2025 Australian flu season: Who should get a flu shot, which vaccines are available and what to expect in the days following your vaccination

With the onset of cooler weather across most of the country and many Australians already opting for jackets over t-shirts, Australia has officially entered the start of influenza (flu) season.

The timing of flu season in Australia changes every year but generally spans from April until October, peaking between June and September.

While it is still too early to predict the severity of the 2025 season, early National Notifiable Disease Surveillance System (NNDSS) case data indicate Australia may be on track for another challenging flu season.

There were 70,279 laboratory-confirmed flu cases reported in Australia from 1 January 2025 to 30 April 2025 – a 58.6% increase compared with same period of 2024 (44,320 cases) and more than at the same point of any year since the NNDSS began collecting data in 1991.

Vaccination, in conjunction with good infection control measures – including hand hygiene and covering up coughs and sneezes – is the best defence against flu infection.

With current flu vaccination coverage in 2025 below the same period in some previous years – particularly for infants – we examine the importance of getting a flu vaccine ahead of peak flu season.

What is flu?

Flu is an acute respiratory illness that occurs after infection with one of the flu viruses. It is spread through contact with respiratory secretions – such as a sneeze or cough – from an infected person. Symptoms generally include:

• fever
• dry cough
• nasal congestion/runny nose
• headache
• sore throat
• general symptoms such as feeling unwell, muscle aches and pains and fatigue.

While most people recover without lasting effects, in some cases flu can cause serious illness leading to hospitalisation or even death.

Who should get a flu vaccine?

Flu can affect anyone – and the Australian Technical Advisory Group on Immunisation (ATAGI) recommends annual flu vaccination for all people aged 6 months and over.

Babies, young children (aged less than 5 years), pregnant people, people with medical conditions and older people have a higher risk of flu-associated complications. For these high-risk individuals, flu vaccination is particularly recommended and flu vaccines are funded under the National Immunisation Program.

Which flu vaccines are available in Australia in 2025?

Seven flu vaccines have been approved for use in Australia in 2025:

Standard dose influenza vaccines

• Afluria Quad (individuals aged 5 years and over)
• Flucelvax Quad (individuals aged 6 months and over)
• FluQuadri (individuals aged 6 months and over)
• Influvac Tetra (individuals aged 6 months and over)
• Vaxigrip Tetra (individuals aged 6 months and over)

Adjuvanted or high-dose vaccines (preferred for older adults)

• Fluad Quad (individuals aged 65 years and over)
• Fluzone High-Dose (individuals aged 60 years and over)

Because circulating influenza strains change over time, the formulation of flu vaccines is edited and tailored yearly to ensure optimal protection against the predicted dominant circulating flu strains each flu season.

Why do different age groups get different flu vaccines?

Older people are one of the groups most affected by flu, with more cases of serious flu-associated complications and deaths occurring in this cohort.

Because the immune system weakens with age, older people do not respond as well to standard flu vaccines – and therefore don’t get the same level of protection – compared to younger people.

To counter this, ‘enhanced’ flu vaccines – which are specifically designed to increase the response of the immune system to the vaccine – are available for use in individuals aged 60 years and older.

Enhanced flu vaccines can contain either:

• the same amount of antigen as a standard flu vaccine with an adjuvant (a compound that stimulates a higher immune response to a vaccine) added
• a higher amount of antigen (to stimulate a higher immune response) with no adjuvant added.

Can I get my flu vaccine at the same time as another vaccine?

People – including infants and children aged 6 months and over – can receive a flu vaccine at the same time as most other vaccines.

How effective are flu vaccines?

Comprehensive research has shown the flu vaccine is effective, especially against serious consequences of flu such as hospitalisation and intensive care admission.

It takes around two weeks from the time of your flu vaccination for you to develop immunity, and the flu vaccine provides approximately 3–4 months of protection following vaccination.

How well the vaccine prevents illness varies depending on:

• the age, health and immune response of the person getting vaccinated
• how similar the virus strains in the vaccine are to the strains that are circulating.

In young children and healthy adults aged less than 65 years who have received influenza vaccination, the likelihood of getting flu is reduced by around 50–60%. This figure varies from year to year.

Children aged under 9 years may respond less effectively when receiving their very first dose of flu vaccine. Therefore, two doses one month apart are recommended for children aged under 9 years who are receiving a flu vaccine for the first time to ensure optimal protection. After this, only one dose is required in subsequent flu seasons.  

Similarly, people with an underlying medical condition and older people may not respond as well to the flu vaccine, so their level of protection from the vaccine may be lower; however, the vaccine is effective at reducing the risk of flu-associated pneumonia and hospitalisations.

Is the flu vaccine safe?

Extensive research and years of close monitoring of real-world use in countries around the world have shown flu vaccines to be safe.

In Australia, the safety of vaccines is reviewed and monitored at all stages of the vaccine development and delivery process – from initial lab-based research to vaccine registration to recommendations on the use of the vaccine and ongoing surveillance once the vaccine is being used in the population. Any safety concerns are investigated immediately.

What are the likely adverse events after a flu vaccine?

Like most medicines used in healthcare, flu vaccines can have side effects, also known as adverse events following immunisation (AEFIs). These adverse events are usually mild and temporary, with the overwhelming majority resolving without the need for medical intervention.

AusVaxSafety has monitored the safety of flu vaccines administered to Australians of all ages since 2017. Since then, more than 1.2 million individuals (or their parents/carers) have supplied details about any adverse events experienced after flu vaccination.

So far in 2025, AusVaxSafety has received responses from more than 114,000 flu vaccine recipients who participated in active vaccine safety surveillance via the AusVaxSafety system. The resulting data show 83% of respondents experienced no adverse events in the three days following flu vaccination.  

Among those who did experience a side effect, local reactions (including pain, itching, redness and swelling at the injection site), fatigue, muscle/joint pain and headache were the most common across flu vaccines. These adverse events were generally mild and short-lived, with most resolving within one day or less.

The level of impact on routine activities was low, with 2% of respondents reporting missing work, study or routine duties in the week following vaccination. Reported medical attendance rates also remained very low at 0.2%, indicating the 2025 flu vaccine formulations are well-tolerated.

What is being done to monitor the safety of flu vaccines in Australia?

Australia has one of the most robust vaccine safety monitoring systems in the world.

Given the flu vaccines used in Australia can change yearly, as existing vaccines undergo formulation changes to ensure optimised protection against predicted circulating strains, AusVaxSafety conducts ongoing safety surveillance to reassure the public that the flu vaccines used each year are performing as safely as expected in real-world conditions.

The Therapeutic Goods Administration (TGA) monitors reports of any AEFI, including serious AEFIs, following flu vaccination via its passive reporting system. Individuals can report any adverse events they are worried about following vaccination – especially if they think it is serious – via the TGA website.

AusVaxSafety 2025 flu vaccine safety data

Influenza frequently asked questions – NCIRS