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Influenza ImmunizationPhase 1/2NCT06727058

Study to Evaluate Safety and Immunogenicity of a Pandemic Flu H5 mRNA Vaccine in Healthy Adults Aged 18 Years and Older

A Phase 1/2 study testing Pandemic flu H5 mRNA vaccine in people with Influenza Immunization, run by Sanofi Pasteur, a Sanofi Company at 14 sites in United States.

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

The purpose of this study is to evaluate a pandemic flu H5 strain messenger ribonucleic acid (mRNA) vaccine at 3 dose levels (low, medium, and high) in comparison with placebo in 276 healthy adult participants to select the adequate dose for further clinical development. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for
Influenza Immunization
What is being tested?
Pandemic flu H5 mRNA vaccine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
276 participants
Where
14 sitesUnited States
Study dates
9 Dec 2024to 24 Mar 2026
Phase
Phase 1/2
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 18 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Aged 18 years or older on the day of inclusion.
  • A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
  • Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year, or surgically sterile.
  • OR
  • Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to each study intervention administration until at least 12 weeks after the last study intervention administration.
  • A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) within 8 hours before the first dose of study intervention.

Who cannot join

  • 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 study intervention components (eg, polyethylene glycol, polysorbate); history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances; any allergic reaction (eg, anaphylaxis) after administration of an mRNA vaccine .
  • Previous history of myocarditis, pericarditis, and/or myopericarditis.
  • Known history of previous episodes of Guillain-Barré Syndrome (GBS), neuritis (including Bell's palsy), convulsions , encephalitis, transverse myelitis, and vasculitis.
  • Participants with an electrocardiogram that is consistent with possible myocarditis or pericarditis or, in the opinion of the investigator, demonstrates clinically relevant abnormalities that may affect participant safety or study results.
  • Self-reported thrombocytopenia, contraindicating IM injection based on investigator's judgment.
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  • Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection based on investigator's judgment.
  • Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
  • Moderate or severe acute illness / infection (according to investigator's judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
  • Alcohol, prescription drug, or substance abuse that, in the opinion of the investigator, might interfere with the study conduct or completion.
  • Participant who had acute infectious symptoms or a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase polymerase chain reaction (RT PCR) or antigen test in the past 10 days prior to the first visit (V)01.
  • Receipt of any vaccine other than an mRNA vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine other than an mRNA vaccine in the 3 weeks following the second dose of the study intervention .
  • Receipt of immune globulins, blood or blood-derived products in the past 3 months.
  • Receipt of any mRNA vaccine/product in the 2 months preceding study intervention administration or planned receipt of any mRNA vaccine in the 2 months after the second dose of the study intervention.
  • Participation at the time of study enrollment (or in the 4 weeks preceding study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
  • Previous history of participation in an H5 influenza A vaccine study. This includes any influenza subtypes that contain H5 such as H5N1, H5N8, or H5N6.
  • Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Trial locations and contacts

14 sites in 1 country.

14 sites in 1 country

United States14 sites

  • Atlanta Clinical Research Center- Site Number : 8400007

    Atlanta, Georgia, 30342

  • QUEST Research Institute- Site Number : 8400014

    Bingham Farms, Michigan, 48334

  • Charlottesville Medical Research- Site Number : 8400005

    Charlottesville, Virginia, 22911

  • Velocity Clinical Research - Springdale- Site Number : 8400010

    Cincinnati, Ohio, 45246

  • Accel Research Site - NeuroStudies.net, LLC - ERN - PPDS- Site Number : 8400003

    Decatur, Georgia, 30030-2627

  • Accel Research Sites Network - DeLand Clinical Research Unit- Site Number : 8400002

    DeLand, Florida, 32720

  • Velocity Clinical Research - San Diego- Site Number : 8400013

    La Mesa, California, 91942

  • ARSN-Lakeland CRU- Site Number : 8400006

    Lakeland, Florida, 33803

  • Accel Research Sites - St. Petersburg- Site Number : 8400004

    Largo, Florida, 33777

  • Velocity Clinical Research - Norfolk- Site Number : 8400015

    Norfolk, Nebraska, 68701

  • Coastal Carolina Research Center - North Charleston- Site Number : 8400001

    North Charleston, South Carolina, 29405

  • Velocity Clinical Research - Omaha- Site Number : 8400012

    Omaha, Nebraska, 68134

  • Olympus Clinical Research - Sugar Land- Site Number : 8400009

    Sugar Land, Texas, 77479

  • Velocity Clinical Research, Salt Lake City- Site Number : 8400011

    West Jordan, Utah, 84088

Other trials in United States

About this study

Official title: A Phase 1/2, Randomized, Modified Double-blind, Placebo-controlled, Multi-center, Dose Escalating Study to Evaluate the Safety and Immunogenicity of a Pandemic Flu H5 mRNA Vaccine in Healthy Adults Aged 18 Years and Older

The purpose of this study is to evaluate a pandemic flu H5 strain messenger ribonucleic acid (mRNA) vaccine at 3 dose levels (low, medium, and high) in comparison with placebo in 276 healthy adult participants to select the adequate dose for further clinical development.

The duration per participant will be approximately 13 months.

Being tested
Pandemic flu H5 mRNA vaccine, Placebo
Keywords
pandemic influenza infection, H5 strain
Medical subject headings
Influenza, Human

What participants receive

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

  • Pandemic flu H5 mRNA vaccineBiological

    Pharmaceutical Form: Suspension for injection

    Route of Administration: Intramuscular (IM)

  • PlaceboOther

    Pharmaceutical Form: Liquid solution for injection

    Route of Administration: Intramuscular (IM)

Study groups in NCT06727058
Study groupRoleWhat they receive
Group 1: Low Dose Pandemic flu H5 mRNA vaccineExperimentalParticipants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)
Receives: Biological: Pandemic flu H5 mRNA vaccine
Group 2: Medium Dose Pandemic flu H5 mRNA vaccineExperimentalParticipants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)
Receives: Biological: Pandemic flu H5 mRNA vaccine
Group 3: High Dose Pandemic flu H5 mRNA vaccineExperimentalParticipants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)
Receives: Biological: Pandemic flu H5 mRNA vaccine
Group 4: PlaceboPlacebo comparatorParticipants will receive 2 injections of placebo 21 days apart (at Day 01 and Day 22)
Receives: Other: Placebo

What is being measured

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

  1. Presence of immediate adverse events (AEs) within 30 minutes after each/any injection

    Number of participants experiencing immediate AEs

    Measured: Within 30 minutes of any/each injections

  2. Presence of solicited injection site reactions through 7 days after each/any injection

    Number of participants experiencing solicited injection site reactions

    Measured: Through 7 days after each/any injections

  3. Presence of solicited systemic site reactions through 7 days after each/any injection

    Number of participants experiencing solicited systemic site reactions

    Measured: Through 7 days after each/any injections

  4. Presence of unsolicited AEs through 21 days after the first injection and through 28 days after the second injection

    Number of participants experiencing unsolicited AEs

    Measured: Through 21 days after the first injection and through 28 days after the second injection

  5. Presence of medically attended adverse events (MAAEs) through 180 days after the last injection

    Number of participants experiencing MAAEs

    Measured: Through 180 days after the last injection

  6. Presence of adverse events of special interest (AESIs) throughout the study

    Number of participants experiencing AESIs

    Measured: Throughout the study, approximately 13 months

  7. Presence of serious adverse events (SAEs) throughout the study

    Number of participants experiencing SAEs

    Measured: Throughout the study, approximately 13 months

  8. Presence of out-of-range biological test results (including shift from baseline values) through a maximum of 8 days after each injection

    Number of participants with out-of-range biological test results

    Measured: Through a maximum of 8 days after each injection

Secondary outcomes (14)

  1. Antibody titers measured by Hemagglutination Inhibition (HAI) Assay

    Antibody titers are expressed as geometric mean titers (GMTs)

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  2. Individual HAI titer ratio

    Measured: At Day 22/Day 01, Day 43/Day 01, Day 112/Day 01, and Day 202/Day 01

  3. ≥ 4-fold increase in HAI titer [1/dilution])

    Measured: At Day 22 or Day 43

  4. HAI titer ≥ 10 [1/dilution]

    Measured: At day 01

  5. HAI titer ≥ 40 [1/dilution]

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  6. Detectable HAI titer ≥ 10 [1/dilution]

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  7. Antibody titers measured by Seroneutralization (SN) test

    Antibody titers are expressed as GMTs

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  8. Individual SN titer ratio

    Measured: Day 22/Day 01, Day 43/Day 01, Day 112/Day 01, and Day 202/Day 01

  9. SN titer ≥ 20 (1/dilution)

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  10. SN titer ≥ 40 (1/dilution)

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  11. SN titer ≥ 80 (1/dilution)

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  12. Detectable SN titer ≥ 10 (1/dilution)

    Measured: At Day 01, Day 22, Day 43, Day 112, and Day 202

  13. 2-fold rise in SN titer

    Measured: At Day 22 and Day 43

  14. 4-fold rise in SN titer

    Measured: At Day 22 and Day 43

Timeline

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

  1. First posted10 Dec 2024
  2. Study start9 Dec 2024
  3. Primary completion24 Mar 2026
  4. Study completion24 Mar 2026

Resources

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 1/2
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Sequential
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
276 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06727058
Sponsor's protocol ID
VBS00001
Other IDs
U1111-1309-8833
Status last verified
Apr 2026
First submitted
5 Dec 2024
Last updated
23 Apr 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
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

Questions about this trial

What is this clinical trial studying?

A Phase 1/2 study testing Pandemic flu H5 mRNA vaccine in people with Influenza Immunization, run by Sanofi Pasteur, a Sanofi Company at 14 sites in United States.

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 6 inclusion and 17 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 23 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 14 sites in United States. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

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?

Presence of immediate adverse events (AEs) within 30 minutes after each/any injection (time frame: Within 30 minutes of any/each injections). The study lists 8 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 NCT06727058.

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 23 Apr 2026.

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