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IIV-HD

Phase 1

COVID-19 Immunization | Monoclonal antibody | Infectious Disease |Sanofi|Last Updated: May 5, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLED
Total Trials1
Total Enrollment980

FDA Designations

No designations recorded

Clinical trial landscape

IIV-HD · 1 trial · 2 indications

Phase 1 1
NCT06695117Study of a Combination Vaccine Comprised of Different Recombinant Spike Antigen Levels of a Matrix-M Adjuvanted Recombinant COVID-19 Vaccine and High-Dose Inactivated Influenza Vaccine in Adult Participants 50 Years of Age and OlderCOVID-19 Immunization
COMPLETED980 Analytics
PHASE1COMPLETED
Study of a Combination Vaccine Comprised of Different Recombinant Spike Antigen Levels of a Matrix-M Adjuvanted Recombinant COVID-19 Vaccine and High-Dose Inactivated Influenza Vaccine in Adult Participants 50 Years of Age and Older
COVID-19 ImmunizationUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of participants with immediate adverse events (AEs)
Within 30 minutes after each vaccination

Immediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination

Number of participants with solicited injection site reactions
Up to 7 each days after vaccination

Solicited injection site reactions include injection site pain, erythema and swelling

Number of participants with solicited systemic reactions
Up to 7 days after each vaccination

Solicited systemic reactions include fever, headache, fatigue, myalgia and chills

Number of participants with unsolicited AEs
Up to 28 days after each vaccination

Unsolicited (spontaneously reported) AEs, not fulfilling criteria for solicited adverse reactions

Number of participants with adverse events of special interest (AESIs)
Up to 180 days after each vaccination

AESIs

Number of participants with medical attended adverse events (MAAEs)
Up to 180 days after each vaccination

MAAEs

Number of MAAEs relating to predefined potential immune-mediated disease (PIMDs)
From D182 through 12 months following the last study vaccination

MAAEs relating to predefined PIMDs

Number of participants with serious adverse events (SAEs)
Up to 180 days after each vaccination

SAEs

Number of participants with related SAEs
From D182 through 12 months following the last study vaccination

Related SAEs

Number of MAAEs relating to predefined PIMDs that meet the criteria for SAEs
From D182 through 12 months following the last study vaccination

MAAEs relating to predefined PIMDs that meet the criteria for SAEs

Geometric mean (GM) of HAI titers in all participants
At D01 and D30

HAI titers

Geometric mean ratio (GMR) HAI titers ratio D30/D01 in all participants
At D01 and D30

Individual HAI titers ratio D30/D01

GM of SARS-CoV-2 neutralizing titers in all participants
At D01 and D30

SARS-CoV-2 neutralizing titers

GMR of SARS-CoV-2 neutralizing titers ratio D30/D01 in all participants
At D01 and D30

Individual SARS-CoV-2 neutralizing titers ratio D30/D01

Secondary Endpoints

Percentage of participants with seroconversion in all participants
At D30
Percentage of participants with HAI titer ≥ 10 (1/dil) in all participants
At D01 and D30
Percentage of participants with HAI titer ≥ 40 (1/dil) in all participants
At D01 and D30
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
Group 1: IIV-HD (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 2: rC19 (dose 1) (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 3: IIV-HD (in right or left deltoid) and rC19 (dose1) (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 4: IIV-HD + rC19 (dose 1) (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 5: IIV-HD + rC19 (dose 2) (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 6: IIV-HD + rC19 (dose 3) (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01
Group 7: IIV-HD + rC19 (dose 4) (in right or left deltoid) and placebo (in opposite deltoid)EXPERIMENTALtwo IM injections on D01

Interventions

NameTypeDescription
IIV-HDBIOLOGICALInactivated, split-virion
rC19 (dose 1)BIOLOGICALProtein subunit
IIV-HD + rC19 (dose 1)BIOLOGICALIIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
IIV-HD + rC19 (dose 2)BIOLOGICALIIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
IIV-HD + rC19 (dose 3)BIOLOGICALIIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
IIV-HD + rC19 (dose 4)BIOLOGICALIIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
Placebo (0.9% NaCl)OTHERNormal saline
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Eligibility Criteria

Age Range50 Years to N/A
SexALL
Healthy VolunteersYes
Study Sites12

Inclusion Criteria: Inclusion criteria to be checked at Screening Visit * Aged 50 years or older on the day of inclusion * Informed consent form has been signed and dated. * Able to attend all scheduled visits and to comply with all study procedures. * Participant must be able to receive an inject...

Countries:United States
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Frequently asked questions about IIV-HD

What is IIV-HD used for?

IIV-HD is an investigational high-dose inactivated influenza vaccine being studied for immunization against influenza. It is being evaluated in combination with a recombinant COVID-19 vaccine for adult participants 50 years of age and older, as part of a Phase 1 clinical trial.

Who makes IIV-HD?

IIV-HD is being developed by Sanofi, a biopharmaceutical company listed on the stock exchange under the ticker symbol SNY. The company is conducting clinical research on this vaccine candidate for influenza immunization.

What phase is IIV-HD in?

IIV-HD is in Phase 1 clinical development. It is an investigational vaccine and has not been approved by regulatory authorities. The Phase 1 trial has been completed, with results not yet publicly reported.

What clinical trials is IIV-HD in?

IIV-HD was studied in a Phase 1 clinical trial with the identifier NCT06695117. This completed trial enrolled 980 participants aged 50 years and older in the United States and evaluated a combination vaccine comprising different recombinant spike antigen levels of a Matrix-M adjuvanted recombinant COVID-19 vaccine and high-dose inactivated influenza vaccine.

Is IIV-HD the same as a COVID-19 vaccine?

IIV-HD is a high-dose inactivated influenza vaccine, not a COVID-19 vaccine. It is being studied in combination with a recombinant COVID-19 vaccine to assess the safety and immune response of the combined formulation in older adults.