With over 63,000 influenza cases reported in Australia this year—surpassing totals from both 2023 and 2024—health authorities are urging Australians to get vaccinated . While the flu vaccine is safe and effective, it’s natural to have questions about potential side effects. This guide provides detailed insights into common and rare reactions, helping you understand what to expect after vaccination.
Common Side Effects of the Flu Vaccine
Most people tolerate the flu shot well, with only mild and short-lived side effects. These are a normal sign that your body is developing immunity.
Typical side effects include:
- Soreness, redness or swelling at the injection site
- Muscle aches or joint pain
- Mild fever
- Fatigue or tiredness
- Headache
- Occasionally, a small lump at the injection site (may last a few weeks)
These symptoms usually start within 12–24 hours of the injection and resolve within 1–3 days. You can manage discomfort with rest, fluids, and over-the-counter pain relievers like paracetamol or ibuprofen.
Can the Flu Shot Cause the Flu?
No, the flu vaccine cannot cause the flu. It contains inactivated (killed) viruses or purified viral proteins, which means it cannot cause infection .
Some people report feeling “flu-like” symptoms after vaccination, such as fatigue, muscle aches, or mild fever. These are signs that your immune system is responding to the vaccine, not indications of actual influenza.
Understanding Flu-Like Symptoms Post-Vaccination
Feeling a bit under the weather after your flu shot? That’s common and often described as “flu-like” symptoms, which may include:
- Low-grade fever (under 38.5°C)
- Mild chills
- Generalised muscle aches
- Fatigue or drowsiness
- Headache
These symptoms are usually short-lived and much milder than actual influenza. They’re a sign your body is creating antibodies to protect you. If these symptoms persist beyond a few days or worsen, contact your GP.
How Long Do Side Effects Last?
Most side effects appear within the first day after vaccination and typically last between 1 to 3 days. Redness or tenderness at the injection site may linger slightly longer.
If side effects persist for more than 3 days, or if you feel unusually unwell, consult your healthcare provider to rule out other causes.
Are Severe Reactions Possible?
Severe side effects following a flu vaccination are very rare. These may include:
- Severe allergic reaction (anaphylaxis)
- Guillain-Barré Syndrome (GBS), a rare autoimmune condition
The risk of GBS after the flu shot is extremely low—about 1 in a million doses. If you’ve experienced GBS before or have concerns about severe reactions, speak to your GP before vaccination.
Is It Normal to Feel Unwell After the Flu Vaccine?
Yes, it’s completely normal to feel a little off for a day or two after the flu shot. Common post-vaccine symptoms like fatigue, mild fever, or chills are all indicators that your body is building immunity.
This does not mean you’re sick. In fact, these side effects are usually milder than the actual flu, which can lead to weeks of illness or complications in vulnerable groups.
Can I Take Pain Relief After the Flu Shot?
Yes. Pain relief medicines like paracetamol or ibuprofen can help reduce symptoms like:
- Fever
- Headache
- Muscle soreness
- Injection site pain
Always follow the dosage instructions and consult a pharmacist or GP if you’re unsure.
Flu Vaccination and Egg Allergy
Most flu vaccines available in Australia are manufactured using an egg-based process, which may result in the presence of very small amounts of egg protein. However, studies have shown that individuals with egg allergies, including those with a history of anaphylaxis, can safely receive the influenza vaccine. It’s important to discuss any allergies with your healthcare provider before vaccination.
Can I Get the Flu Shot and COVID-19 Vaccine Together?
Yes. It is safe to receive both the flu and COVID-19 vaccines at the same visit. You might experience a few more side effects—such as fatigue or muscle aches—but these are usually mild and temporary.
Conclusion
While the flu shot can cause some mild side effects, they are far outweighed by the benefits of protection against a potentially serious illness. With flu cases rising earlier and more aggressively this year, now is the time to protect yourself and your community.
If you’re unsure whether the flu vaccine is right for you, or if you’ve experienced vaccine side effects before, speak with your GP for personalised advice.
Need Advice From a GP?
If you’re unsure whether the flu vaccine is right for you or have concerns about side effects, talk to your local GP. At Tewantin Medical Centre, we provide personalised advice for patients across Tewantin, Noosa Heads, Noosaville, and surrounding areas — tailored to your health history, allergies, and lifestyle.
