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Influenza is back in Australia in 2023: Why a flu shot is so important, who is eligible and what to expect in the days following your vaccination

With COVID-19 dominating headlines – and seemingly every conversation – since the global pandemic was declared by the World Health Organization in March 2020, you are not alone in letting the risk of influenza (flu) slip down your priority list.  

Flu is already circulating in Australia in 2023, and early flu surveillance data are indicating similar levels of infection as in pre-pandemic flu seasons, highlighting the importance of putting the flu shot back on your agenda to ensure you are optimally protected before the cooler months ahead.

With lower flu vaccine uptake and decreased exposure to influenza virus over the past few years during COVID-19 restrictions, we examine the importance of getting a flu vaccine ahead of the peak of the Aussie flu season.

What is flu, when am I most at risk and how can I protect myself? 

Flu is a respiratory illness that occurs after infection with one of the flu viruses. It is spread by contact with body fluids – such as a sneeze or cough – from an infected person. Symptoms generally include fever, body aches, a runny nose and a sore throat. While most people recover without lasting effects, in some cases flu can cause serious illness leading to hospitalisation or even death. 

Flu cases are reported in Australia all year round; however, flu is more prevalent during the cooler months, which are often referred to as the ‘flu season’. The timing of flu season in Australia changes from year to year but generally starts in April and subsides by October, peaking between June and September. 

Vaccination, in conjunction with good infection control measures – such as hand hygiene – is your best defence against flu infection.

Who should get vaccinated, is it safe and how effective is a flu vaccine?

While babies, young children (less than 5 years), pregnant people, people with medical conditions and older people are at highest risk of getting severe illness from flu, flu can affect anyone. The Australian Technical Advisory Group on Immunisation (ATAGI) therefore recommends annual flu vaccination for all people aged 6 months and older.

Extensive research has shown that flu vaccines are safe and effective. The safety of vaccines is reviewed and monitored at all stages of the vaccine development 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 – and any safety concerns are investigated immediately.

It takes 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 and immune response of the person getting vaccinated as well as how similar the virus strain in the vaccine is to the virus strain that is circulating. 

The immune response of people with underlying medical conditions and the elderly may be lower than healthy adults, so these groups may get a lesser level of protection. However, the flu vaccine has been shown to reduce hospitalisation due to flu in these cohorts – and, given their higher risk of severe flu, any protection provided is extremely worthwhile.  

Which flu vaccines are available in Australia, and why do different age groups get different vaccines?

Fortunately, several safe and effective flu vaccines are approved for use in Australia. Given that circulating flu strains change and evolve over time, the formulation of flu vaccines is tailored yearly to ensure optimal protection against the predicted dominant circulating strains each flu season. Vaccines approved for use in Australia in 2023 include:

  • Vaxigrip Tetra
  • Fluarix Tetra
  • Afluria Quad (5 years and older)
  • FluQuadri
  • Influvac Tetra
  • Flucelvax Quad (2 years and older)
  • Fluad Quad* (65 years and older)
  • Fluzone High* – Dose Quad (60 years and older).

*Enhanced vaccine

Elderly people are the group most affected by flu, with more cases of serious complications and deaths in this cohort. Unfortunately, they also don’t get the same level of protection from the standard flu vaccine compared to younger adults; the immune system weakens with age, and so elderly people don’t respond as well to the standard vaccines.

To counter this, enhanced flu vaccines – those that 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 the standard amount of antigen as a regular flu vaccine, but with an adjuvant (a compound that stimulates a higher immune response to a vaccine) added, or a higher amount of antigen (to stimulate a higher immune response) but with no adjuvant added. 

Can I get my COVID-19 vaccine and my flu vaccine at the same time?

Yes, flu vaccines can be co-administered (i.e. given at the same time or on the same day) as any COVID-19 vaccine. Studies show that co-administration of flu and COVID-19 vaccines is safe and produces a good immune response against both viruses.

What are the likely side effects 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 side effects 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 900,000 individuals (or their parent/carer) have provided details about any side effects experienced after flu vaccination.

In 2023, AusVaxSafety has received data from more than 30,000 flu vaccine recipients who participated in active vaccine safety surveillance via the AusVaxSafety system. Data published by AusVaxSafety show that 84% of the participants experienced no side effects in the first 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. They were generally mild and short-lived, with most resolving within one day or less. 

The rate 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%. 


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

The Therapeutic Goods Administration monitors any reports of serious AEFIs following flu vaccination via its passive reporting system.

Access AusVaxSafety 2023 flu vaccine safety data here

Access NCIRS influenza vaccines – Frequently Asked Questions here