NCT07779408ClinicalTrials.gov

Study to Assess Safety and Immunogenicity of an Egg-based H5N8 Influenza Vaccine at Multiple Dose Levels Adjuvanted With Matrix-M in Healthy Participants 18 Years of Age and Above.

A Phase 1/2, Parallel, Observer-blind Study to Assess the Safety and Immunogenicity of an Egg-based H5N8 Influenza Vaccine at Multiple Dose Levels Adjuvanted With Matrix-M in Healthy Participants 18 Years of Age and Above.

RecruitingTaking participants now, according to the registry record.

Contact this study

In brief

Phase 1 / Phase 2640 participants sought16 sites1 country

Registered in 1 registry

ClinicalTrials.govNCT07779408Open this record at ClinicalTrials.govSynced 5 days ago

One study can be registered in several registries. We show it once and link every record we hold.

Trial information is shown as published by the registry, in its original language.

Interested in this study?

How this study is set up

The points below are drawn from the public registry record for this study. Each one cites the field or sentence it came from. A dash (—) means the record does not state something — not that it is missing or wrong. Many well-run studies, especially small ones, leave some of these blank.

Not stated: Registered after enrolment began (about 18 days after the recorded start)First posted 2026-08-21; recorded start 2026-08-03
Present: Has a defined primary outcomeA primary outcome measure is listed in the record
Present: The primary outcome states a time frameThe primary outcome measure records a time frame
Present: Participants are randomly assignedAllocation is recorded as randomised
Present: Has a comparison groupThe record lists a placebo or comparator arm, or more than one study arm
Present: Uses blinding (masking)A masking level is recorded in the record
Not stated: An ethics committee is not stated in the registry recordThis registry's ingested record has no ethics-committee field
Not stated: Regulatory oversight (such as an IND or IDE) is not stated in the registry recordThis registry's ingested record has no regulatory-authorisation field
Not stated: A data monitoring committee is not stated in the registry recordThis registry's ingested record has no data-monitoring-committee fieldA data monitoring committee is not required for many smaller studies, and its absence here is not unusual.
Present: No cost to participants is mentioned in the recordChecked the summary, description and eligibility text; no cost-to-participant phrase found
Present: Sponsor has 351 other studies in this databaseCounted from the lead sponsor named in the record (Sanofi)
Present: Sponsor has posted results for at least one studyBased on the sponsor’s studies in this database

The record lists 2 conditions.
Lead sponsor type recorded as: industry.
Intervention regulatory context: investigational, within a phased regulatory pathway.

These are facts from the public registry record, not a judgement about the study. Discuss any trial with your own doctor before taking part.

What these facts mean, and what to ask · ruleset v1

Trial stature

Three independent measures of this study, described from its registry record — not a recommendation about it. A rigorous study by investigators nobody has heard of is better evidence than a weak study led by a famous one. How these are scored.

Methodological rigourMODERATE

A moderately rigorous design for a phase 2 study, judged from its ClinicalTrials.gov record.

How this score is built

Randomised allocation20/20
Participants are randomly allocated between arms
Blinding13/20
Double-blind
Control arm0/15
No comparator arm stated in the record
Primary-outcome specificity10/10
Named primary outcome with a defined time frame
Endpoint type3/10
Surrogate or intermediate endpoint (conservative default)
Multi-centre0/8
Single site, or site count not stated
Data monitoring committee0/7
No data monitoring committee stated
Prospective registration5/5
Registered before the study start date
Protocol / SAP posted0/5
No protocol or SAP posted to the registry

ScaleMEDIUM

A medium-sized study: 640 participants (target), run at 16 sites.

How this score is built

Enrolment28/40
640 participants (target)
Site count0/25
Site count not stated in the record
Country count0/15
Country count not stated in the record
Planned duration6/10
Planned over about 19 months
Sponsor scale9/10
Sanofi has led 348 trials in our corpus

Investigator standingUNKNOWN

We have no verifiable track record for the investigator named on this trial. That is common for early-career investigators and for records held outside ClinicalTrials.gov — it is not a negative signal.

How this score is built

Investigator standing0/100
No investigator recorded in the registry for this trial

These describe the registry record only, and today we hold ClinicalTrials.gov data. Absent fields lower a score, and absence often reflects registration practice rather than study quality. A high-stature trial is not necessarily safer or a better choice for you — enrolling in a large definitive trial can mean a higher chance of receiving placebo, while a small early-phase study may be the only route to a new therapy.

Summary

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).

Conditions

Healthy Volunteers
Influenza

Eligibility

Eligibility
Sex	All
Ages	18 Years – No maximum
Healthy volunteers	Yes

Eligibility as written in the registry

Inclusion Criteria: * Aged 18 years or above on the day of inclusion * Participants who are healthy as determined by medical evaluation including medical history * Not pregnant/breastfeeding; non-childbearing potential or uses effective contraception/abstinence from ≥4 weeks before the first study intervention dose to ≥8 weeks after the last dose * Informed consent form has been signed and dated * Able to attend all scheduled visits and to comply with all study procedures * Covered by health insurance, if required by local regulations Exclusion Criteria: * Known or suspected immunodeficiency; immunosuppressive therapy in past 6 months; or long-term systemic corticosteroid (eg, prednisone for more than 2 weeks in the past 3 months) * Known hepatitis B or hepatitis C infection (based on medical history) * Known personal or family history of previous episodes of Guillan-Barré syndrome (GBS), neuritis (including Bell's palsy), convulsions, encephalitis, transverse myelitis, and vasculitis * Known systemic hypersensitivity to any of the study intervention components or history of life-threatening reaction to the study interventions or products with same substances * Self-reported thrombocytopenia contraindicating intramuscular (IM) injection based on investigator's judgment * 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 * History of A/H5 infection prior to the study participation * Moderate or severe acute illness/infection (per investigator judgment)/fever (≥ 38.0°C \[≥ 100.4°F\]) on study intervention day. Include participant only after the condition or fever has resolved * Alcohol, prescription drug, or substance abuse that, in the opinion of the investigator, might interfere with the study conduct or completion * Any vaccine given 4 weeks before first study intervention or any planned vaccination to be given prior to Day 43 (ie, approximately 21 days after the second study intervention) * Previous vaccination against A(H5) with an investigational or marketed vaccine. This includes, but is not limited to, influenza subtypes A(H5N1), A(H5N8), and A(H5N6) * Has received a blood transfusion or blood-derived products, including immunoglobulins in the past 3 months * Participation in another clinical study for a vaccine, drug, medical device, or medical procedure within 4 weeks before enrollment or planned participation during the present study period * Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily * Is an investigator, investigator/study center employee, or immediate family member (parent, spouse, natural/adopted child) of the investigator/employee with direct involvement in the study * Any screening safety laboratory parameters out of normal ranges and assessed as \> Grade 2 The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Eligibility in plain statements

This record's criteria have not been broken into separate statements yet. The registry text above is complete and is the authoritative version.

Study design

Study design
Study type	Interventional
Phase	Phase 1 / Phase 2
Allocation	Randomised
Intervention model	PARALLEL
Primary purpose	PREVENTION
Masking	DOUBLE (2)
Enrolment	640 participants sought

Sponsor and collaborators

Sanofi Sponsor

Arms and interventions

Group 4: Flu H5 Egg Pandemic high dose vaccine, without adjuvantEXPERIMENTAL
Participants receive 2 intramuscular injections of flu H5 egg pandemic high dose vaccine, without adjuvant
Group 1: Flu H5 egg pandemic low dose vaccine, with adjuvantEXPERIMENTAL
Participants receive 2 intramuscular injections of flu H5 egg pandemic low dose vaccine, with adjuvant
Group 2: Flu H5 Egg Pandemic medium dose vaccine, with adjuvantEXPERIMENTAL
Participants receive 2 intramuscular injections of flu H5 egg pandemic medium dose vaccine, with adjuvant
Group 3: Flu H5 Egg Pandemic high dose vaccine, with adjuvantEXPERIMENTAL
Participants receive 2 intramuscular injections of flu H5 egg pandemic high dose vaccine, with adjuvant

Interventions

Biological Flu H5 Egg Pandemic high dose vaccine, with adjuvant
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Biological Flu H5 Egg Pandemic high dose vaccine, without adjuvant
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Biological Flu H5 Egg Pandemic medium dose vaccine, with adjuvant
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Biological Flu H5 egg pandemic low dose vaccine, with adjuvant
Pharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)

Outcome measures

Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Primary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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
Secondary outcome
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

Dates

Dates
Start date	August 3, 2026 (actual)
Primary completion	February 22, 2028 (estimated)
Completion	February 22, 2028 (estimated)
First posted	August 21, 2026 (actual)
Last updated	September 15, 2026
Results posted	Not stated in the registry record
Status last verified	September 2026

Actual means the event happened. Estimated means the sponsor expects it. The two mean different things.

Locations

16 sites are recruiting

United States

United States
Facility	City	State or region	Status
Charlottesville Medical Research- Site Number : 8400016	Charlottesville	Virginia	Recruiting
Alliance for Multispeciality Research - Coral Gables- Site Number : 8400003	Coral Gables	Florida	Recruiting
Accel Research Sites Network - DeLand Clinical Research Unit- Site Number : 8400017	DeLand	Florida	Recruiting
iResearch Atlanta- Site Number : 8400008	Decatur	Georgia	Recruiting
Accel Research Sites - NeuroStudies- Site Number : 8400014	Decatur	Georgia	Recruiting
Alliance for Multispeciality Research - Fort Myers- Site Number : 8400001	Fort Myers	Florida	Recruiting
Alliance for Multispecialty Research - Weisgarber Medical Park- Site Number : 8400002	Knoxville	Tennessee	Recruiting
Indago Research & Health Center- Site Number : 8400010	Miami Lakes	Florida	Recruiting
AMR Clinical Newton, Kansas- Site Number : 8400006	Newton	Kansas	Recruiting
Coastal Carolina Research Center - North Charleston- Site Number : 8400018	North Charleston	South Carolina	Recruiting
AMR Chicago- Site Number : 8400005	Oak Brook	Illinois	Recruiting
Rochester Clinical Research- Site Number : 8400012	Rochester	New York	Recruiting
Peninsula Research Associates- Site Number : 8400011	Rolling Hills Estates	California	Recruiting
CenExel JRB - Salth Lake City- Site Number : 8400009	Salt Lake City	Utah	Recruiting
California Research Foundation- Site Number : 8400007	San Diego	California	Recruiting
AMR Clinical Phoenix, Arizona- Site Number : 8400004	Tempe	Arizona	Recruiting

Study documents

No documents are linked in this registry record.

Changes over time

September 15, 2026
Status changed
Status changed from Not yet recruiting to Recruiting
NOT_YET_RECRUITINGRECRUITING
September 15, 2026
Recruitment opened
Recruitment opened
NOT_YET_RECRUITINGRECRUITING
September 15, 2026
Site added
16 sites added (16 total)
016

Registry: ClinicalTrials.gov · NCT########

https://xmedica.io/trials/ctgov/NCT07779408

Categories

Registered in 1 registry

Interested in this study?

How this study is set up

Summary

Conditions

Eligibility

Eligibility as written in the registry

Eligibility in plain statements

Study design

Sponsor and collaborators

Arms and interventions

Interventions

Outcome measures

Dates

Locations

United States

Study documents

Changes over time