Is it too late to get a flu shot?
- Written by Adrian Esterman, Professor of Biostatistics and Epidemiology, University of South Australia
It’s almost spring. And while respiratory infections[1] seem to have passed their peak[2] many people are still getting sick.
So is it still worth getting a flu shot?
The short answer is “yes”. If you haven’t had one already this year, it’s not too late.
Flu season started early, could end late
Flu seasons are notoriously unpredictable[3]. Temperature swings, population immunity, and new viral strains are among factors[4] influencing how widely the virus spreads.
Australia’s flu season usually runs[5] from April to October, peaking between June and September.
But this year was different. It started early[6]. Laboratory-confirmed cases between January and March 2025 were almost 60% higher than the same period in 2024. Since then, numbers have dipped slightly compared to last year.
However, we could still see thousands more cases before 2025 ends if the season follows last year’s pattern, and extends well beyond October.
This year[7], influenza A has been the dominant strain across all age groups. Think[8] of influenza A as the more common, quickly evolving[9] type of flu that often triggers larger, more severe outbreaks. The other main type, influenza B, evolves more slowly and usually causes milder illness, although it can still be serious, especially for children.
Is it still worth getting vaccinated in August?
Absolutely. While flu activity usually declines after July, the number of laboratory-confirmed cases of flu shows the virus does still circulate outside the typical flu season.
If you’ve already had flu this year, natural infection offers some protection[10]. But this is generally less reliable and narrower than vaccination. Natural infection cannot reliably provide immunity in older people, who have a much poorer immune response to infection. For younger people, although their immmune system mounts a strong response, it is against the specific influenza strain that has infected them, and gives little protection against other strains. This is why vaccination[11] is preferable.
If you are still sick with the flu, current recommendations[12] are that you should wait until you are recovered before getting a flu shot. This allows your immune system to generate a strong response to the vaccine.
Once vaccinated, it takes about two weeks[13] to develop immunity. Protection is strongest in the first few months[14].
Pregnant women and international travellers can benefit from vaccination at any time of year.
How well do they work?
Effectiveness of flu vaccines varies year to year, depending on how well the vaccine strains match those going around. This season, the match appears excellent – about a 98% match[15] (for key strains).
However, the vaccine doesn’t completely protect you from getting infected (no vaccine does[16]). This is because levels of immunity and our response to infection vary from person to person.
Flu vaccines are generally 40–60% effective[17] against experiencing a negative health outcome, for example developing the flu and attending a GP practice or being hospitalised.
So vaccination against the flu is particularly important for high-risk groups such as elderly people, young children, pregnant women, and people with chronic (long-term) conditions.
Are they safe?
Data about vaccine safety are reassuring. According to AusVaxSafety, a surveillance system that monitors vaccine safety, so far in 2025 more than 114,000 people have reported their experience after a flu shot, and 83% had no adverse reactions[18] within three days of their shot.
The most common were mild and short-lived, such as a sore arm, headache or fatigue. Only 0.2% needed to see a doctor.
You cannot catch the flu from the vaccine itself. This is because it contains an inactivated or “killed” version of the virus. This means it is not live and cannot cause infection.
Which flu vaccine should I get?
All flu vaccines[19] in Australia this year are quadrivalent, which means they protect against four strains.
For people with egg allergies, there’s a newer option called Flucelvax Quad, which is produced in mammalian cells instead of chicken eggs. There are also special, higher-dose formulations for older adults, such as Fluad Quad for those 65 and older, and Fluzone High-Dose Quadrivalent for those 60 and over.
Your health-care provider will discuss the best option for you.
Is it free?
Under the National Immunisation Program[20], the flu vaccine is free for[21]:
- children aged six months to under five years
- pregnant women
- adults aged 65 and over
- Aboriginal and Torres Strait Islander people from six months of age
- people with certain medical conditions, such as heart disease or with weakened immunity.
Everyone else can pay[22] about A$20–30 at GPs or pharmacies. If your GP does not bulk bill, you may also need to pay an out-of-pocket cost for the consultation.
Currently, Queensland[23] is the only state offering free flu vaccination to all ages over six months. But that program ends on September 30.
So what’s the verdict?
The bottom line is that it’s not too late to get vaccinated. Even as winter eases, getting a flu shot can make a real difference, protecting both you and the people around you from serious illness.
References
- ^ respiratory infections (theconversation.com)
- ^ passed their peak (nindss.health.gov.au)
- ^ unpredictable (doi.org)
- ^ factors (doi.org)
- ^ usually runs (ausvaxsafety.org.au)
- ^ started early (nindss.health.gov.au)
- ^ This year (www.health.gov.au)
- ^ Think (biologyinsights.com)
- ^ quickly evolving (doi.org)
- ^ protection (www.sciencedirect.com)
- ^ vaccination (doi.org)
- ^ recommendations (ncirs.org.au)
- ^ two weeks (ausvaxsafety.org.au)
- ^ few months (www.health.gov.au)
- ^ about a 98% match (www.health.gov.au)
- ^ no vaccine does (www.who.int)
- ^ 40–60% effective (www.health.nsw.gov.au)
- ^ 83% had no adverse reactions (ausvaxsafety.org.au)
- ^ All flu vaccines (www.tga.gov.au)
- ^ National Immunisation Program (www.health.gov.au)
- ^ is free for (www.health.gov.au)
- ^ can pay (theconversation.com)
- ^ Queensland (statements.qld.gov.au)
Read more https://theconversation.com/is-it-too-late-to-get-a-flu-shot-263196
