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Influenza A/Victoria/4897/2022 Ivr-238 (H1N1), Inactivated

This article examines several clinical trials investigating the use of the Influenza A/Victoria/4897/2022 IVR-238 (H1N1), Inactivated vaccine. These studies aim to assess the safety, efficacy, and immune responses generated by this influenza vaccine in various populations and contexts. The trials cover topics such as vaccine combinations, timing of administration, and effects on specific patient groups like those with coronary artery disease.

Table of Contents

What is this influenza vaccine?

The influenza A/Victoria/4897/2022 IVR-238 (H1N1) inactivated vaccine is a component of several quadrivalent (four-strain) influenza vaccines developed for the 2023-2024 flu season[1]. It contains an inactivated form of the influenza A H1N1 virus strain that was predicted to circulate. This particular strain is named after Victoria, Australia where it was first isolated in 2022.

This vaccine is included in products like VaxigripTetra, Influvac Tetra, and Fluad Tetra, which are designed to protect against four different influenza virus strains[2][3][4]. The other strains typically include another influenza A subtype (H3N2) and two influenza B virus lineages.

How does it work?

As an inactivated vaccine, it contains killed influenza virus particles. When injected, these particles stimulate the immune system to produce antibodies against that specific strain of flu virus. If the vaccinated person later encounters the live virus, their immune system is primed to recognize and fight it off more effectively, reducing the risk of infection or severity of illness.

The inactivation process ensures the vaccine cannot cause influenza, as the virus particles are no longer capable of replication or causing disease[1].

Who is this vaccine for?

This influenza vaccine is generally recommended for individuals aged 6 months and older, with a particular focus on:

  • Adults aged 65 years and older
  • People with certain chronic medical conditions
  • Pregnant women
  • Healthcare workers
  • Caregivers of high-risk individuals

Some formulations, like Fluad Tetra, are specifically designed for older adults (65+) and contain an adjuvant to boost immune response[4].

How effective is it?

The effectiveness of influenza vaccines can vary from year to year, depending on how well the selected strains match the circulating viruses. Generally, when there is a good match, flu vaccines can reduce the risk of illness by 40-60%[5].

Ongoing studies are evaluating the specific effectiveness of vaccines containing the A/Victoria/4897/2022 IVR-238 (H1N1) strain for the 2023-2024 season. Early results from clinical trials show promising immune responses, but real-world effectiveness data will be collected throughout the flu season.

How is it administered?

The vaccine is typically given as a single dose via intramuscular injection, usually in the upper arm (deltoid muscle) for adults and older children, or the thigh for infants[2][3]. Some specific administration details include:

  • Dosage: 0.5 ml for most formulations
  • Timing: Ideally given before the start of flu season (usually September-November in the Northern Hemisphere)
  • Frequency: Annual vaccination is recommended due to evolving flu strains and waning immunity

What are the potential side effects?

Most side effects of influenza vaccines containing the A/Victoria/4897/2022 IVR-238 (H1N1) strain are mild and short-lived. Common side effects may include[2][3][4]:

  • Pain, redness, or swelling at the injection site
  • Headache
  • Fatigue
  • Muscle aches
  • Low-grade fever

Serious allergic reactions are rare but can occur. Patients should seek immediate medical attention if they experience symptoms of a severe allergic reaction, such as difficulty breathing, rapid heartbeat, or dizziness.

Ongoing research

Several clinical trials are currently underway to further evaluate vaccines containing the A/Victoria/4897/2022 IVR-238 (H1N1) strain:

  • A study is examining the effect of influenza vaccination timing on immune responses in adults aged 65 and over[3].
  • Another trial is investigating the impact of influenza vaccination on inflammatory markers in patients with stable coronary artery disease[6].
  • Researchers are also studying the co-administration of COVID-19 and influenza vaccines in older adults[4].

These ongoing studies aim to optimize vaccination strategies and understand the broader health impacts of influenza immunization, particularly in vulnerable populations.

Trial Aspect Details
Vaccine Types Influenza A/Victoria/4897/2022 IVR-238 (H1N1), Inactivated; often part of quadrivalent influenza vaccines
Study Populations Healthy adults (18-85 years), older adults (65+ years), patients with stable coronary artery disease
Primary Outcomes Antibody responses, safety profile, reactogenicity
Secondary Outcomes T cell responses, long-term immunity, effects on inflammatory markers
Study Designs Randomized controlled trials, some with delayed-start or co-administration designs
Special Focus Areas Co-administration with COVID-19 vaccines, timing of vaccination, effects in cardiovascular patients
Follow-up Periods Ranging from 28 days to 6 months post-vaccination
Safety Monitoring Adverse events, serious adverse events, local and systemic reactions

FAQ

  • What is the main purpose of these clinical trials? The main purpose of these clinical trials is to evaluate the safety, efficacy, and immune responses generated by the Influenza A/Victoria/4897/2022 IVR-238 (H1N1), Inactivated vaccine in different populations and contexts.
  • Who are the typical participants in these trials? Participants in these trials vary but generally include healthy adults, older adults (aged 65 and over), and in some cases, patients with specific conditions like stable coronary artery disease. The age range can be from 18 to 85 years old, depending on the specific trial.
  • What are some of the key outcomes being measured? Key outcomes being measured include antibody responses to the vaccine, T cell responses, safety and reactogenicity (side effects), and in some cases, the impact on inflammatory markers or protection against influenza infection.
  • Are there any combination vaccine studies? Yes, some trials are investigating the co-administration of the influenza vaccine with other vaccines, such as COVID-19 vaccines, to assess their combined efficacy and safety.
  • How long do these clinical trials typically last? The duration of these trials varies, but they often include follow-up periods ranging from 28 days to 6 months after vaccination to assess both short-term and longer-term outcomes.

Ongoing Clinical Trials on Influenza A/Victoria/4897/2022 Ivr-238 (H1N1), Inactivated

  • 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 on Antibody Responses in Healthy Individuals After Intranasal and Intramuscular Influenza Vaccination with Fluenz Tetra and Vaxigrip Tetra

    Recruiting

    3 1 1 1
    Investigated drugs:
    The Netherlands

  • Study on the Effect of Influenza Vaccine on Heart Inflammation After Heart Attack for Patients with Myocardial Infarction

    Recruiting

    3 1 1
    Investigated diseases:
    Investigated drugs:
    Denmark Sweden

  • Study of Flu Vaccine and Pembrolizumab for Patients with Early Colorectal Cancer

    Recruiting

    2 1 1 1
    Investigated diseases:
    Investigated drugs:
    Denmark

  • Testing the Immune Response to Trivalent Inactivated Influenza Vaccine in People with Obesity and Type 2 Diabetes

    Not yet recruiting

    3 1 1 1
    Investigated diseases:
    Investigated drugs:
    Sweden

  • Study of Influenza Vaccine Effects on Immune Response in the Nose and Airways in Adults Seeking Protection Against Seasonal Flu

    Not recruiting

    3 1 1 1
    Investigated drugs:
    France

  • 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 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 Influenza Immunity: Comparing Nasal FluMist and Injectable Vaxigriptetra Vaccines for Adults

    Not recruiting

    3 1 1
    Investigated diseases:
    Investigated drugs:
    Denmark

Glossary

  • Influenza A/Victoria/4897/2022 IVR-238 (H1N1), Inactivated: A specific strain of influenza virus used in vaccine formulations. It is inactivated, meaning the virus has been treated to prevent it from causing infection while still stimulating an immune response.
  • Reactogenicity: The ability of a vaccine to produce common, expected adverse reactions, particularly excessive immunological responses and associated signs and symptoms, such as fever and sore arm at the injection site.
  • Immunogenicity: The ability of a substance, such as a vaccine, to provoke an immune response in the body.
  • Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating a response to vaccination or infection.
  • Geometric Mean Titer (GMT): A measure of the average antibody level in a group of subjects, calculated using the geometric mean to reduce the impact of outliers.
  • T cell response: The activation of T lymphocytes (a type of white blood cell) in response to a specific antigen, such as a vaccine component.
  • Adjuvant: A substance added to a vaccine to enhance the body's immune response to the vaccine.
  • Hemagglutination inhibition titer: A laboratory test used to measure the level of antibodies that can prevent the influenza virus from attaching to red blood cells.
  • Coronary artery disease: A condition where the major blood vessels that supply the heart become damaged or diseased, often due to plaque buildup.
  • hsCRP: High-sensitivity C-reactive protein, a marker of inflammation in the body often used to assess cardiovascular risk.

References

  1. http://clinicaltrials.eu/trial-id/2022-502308-66-00
  2. http://clinicaltrials.eu/trial-id/2023-509178-44-00
  3. http://clinicaltrials.eu/trial-id/2024-513558-30-00
  4. http://clinicaltrials.eu/trial-id/2024-514798-23-00
  5. http://clinicaltrials.eu/trial-id/2023-503228-17-00
  6. http://clinicaltrials.eu/trial-id/2024-514543-28-00