Pandemic Influenza ImmunizationPhase 1/2NCT06907511
Study to Evaluate the Safety and the Immunogenicity of a Second Generation Structurally Designed mRNA Vaccine Candidate Against Pandemic Influenza H5 HA Strain in Healthy Adult Participants Aged 18 Years and Older
A Phase 1/2 study testing Pandemic flu H5 HA mRNA SD2 vaccine in people with Pandemic Influenza Immunization and Healthy Volunteers, run by Sanofi at 13 sites in United States.
Trial summary
The purpose of this phase 1/2 study is to investigate the safety and immunogenicity of different doses (high, medium and low) of a second generation structurally designed (SD2) H5 messenger ribonucleic acid (mRNA) vaccine against pandemic H5 influenza virus (pandemic flu H5 hemagglutinin (HA) mRNA SD2) in healthy… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Pandemic Influenza Immunization, Healthy Volunteers
- What is being tested?
- Pandemic flu H5 HA mRNA SD2 vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 720 participants
- Where
- 13 sitesUnited States
- Study dates
- 17 Apr 2025to 1 Dec 2026
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
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
Show all 17Show fewer
- 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 patient's potential participation in a clinical trial.
Trial locations and contacts
13 sites in 1 country.
13 sites in 1 country
United States13 sites
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
Accel Research Sites - Lakeland Clinical Research Unit- Site Number : 8400006
Lakeland, Florida, 33803
Accel Research Sites - St. Petersburg - Largo- Site Number : 8400004
Largo, Florida, 33777
Velocity Clinical Research - Norfolk- Site Number : 8400015
Norfolk, Nebraska, 68701
Coastal Carolina Research Center- Site Number : 8400001
North Charleston, South Carolina, 29406
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
About this study
Official title: A Phase 1/2, Parallel-group, Randomized, Modified Double-blind, Placebo-controlled, Multi-center, Dose Ranging Study to Evaluate the Safety and Immunogenicity of a Second Generation Structurally Designed Pandemic Influenza H5 HA mRNA Vaccine in Healthy Adults Aged 18 Years and Older
The purpose of this phase 1/2 study is to investigate the safety and immunogenicity of different doses (high, medium and low) of a second generation structurally designed (SD2) H5 messenger ribonucleic acid (mRNA) vaccine against pandemic H5 influenza virus (pandemic flu H5 hemagglutinin (HA) mRNA SD2) in healthy younger and older adults.
The study will aim to identify the appropriate dose for further clinical development of a potential pandemic response vaccine.
Read more
The study also includes an extension phase for one of the 3 dose levels of the pandemic flu H5 HA mRNA SD2 vaccine to collect additional safety and the immunogenicity data for this specific dose of the vaccine. During this Extension Phase, an additional 480 participants will be randomized according to a 1:1 ratio and stratified by age (≥ 18 to < 65 years and ≥ 65 years) to receive either the low dose of the pandemic flu H5 HA mRNA DS2 vaccine (Group 1) or placebo (Group 4). This extension will enhance the safety database and improve precision of the immunogenicity results for the selected dose while preserving the original study design integrity.
The study duration per participant will be approximately 13 months. There will be two injections of placebo or pandemic flu H5 mRNA vaccine 21 days apart at high, medium and low doses.
Study visits/contact include: 7 study visits and 1 telephone call. Vaccination visits (including blood samples) will occur at Day 01 and Day 22. Short-term follow-up visits (including blood samples) will occur 8 and 21 days after each injection. Participants will be also followed up (including blood samples) at 3 and 6 months after 2nd injection, and at 12 months after 2nd injection for safety.
- Being tested
- Pandemic flu H5 HA mRNA SD2 vaccine, Placebo
- Keywords
- Pandemic Flu H5 Vaccination
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pandemic flu H5 HA mRNA SD2 vaccineBiological
Pharmaceutical Form:
Suspension in a vial
Route of Administration:
Intramuscular injection
PlaceboOther
Pharmaceutical Form:
Liquid solution in a vial
Route of Administration:
Intramuscular injection
| Study group | Role | What they receive |
|---|---|---|
| Group 1: Pandemic flu H5 HA mRNA SD2 vaccine (Low dose) | Experimental | Participants will receive two injections of low dose pandemic flu H5 HA mRNA SD2 vaccine
Extension Phase:
Additional participants will receive two injections 21 days apart of pandemic flu H5 HA mRNA SD2 vaccine at low dose Receives: Biological: Pandemic flu H5 HA mRNA SD2 vaccine |
| Group 2: Pandemic flu H5 HA mRNA SD2 vaccine (Medium dose) | Experimental | Participants will receive two injections of medium dose pandemic flu H5 HA mRNA SD2 vaccine Receives: Biological: Pandemic flu H5 HA mRNA SD2 vaccine |
| Group 3: Pandemic flu H5 HA mRNA SD2 vaccine (High dose) | Experimental | Participants will receive two injections of high dose pandemic flu H5 HA mRNA SD2 vaccine Receives: Biological: Pandemic flu H5 HA mRNA SD2 vaccine |
| Group 4: Placebo | Placebo comparator | Participants will receive two injections of placebo
Extension Phase:
Additional participants will receive two injections 21 days apart of placebo Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Presence of immediate adverse events (AEs)
Number of participants with immediate AEs
Measured: Within 30 minutes after each/any injection
Presence of solicited injection site reactions
Number of participants with solicited injection site reactions
Measured: Through 7 days after each/any injection
Presence of solicited systemic reactions
Number of participants with solicited systemic reactions
Measured: Through 7 days after each/any injection
Presence of unsolicited AEs
Number of participants with unsolicited AEs
Measured: Through 21 days after the first injection through 28 days after the second injection
Presence of medically attended adverse events (MAAEs)
Number of participants with MAAEs
Measured: Through 180 days after the last injection
Presence of adverse events of special interest (AESIs)
Number of participants with AESIs
Measured: Throughout the study, approximately 13 months
Presence of serious adverse events (SAEs)
Number of participants with SAEs
Measured: Throughout the study, approximately 13 months
Presence of out-of-range biological test results (including shift from baseline values)
Number of participants with out-of-range biological test results
Measured: Through a maximum of 8 days after each injection
Secondary outcomes (12)
Geometric mean titers (GMTs) of antibodies (Abs) against investigational pandemic flu H5 HA mRNA SD2 vaccine
Ab titer measured by hemagglutination inhibition (HAI) assay
Measured: Day 01, Day 22, Day 43, Day 112 and Day 202
Individual HA titer ratio
Geometric mean ratio (GMR) HAI titers ratio
Measured: Day22/Day01, Day43/Day01, Day112/Day01, and Day202/Day01
Seroconversion HAI Titer
Percentage of participants with seroconversion
Seroconversion is defined by:
HAI titer < 10 [1/dilution (dil)] on Day 01 and post-injection titer ≥ 40 [1/dil] on Day 22 or Day 43; or defined as HAI titer ≥ 10 [1/dil] on D01 and a ≥ 4-fold increase in titer [1/dil]) on Day 22 or Day 43
Measured: Day 01, Day 22 and Day 43
HAI titer ≥ 40 (1/dil)
Percentage of participants with HAI titer ≥ 40 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112, and Day 202
Detectable HAI titer ≥ 10 (1/dil)
Percentage of participants with HAI titer ≥ 10 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112, and Day 202
GMTs of Abs against investigational pandemic flu H5 HA mRNA SD2 vaccine
Ab titer measured by seroneutralization (SN) test
Measured: Day 01, Day 22, Day 43, Day 112 and Day 202
Individual SN titer ratio
GMR SN titers ratio
Measured: Day 22/Day 02, Day 43/Day 01, Day 112/Day 01 and Day 202/Day 01
SN titer ≥ 20 (1/dil)
Percentage of participants with SN titer ≥ 20 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112 and Day 202
SN titer ≥ 40 (1/dil)
Percentage of participants with SN titer ≥ 40 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112 and Day 202
SN titer ≥ 80 (1/dil)
Percentage of participants with SN titer ≥ 80 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112 and Day 202
Detectable SN titer ≥ 10 (1/dil)
Percentage of participants with SN titer ≥ 10 (1/dil)
Measured: Day 01, Day 22, Day 43, Day 112, and Day 202
2-fold and 4-fold rise in SN titer
Percentage of participants with fold increase in SN Ab titer [post-vaccination / pre- vaccination] ≥ 2 and ≥ 4 on D22 and D43
Measured: 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.
- First posted2 Apr 2025
- Study start17 Apr 2025
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pandemic Influenza ImmunizationStudies of the same condition, open and under way.
- More trials run by SanofiThe 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 1/2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 720 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sanofi
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06907511
- Sponsor's protocol ID
- VBS00002
- Other IDs
- U1111-1314-5493
- Status last verified
- Jan 2026
- First submitted
- 26 Mar 2025
- Last updated
- 16 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- 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.
Study at a glance
From the registry record, last updated by the sponsor on 16 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1/2, Parallel-group, Randomized, Modified Double-blind, Placebo-controlled, Multi-center, Dose Ranging Study to Evaluate the Safety and Immunogenicity of a Second Generation Structurally Designed Pandemic Influenza H5 HA mRNA Vaccine in Healthy Adults Aged 18 Years and Older
- ClinicalTrials.gov ID
- NCT06907511
- Acronym / sponsor ID
- VBS00002
- Keywords
- Pandemic Flu H5 Vaccination
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 720 participants (actual)
- Lead sponsor
- SanofiIndustry (pharma, biotech, devices)
- Study start
- 17 Apr 2025 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 2 Apr 2025 (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.
The purpose of this phase 1/2 study is to investigate the safety and immunogenicity of different doses (high, medium and low) of a second generation structurally designed (SD2) H5 messenger ribonucleic acid (mRNA) vaccine against pandemic H5 influenza virus (pandemic flu H5 hemagglutinin (HA) mRNA SD2) in healthy younger and older adults.
The study will aim to identify the appropriate dose for further clinical development of a potential pandemic response vaccine.
The study also includes an extension phase for one of the 3 dose levels of the pandemic flu H5 HA mRNA SD2 vaccine to collect additional safety and the immunogenicity data for this specific dose of the vaccine. During this Extension Phase, an additional 480 participants will be randomized according to a 1:1 ratio and stratified by age (≥ 18 to < 65 years and ≥ 65 years) to receive either the low dose of the pandemic flu H5 HA mRNA DS2 vaccine (Group 1) or placebo (Group 4). This extension will enhance the safety database and improve precision of the immunogenicity results for the selected dose while preserving the original study design integrity.
The study duration per participant will be approximately 13 months. There will be two injections of placebo or pandemic flu H5 mRNA vaccine 21 days apart at high, medium and low doses.
Study visits/contact include: 7 study visits and 1 telephone call. Vaccination visits (including blood samples) will occur at Day 01 and Day 22. Short-term follow-up visits (including blood samples) will occur 8 and 21 days after each injection. Participants will be also followed up (including blood samples) at 3 and 6 months after 2nd injection, and at 12 months after 2nd injection for safety.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Group 1: Pandemic flu H5 HA mRNA SD2 vaccine (Low dose) | Experimental | Biological: Pandemic flu H5 HA mRNA SD2 vaccineParticipants will receive two injections of low dose pandemic flu H5 HA mRNA SD2 vaccine Extension Phase: Additional participants will receive two injections 21 days apart of pandemic flu H5 HA mRNA SD2 vaccine at low dose |
| Group 2: Pandemic flu H5 HA mRNA SD2 vaccine (Medium dose) | Experimental | Biological: Pandemic flu H5 HA mRNA SD2 vaccineParticipants will receive two injections of medium dose pandemic flu H5 HA mRNA SD2 vaccine |
| Group 3: Pandemic flu H5 HA mRNA SD2 vaccine (High dose) | Experimental | Biological: Pandemic flu H5 HA mRNA SD2 vaccineParticipants will receive two injections of high dose pandemic flu H5 HA mRNA SD2 vaccine |
| Group 4: Placebo | Placebo comparator | Other: PlaceboParticipants will receive two injections of placebo Extension Phase: Additional participants will receive two injections 21 days apart of placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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:
- 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
Key exclusion criteria (17 listed)
- 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
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 |
|---|---|---|
| Pandemic flu H5 HA mRNA SD2 vaccinePharmaceutical Form: Suspension in a vial Route of Administration: Intramuscular injection | Biological | Group 1: Pandemic flu H5 HA mRNA SD2 vaccine (Low dose), Group 2: Pandemic flu H5 HA mRNA SD2 vaccine (Medium dose), Group 3: Pandemic flu H5 HA mRNA SD2 vaccine (High dose) |
| PlaceboPharmaceutical Form: Liquid solution in a vial Route of Administration: Intramuscular injection | Other | Group 4: Placebo |
Primary outcome
Presence of immediate adverse events (AEs)
Time frame: Within 30 minutes after each/any injection
Number of participants with immediate AEs
Presence of solicited injection site reactions
Time frame: Through 7 days after each/any injection
Number of participants with solicited injection site reactions
Presence of solicited systemic reactions
Time frame: Through 7 days after each/any injection
Number of participants with solicited systemic reactions
Presence of unsolicited AEs
Time frame: Through 21 days after the first injection through 28 days after the second injection
Number of participants with unsolicited AEs
Presence of medically attended adverse events (MAAEs)
Time frame: Through 180 days after the last injection
Number of participants with MAAEs
Presence of adverse events of special interest (AESIs)
Time frame: Throughout the study, approximately 13 months
Number of participants with AESIs
Presence of serious adverse events (SAEs)
Time frame: Throughout the study, approximately 13 months
Number of participants with SAEs
Presence of out-of-range biological test results (including shift from baseline values)
Time frame: Through a maximum of 8 days after each injection
Number of participants with out-of-range biological test results
12 secondary outcomes
Geometric mean titers (GMTs) of antibodies (Abs) against investigational pandemic flu H5 HA mRNA SD2 vaccine
Time frame: Day 01, Day 22, Day 43, Day 112 and Day 202
Individual HA titer ratio
Time frame: Day22/Day01, Day43/Day01, Day112/Day01, and Day202/Day01
Seroconversion HAI Titer
Time frame: Day 01, Day 22 and Day 43
HAI titer ≥ 40 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112, and Day 202
Detectable HAI titer ≥ 10 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112, and Day 202
GMTs of Abs against investigational pandemic flu H5 HA mRNA SD2 vaccine
Time frame: Day 01, Day 22, Day 43, Day 112 and Day 202
Individual SN titer ratio
Time frame: Day 22/Day 02, Day 43/Day 01, Day 112/Day 01 and Day 202/Day 01
SN titer ≥ 20 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112 and Day 202
SN titer ≥ 40 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112 and Day 202
SN titer ≥ 80 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112 and Day 202
Detectable SN titer ≥ 10 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 112, and Day 202
2-fold and 4-fold rise in SN titer
Time frame: Day 22 and Day 43
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Jan 2026.
- VBS00002 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.
The record lists no contact. Use the official record to reach the sponsor.
13 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Pandemic flu H5 HA mRNA SD2 vaccine in people with Pandemic Influenza Immunization and Healthy Volunteers, run by Sanofi at 13 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: under way, not looking for participants, as of the sponsor's last update on 16 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 13 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?
This study is still under way. Results are not available in the source record yet.
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) (time frame: Within 30 minutes after each/any injection). 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?
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 16 Jan 2026.