A Phase 1/2 interventional study of Flu H5 egg pandemic low dose vaccine, with adjuvant and Flu H5 Egg Pandemic medium dose vaccine, with adjuvant in Healthy Volunteers and Influenza, sponsored by Sanofi. Recruiting at 16 sites in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by Sanofi · Phase 1/2, Interventional, and Prevention
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Among 139 studies in Influenza, Human by Sanofi — 4 open to participants now, 6 under way, 1 of them phase 3. Influenza, Human · Sanofi.
Among the 139 studies in Influenza, Human by Sanofi, this one is the 44th largest by planned enrollment of the 126 interventional ones that give a count, is one of 5 that started in 2026, is one of 13 in phase 1/2, and was the 138th registered.
2,358 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
Browse Influenza, Human studies →4 of the 139 studies in Influenza, Human by Sanofi are open now, in 3 countries. Recruiting first, the newest first:
Sanofi · Sites in Poland
Ages 60+ · Healthy volunteers
Sanofi · Sites in Korea, Republic of
Ages 65+ · Healthy volunteers
Sanofi · Sites in Korea, Republic of
Ages 65+ · Healthy volunteers
By country, each count listing its studies:
Of the 121 Influenza, Human studies recruiting now, 66 (55%) set no upper age limit and 45 (37%) stop at 75 or younger; 33 take children under 18; 67 take healthy volunteers.
This study: 18 Years and older · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
139 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 24 · Phase 2 47 · Phase 3 35 · Phase 4 33
First in 2003; this study’s year is marked. 5 started in 2026.
This study's planned enrollment of 640 is above the median of 227 across 1,957 interventional studies indexed under Influenza, Human.
Median enrollment 305 across the 126 interventional studies, 1,001 across the 13 observational. Of the 133 that completed or were terminated, 73 (55%) have results posted.
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Sanofi is the lead sponsor of 1,558 studies on the registry; 89 are open to participants now.
Of its 205 completed or terminated interventional studies of FDA-regulated products, 123 (60%) have results posted.
2 of the studies in Influenza, Human by Sanofi that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06907511SanofiStudy 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 | 2026-12-01 |
| NCT07516418SanofiStudy of Different Formulations of Vaccines Encoding the RSV Monovalent Antigen or the Flu H5 Antigen in Participants 18 to 49 Years of Age | 2027-04-04 |
Add all 2 to your calendar (.ics) → With an account.
Among the 139 studies in Influenza, Human by Sanofi, from their registry updates:
This tab as a report to print or save as PDF → With an account.
The study aims to evaluate an egg-based H5N8 influenza vaccine up to 3 dose levels (low, medium, and high dose) given with or without adjuvant to see if the adjuvant improves vaccine effectiveness.
The study will enroll healthy adults aged 18 years and over. Participants will receive 2 injections in their arm of either one of the 3 dose levels of the study vaccine (low, medium, or high dose) with the adjuvant or the unadjuvanted vaccine (high dose).
Study duration per participant: approximately 14 months (including screening visit).
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive 2 intramuscular injections of flu H5 egg pandemic low dose vaccine, with adjuvant
Biological: Flu H5 egg pandemic low dose vaccine, with adjuvant
Participants receive 2 intramuscular injections of flu H5 egg pandemic medium dose vaccine, with adjuvant
Biological: Flu H5 Egg Pandemic medium dose vaccine, with adjuvant
Participants receive 2 intramuscular injections of flu H5 egg pandemic high dose vaccine, with adjuvant
Biological: Flu H5 Egg Pandemic high dose vaccine, with adjuvant
Participants receive 2 intramuscular injections of flu H5 egg pandemic high dose vaccine, without adjuvant
Biological: Flu H5 Egg Pandemic high dose vaccine, without adjuvant
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Number of participants with immediate Adverse Events (AEs)
Immediate adverse events are medically relevant unsolicited systemic adverse events reported in the 30 minutes after vaccination
Time frame: Within 30 minutes after each vaccination
Number of participants experiencing solicited administration site reactions (pre-listed in the participant diary and case report form [CRF])
A solicited reaction is an adverse reaction (sign or symptom) observed and reported under the conditions pre-listed (for example: injection site pain or headache). Solicited administration site reactions are reactions at and around the injection/administration site
Time frame: Within 8 days of each vaccination, including the day of vaccination
Number of participants experiencing solicited systemic reactions (pre-listed in the participant diary and CRF)
All solicited reactions that are not solicited injection or administration site reactions
Time frame: Within 8 days of each vaccination, including the day of vaccination
Number of participants experiencing unsolicited AEs
Unsolicited AE: an observed AE that does not fulfill the conditions of solicited reactions
Time frame: Within 21 days after the first vaccination, including the day of the first vaccination, and within 28 days after the second vaccination, including the day of the second vaccination
Number of participants experiencing Medically Attended Adverse Events (MAAEs)
MAAEs are collected throughout the study
Time frame: From Day 01 until the end of the study, approximately 14 months
Number of participants experiencing Adverse Events of Special Interest (AESIs)
AESIs are collected throughout the study
Time frame: From Day 01 until the end of the study, approximately 14 months
Number of participants experiencing Serious Adverse Events (SAEs)
SAEs are collected throughout the study
Time frame: From Day 01 until the end of the study, approximately 14 months
Number of participants experiencing out-of-range biological test results (including shift from baseline values)
Safety laboratory assessments will include clinical chemistry and hematology
Time frame: Up to 8 days after each vaccination
Number of participants experiencing AEs leading to discontinuation
AEs leading to discontinuation are collected throughout the study
Time frame: From Day 01 until the end of the study, approximately 14 months
Geometric mean titer of hemagglutination inhibition (HAI) assay antibody (Ab) titer
Influenza vaccine antibody titers are measured by HAI assay
Time frame: Day 01 and Day 43
Number of participants with HAI Ab titer ≥ 40 (1 dilution [dil]; ie, seroprotection)
Influenza vaccine antibody titers are measured by HAI assay
Time frame: Day 43
Number of participants with seroconversion
Seroconversion is defined as HAI Ab titer \< 10 (1/dil) on Day 01 and post-injection titer ≥ 40 (1/dil) on Day 43; or defined as HAI Ab titer ≥ 10 (1/dil) on Day 01 and a ≥ 4-fold increase in titer (1/dil) on Day 43
Time frame: Day 01 and Day 43
Geometric mean titer ratio of individual HAI Ab titer ratio Day 43/Day 01
Influenza vaccine antibody titers are measured by HAI assay
Time frame: Day 01 and Day 43
Geometric mean titer of hemagglutination inhibition (HAI) assay antibody (Ab) titer obtained on Day 01, Day 22, Day 43, Day 202
Influenza vaccine antibody titers are measured by HAI assay
Time frame: Day 01, Day 22, Day 43, Day 202
Geometric mean titer ratio of individual HAI Ab titer ratios Day 22/Day 01, Day 43/Day 01, Day 202/Day 43
Individual HAI Ab titer ratios are calculated for the following time points: Day 22/Day 01, Day 43/Day 01 and Day 202/Day 43
Time frame: Day 01, Day 22, Day 43, Day 202
Number of participants with individual HAI Ab titer ≥ 40 (1/dil) on Day 01, Day 22, Day 43, Day 202
Influenza vaccine antibody titers are measured by HAI assay
Time frame: Day 01, Day 22, Day 43, Day 202
Number of participants with seroconversion on Day 22 compared to Day 01 (baseline)
Seroconversion is defined as titer \< 10 (1/dil) on Day 01 and post-injection titer ≥ 40 (1/dil) on Day 22; or defined as titer ≥ 10 (1/dil) on Day 01 and a ≥ 4 fold increase in titer (1/dil) on Day 22
Time frame: Day 01, Day 22
Number of participants with detectable HAI Ab titer
Detectable HAI Ab titer: a titer ≥ 10 (1/dil)
Time frame: Day 01, Day 22, Day 43, Day 202
Geometric mean titer of neutralization (NT) Ab titer
Influenza vaccine antibody titers are measured by serum neutralization (SN) assay
Time frame: Day 01, Day 22, Day 43, Day 202
Geometric mean titer ratio of individual NT Ab titer ratio
Individual NT Ab titer ratios are calculated for the following time points: Day 22/Day 01, Day 43/Day 01 and Day 202/Day 43
Time frame: Day 01, Day 22, Day 43, Day 202
Number of participants with NT Ab titer ≥ 20 (1/dil)
NT Ab titer ≥ 20 (1/dil) on Day 43; compared to Day 01 and Day 202
Time frame: Day 01, Day 43, Day 202
Number of participants with NT Ab titer ≥ 40 (1/dil)
NT Ab titer ≥ 40 (1/dil) on Day 43; compared to Day 01 and Day 202
Time frame: Day 01, Day 43, Day 202
Number of participants with NT Ab titer ≥ 80 (1/dil)
NT Ab titer ≥ 80 (1/dil) on Day 43; compared to Day 01 and Day 202
Time frame: Day 01, Day 43, Day 202
Geometric mean fold-rise of fold increase in NT Ab titer [post/pre] ≥ 2 and ≥ 4
Influenza vaccine antibody titers are measured by serum neutralization (SN) assay
Time frame: Day 43
Number of participants with detectable NT Ab titer
Detectable NT Ab titer: a titer ≥ 10 (1/dil) on Day 01, Day 22, Day 43, Day 202
Time frame: Day 01, Day 22, Day 43, Day 202
Plan to share: 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
No publications or documents are linked to this record.
Started Aug 2026 (actual). Primary completion is estimated for Feb 2028, 18 months after the start.
Of 41 industry-sponsored phase 1/2 interventional studies under Influenza, Human, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 16. This study's planned 18 months is above that.
Counting every sponsor, half of 43 studies reached it within 12 months; a quarter within 7 and three quarters within 16.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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