In short
This article summarizes several clinical trials investigating influenza vaccines containing the Influenza Virus B/Austria/1359417/2021-Like Strain (B/Austria/1359417/2021, BVR-26). These trials aim to evaluate the safety, immunogenicity, and efficacy of various influenza vaccine formulations in different populations, including healthy adults, older adults, and individuals with certain medical conditions. The studies explore factors such as vaccine dosage, adjuvants, and timing of administration to optimize protection against seasonal influenza.
At a glance
- Vaccine Formulations
- Various, including adjuvanted and non-adjuvanted, cell-derived and egg-derived, standard-dose and high-dose
- Study Populations
- Adults 18-85 years old, with focus on older adults (50+, 65+) and some specific populations (e.g., hematological cancer patients)
- Primary Outcomes
- Safety, reactogenicity, immunogenicity (antibody responses), and in some cases efficacy against influenza illness
- Secondary Outcomes
- T cell responses, comparison between vaccine types, optimal administration timing, chronotype effects
- Safety Assessments
- Solicited and unsolicited adverse events, serious adverse events, adverse events of special interest
- Immunogenicity Measures
- Hemagglutination inhibition (HI) assay, seroconversion rates, geometric mean titers (GMT)
- Special Considerations
- Co-administration with COVID-19 vaccines, time-of-day effects on vaccination, lot consistency
Introduction
Influenza, commonly known as the flu, is a serious respiratory illness that affects millions of people worldwide each year. To combat this virus, researchers and pharmaceutical companies continually develop and update vaccines. One such component used in recent flu vaccines is the INFLUENZA VIRUS B/AUSTRIA/1359417/2021-LIKE STRAIN (B/AUSTRIA/1359417/2021, BVR-26). This article aims to provide patients with a comprehensive understanding of this vaccine strain, its purpose, and its role in protecting against influenza.
What is INFLUENZA VIRUS B/AUSTRIA/1359417/2021-LIKE STRAIN?
The INFLUENZA VIRUS B/AUSTRIA/1359417/2021-LIKE STRAIN (B/AUSTRIA/1359417/2021, BVR-26) is a specific strain of influenza virus used in the development of flu vaccines. It is also known by its shorter name, B/Austria/1359417/2021 (B/Victoria lineage)-like virus. This strain represents a type B influenza virus, which is one of the main types of influenza viruses that cause seasonal flu epidemics in humans.
The name of this strain provides important information:
- "B" indicates it's a type B influenza virus
- "Austria" refers to the geographical location where the virus was first isolated
- "1359417" is the identification number of the specific isolate
- "2021" is the year the strain was identified
- "BVR-26" is likely a laboratory designation for this particular variant
Purpose and Use
The primary purpose of including the B/Austria/1359417/2021-like strain in flu vaccines is to provide protection against circulating B/Victoria lineage influenza viruses. Influenza vaccines typically contain multiple strains to offer broad protection against different flu viruses expected to be prevalent in a given flu season.
This strain is used in various types of influenza vaccines, including:
- Quadrivalent vaccines: These contain four different flu strains, typically two influenza A strains and two influenza B strains
- Inactivated vaccines: Where the virus has been killed and cannot cause infection
- Adjuvanted vaccines: Which include substances to enhance the body's immune response
Clinical Trials and Research
Several clinical trials have been conducted or are ongoing to evaluate vaccines containing the B/Austria/1359417/2021-like strain. These studies aim to assess the safety, effectiveness, and immune response generated by the vaccines. Some notable trials include:
- A Phase 1/2 study evaluating the safety and immunogenicity of mRNA-based multivalent seasonal influenza vaccine candidates in healthy adults
- A Phase 3 trial comparing an MF59-adjuvanted quadrivalent influenza vaccine to non-adjuvanted vaccines in adults 50 years and older
- A study investigating the coadministration of influenza vaccines with COVID-19 vaccines in adults over 65 years of age
- Research on optimizing the time of day for influenza vaccine administration in adults aged 60-85 years
Administration and Dosage
Vaccines containing the B/Austria/1359417/2021-like strain are typically administered as an intramuscular injection. The standard dose for most adult formulations is 0.5 ml. However, specific dosages may vary depending on the particular vaccine product and the age of the recipient.
Some key points about administration:
- Usually given as a single dose annually before the flu season
- Can be administered to adults of various age groups, including those 65 years and older
- May be given at the same time as other vaccines, including COVID-19 vaccines (as studied in some trials)
Safety and Side Effects
Vaccines containing the B/Austria/1359417/2021-like strain generally have a good safety profile, similar to other influenza vaccines. However, like all medical interventions, they can cause side effects. Common reactions may include:
- Pain, redness, or swelling at the injection site
- Fatigue
- Headache
- Muscle aches
- Low-grade fever
These side effects are usually mild and resolve within a few days. Serious allergic reactions are rare but can occur. It's important to discuss any concerns or medical history with your healthcare provider before receiving the vaccine.
Effectiveness and Immune Response
The effectiveness of vaccines containing the B/Austria/1359417/2021-like strain is measured through various immunological parameters in clinical trials. These include:
- Hemagglutination inhibition (HI) antibody titers: This measures the level of antibodies produced against the virus
- Seroconversion rates (SCR): The percentage of individuals who develop a significant increase in antibody levels after vaccination
- Geometric mean titers (GMT): An average measure of antibody levels in a group of vaccinated individuals
Clinical trials aim to demonstrate that vaccines containing this strain can produce a robust immune response, potentially providing protection against influenza B viruses of the Victoria lineage.
Special Populations
Research on vaccines containing the B/Austria/1359417/2021-like strain includes studies in various populations:
- Older adults: Several trials focus on adults aged 50, 60, or 65 years and older, as this group is at higher risk for flu complications
- Individuals with chronic conditions: Some studies include participants with stable chronic diseases, recognizing the importance of protection for these at-risk groups
- Immunocompromised individuals: While generally excluded from initial trials, some studies may evaluate the vaccine's safety and effectiveness in this population in later phases
Conclusion
The INFLUENZA VIRUS B/AUSTRIA/1359417/2021-LIKE STRAIN (B/AUSTRIA/1359417/2021, BVR-26) is an important component of current influenza vaccines, designed to protect against B/Victoria lineage flu viruses. Ongoing research and clinical trials continue to evaluate its safety, effectiveness, and potential benefits when combined with other vaccine strains or administered to different populations. As with all medical decisions, it's important to consult with your healthcare provider to determine if a flu vaccine containing this strain is appropriate for you based on your individual health status and risk factors.