A/Victoria/2570/2019 (H1N1)Pdm09-Like Strain (A/Victoria/2570/2019, Ivr-215)

This article summarizes several clinical trials investigating the use of influenza vaccines containing the A/Victoria/2570/2019 (H1N1)pdm09-like strain. These trials aim to evaluate the safety, immunogenicity, and effectiveness of various influenza vaccine formulations in different populations, including older adults, patients with hematological cancers, and the general adult population. The studies compare high-dose and standard-dose vaccines, as well as different administration methods and combinations with other vaccines.

What is A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN?
Role in Influenza Vaccines
Clinical Trials and Research
Effectiveness and Immune Response
Safety Profile
Use in Special Populations
Conclusion

What is A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN?

A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN (A/VICTORIA/2570/2019, IVR-215) is a specific strain of the influenza A virus used in the development of flu vaccines^[1]. This strain is derived from the H1N1 subtype of influenza A, which was responsible for the 2009 swine flu pandemic. The “PDM09” in its name refers to this pandemic origin.

Influenza viruses are constantly evolving, which is why flu vaccines are updated regularly. This particular strain was isolated in Victoria, Australia in 2019 and has been selected for inclusion in recent flu vaccines due to its representation of currently circulating H1N1 viruses.

Role in Influenza Vaccines

This strain is a key component in many quadrivalent (four-strain) influenza vaccines. It’s included to provide protection against H1N1 influenza A viruses that are similar to this strain. Quadrivalent vaccines typically contain:

Two influenza A strains (including this H1N1 strain)
Two influenza B strains

The A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN is found in various flu vaccine formulations, including:

Standard-dose quadrivalent vaccines (like Vaxigrip Tetra and Influvac Tetra)^[1]
High-dose quadrivalent vaccines (like Efluelda)^[2]

Clinical Trials and Research

Several clinical trials have been conducted or are ongoing to evaluate vaccines containing this strain:

A study comparing high-dose and standard-dose quadrivalent influenza vaccines in adults aged 65 and older^[3]
Research on the effectiveness of influenza vaccines in patients with hematological cancers^[4]
Trials evaluating new mRNA-based influenza vaccines that include this strain^[5]

These studies aim to assess the immunogenicity (ability to provoke an immune response) and safety of vaccines containing this strain in various populations.

Effectiveness and Immune Response

The effectiveness of vaccines containing the A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN is typically measured by looking at:

Seroconversion rates: The percentage of people who develop a significant increase in antibodies after vaccination
Geometric mean titers (GMTs): A measure of the average antibody levels in a group of vaccinated individuals

Clinical trials have shown that vaccines containing this strain can elicit a strong immune response in many individuals. However, the strength of the response can vary based on factors such as age, overall health, and the specific vaccine formulation used^[3].

Safety Profile

Vaccines containing the A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN have generally demonstrated a good safety profile in clinical trials. Common side effects may include:

Pain, redness, or swelling at the injection site
Headache
Fatigue
Muscle aches

These side effects are typically mild and resolve within a few days. Serious adverse events are rare^[5].

Use in Special Populations

Research has been conducted on the use of vaccines containing this strain in various populations, including:

Older adults (65 years and above)
Patients with hematological cancers
Individuals with chronic medical conditions

These studies aim to ensure that the vaccine is safe and effective in populations that may be at higher risk for influenza complications^[4].

Conclusion

A/VICTORIA/2570/2019 (H1N1)PDM09-LIKE STRAIN (A/VICTORIA/2570/2019, IVR-215) is an important component of current influenza vaccines, providing protection against circulating H1N1 influenza A viruses. Ongoing research continues to evaluate its effectiveness and safety in various populations and vaccine formulations. As with all influenza vaccines, it’s important to receive annual vaccination to ensure protection against the most current strains.

Trial Characteristic	Details
Vaccine Types	Quadrivalent inactivated influenza vaccines (QIV), High-dose (HD) and Standard-dose (SD) formulations, mRNA-based candidates, Cell-derived and Egg-derived vaccines
Study Populations	Adults aged 50 years and older, Patients with hematological cancers, General adult population
Primary Objectives	Evaluate immunogenicity, safety, and effectiveness of vaccines; Compare HD vs SD formulations; Assess co-administration with other vaccines
Key Outcome Measures	Antibody responses (HI assay), Seroconversion rates, Geometric mean titers, Clinical outcomes (e.g., hospitalization rates)
Special Focus Areas	Older adult populations, Patients with compromised immune systems, Lot-to-lot consistency, Systems biology approaches

Trial Characteristic

Details

Vaccine Types

Quadrivalent inactivated influenza vaccines (QIV), High-dose (HD) and Standard-dose (SD) formulations, mRNA-based candidates, Cell-derived and Egg-derived vaccines

Study Populations

Adults aged 50 years and older, Patients with hematological cancers, General adult population

Primary Objectives

Evaluate immunogenicity, safety, and effectiveness of vaccines; Compare HD vs SD formulations; Assess co-administration with other vaccines

Key Outcome Measures

Antibody responses (HI assay), Seroconversion rates, Geometric mean titers, Clinical outcomes (e.g., hospitalization rates)

Special Focus Areas

Older adult populations, Patients with compromised immune systems, Lot-to-lot consistency, Systems biology approaches

Ongoing Clinical Trials on A/Victoria/2570/2019 (H1N1)Pdm09-Like Strain (A/Victoria/2570/2019, Ivr-215)

Glossary

Quadrivalent influenza vaccine: A type of flu vaccine that protects against four different influenza viruses: two influenza A viruses and two influenza B viruses.
Hemagglutination inhibition (HI) assay: A laboratory test used to measure antibody levels in blood samples, which helps determine the immune response to influenza vaccines.
Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating an immune response to vaccination or infection.
Geometric mean titer (GMT): A measure of the average antibody level in a group of individuals, calculated using the geometric mean of individual antibody titers.
Immunogenicity: The ability of a substance, such as a vaccine, to provoke an immune response in the body.
High-dose vaccine: A vaccine formulation that contains a higher amount of antigen (the substance that stimulates an immune response) compared to the standard-dose vaccine.
mRNA vaccine: A type of vaccine that uses messenger RNA to instruct cells to produce a specific protein, which then triggers an immune response.
Adjuvant: A substance added to vaccines to enhance the body's immune response to the vaccine.
Cell-derived vaccine: A vaccine produced using cell culture technology rather than egg-based methods.
Reactogenicity: The capacity of a vaccine to produce common, expected adverse reactions, usually mild and self-limited, such as pain at injection site or fever.

References

http://clinicaltrials.eu/trial-id/2022-500657-17-00
http://clinicaltrials.eu/trial-id/2023-504168-40-00
http://clinicaltrials.eu/trial-id/2023-503763-42-00
http://clinicaltrials.eu/trial-id/2023-505357-40-00
http://clinicaltrials.eu/trial-id/2022-502308-66-00

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