INFLUENZA A VIRUS SUBTYPE H3N2 HAEMAGGLUTININ, RECOMBINANT

Clinical trials are studying INFLUENZA A VIRUS SUBTYPE H3N2 HAEMAGGLUTININ, RECOMBINANT as part of influenza vaccine research. These studies mainly look at immune response, safety, and how well the vaccine works in adults, including people 18 years and older and adults 50 years and older, with some healthy people and some with stable health conditions.

Table of Contents

Trial overview

The trials in this data set study INFLUENZA A VIRUS SUBTYPE H3N2 HAEMAGGLUTININ, RECOMBINANT as part of influenza vaccine research in adults.[1] The studies focus on whether the vaccine helps the body make antibodies and whether it is safe and well tolerated.[1] The research includes both Phase 2 and Phase 3 studies.[1][2]

Who participates in these studies

One Phase 2 study includes adults 18 years of age and older with influenza, human.[1] Another Phase 2 study also includes adults 18 years and older, and it compares different vaccine groups.[3] The Phase 3 study focuses on adults 50 years and older, including healthy people and people with stable comorbidities, which means long-term health conditions that do not change quickly.[2]

What the trials measure

The main immune measures are antibody titer, fold increase in antibody levels, seroconversion, and seroprotection.[1][3] These measures show whether the vaccine causes the body to build a response against influenza.[1][3] The studies also measure safety outcomes such as solicited administration site or systemic events, unsolicited adverse events, serious adverse events, adverse events of special interest, medically attended adverse events, and laboratory abnormalities.[1][3]

The Phase 3 study uses hemagglutination inhibition (HI) assay results to compare immune responses across vaccine lots and between vaccines.[2] It reports outcomes such as geometric mean titers and seroconversion rates at Day 29.[2] This helps researchers compare how strong the immune response is after vaccination.[2]

Trial phases and study design

The Phase 2 studies are interventional trials, which means researchers assign study interventions and then measure the results.[1][3] These studies mainly look at humoral immune response, which means the antibody response in the blood, and safety/reactogenicity, which means how the body reacts after vaccination.[1][3] The Phase 3 study is designed to first show lot-to-lot consistency and then compare immunological noninferiority against other influenza vaccines.[2]

Noninferiority means the study is checking whether one vaccine performs at least as well as another by a pre-set rule, rather than trying to prove it is better.[2] Lot-to-lot consistency means different production batches of the same vaccine are compared to see if they give similar immune responses.[2]

Main trials in the data

NCT07204964 is a Phase 2 study in adults 18 years and older with influenza, human.[1] It is authorised and has an enrollment of 960 participants.[1] The study measures antibody response at Day 29 and safety events over days to months after vaccination.[1]

2023-503763-42-00, called the Celljuvant study, is a Phase 3 study in adults 50 years and older.[2] It is completed and enrolled 6,300 participants.[2] The study compares three lots of the vaccine and then compares the vaccine with other influenza vaccines using HI assay results at Day 29.[2]

2025-522278-35-00 is another Phase 2 study in adults 18 years and older with influenza, human.[3] It is completed and enrolled 770 participants.[3] The study looks at immune response and safety, including antibody titer, seroconversion, seroprotection, and different safety events.[3]

Patient glossary

Adjuvanted vaccine means a vaccine that includes an added ingredient to help improve the immune response.[2] Intramuscular use means the vaccine is given into a muscle.[1][3] Injection and injection site events refer to the shot and any local reactions where it is given.[2][3]

Humoral immune response means the antibody response in the blood.[1][3] Safety and reactogenicity profile means the pattern of side effects and body reactions seen after the study intervention.[1][3] Stable comorbidities means other health problems that are not changing quickly.[2]

Trial ID Phase Condition studied Status Enrollment
NCT07204964 Phase 2 Influenza, Human Authorised 960
2023-503763-42-00 Phase 3 Healthy individuals or individuals with stable comorbidities which increase their risk of complications from influenza infection Completed 6300
2025-522278-35-00 Phase 2 Influenza, Human Completed 770

Ongoing Clinical Trials on INFLUENZA A VIRUS SUBTYPE H3N2 HAEMAGGLUTININ, RECOMBINANT

  • Study of mRNA-based seasonal influenza vaccine to evaluate immune response and safety in adults 18 years and older

    Not recruiting

    1 1 1
    Investigated diseases:
    Belgium
  • Study of mRNA-based seasonal influenza vaccine combinations compared to standard influenza vaccines in adults aged 18 and older

    Not recruiting

    1 1 1
    Investigated diseases:
    Belgium
  • Study on the Safety and Immune Response of aQIVc HD Vaccine Compared to a Drug Combination for Adults 50 Years and Older at Risk of Flu Complications

    Not recruiting

    1 1 1 1
    Investigated diseases:
    Denmark Estonia Germany

Glossary

  • Antibody titer: A measure of how much antibody is in the blood. Higher levels can mean a stronger immune response.
  • Seroconversion: A change from a low or negative antibody level to a higher one after vaccination. It shows the body has responded.
  • Seroprotection: A blood antibody level that is thought to give protection against infection.
  • Geometric mean titer (GMT): An average way to describe antibody levels in a group. It is often used in vaccine studies.
  • Hemagglutination inhibition (HI) assay: A lab test used to measure antibodies against influenza.
  • Reactogenicity: The short-term, expected body reactions after vaccination, such as local or general symptoms.
  • Solicited events: Side effects that the study team asks participants to report because they are expected or commonly monitored.
  • Unsolicited adverse events: Any unwanted medical events that are reported even if the study did not specifically ask about them.
  • Serious adverse events (SAEs): Medical problems that are severe, such as those causing hospital care or being life-threatening.
  • Adverse events of special interest (AESIs): Side effects that the study watches closely because they may be especially important for that vaccine or study.
  • Medically attended adverse events (MAAEs): Health problems that lead a person to seek medical care.

References

  1. https://clinicaltrials.eu/trial/study-of-mrna-based-seasonal-influenza-vaccine-to-evaluate-immune-response-and-safety-in-adults-18-years-and-older/
  2. https://clinicaltrials.gov/study/2023-503763-42-00
  3. https://clinicaltrials.gov/study/2025-522278-35-00