As per the Australian Pharmaceutical Journal’s recent news coverage, there is an overall lack of education regarding types of flu vaccines available in the country this year, their efficacy and age-group suitability. To address this, here’s a short summary of how annual flu vaccines are made and approved.
How flu vaccines are made each year
Each year, the flu or influenza vaccines can change as new strains of the influenza virus appear. The World Health Organization identifies these strains based on global influenza epidemiology. The Australian Influenza Vaccine Committee uses their recommendation to determine the influenza vaccine composition for use in Australia.
Quadrivalent flu vaccines vs trivalent flu vaccines
Trivalent vaccines protect against two variants of the influenza A virus and one influenza B virus, even though there are two different lineages of B viruses that both circulate during most seasons. Whereas a quadrivalent influenza vaccine is designed to protect against four different flu viruses, including two influenza A viruses and two influenza B viruses.
Efficacy and effectiveness of flu vaccines
Based on studies comparing the immune response of quadrivalent and trivalent standard flu vaccines, the overall efficacy of the quadrivalent vaccines is expected to be similar to the trivalent vaccines, noting that quadrivalent vaccines protect against an extra influenza B lineage. This year’s list of TGA approved vaccines for each age group can be found here.
Flu vaccines for people over 65 years of age
Standard influenza vaccines provide less protection against the flu in people over 65 years of age than in younger people. Because of this, ‘enhanced’ formulations were developed to increase the immune system’s response to the vaccine. These special flu vaccines are only available at GP clinics.
Information sources:
1. Immunisationhandbook.health.gov.au
2. cdc.gov/flu/prevent/quadrivalent.htm
3. tga.gov.au/alert/2021-seasonal-influenza-vaccines
4. tga.gov.au/aivc-recommendation-composition-influenza-vaccine-australia-2021
