclusion, randomization, and vaccine administration and the Galician health registries for data collection including baseline information, follow-up data and safety monitoring. Participants will have the opportunity of receiving all the information for the trial prior to the vaccination appointment. Informed consent will be obtained during the vaccination appointment by the study team prior to their vaccine administration. The participation in the study is voluntary, and only individuals who accept signing the informed consent will be recruited. Participants may withdraw from the study at any point.
The study aims to randomize at least 114.011 participants over 2 influenza seasons (2023/2024 and 2024/2025) with approximately 57,000 participants per season (pending any further potential sample size adjustments following interim analysis).
- Conditions
- Influenza
- Being tested
- Influenza vaccine
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Influenza vaccineDrug
Participants will be individually randomized 1:1 to receive either QIV-HD or QIV-SD, one dose, the day of the inclusion in the trial
| Study group | Role | What they receive |
|---|---|---|
| QIV-HD vaccine | Experimental | EFLUELDA, Suspension for injection, one dose Receives: Drug: Influenza vaccine |
| QIV-SD vaccine | Active comparator | INFLUVAC TETRA, Suspension for injection, one dose Receives: Drug: Influenza vaccine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Occurrence of a hospitalization due to influenza or pneumonia
Measured: ≥14 days after vaccination and up to May 31 the following year
Secondary outcomes (5)
Hospitalization for any cardio-respiratory disease [composite endpoint]
Measured: ≥14 days after vaccination and up to May 31 the following year
All-cause hospitalization
Measured: ≥14 days after vaccination and up to May 31 the following year
All-cause mortality
Measured: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for influenza
Measured: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for pneumonia
Measured: ≥14 days after vaccination and up to May 31 the following year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Nov 2023
- Study start26 Oct 2023
- Primary completion31 May 2025
- Study completion31 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)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 4
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 134,476 participants (actual)
Sponsor and investigators
- Lead sponsor
- Federico Martinón Torres
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Federico Martinón Torres, Hospital Clinico Universitario de Santiago
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06141655
- Sponsor's protocol ID
- GALFLU
- Status last verified
- Nov 2023
- First submitted
- 26 Oct 2023
- Last updated
- 8 Aug 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Mallah N, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro Gonzalez M, Conde Pajaro M, Gonzalez-Perez JM, Rivero-Calle I, Bello X, Razzini JL, Salas A, Harris RC, Loiacono MM, van Aalst R, Farre M, Dufournet M, Dyrby Johansen N, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU Trial Team. A Bayesian Re-analysis of the GALFLU Trial of High-Dose vs Standard-Dose Influenza Vaccine Against Hospitalization Outcomes. Clin Infect Dis. 2026 Oct 28;83(4):e887-e891. doi: 10.1093/cid/ciag466.
PubMed 42546169Mallah N, Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro-Gonzalez M, Conde-Pajaro M, Gonzalez-Perez JM, Razzini JL, Rivero-Calle I, Dacosta-Urbieta AI, Harris RC, Loiacono MM, van Aalst R, Farre JM, Dufournet M, Johansen ND, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU trial team. Methods and operational framework of GALFLU: Individually randomized pragmatic controlled trial of high- versus standard-dose influenza vaccination in older adults. Vaccine. 2026 Apr 19;79:128435. doi: 10.1016/j.vaccine.2026.128435. Epub 2026 Mar 9.
PubMed 41806760Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Mallah N, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro-Gonzalez M, Conde-Pajaro M, Gonzalez-Perez JM, Rivero-Calle I, Bello X, Razzini JL, Dacosta-Urbieta A, Salas A, Harris RC, Loiacono MM, van Aalst R, Farre JM, Dufournet M, Johansen ND, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU Trial Team. High-Dose Influenza Vaccine to Reduce Hospitalizations. N Engl J Med. 2025 Dec 11;393(23):2303-2312. doi: 10.1056/NEJMoa2509834. Epub 2025 Aug 30.
PubMed 40888694
Study at a glance
From the registry record, last updated by the sponsor on 8 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pragmatic Randomized Trial to Evaluate the Effectiveness of High-Dose Quadrivalent Influenza Vaccine vs. Standard-Dose Quadrivalent Influenza Vaccine in Adults Aged 65 to 79 Years in Galicia, Spain
- ClinicalTrials.gov ID
- NCT06141655
- Acronym / sponsor ID
- GALFLU
- Conditions
- Influenza
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 134,476 participants (actual)
- Lead sponsor
- Federico Martinón TorresUniversity, hospital or other
- Study start
- 26 Oct 2023 (actual)
- Primary completion
- 31 May 2025 (actual)
- Study completion
- 31 May 2025 (actual)
- First posted
- 21 Nov 2023 (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.
This pragmatic randomized trial is designed to evaluate the relative vaccine effectiveness of QIV-HD vs. QIV-SD in reducing the risk of hospitalization for influenza or pneumonia in adults 65-79 years of age in Galicia during 2023/2024 and 2024/2025 seasons.
Detailed description
The study is a pragmatic, registry-based, open-label, active-controlled, individually randomized trial using the infrastructure of the Regional Vaccination Program of Galicia for patient recruitment, inclusion, randomization, and vaccine administration and the Galician health registries for data collection including baseline information, follow-up data and safety monitoring. Participants will have the opportunity of receiving all the information for the trial prior to the vaccination appointment. Informed consent will be obtained during the vaccination appointment by the study team prior to their vaccine administration. The participation in the study is voluntary, and only individuals who accept signing the informed consent will be recruited. Participants may withdraw from the study at any point.
The study aims to randomize at least 114.011 participants over 2 influenza seasons (2023/2024 and 2024/2025) with approximately 57,000 participants per season (pending any further potential sample size adjustments following interim analysis).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| QIV-HD vaccine | Experimental | Drug: Influenza vaccineEFLUELDA, Suspension for injection, one dose |
| QIV-SD vaccine | Active comparator | Drug: Influenza vaccineINFLUVAC TETRA, Suspension for injection, one dose |
Who may qualify
- Ages
- 65 to 79 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (2 listed)
- 1. Age 65-79 years residing in the community (only individuals who are not eligible to receive QIV-HD as part of the standard of care)
- 2. Informed consent form has been signed and dated
Key exclusion criteria (1 listed)
- There are no specific exclusion criteria for this study
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 |
|---|---|---|
| Influenza vaccineParticipants will be individually randomized 1:1 to receive either QIV-HD or QIV-SD, one dose, the day of the inclusion in the trial | Drug | QIV-HD vaccine, QIV-SD vaccine |
Primary outcome
Occurrence of a hospitalization due to influenza or pneumonia
Time frame: ≥14 days after vaccination and up to May 31 the following year
5 secondary outcomes
Hospitalization for any cardio-respiratory disease [composite endpoint]
Time frame: ≥14 days after vaccination and up to May 31 the following year
All-cause hospitalization
Time frame: ≥14 days after vaccination and up to May 31 the following year
All-cause mortality
Time frame: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for influenza
Time frame: ≥14 days after vaccination and up to May 31 the following year
Hospitalization for pneumonia
Time frame: ≥14 days after vaccination and up to May 31 the following year
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 8 Aug 2025.
- Derived from this study: PubMed 42546169Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Mallah N, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro Gonzalez M, Conde Pajaro M, Gonzalez-Perez JM, Rivero-Calle I, Bello X, Razzini JL, Salas A, Harris RC, Loiacono MM, van Aalst R, Farre M, Dufournet M, Dyrby Johansen N, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU Trial Team. A Bayesian Re-analysis of the GALFLU Trial of High-Dose vs Standard-Dose Influenza Vaccine Against Hospitalization Outcomes. Clin Infect Dis. 2026 Oct 28;83(4):e887-e891. doi: 10.1093/cid/ciag466.
- Derived from this study: PubMed 41806760Mallah N, Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro-Gonzalez M, Conde-Pajaro M, Gonzalez-Perez JM, Razzini JL, Rivero-Calle I, Dacosta-Urbieta AI, Harris RC, Loiacono MM, van Aalst R, Farre JM, Dufournet M, Johansen ND, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU trial team. Methods and operational framework of GALFLU: Individually randomized pragmatic controlled trial of high- versus standard-dose influenza vaccination in older adults. Vaccine. 2026 Apr 19;79:128435. doi: 10.1016/j.vaccine.2026.128435. Epub 2026 Mar 9.
- Derived from this study: PubMed 40888694Pardo-Seco J, Rodriguez-Tenreiro-Sanchez C, Gine-Vazquez I, Mallah N, Miras-Carballal S, Pineiro-Sotelo M, Cribeiro-Gonzalez M, Conde-Pajaro M, Gonzalez-Perez JM, Rivero-Calle I, Bello X, Razzini JL, Dacosta-Urbieta A, Salas A, Harris RC, Loiacono MM, van Aalst R, Farre JM, Dufournet M, Johansen ND, Modin D, Biering-Sorensen T, Duran-Parrondo C, Martinon-Torres F; GALFLU Trial Team. High-Dose Influenza Vaccine to Reduce Hospitalizations. N Engl J Med. 2025 Dec 11;393(23):2303-2312. doi: 10.1056/NEJMoa2509834. Epub 2025 Aug 30.
- Individual participant dataSharing planned: No
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Influenza vaccine in people with Influenza, run by Federico Martinón Torres at 1 site in Spain.
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 2 inclusion and 1 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 8 Aug 2025. 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 Spain. 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.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
Occurrence of a hospitalization due to influenza or pneumonia (time frame: ≥14 days after vaccination and up to May 31 the following year). 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 NCT06141655, which also lists 3 linked publications.
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 8 Aug 2025.