Influenza (Healthy Volunteers)Phase 3NCT04537234

Study to Assess the Immune Response and the Safety Profile of a High-Dose Quadrivalent Influenza Vaccine (QIV-HD) Compared to a Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) in Taiwanese Adults 65 Years of Age and Older

A Phase 3 study testing High-Dose Quadrivalent Influenza Vaccine and Standard-Dose Quadrivalent Influenza Vaccine in people with Influenza (Healthy Volunteers), run by Sanofi Pasteur, a Sanofi Company at 4 sites in Taiwan.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Primary Objective: Immunogenicity: To describe the immune response induced by high-dose quadrivalent influenza vaccine (QIV-HD) and AdimFlu-S (QIS) by hemagglutinin inhibition (HAI) measurement method in all participants. Safety: To describe the safety profile of all participants in each study groups. Read more about this study

Who is it for?: Ages 65 years and olderHealthy volunteers can take part
Conditions the study is for: Influenza (Healthy Volunteers)
What is being tested?: High-Dose Quadrivalent Influenza Vaccine and Standard-Dose Quadrivalent Influenza Vaccine
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 165 participants
Where: 4 sitesTaiwan
Study dates: 10 Nov 2020to 9 Feb 2021
Phase: Phase 3
Are there results?: Yes, posted in the registrySummary in the doctors' view

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
Healthy volunteers accepted
Older adult

Who may be able to join

65 years and older on the day of inclusion.
Able to attend all scheduled visits and complied with all study procedures.

Who cannot join

Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
Receipt of any vaccine in the 4 weeks (28 days) preceding the study vaccination or planned receipt of any vaccine prior to Visit 2.
Previous vaccination against influenza (in the preceding 6 months) with either the study vaccine or another vaccine.
Receipt of immune globulins, blood or blood-derived products in the past 3 months.
Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine(s) used in the study or to a vaccine containing any of the same substances.

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Thrombocytopenia, bleeding disorder, or receipt of anticoagulants that based on Investigator's judgment contraindicate intramuscular vaccination.
Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion.
Chronic illness that, in the opinion of the investigator, was at a stage where it might interfere with trial conduct or completion.
Moderate or severe acute illness/infection (according to investigator judgment) on the day of vaccination or febrile illness (temperature greater than or equal to [>=] 38.0 degree Celsius). A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
Personal or family history of Guillain-Barré syndrome.
Neoplastic disease or any hematologic malignancy (except localized skin or prostate cancer that was stable at the time of vaccination in the absence of therapy and participants who had a history of neoplastic disease and had been disease free for >=5 years).
Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (i.e., parent, spouse) of the Investigator or employee with direct involvement in the proposed study.
The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Trial locations and contacts

4 sites in 1 country.

Taiwan4 sites

Investigational Site Number 1580004
Taichung, 40447
Investigational Site Number 1580001
Taipei, 100
Investigational Site Number 1580002
Taipei, 112
Investigational Site Number 1580003
Taoyuan, 333

Other trials in Taiwan

About this study

Official title: Immunogenicity and Safety of a High-Dose Quadrivalent Influenza Vaccine in Subjects 65 Years of Age and Older in Taiwan

Primary Objective:

Immunogenicity: To describe the immune response induced by high-dose quadrivalent influenza vaccine (QIV-HD) and AdimFlu-S (QIS) by hemagglutinin inhibition (HAI) measurement method in all participants.

Safety: To describe the safety profile of all participants in each study groups.

Read the detailed description

The duration of each participant's participation was approximately 28 days (Day 0 through Day 28 [+ 7 days]).

Conditions: Influenza (Healthy Volunteers)
Being tested: High-Dose Quadrivalent Influenza Vaccine, Standard-Dose Quadrivalent Influenza Vaccine
Keywords: Influenza
Medical subject headings: Influenza, Human

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

High-Dose Quadrivalent Influenza VaccineBiological
Also called Fluzone® High Dose, Efluelda™
Pharmaceutical form: Suspension for injection in pre-filled syringe,
Route of administration: IM
Standard-Dose Quadrivalent Influenza VaccineBiological
Also called AdimFlu-S (QIS)
Pharmaceutical form: Suspension for injection in pre-filled syringe,
Route of administration: IM

Study groups in NCT04537234
Study group	Role	What they receive
Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)	Experimental	Participants received a single injection of 0.7 milliliters (mL) QIV-HD, intramuscularly (IM) at Day 0. Receives: Biological: High-Dose Quadrivalent Influenza Vaccine
Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)	Active comparator	Participants received a single injection of 0.5 mL QIV-SD, IM at Day 0. Receives: Biological: Standard-Dose Quadrivalent Influenza Vaccine

What is being measured

The primary outcome is the main question the study is designed to answer.

Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies at Day 0
GMTs of anti-influenza antibodies were measured using hemagglutination inhibition (HAI) assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria Lineage), and B2 (B Yamagata Lineage). Titers were expressed in terms of 1/dilution.
Measured: Day 0 (pre-vaccination)
Geometric Mean Titers of Influenza Vaccine Antibodies at Day 28
GMTs of anti-influenza antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Titers were expressed in terms of 1/dilution.
Measured: Day 28 (post-vaccination)
Geometric Mean Titers Ratio (GMTR) of Influenza Vaccine Antibodies
GMTRs of anti-influenza antibodies were measured by using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). GMTRs were calculated as the ratio of GMTs post-vaccination (on Day 28) and pre-vaccination (on Day 0).
Measured: Day 0 (pre-vaccination), Day 28 (post-vaccination)
Percentage of Participants Achieving Seroconversion Against Influenza Virus Antigens
Anti-influenza antibodies were measured by HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Seroconversion was defined as either a pre-vaccination HAI titer less than (<) 10 (1/dilution) at Day 0 and a post-vaccination titer greater than or equal to (>=) 40 (1/dilution) at Day 28 or a pre-vaccination titer >=10 (1/dilution) at Day 0 and a >= four-fold increase in post-vaccination titer at Day 28.
Measured: Day 28 (post-vaccination)
Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 0
Antibody titer was measured by using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).
Measured: Day 0 (pre-vaccination)
Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 28
Antibody titer was measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).
Measured: Day 28 (post-vaccination)
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the case report book (CRB) in terms of diagnosis and/or onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited systemic AEs occurred during that time were recorded as immediate unsolicited AEs in the CRB.
Measured: Within 30 minutes post-vaccination
Number of Participants With Solicited Injection Site and Systemic Reactions
A solicited reaction was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRB and considered as related to the product administered. Solicited injection site reactions included pain, erythema, swelling, induration, and bruising. Solicited systemic reactions included fever, headache, malaise, myalgia and shivering.
Measured: Within 7 days post-vaccination
Number of Participants With Unsolicited Adverse Events
An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRB in terms of diagnosis and/or onset window post-vaccination.
Measured: Within 28 days post-vaccination
Number of Participants With Serious Adverse Events (SAEs) Including Adverse Event of Special Interest (AESIs)
An SAE was any untoward medical occurrence that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. AESIs was defined as event for which ongoing monitoring and rapid communication by the investigator to the sponsor was done.
Measured: From Day 0 up to 28 days post-vaccination

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

10 Nov 20209 Feb 2021

First posted3 Sep 2020
Study start10 Nov 2020
Primary completion9 Feb 2021
Study completion9 Feb 2021

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Influenza (Healthy Volunteers)Studies of the same condition, open and under way.
More trials run by Sanofi Pasteur, a Sanofi CompanyThe sponsor's other registered studies.
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 3
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 165 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04537234
Sponsor's protocol ID: QHD00023
Other IDs: U1111-1238-1970
Status last verified: Sep 2025
First submitted: 26 Aug 2020
Last updated: 24 Sep 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: Yes: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Publications

Chen JY, Hsieh SM, Hwang SJ, Liu CS, Li X, Fournier M, Yeh TY, Yin JK, Samson SI. Immunogenicity and safety of high-dose quadrivalent influenza vaccine in older adults in Taiwan: A phase III, randomized, multi-center study. Vaccine. 2022 Oct 26;40(45):6450-6454. doi: 10.1016/j.vaccine.2022.09.078. Epub 2022 Oct 7.
PubMed 36216650

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Influenza (Healthy Volunteers) trials

Study at a glance

From the registry record, last updated by the sponsor on 24 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Immunogenicity and Safety of a High-Dose Quadrivalent Influenza Vaccine in Subjects 65 Years of Age and Older in Taiwan
ClinicalTrials.gov ID: NCT04537234
Acronym / sponsor ID: QHD00023
Conditions: Influenza (Healthy Volunteers)
Keywords: Influenza
Phase: Phase 3
Study type: Interventional
Recruitment status: Completed
Enrolment: 165 participants (actual)
Lead sponsor: Sanofi Pasteur, a Sanofi CompanyIndustry (pharma, biotech, devices)
Study start: 10 Nov 2020 (actual)
Primary completion: 9 Feb 2021 (actual)
Study completion: 9 Feb 2021 (actual)
First posted: 3 Sep 2020 (actual)
Results: Posted 8 Nov 2021

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Primary Objective:

Safety: To describe the safety profile of all participants in each study groups.

Detailed description

The duration of each participant's participation was approximately 28 days (Day 0 through Day 28 [+ 7 days]).

Study design

Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 2

Arm	Type	Receives
Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)	Experimental	Biological: High-Dose Quadrivalent Influenza VaccineParticipants received a single injection of 0.7 milliliters (mL) QIV-HD, intramuscularly (IM) at Day 0.
Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)	Active comparator	Biological: Standard-Dose Quadrivalent Influenza VaccineParticipants received a single injection of 0.5 mL QIV-SD, IM at Day 0.

Who may qualify

Ages: 65 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Older adult

Key inclusion criteria (2 listed)

65 years and older on the day of inclusion.
Able to attend all scheduled visits and complied with all study procedures.

Key exclusion criteria (15 listed)

Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
Receipt of any vaccine in the 4 weeks (28 days) preceding the study vaccination or planned receipt of any vaccine prior to Visit 2.
Previous vaccination against influenza (in the preceding 6 months) with either the study vaccine or another vaccine.
Receipt of immune globulins, blood or blood-derived products in the past 3 months.
Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).

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
High-Dose Quadrivalent Influenza VaccineAlso: Fluzone® High Dose, Efluelda™Pharmaceutical form: Suspension for injection in pre-filled syringe, Route of administration: IM	Biological	Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)
Standard-Dose Quadrivalent Influenza VaccineAlso: AdimFlu-S (QIS)Pharmaceutical form: Suspension for injection in pre-filled syringe, Route of administration: IM	Biological	Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)

Primary outcome

Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies at Day 0
Time frame: Day 0 (pre-vaccination)
GMTs of anti-influenza antibodies were measured using hemagglutination inhibition (HAI) assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria Lineage), and B2 (B Yamagata Lineage). Titers were expressed in terms of 1/dilution.
Geometric Mean Titers of Influenza Vaccine Antibodies at Day 28
Time frame: Day 28 (post-vaccination)
GMTs of anti-influenza antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Titers were expressed in terms of 1/dilution.
Geometric Mean Titers Ratio (GMTR) of Influenza Vaccine Antibodies
Time frame: Day 0 (pre-vaccination), Day 28 (post-vaccination)
GMTRs of anti-influenza antibodies were measured by using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). GMTRs were calculated as the ratio of GMTs post-vaccination (on Day 28) and pre-vaccination (on Day 0).
Percentage of Participants Achieving Seroconversion Against Influenza Virus Antigens
Time frame: Day 28 (post-vaccination)
Anti-influenza antibodies were measured by HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage). Seroconversion was defined as either a pre-vaccination HAI titer less than (<) 10 (1/dilution) at Day 0 and a post-vaccination titer greater than or equal to (>=) 40 (1/dilution) at Day 28 or a pre-vaccination titer >=10 (1/dilution) at Day 0 and a >= four-fold increase in post-vaccination titer at Day 28.
Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 0
Time frame: Day 0 (pre-vaccination)
Antibody titer was measured by using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).
Percentage of Participants With Antibody Titers >=40 (1/Dilution) at Day 28
Time frame: Day 28 (post-vaccination)
Antibody titer was measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B1 (B Victoria lineage), and B2 (B Yamagata lineage).
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
Time frame: Within 30 minutes post-vaccination
An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the case report book (CRB) in terms of diagnosis and/or onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited systemic AEs occurred during that time were recorded as immediate unsolicited AEs in the CRB.
Number of Participants With Solicited Injection Site and Systemic Reactions
Time frame: Within 7 days post-vaccination
A solicited reaction was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRB and considered as related to the product administered. Solicited injection site reactions included pain, erythema, swelling, induration, and bruising. Solicited systemic reactions included fever, headache, malaise, myalgia and shivering.
Number of Participants With Unsolicited Adverse Events
Time frame: Within 28 days post-vaccination
An AE was any untoward medical occurrence in a patient or in a clinical investigation participant administered a medicinal product and which did not had any causal relationship with the treatment. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRB in terms of diagnosis and/or onset window post-vaccination.
Number of Participants With Serious Adverse Events (SAEs) Including Adverse Event of Special Interest (AESIs)
Time frame: From Day 0 up to 28 days post-vaccination
An SAE was any untoward medical occurrence that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. AESIs was defined as event for which ongoing monitoring and rapid communication by the investigator to the sponsor was done.

Results and safety

Results posted to the registry on 8 Nov 2021, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)	82	80
Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)	83	83

Primary outcome: Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies at Day 0

Time frame: Day 0 (pre-vaccination). Geometric mean (95% Confidence Interval). Unit: titers

Measure	Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD) n = 80	Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) n = 83
A/H1N1	23.6 (18.1 to 30.6)	24.1 (18.5 to 31.5)
A/H3N2	111 (78.4 to 156)	169 (120 to 238)
B1	88.0 (66.7 to 116)	98.2 (76.6 to 126)
B2	149 (111 to 199)	160 (121 to 211)

Population analysed: Analysis was performed on the full analysis set (FAS) that included randomized participants who received one of the study vaccine and had a post-vaccination blood sample. Participants were analyzed according to the vaccine group to which they were randomized.

Primary outcome: Geometric Mean Titers of Influenza Vaccine Antibodies at Day 28

Time frame: Day 28 (post-vaccination). Geometric mean (95% Confidence Interval). Unit: titers

Measure	Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD) n = 80	Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) n = 83
A/H1N1	283 (221 to 364)	109 (78.2 to 151)
A/H3N2	643 (522 to 791)	427 (324 to 563)
B1	812 (645 to 1023)	324 (253 to 414)
B2	707 (595 to 840)	361 (290 to 450)

Population analysed: Analysis was performed on FAS.

Primary outcome: Geometric Mean Titers Ratio (GMTR) of Influenza Vaccine Antibodies

Time frame: Day 0 (pre-vaccination), Day 28 (post-vaccination). Geometric mean (95% Confidence Interval). Unit: ratio

Measure	Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD) n = 80	Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) n = 83
A/H1N1	12.0 (9.09 to 15.9)	4.50 (3.47 to 5.82)
A/H3N2	5.81 (4.28 to 7.87)	2.53 (1.87 to 3.41)
B1	9.23 (7.00 to 12.2)	3.30 (2.48 to 4.39)
B2	4.76 (3.65 to 6.21)	2.26 (1.76 to 2.89)

Population analysed: Analysis was performed on FAS.

Primary outcome: Percentage of Participants Achieving Seroconversion Against Influenza Virus Antigens

Time frame: Day 28 (post-vaccination). Number (95% Confidence Interval). Unit: percentage of participants

Measure	Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD) n = 80	Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) n = 83
A/H1N1	86.3 (76.7 to 92.9)	50.6 (39.4 to 61.8)
A/H3N2	61.3 (49.7 to 71.9)	28.9 (19.5 to 39.9)
B1	78.8 (68.2 to 87.1)	37.3 (27.0 to 48.7)
B2	50.0 (38.6 to 61.4)	24.1 (15.4 to 34.7)

Population analysed: Analysis was performed on FAS.

Adverse events

Time frame: Unsolicited AEs were collected from Day 0 (post-vaccination) up to 28 days post-vaccination. Solicited reaction data were collected up to Day 7 post-vaccination. SAE data were collected from Day 0 (post-vaccination) up to 28 days post-vaccination.. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Group 1: High-Dose Quadrivalent Influenza Vaccine (QIV-HD)	0 of 82 (0%)	46 of 82 (56.1%)	0 of 82
Group 2: Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD)	0 of 83 (0%)	35 of 83 (42.2%)	0 of 83

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 24 Sep 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 36216650Chen JY, Hsieh SM, Hwang SJ, Liu CS, Li X, Fournier M, Yeh TY, Yin JK, Samson SI. Immunogenicity and safety of high-dose quadrivalent influenza vaccine in older adults in Taiwan: A phase III, randomized, multi-center study. Vaccine. 2022 Oct 26;40(45):6450-6454. doi: 10.1016/j.vaccine.2022.09.078. Epub 2022 Oct 7.
QHD00023 Plain Language Results SummaryLink provided by the sponsor.
Individual participant dataSharing planned: Yes. Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

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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.

Clinical Sciences & Operations study director

Sanofi

4 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

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 15 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 24 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 4 sites in Taiwan. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 8 Nov 2021). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies at Day 0 (time frame: Day 0 (pre-vaccination)). The study lists 10 primary outcomes in all. 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 NCT04537234, 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 24 Sep 2025.