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Influenza Virus A/Darwin/9/2021 San-010 (H3N2)

This article examines several clinical trials investigating the use of influenza vaccines containing the Influenza Virus A/Darwin/9/2021 San-010 (H3N2) strain. These studies aim to evaluate the safety, efficacy, and immune responses generated by various influenza vaccine formulations in different populations and administration scenarios. The trials cover topics such as combination with other vaccines, timing of administration, and comparisons between vaccine types.

Table of Contents

What is INFLUENZA VIRUS A/DARWIN/9/2021 SAN-010 (H3N2)?

INFLUENZA VIRUS A/DARWIN/9/2021 SAN-010 (H3N2) is a component of the seasonal influenza (flu) vaccine[1]. It is a specific strain of the influenza virus that has been selected for inclusion in the current season’s flu vaccine. This strain is also known as Influenza virus A/Darwin/9/2021 (H3N2)-like strain or A/Darwin/9/2021, SAN-010[2].

How does the vaccine work?

The vaccine works by introducing a small, inactivated portion of the influenza virus into your body. This stimulates your immune system to produce antibodies against the virus. If you’re later exposed to the actual flu virus, your body will recognize it and be better prepared to fight it off, potentially preventing illness or reducing its severity[3].

What is it used for?

This vaccine component is used as part of the seasonal flu vaccine to protect against influenza A (H3N2) viruses. It’s typically included in quadrivalent (four-strain) flu vaccines, which offer protection against four different flu viruses that are expected to circulate during the flu season[1][2].

How is it administered?

The vaccine containing this strain is usually administered as an injection, typically in the upper arm. Depending on the specific vaccine product, it may be given as:

  • An intramuscular injection (into the muscle)[2]
  • A subcutaneous injection (under the skin)[2]
  • An intranasal spray (in some live attenuated flu vaccines)[1]

The most common method is intramuscular injection. The dose is typically 0.5 ml for adults[1][2].

How effective is it?

The effectiveness of flu vaccines can vary from year to year, depending on how well the vaccine strains match the circulating viruses. Researchers are constantly studying the effectiveness of flu vaccines, including this specific strain. Some studies are looking at factors that might influence vaccine effectiveness, such as the time of day the vaccine is administered[4].

What are the potential side effects?

Most people who receive flu vaccines experience mild side effects, if any. Common side effects may include:

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

Serious allergic reactions are rare but can occur. If you experience difficulty breathing, rapid heartbeat, dizziness, or severe swelling after receiving the vaccine, seek medical attention immediately[5].

Who should not receive this vaccine?

While the flu vaccine is recommended for most people, some individuals should not receive it or should consult with their healthcare provider first. These include:

  • People with severe, life-threatening allergies to any component of the vaccine, including egg proteins
  • Infants younger than 6 months old
  • People who have had a severe allergic reaction to a flu vaccine in the past
  • People who are currently feeling moderately or severely ill

Always consult with your healthcare provider to determine if the flu vaccine is appropriate for you[1].

Current research and future directions

Ongoing research is exploring various aspects of flu vaccines, including the INFLUENZA VIRUS A/DARWIN/9/2021 SAN-010 (H3N2) strain. Some current areas of study include:

  • Optimizing vaccine administration timing to enhance immune response[4]
  • Investigating the effects of co-administering flu vaccines with COVID-19 vaccines[6]
  • Studying the immune responses in different age groups, including older adults[4]
  • Exploring the use of adjuvants (substances added to vaccines to boost immune response)[6]

These studies aim to improve the effectiveness of flu vaccines and our understanding of how they work in different populations.

Trial Aspect Details
Vaccine Types Quadrivalent influenza vaccines containing Influenza Virus A/Darwin/9/2021 San-010 (H3N2)
Study Populations Adults aged 18-65, older adults aged 60-85, and individuals aged 65 and over
Administration Methods Intramuscular injection, intranasal spray
Combination Studies Co-administration with COVID-19 vaccines, comparison of adjuvanted and unadjuvanted flu vaccines
Primary Outcomes Antibody responses, seroconversion rates, T cell responses
Secondary Outcomes Safety and reactogenicity, longevity of immune responses, cellular immunity
Follow-up Periods Ranging from 28 days to 6 months post-vaccination
Special Considerations Timing of vaccination, effects on mucosal immunity, comparison of different vaccine types

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 influenza vaccines containing the Influenza Virus A/Darwin/9/2021 San-010 (H3N2) strain in various populations and administration scenarios.
  • What age groups are being studied in these trials? The trials involve various age groups, including adults aged 18-65, older adults aged 60-85, and in some cases, specifically targeting individuals aged 65 and over.
  • Are these vaccines being studied in combination with other vaccines? Yes, some trials are investigating the co-administration of influenza vaccines with other vaccines, such as COVID-19 vaccines, to assess their combined safety and efficacy.
  • What types of immune responses are being measured in these trials? The trials are measuring both humoral (antibody-mediated) and cellular immune responses. This includes assessing antibody titers, T cell responses, and in some cases, mucosal immunity.
  • How long do these clinical trials typically last? The duration of these trials varies, but many include follow-up periods ranging from 28 days to 6 months after vaccination to assess both short-term and longer-term immune responses and safety outcomes.

Ongoing Clinical Trials on Influenza Virus A/Darwin/9/2021 San-010 (H3N2)

  • 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 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

  • A Study to Test the Safety and Body’s Response to TETRALITE Influenza Vaccine Compared to Vaxigrip Tetra Vaccine in Healthy Adults Aged 18 to 50 Years

    Not recruiting

    1 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 the Best Time for Influenza Vaccine Administration in Adults Aged 60-85 Using Influenza Vaccine and Drug Combination

    Not recruiting

    3 1 1 1
    Investigated diseases:
    Investigated drugs:
    The Netherlands

  • 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

Glossary

  • Influenza Virus A/Darwin/9/2021 San-010 (H3N2): A specific strain of influenza virus used in the development of seasonal flu vaccines to protect against H3N2 type influenza.
  • Humoral immune response: The aspect of immunity that involves antibodies produced by B lymphocytes, which can neutralize or mark pathogens for destruction.
  • Cellular immune response: The aspect of immunity mediated by T lymphocytes, which can directly attack infected cells or help other immune cells in their functions.
  • Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating an immune response to vaccination or infection.
  • Microneutralization test (MNT): A laboratory test used to measure the ability of antibodies in a person's serum to neutralize a specific virus.
  • Geometric mean titers (GMT): A way of averaging antibody levels in a group of individuals, often used to assess the overall immune response to a vaccine.
  • ELISpot: Enzyme-Linked ImmunoSpot, a laboratory technique used to measure cellular immune responses by detecting cytokine-producing cells.
  • Adjuvant: A substance added to a vaccine to enhance the body's immune response to the vaccine.
  • Quadrivalent influenza vaccine: A flu vaccine that protects against four different influenza viruses: two influenza A viruses and two influenza B viruses.
  • Intramuscular (IM): A method of administering a vaccine by injecting it directly into a muscle.
  • Intranasal (IN): A method of administering a vaccine through the nose, typically as a spray.
  • Live Attenuated Influenza Vaccine (LAIV): A type of flu vaccine containing weakened live viruses, typically administered as a nasal spray.
  • Inactivated Influenza Vaccine (IIV): A type of flu vaccine containing killed viruses, typically administered as an injection.
  • Adverse event (AE): Any unfavorable and unintended sign, symptom, or disease temporarily associated with the use of a medical treatment or procedure.
  • Serious Adverse Event (SAE): An adverse event that results in death, is life-threatening, requires hospitalization, or causes significant disability.

References

  1. http://clinicaltrials.eu/trial/2023-506166-31-01
  2. http://clinicaltrials.eu/trial/2023-509178-44-00
  3. http://clinicaltrials.eu/trial/2023-503228-17-00
  4. http://clinicaltrials.eu/trial-id/2024-513558-30-00
  5. http://clinicaltrials.eu/trial/2023-505361-86-00
  6. http://clinicaltrials.eu/trial-id/2024-514798-23-00