Vaccination is one of the safest interventions in medicine. But like any medication, vaccines can produce side effects. The vast majority are mild and self-limiting. Knowing the difference between an expected reaction and a red flag means you’ll respond appropriately, neither dismissing something important nor worrying needlessly.
Expected, normal, no action needed
- Soreness, redness, swelling at the injection site, peaks 12–24 hours, gone in 2–3 days.
- Tiredness or mild headache for 24 hours.
- Low-grade fever (under 38.5°C) for 24 hours.
- Mild muscle aches.
Manage with rest, fluids, paracetamol or ibuprofen if comfortable doing so.
Worth a call to your GP or 13 SICK (13 7425)
- Fever lasting more than 48 hours, or above 38.5°C.
- Significant injection-site swelling or redness lasting more than 3 days.
- Persistent vomiting, severe headache, neck stiffness.
- Unusual bruising or bleeding.
Call 000 immediately
- Wheeze, throat tightness, swelling of lips/face/tongue.
- Hives spreading rapidly.
- Sudden drop in blood pressure (feeling faint, pale, clammy).
- Difficulty breathing or talking.
These are signs of anaphylaxis. They are very rare after vaccination, but treatable when recognised early.
Reporting
Any unexpected reaction can be reported to SAFEVAC, the Victorian post-vaccination safety surveillance service. Reports feed national signals about vaccine safety. We can help you report.
Sources & further reading
General information only. This article is educational and is not a substitute for personal medical advice. Your immuniser will confirm eligibility and contraindications on the day.
TGA advertising compliance. Vaccines are referred to by disease or category in line with the Therapeutic Goods Advertising Code. Specific brands and registered indications are discussed at the consultation.