Influenza vaccines can change from year to year as new strains of influenza virus appear. This is one reason vaccination against influenza is given every year.
The Australian Influenza Vaccine Committee (AIVC) has reviewed data related to epidemiology, antigenic and genetic characteristics of recent influenza isolates circulating in Australia and the Southern Hemisphere, serological responses to 2019-2020 vaccines, and the availability of candidate vaccines viruses and reagents. Based on this review and the World Health Organization's recommendation, the AIVC recommended the viral strains to be used for influenza vaccines in the 2021 southern hemisphere influenza season.
The TGA has accepted the recommendations of AIVC. This year there is a new A (H1N1)-like virus strain and a new A (H3N2)-like virus strain when compared to the composition of quadrivalent vaccines for Australia in 2020.
The egg-based quadrivalent influenza vaccines contain the following four viral strains:
- an A/Victoria/2570/2019 (H1N1)pdm09-like virus;
- an A/Hong Kong/2671/2019 (H3N2)-like virus;
- a B/Washington/02/2019 (B/Victoria lineage)-like virus; and
- a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.
The composition of trivalent influenza vaccines is recommended to include the H1N1, H3N2 and the B Victoria lineage virus.
Cell-based quadrivalent influenza vaccines contain the following four viral strains:
- an A/Wisconsin/588/2019 (H1N1)pdm09-like virus;
- an A/Hong Kong/45/2019 (H3N2)-like virus;
- a B/Washington/02/2019 (B/Victoria lineage)-like virus; and
- a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.
Influenza and COVID-19 vaccination
Can I have the Influenza and COVID vaccine at the same time?
The Australian Technical Advisory Group on Immunisation (ATAGI) has advised that routine scheduling and giving of an influenza vaccine with a COVID-19 vaccine on the same day is not recommended. The preferred minimum interval between a dose of seasonal influenza vaccine and a dose of BNT162b2 (Pfizer) or ChAdOx1-S (AstraZeneca) is 14 days.
If an influenza vaccine has been inadvertently co-administered or given within a shorter interval than 14 days with a COVID-19 vaccine, revaccination with either vaccine is not considered necessary.
