The government is now operating in accordance with the Guidance on Caretaker Conventions, pending the outcome of the 2025 federal election.
An overview of the process for consumers
Determining the most effective composition of the annual influenza virus is an exercise in global cooperation coordinated by the World Health Organisation's (WHO) Global Influenza Surveillance and Response System (GISRS) - external site and network of laboratories. This indicative timeline gives an overview of Australian, and particularly the TGA's activities, in the ongoing selection, evaluation and monitoring of seasonal influenza vaccines.
Throughout the year - January to December
Surveillance and monitoring
Influenza viruses are monitored throughout the year by Australia's National Influenza Centres (NICs) - external site - located in Western Australia, New South Wales and Victoria. They collect samples of the different viruses, and are particularly interested in viruses that are unusual or uncommon. Unusual viruses have more potential to cause a pandemic, and may be considered for inclusion in the seasonal influenza vaccine. Samples are sent to the WHO collaborating centre in Melbourne for further analysis.
The NICs also monitor the impact that the influenza viruses are having on the population and the development of any resistance to treatments. This surveillance and monitoring is the first step in determining which viruses should be included in a new vaccine. This occurs for each of the virus strains in the seasonal influenza vaccine.
Production of reassortant viruses
Virus strains that have been selected for the seasonal vaccine may need to be modified so that the vaccine can be produced successfully. This means creating a 'reassortant' virus.
A reassortant virus is a hybrid created by mixing the influenza virus strain with a standard laboratory strain. The reassortant virus is analysed and approved for use in production.
September
The WHO consultation and information meeting on the composition of influenza virus vaccines for the Southern Hemisphere
The WHO makes its recommendation - external site at this meeting about what viruses should be included in the influenza vaccines that will be used in the southern hemisphere. This group also recommends viruses for the Northern Hemisphere vaccine in February. Along with its recommendation, the WHO provides a list of suitable candidate vaccine viruses and standards for ensuring that each vaccine produced contains the same amount and type of virus.
October
Australian Influenza Vaccine Committee (AIVC) meeting
The AIVC considers the WHO decision along with the most recent data on virus circulation in Australia. It then makes a recommendation to the Therapeutic Goods Administration (TGA). The TGA can accept, reject, or modify the recommendation.
Once the composition has been decided, manufacturing of the vaccine can begin.
October-December
*Potency reagents preparation and calibration
Essential Regulatory Laboratories - external site (ERLs) supply and calibrate specific standards for each virus strain included in the vaccine. This enables manufacturers to formulate the vaccine correctly. TGA is an ERL for Influenza and may coordinate or participate in these studies.
Reagents need to be calibrated by ERLs to enable manufacturers to standardise the vaccine dosage.
ERLs analyse and supply reagents - external site, these are standards that ensure that each vaccine contains the correct dosage. There is a separate reagent for each virus used by manufacturers. This process also allows regulators, like the TGA, to independently assess the dosage of each vaccine.
October-January
*Submission of influenza strain change variation to TGA for evaluation
Manufacturers may change their processes for producing new strains of vaccines (for example, they might inactivate the virus for longer periods). Any changes will also include updates to the vaccine label, packaging, and Product Information.
All changes must be submitted to TGA for evaluation. The TGA may ask them to provide additional information to support their request.
November-March
*Supply of vaccine lots to the TGA for laboratory testing
The TGA receives a small quantity of each lot of vaccine that the manufacturer supplies in Australia. The TGA laboratories evaluate each sample, including laboratory testing of selected samples, to ensure that lots meet quality and safety requirements for influenza vaccines.
*Supply of protocol information to TGA for evaluation
The manufacturing information is also evaluated by the TGA to ensure that the results of testing undertaken by the manufacturer comply with what has been previously approved.
January-March
Vaccine lot release by TGA
The manufacturer will submit multiple lots of vaccines and accompanying information throughout this time for 'lot release' by the TGA. Each lot of vaccine must be specifically 'released' by the TGA before the vaccine can be supplied for immunisation. The release process includes a review of the lot specific information and a decision to either accept or reject information about each lot. The TGA may ask for further lot-specific information from the manufacturer.
Distribution of first lots of vaccines
Following TGA's review of the information and vaccine, the first lots are made available for distribution.
Adverse event monitoring
The TGA continually monitors the safety of influenza vaccines through adverse event monitoring.
When people tell the TGA about any side effects they have experienced using the flu vaccination, it helps the TGA to understand more about the possible side effects that may be previously unknown.
Health professionals and consumers are encouraged to report all side effects associated with influenza vaccine in patients of any age to the TGA or through the current arrangements in their State or Territory.