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A/Victoria/4897/2022 (H1N1)Pdm09-Like Strain (A/Victoria/4897/2022, Ivr-238)

This article summarizes clinical trials investigating the use of influenza vaccines containing the A/Victoria/4897/2022 (H1N1)pdm09-like strain. These trials aim to evaluate the safety, efficacy, and immunogenicity of various influenza vaccine formulations in different age groups. The studies compare adjuvanted and non-adjuvanted vaccines, as well as novel mRNA-based vaccines, to assess their potential in preventing seasonal influenza.

Table of Contents

What is A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN?

A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN (A/VICTORIA/4897/2022, IVR-238) is a specific strain of the influenza virus used in the development of flu vaccines[1]. This strain is part of the H1N1 subtype, which is known for causing the 2009 swine flu pandemic. The term “PDM09” refers to the pandemic strain that emerged in 2009.

This particular strain is included in various influenza vaccines to provide protection against the H1N1 virus that is expected to circulate in the upcoming flu season. It’s important to note that flu viruses constantly evolve, which is why vaccine compositions are updated annually based on surveillance data and predictions about which strains will be most prevalent.

What is the purpose of this vaccine?

The primary purpose of including the A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN in flu vaccines is to prevent influenza infection caused by the H1N1 virus[2]. Influenza, commonly known as the flu, is a contagious respiratory illness that can cause mild to severe illness, and in some cases, can lead to hospitalization or even death, particularly in high-risk groups such as older adults, young children, and people with certain health conditions.

By including this strain in the vaccine, the goal is to stimulate the immune system to produce antibodies that can recognize and fight off the H1N1 virus if a person is exposed to it. This helps to reduce the risk of infection, and if infection does occur, it may help to reduce the severity of symptoms.

Current Clinical Trials

Several clinical trials are currently underway to evaluate vaccines containing the A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN. These trials aim to assess the safety, efficacy, and immunogenicity of various influenza vaccine formulations. Here are some notable studies:

  • A Phase 1/2 trial is evaluating mRNA-based multivalent seasonal influenza vaccine candidates in healthy younger and older adults[1]. This study is exploring new mRNA technology for flu vaccines, which could potentially offer advantages over traditional vaccine production methods.
  • A Phase 3/3b study is comparing an MF59-adjuvanted subunit inactivated influenza vaccine to a non-adjuvanted influenza vaccine in adults aged 65 and older[3]. This trial aims to demonstrate the efficacy of the adjuvanted vaccine in preventing RT-PCR-confirmed influenza A and/or B disease.
  • Another Phase 3 study is investigating the safety, efficacy, and immunogenicity of an mRNA-1010 candidate seasonal influenza vaccine compared to a licensed inactivated seasonal influenza vaccine in adults 50 years of age and older[4]. This study is particularly focused on evaluating the relative vaccine efficacy (rVE) against influenza-like illness (ILI) caused by any influenza A or B strains.

How is the vaccine administered?

The A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN is typically included in influenza vaccines that are administered via intramuscular injection[2]. Most commonly, these vaccines are given as a single dose of 0.5 ml. The injection is usually given in the upper arm (deltoid muscle) for adults and older children, or in the thigh for infants and young children.

It’s important to note that the specific administration details may vary depending on the particular vaccine formulation and the age group it’s intended for. Always follow the instructions provided by your healthcare provider or the vaccine manufacturer.

Safety and Side Effects

The safety profile of vaccines containing the A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN is generally similar to that of other influenza vaccines. Common side effects may include[1][4]:

  • Pain, redness, or swelling at the injection site
  • Fatigue
  • Headache
  • Muscle aches
  • Fever (usually low-grade)

These side effects are typically mild and resolve within a few days. Serious allergic reactions are rare but can occur. If you experience symptoms of a severe allergic reaction (such as difficulty breathing, rapid heartbeat, or dizziness) after receiving the vaccine, seek medical attention immediately.

Clinical trials are closely monitoring the safety of new vaccine formulations, including those using mRNA technology or adjuvants. These studies will provide more detailed information about the safety profile of these specific vaccine formulations[1][3][4].

Effectiveness of the Vaccine

The effectiveness of influenza vaccines can vary from year to year, depending on how well the vaccine strains match the circulating viruses. However, even when the match is not perfect, vaccination can still provide significant protection against severe illness, hospitalization, and death from influenza[2].

Current clinical trials are evaluating the effectiveness of various vaccine formulations containing the A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN. These studies are measuring effectiveness in several ways, including[3][4]:

  • Prevention of RT-PCR-confirmed influenza
  • Prevention of influenza-like illness (ILI)
  • Immune response as measured by antibody levels (hemagglutination inhibition titers)

The results of these trials will provide more specific information about the effectiveness of vaccines containing this particular strain.

Who can receive this vaccine?

Influenza vaccines containing the A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN are generally recommended for most people aged 6 months and older. However, specific recommendations may vary depending on the particular vaccine formulation.

Some of the current clinical trials are focusing on specific age groups:

  • Adults aged 65 and older[3]
  • Adults aged 50 and older[4]
  • Both younger and older adults[1]

It’s important to consult with a healthcare provider to determine if you should receive the influenza vaccine, as there may be certain contraindications or precautions based on individual health conditions or circumstances.

Conclusion

The A/VICTORIA/4897/2022 (H1N1)PDM09-LIKE STRAIN is an important component of current influenza vaccines, designed to protect against the H1N1 subtype of the influenza virus. While it’s part of many standard flu vaccines, it’s also being studied in new vaccine formulations that may offer improved effectiveness or other benefits. Ongoing clinical trials will provide more information about the safety, efficacy, and immunogenicity of these vaccines. As always, the decision to receive a flu vaccine should be made in consultation with a healthcare provider, taking into account individual health status and risk factors.

Trial Characteristic Details
Vaccine Types Inactivated influenza vaccines, MF59-adjuvanted vaccines, mRNA-based vaccines
Age Groups 18-50 years, 18-85 years, ≥65 years
Primary Objectives Safety, reactogenicity, efficacy, immunogenicity
Key Endpoints Adverse events, antibody responses, confirmed influenza cases
Study Designs Randomized, observer-blind, active-controlled
Duration Typically one influenza season (approximately 6 months)
Special Considerations Co-administration with COVID-19 vaccines, focus on older adult populations

FAQ

  • What is the A/Victoria/4897/2022 (H1N1)pdm09-like strain? The A/Victoria/4897/2022 (H1N1)pdm09-like strain is a specific influenza virus strain used in seasonal flu vaccines. It represents a variant of the H1N1 influenza subtype that is similar to the 2009 pandemic strain and is included in current vaccine formulations to provide protection against circulating H1N1 viruses.
  • What types of vaccines are being studied in these clinical trials? The clinical trials are studying various types of influenza vaccines, including traditional inactivated vaccines, MF59-adjuvanted vaccines, and novel mRNA-based vaccines. Some trials are also investigating the co-administration of influenza vaccines with COVID-19 vaccines.
  • Who are the target populations for these vaccine trials? The trials target different age groups, including healthy adults aged 18-50, adults aged 18-85, and older adults aged 65 and over. Some studies specifically focus on the elderly population, who are at higher risk of complications from influenza.
  • What are the main objectives of these clinical trials? The main objectives of these trials include evaluating the safety and reactogenicity of the vaccines, assessing their efficacy in preventing influenza, measuring the immune responses they generate, and comparing the performance of different vaccine formulations or administration strategies.
  • How is the effectiveness of these vaccines measured? Vaccine effectiveness is measured through various methods, including monitoring for influenza-like illness, conducting RT-PCR tests to confirm influenza infections, measuring antibody responses through blood tests, and assessing cellular immune responses. Some trials also use statistical measures like relative vaccine efficacy (rVE) to compare different vaccines.

Ongoing Clinical Trials on A/Victoria/4897/2022 (H1N1)Pdm09-Like Strain (A/Victoria/4897/2022, Ivr-238)

  • Study on the Safety and Immune Response of a High-Dose Influenza Vaccine in Adults Aged 60 and Over, Comparing Trivalent Influenza Vaccine with a Drug Combination

    Not recruiting

    3 1 1 1
    Investigated drugs:
    Belgium Bulgaria Estonia Finland Spain

  • Study on the Immune Response of COVID-19 Vaccine Tozinameran with Flu Vaccine Combinations in Adults Aged 65 and Over

    Not recruiting

    2 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium The Netherlands

  • 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 on the Safety and Immune Response of a New Influenza Vaccine with GSKVX000000034794 in Healthy Younger and Older Adults

    Not recruiting

    2 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium

  • 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, especially in older adults.
  • Antibody titer: A measurement of the amount or concentration of antibodies in the blood, used to determine the strength of the immune response to a vaccine or infection.
  • 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 the level of antibodies that can prevent influenza viruses from binding to red blood cells, indicating potential protection against infection.
  • 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, often used as a clinical definition in vaccine studies to identify potential cases of flu.
  • mRNA vaccine: A type of vaccine that uses messenger RNA to instruct cells to produce a protein that triggers an immune response, rather than introducing an inactivated or weakened virus.
  • Reactogenicity: The capacity of a vaccine to produce common, expected adverse reactions, usually mild and self-limited, such as pain at the injection site or fever.
  • RT-PCR: Reverse Transcription Polymerase Chain Reaction, a laboratory technique used to detect and confirm the presence of specific viral genetic material, such as influenza virus RNA.
  • Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating a significant immune response to a vaccine or infection.

References

  1. http://clinicaltrials.eu/trial-id/2022-502308-66-00
  2. http://clinicaltrials.eu/trial-id/2022-503004-24-00
  3. http://clinicaltrials.eu/trial-id/2024-514798-23-00
  4. 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/