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Quadrivalent Inactivated Influenza High Dose

Phase 3

Influenza | Vaccine | Infectious Disease |Sanofi|Trials Updated: Sep 12, 2025

Quadrivalent Inactivated Influenza High Dose development status

Highest phase Phase 3
Registered trials 1 across 1 sponsor since Jul 2021

Quadrivalent Inactivated Influenza High Dose target and mechanism

ModalityVaccine

Also known as Quadrivalent inactivated influenza vaccine (IIV4), Quadrivalent inactivated influenza vaccine, Fluzone HD Quadrivalent vaccine

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLEDDMC
Total Trials2
Total Enrollment706

FDA Designations

No designations recorded

Quadrivalent Inactivated Influenza High Dose clinical trials

Quadrivalent Inactivated Influenza High Dose · 2 trials · 3 indications

Phase 3 1Phase 2 1
NCT02451358Study of a Single Dose or Two Doses of a Quadrivalent Influenza Vaccine in Subjects Aged 6 Months or Older in IndiaInfluenza
COMPLETED400 Analytics
PHASE3COMPLETED
Study of a Single Dose or Two Doses of a Quadrivalent Influenza Vaccine in Subjects Aged 6 Months or Older in India
InfluenzaUnlock trial analytics

Study Endpoints

Primary Endpoints

Geometric Mean Titers (GMTs) of Influenza Vaccine Antibodies
Day 0 (pre-vaccination) and 28 days post-final vaccination (post-vaccination)

Anti-influenza antibodies were measured using hemagglutination inhibition (HAI) assay for 4 strains: H1N1, H3N2, B Victoria, B Yamagata.

Number of Participants With Seroprotection to Influenza Vaccine Antigens
Day 0 (pre-vaccination) and 28 days post-final vaccination (post-vaccination)

Anti-influenza antibodies were measured using HAI assay for 4 strains: H1N1, H3N2, B Victoria and B Yamagata. Seroprotection was defined as an antibody titer \>=40 (1/dilution\[dil\]) at pre-vaccination and at post-final vaccination.

Number of Participants With Seroconversion or Significant Increase to Influenza Vaccine Antigens
28 days post-final vaccination (post-vaccination)

Anti-influenza antibodies were measured using HAI assay for 4 strains: H1N1, H3N2, B Victoria and B Yamagata. Seroconversion was defined as pre-vaccination titer \<10 (1/dil) and post-vaccination titer \>=40 (1/dil), and Significant increase was defined as pre-vaccination titer \>=10 (1/dil) and \>= 4-fold increase of post-vaccination titer.

Number of Participants With Immediate Unsolicited Adverse Events (AEs)
Within 30 minutes post vaccination

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited AEs that occurred during that time were recorded as immediate unsolicited AEs in the CRF. Reported AEs for each arm were presented as pre-specified in the study protocol.

Number of Participants With Solicited Injection Site Reactions
Within 7 days post-vaccination

A solicited reaction (SR) was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. Solicited injection site reactions included injection site pain, axillary swelling and tenderness, injection site erythema, injection site swelling, injection site induration, and injection site bruising. Reported AEs for each arm were presented as pre-specified in the study protocol.

Number of Participants With Solicited Systemic Reactions
Within 7 days post-vaccination

A SR 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 CRF. Solicited systemic reactions included fever, headache, malaise, myalgia, arthralgia, shivering, fatigue, nausea and vomiting. Reported AEs for each arm were presented as pre-specified in the study protocol.

Number of Participants With Unsolicited Adverse Events
Within 21 days post-vaccination

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRF in terms of diagnosis and/or onset window post-vaccination. Reported AEs for each arm were presented as pre-specified in the study protocol.

Number of Participants With Serious Adverse Events (SAEs) and Adverse Event of Special Interest (AESIs)
From Day 1 up to 6 months 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 one of scientific and medical concern specific to the sponsor's study intervention or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor was done. Reported AEs for each arm were presented as pre-specified in the study protocol.

Number of Participants With Medically Attended Adverse Events (MAAEs)
From Day 1 up to 6 months post-vaccination

A MAAE was a new onset or a worsening of a condition that prompted the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department including medical advice seeking during the study visit or routine medical care. Reported AEs for each arm were presented as pre-specified in the study protocol.

Geometric Mean Titers (GMTs) of Influenza Vaccine and COVID-19 Vaccine Antibodies at Day 1
Day 1 (pre-vaccination)

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using hemagglutination inhibition (HAI) assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Titers were expressed in terms of 1/dilution.

Geometric Mean Titers (GMTs) of Influenza Vaccine and COVID-19 Vaccine Antibodies at Day 22
Day 22 (post-vaccination)

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Titers were expressed in terms of 1/dilution.

Geometric Mean Titers Ratio (GMTR) of Influenza Vaccine and COVID-19 Vaccine Antibodies
Day 1 (pre-vaccination) and Day 22 (post-vaccination)

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. GMTRs were calculated as the ratio of GMTs post-vaccination (on Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 01.

Percentage of Participants With Antibody Titers Greater Than or Equal to (>=)10 (1/Dilution)
Day 1 (pre-vaccination)

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers \>=10 (1/dilution) are reported in the outcome measure.

Percentage of Participants Achieving Seroconversion Against Influenza and COVID-19 Virus Antigens
Day 22 (post-vaccination)

Anti-influenza and anti-COVID-19 antibodies were measured by HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Seroconversion was defined as either a pre-vaccination HAI titer less than (\<)10 (1/dilution) and a post-vaccination titer \>=40 (1/dilution) or a pre-vaccination titer \>=10 (1/dilution) and a \>= four-fold increase in post-vaccination titer at Day 22.

Percentage of Participants With Antibody Titers >=40 (1/Dilution)
Day 1 (pre-vaccination)

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers \>=40 (1/dilution) are reported in the outcome measure.

Geometric Mean Concentration (GMC) of Anti-S Binding Immunoglobulin G (IgG) Antibodies
Day 1 (pre-vaccination)

GMCs of Anti-S binding IgG antibodies were assessed using enzyme-linked immunosorbent assay (ELISA) method and were measured in binding antibody units/milliliter (BAU/mL).

Geometric Mean Concentration Ratio (GMCR) of Anti-S Binding IgG Antibodies
Day 1 (pre-vaccination) and Day 22 (post-vaccination)

GMCs of Anti-S binding IgG antibodies were assessed using ELISA method. GMCR was calculated as the ratio of GMC post-vaccination (on Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 01.

Percentage of Participants With >=2-Fold and >=4-Fold Rise in Anti-S Binding IgG Antibodies
Day 22 (post-vaccination)

Percentage of participants with \>=2-fold and \>=4-fold rise in Anti-S binding IgG antibodies at Day 22 (post-vaccination) are reported in this outcome measure. Percentage of participants with \>=2-fold rise are those for whom the computed value at Day 22 was \*2 compared to the computed value at Day 1 and percentage of participants with \>=4-fold rise are those for whom the computed value at Day 22 was \*4 compared to the computed value at Day 1.

Secondary Endpoints

Number of Participants Reporting Solicited Injection Site and Systemic Reactions After Vaccination With Influenza Vaccine
Within 7 days after any vaccination
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
Quadrivalent Influenza Vaccine Group 1: 6 to 35 MonthsEXPERIMENTALParticipants aged 6 to 35 months received 2 doses of 0.25 mL QIV (2016-2017 NH formulation) intramuscularly, 1 injection each at Day 0 and 28.
Quadrivalent Influenza Vaccine Group 2: 3 to 8 YearsEXPERIMENTALParticipants aged 3 to 8 years received 2 doses of 0.5 mL QIV (2016 SH formulation) intramuscularly, 1 injection each at Day 0 and 28.
Quadrivalent Influenza Vaccine Group 3: 9 to 17 YearsEXPERIMENTALParticipants aged 9 to 17 years received 1 dose of 0.5 mL QIV (2015-2016 NH formulation) intramuscularly, at Day 0.
Quadrivalent Influenza Vaccine Group 4: >=18 YearsEXPERIMENTALParticipants aged \>=18 years received 1 dose of 0.5 mL QIV (2015 SH formulation) intramuscularly, at Day 0.
Group 1: Fluzone High-Dose (HD) Quadrivalent Influenza Vaccine and COVID-19 VaccineEXPERIMENTALParticipants received an injection of 0.7 milliliters (mL), fluzone HD quadrivalent influenza vaccine, co-administered with 0.5 mL COVID-19 vaccine, intramuscularly (IM) on Day 1.
Group 2: Fluzone HD Quadrivalent Influenza VaccineACTIVE_COMPARATORParticipants received a single injection of 0.7 mL fluzone HD quadrivalent influenza vaccine, IM on Day 1.
Group 3: COVID-19 VaccineACTIVE_COMPARATORParticipants received a single injection of 0.5 mL COVID-19 mRNA Vaccine, IM on Day 1.

Interventions

NameTypeDescription
Quadrivalent Inactivated Influenza Vaccine (2016-2017 NH formulation), No PreservativeBIOLOGICAL0.25 mL, Intramuscular
Quadrivalent Inactivated Influenza Vaccine (2016 SH formulation), No PreservativeBIOLOGICAL0.5 mL, Intramuscular
Quadrivalent Inactivated Influenza Vaccine (2015-2016 NH formulation), No PreservativeBIOLOGICAL0.5 mL, Intramuscular
Quadrivalent Inactivated Influenza Vaccine (2015 SH formulation), No PreservativeBIOLOGICAL0.5 mL, Intramuscular
Quadrivalent Inactivated Influenza High DoseBIOLOGICALSterile suspension for injection in a pre-filled syringe Intramuscular injection
COVID-19 mRNA Vaccine (nucleoside modified)BIOLOGICALSterile suspension (white to off-white) in multidose vial Intramuscular injection
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Eligibility Criteria

Age Range6 Months to N/A
SexALL
Healthy VolunteersYes
Study Sites8

Inclusion Criteria: * Aged 6 months or older on the day of inclusion * For participants aged 6 to 35 months only: born at full term of pregnancy (\>=37 weeks) or birth weight \>=2.5 kg or both * Informed consent form had been signed and dated by the participants / participants' parent(s) or another...

Countries:IndiaUnited States
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Frequently asked questions about Quadrivalent Inactivated Influenza High Dose

What is Quadrivalent Inactivated Influenza High Dose used for?

Quadrivalent Inactivated Influenza High Dose is a vaccine used for influenza immunization. It is designed to protect against four influenza virus strains and is studied in healthy volunteers, including adults 65 years of age and older and individuals 6 months of age and older. It is given as a single dose or two doses depending on the study.

Who makes Quadrivalent Inactivated Influenza High Dose?

Quadrivalent Inactivated Influenza High Dose is developed by Sanofi, which trades under the ticker SNY. Sanofi is the company responsible for the clinical development of this vaccine candidate.

What phase is Quadrivalent Inactivated Influenza High Dose in?

Quadrivalent Inactivated Influenza High Dose is in Phase 3 clinical development. It is an investigational vaccine and has not been approved by the FDA. The Phase 3 trial NCT02451358 has been completed, and a Phase 2 trial NCT04969276 has also been completed.

What clinical trials is Quadrivalent Inactivated Influenza High Dose in?

Quadrivalent Inactivated Influenza High Dose has been studied in two completed clinical trials. NCT02451358 was a Phase 3 study of a single dose or two doses in subjects aged 6 months or older in India, enrolling 400 participants. NCT04969276 was a Phase 2 study of the vaccine with a Moderna COVID-19 vaccine in participants 65 years and older, enrolling 306 participants in the United States.

Is Quadrivalent Inactivated Influenza High Dose the same as Quadrivalent Inactivated Influenza Vaccine?

Yes, Quadrivalent Inactivated Influenza High Dose is also known as Quadrivalent Inactivated Influenza Vaccine, Quadrivalent inactivated influenza vaccine (IIV4), Quadrivalent Inactivated Influenza Vaccine, No Preservative, and Quadrivalent Inactivated Influenza Vaccine (2016-2017 NH formulation), No Preservative. These names refer to the same vaccine.