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Influenza Virus A/Thailand/8/2022 (H3N2) Ivr-237-Like Strain (A/Thailand/8/2022)

This article provides an overview of clinical trials investigating the use of the Influenza Virus A/Thailand/8/2022 (H3N2) strain in seasonal influenza vaccines. These studies aim to evaluate the safety, efficacy, and immunogenicity of new vaccine formulations containing this strain compared to existing licensed vaccines. The trials focus on adult populations, particularly those aged 65 and older, who are at higher risk for flu complications.

Table of Contents

What is INFLUENZA VIRUS A/THAILAND/8/2022 (H3N2) IVR-237-LIKE STRAIN (A/THAILAND/8/2022)?

INFLUENZA VIRUS A/THAILAND/8/2022 (H3N2) IVR-237-LIKE STRAIN (A/THAILAND/8/2022) is a component of influenza vaccines designed to protect against a specific strain of the influenza virus[1]. This strain is part of the H3N2 subtype of influenza A viruses, which are known to cause seasonal flu epidemics in humans.

The name of this strain provides important information:

  • “A” indicates it’s an influenza A virus
  • “Thailand” refers to where the virus was first isolated
  • “8/2022” likely indicates it was the 8th isolate in 2022
  • “H3N2” describes the specific proteins on the virus surface
  • “IVR-237-like” suggests it’s similar to a laboratory reference strain

How does it work?

This strain is included in influenza vaccines to stimulate the immune system to produce antibodies against the H3N2 virus. When your body encounters the actual virus later, it can recognize and fight it off more effectively, reducing your chances of getting sick or experiencing severe symptoms[1].

Clinical Trials and Research

Clinical trials are being conducted to evaluate the effectiveness of vaccines containing this strain. One such study is a Phase 3/3b trial comparing an MF59-adjuvanted subunit inactivated influenza vaccine to a non-adjuvanted influenza vaccine in adults aged 65 and older[1].

The main objectives of this study include:

  • Demonstrating the efficacy of the adjuvanted vaccine in preventing RT-PCR-confirmed influenza A and/or B disease
  • Evaluating the safety of the adjuvanted vaccine
  • Assessing the immunogenicity (ability to provoke an immune response) of the adjuvanted vaccine compared to the non-adjuvanted vaccine

Another ongoing study is investigating an mRNA-based influenza vaccine (mRNA-1010) compared to a licensed inactivated seasonal influenza vaccine in adults aged 50 and older[2]. This study aims to evaluate the safety, efficacy, and immunogenicity of the mRNA vaccine.

How is it administered?

The vaccine containing this influenza strain is typically administered as an intramuscular injection. The usual dose is 0.5 ml, given once per flu season[1][2]. It’s often delivered using a pre-filled syringe for convenience and accuracy.

Who can receive this vaccine?

The specific vaccines containing this strain are being studied in adults aged 65 and older, as well as those 50 and older, depending on the particular clinical trial[1][2]. However, the exact approved age range may vary based on the final study results and regulatory approvals.

Some people who should not receive the vaccine include:

  • Those with severe allergies to vaccine components
  • Individuals with a history of severe reactions to previous influenza vaccinations
  • People with certain medical conditions (always consult your healthcare provider)

Potential Side Effects

While specific side effects for this particular strain are not detailed in the provided information, common side effects of influenza vaccines may include:

  • Pain, redness, or swelling at the injection site
  • Low-grade fever
  • Mild body aches

Serious side effects are rare but can occur. The clinical trials mentioned are closely monitoring for any adverse events[1][2].

Effectiveness

The effectiveness of this specific strain in preventing influenza is being studied in the ongoing clinical trials. The researchers are looking at various measures of effectiveness, including:

  • Prevention of laboratory-confirmed influenza
  • Reduction in influenza-like illness (ILI) symptoms
  • Immune response as measured by antibody levels

Results from these studies will provide more information about how well this strain protects against the current circulating H3N2 viruses[1][2].

Conclusion

The INFLUENZA VIRUS A/THAILAND/8/2022 (H3N2) IVR-237-LIKE STRAIN (A/THAILAND/8/2022) is an important component of current influenza vaccines. Ongoing research aims to improve vaccine effectiveness and explore new vaccine technologies. As always, consult with your healthcare provider to determine if vaccination is appropriate for you and to address any concerns you may have.

Aspect Trial 2022-503004-24-00 Trial 2024-516240-26-00
Study Type Phase 3/3b, Randomized, Observer-blind Phase 3, Randomized, Observer-blind
Primary Objective Efficacy of MF59-adjuvanted vaccine vs non-adjuvanted vaccine Safety, reactogenicity, and relative vaccine efficacy of mRNA-1010
Target Population Adults ≥65 years Adults ≥50 years
Primary Endpoint RT-PCR-confirmed influenza prevention Adverse reactions, RT-PCR confirmed ILI
Vaccine Type MF59-adjuvanted subunit inactivated vs non-adjuvanted mRNA-1010 vs licensed inactivated vaccine
Duration One influenza season Approximately 181 days

FAQ

  • What is the purpose of these clinical trials? The main purpose is to evaluate the safety, efficacy, and immune response of new influenza vaccine formulations containing the A/Thailand/8/2022 (H3N2) strain compared to existing licensed vaccines.
  • Who are the target participants for these trials? The trials primarily focus on adults, with one study specifically targeting adults aged 65 and older, and another including adults 50 years and older. These age groups are at higher risk for flu complications.
  • What are the main outcomes being measured? The trials are measuring the prevention of influenza illness, immune response (antibody levels), and safety outcomes such as adverse events and reactions to the vaccines.
  • How long do the trials last? The trials typically last for one influenza season, which is approximately 6 months (181 days) from the time of vaccination.
  • What types of vaccines are being compared? The trials are comparing new formulations, such as MF59-adjuvanted vaccines or mRNA vaccines, to standard non-adjuvanted influenza vaccines currently licensed for use.

Ongoing Clinical Trials on Influenza Virus A/Thailand/8/2022 (H3N2) Ivr-237-Like Strain (A/Thailand/8/2022)

  • Study on Immune Responses to Avian Influenza Vaccine with A/Turkey/Turkey/1/05 (H5N1)-Like Strain in Patients with Avian and Seasonal Influenza

    Recruiting

    3 1 1 1
    Investigated diseases:
    Investigated drugs:
    Finland

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

    Not recruiting

    2 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium

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

    Not recruiting

    2 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium

  • Study on the Effectiveness of an MF59-Adjuvanted Influenza Vaccine Compared to a Non-Adjuvanted Vaccine in Adults Aged 65 and Older

    Not recruiting

    3 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium Bulgaria Czechia Finland Italy Lithuania +4

  • Study of mRNA-1010 Influenza Vaccine Compared to Standard Flu Vaccine in Adults 50 Years and Older

    Not recruiting

    3 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium Bulgaria Estonia Finland Germany

Glossary

  • Adjuvant: A substance added to a vaccine to enhance the body's immune response, potentially allowing for a lower dose of the vaccine or improved efficacy.
  • Efficacy: The ability of a vaccine to produce a desired effect under ideal conditions, typically measured in clinical trials.
  • Hemagglutination Inhibition (HAI) Assay: A laboratory test used to measure antibodies against influenza viruses, which helps determine the immune response to vaccination.
  • Immunogenicity: The ability of a substance, such as a vaccine, to provoke an immune response in the body.
  • Influenza-Like Illness (ILI): A set of symptoms similar to those caused by influenza, which may be used to define cases in clinical trials.
  • mRNA Vaccine: A type of vaccine that uses genetic material called messenger RNA to instruct cells to produce proteins that trigger an immune response.
  • RT-PCR: Reverse Transcription Polymerase Chain Reaction, a laboratory technique used to detect and confirm the presence of influenza virus genetic material.
  • Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating an immune response to vaccination or infection.

References

  1. http://clinicaltrials.eu/trial-id/2022-503004-24-00
  2. http://clinicaltrials.eu/trial/study-on-the-safety-and-effectiveness-of-mrna-1010-influenza-vaccine-compared-to-a-licensed-vaccine-for-adults-aged-50-and-older/