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H5N8 pandemic influenza vaccine (adjuvanted)

Phase 1

Healthy Volunteers | Vaccine | Infectious Disease |Sanofi|Last Updated: Sep 15, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLED
Total Trials1
Total Enrollment640

FDA Designations

No designations recorded

Clinical trial landscape

H5N8 pandemic influenza vaccine (adjuvanted) · 1 trial · 2 indications

Phase 1 1
NCT07779408Study 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.Healthy Volunteers
RECRUITING640 Analytics
PHASE1RECRUITING
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.
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Study Endpoints

Primary Endpoints

Number of participants with immediate Adverse Events (AEs)
Within 30 minutes after each vaccination

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

Number of participants experiencing solicited administration site reactions (pre-listed in the participant diary and case report form [CRF])
Within 8 days of each vaccination, including the day of vaccination

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

Number of participants experiencing solicited systemic reactions (pre-listed in the participant diary and CRF)
Within 8 days of each vaccination, including the day of vaccination

All solicited reactions that are not solicited injection or administration site reactions

Number of participants experiencing unsolicited AEs
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

Unsolicited AE: an observed AE that does not fulfill the conditions of solicited reactions

Number of participants experiencing Medically Attended Adverse Events (MAAEs)
From Day 01 until the end of the study, approximately 14 months

MAAEs are collected throughout the study

Number of participants experiencing Adverse Events of Special Interest (AESIs)
From Day 01 until the end of the study, approximately 14 months

AESIs are collected throughout the study

Number of participants experiencing Serious Adverse Events (SAEs)
From Day 01 until the end of the study, approximately 14 months

SAEs are collected throughout the study

Number of participants experiencing out-of-range biological test results (including shift from baseline values)
Up to 8 days after each vaccination

Safety laboratory assessments will include clinical chemistry and hematology

Number of participants experiencing AEs leading to discontinuation
From Day 01 until the end of the study, approximately 14 months

AEs leading to discontinuation are collected throughout the study

Geometric mean titer of hemagglutination inhibition (HAI) assay antibody (Ab) titer
Day 01 and Day 43

Influenza vaccine antibody titers are measured by HAI assay

Number of participants with HAI Ab titer ≥ 40 (1 dilution [dil]; ie, seroprotection)
Day 43

Influenza vaccine antibody titers are measured by HAI assay

Number of participants with seroconversion
Day 01 and Day 43

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

Geometric mean titer ratio of individual HAI Ab titer ratio Day 43/Day 01
Day 01 and Day 43

Influenza vaccine antibody titers are measured by HAI assay

Secondary Endpoints

Geometric mean titer of hemagglutination inhibition (HAI) assay antibody (Ab) titer obtained on Day 01, Day 22, Day 43, Day 202
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
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
Day 01, Day 22, Day 43, Day 202
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

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

Interventions

NameTypeDescription
Flu H5 egg pandemic low dose vaccine, with adjuvantBIOLOGICALPharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Flu H5 Egg Pandemic medium dose vaccine, with adjuvantBIOLOGICALPharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Flu H5 Egg Pandemic high dose vaccine, with adjuvantBIOLOGICALPharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
Flu H5 Egg Pandemic high dose vaccine, without adjuvantBIOLOGICALPharmaceutical form: Suspension for injection Route of administration: Intramuscular (IM)
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersYes
Study Sites16

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 ...

Countries:United States
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Recent Changes (Last 90 Days)

LOWSep 16, 2026NCT07779408Status: NOT_YET_RECRUITING → RECRUITING
LOWSep 16, 2026NCT07779408Status: NOT_YET_RECRUITING → RECRUITING
LOWSep 16, 2026NCT07779408Status: NOT_YET_RECRUITING → RECRUITING
LOWSep 16, 2026NCT07779408Status: NOT_YET_RECRUITING → RECRUITING
LOWAug 21, 2026NCT07779408NEW_TRIAL: changed
LOWAug 21, 2026NCT07779408NEW_TRIAL: changed

Frequently asked questions about H5N8 pandemic influenza vaccine (adjuvanted)

What is the H5N8 pandemic influenza vaccine (adjuvanted)?

The H5N8 pandemic influenza vaccine (adjuvanted) is an investigational egg-based vaccine designed to protect against H5N8 pandemic influenza. It is given with an adjuvant called Matrix-M and is being studied in healthy adult volunteers. It is not an approved product and remains in clinical development.

What is the H5N8 pandemic influenza vaccine (adjuvanted) used for?

It is being developed for prevention of influenza caused by the H5N8 virus, a pandemic-potential avian influenza strain. The current study enrolls healthy volunteers 18 years of age and above, including those with and without underlying conditions, to assess whether the vaccine is safe and generates an immune response.

Who is developing the H5N8 pandemic influenza vaccine (adjuvanted)?

Sanofi, which trades under the ticker SNY, is the developer of the H5N8 pandemic influenza vaccine (adjuvanted). The vaccine uses an egg-based manufacturing approach and is combined with the Matrix-M adjuvant in the clinical program.

What phase is the H5N8 pandemic influenza vaccine (adjuvanted) in?

The H5N8 pandemic influenza vaccine (adjuvanted) is in Phase 1 clinical development. It is investigational and has not been approved by the FDA. The single Phase 1 trial is currently recruiting participants in the United States.

What clinical trials is the H5N8 pandemic influenza vaccine (adjuvanted) in?

It is being evaluated in one Phase 1 trial, NCT07779408, titled a 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. The trial is recruiting, is randomized, double-blind, and controlled, and plans to enroll 640 participants in the United States.