Possible side effects of vaccination
Vaccines, like any medication, can cause side effects.
This information explains common reactions that may be experienced after receiving a vaccine and actions to take if you are concerned.
All vaccines used in Australia have been through a safety testing process then licensed by the Therapeutic Goods Administration (TGA). This is to ensure that each vaccine is safe and proven to be effective based on clinical trials.
Visit the Aust Government: Department of health: Are vaccines safe? (external site).
Visit National Centre for Immunisation Research and Surveillance (external site) for fact sheets, FAQs and other resources on vaccination safety.
Read more about vaccination safety.
Common side effects
Most vaccines can cause mild side effects. These should be explained to you by your immunisation provider.
Side effects after vaccination are usually mild and short lasting and do not need special treatment.
Learn more about COVID-19 vaccination – Side affects you might have after your vaccination (external site).
Table: Common reactions to vaccination
Common reactions
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What can you do
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Local reaction (redness and/or swelling around injection site)
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- Place a cold damp cloth (cold compress) over the affected area to give relief.
- Paracetamol (not aspirin) may be used to ease the discomfort.
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Mild temperature or fever
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- Monitor the temperature regularly (a fever is above 38.5 °C). Paracetamol (not aspirin) may be used to help reduce the temperature.
- Extra fluids are recommended (for example, water, milk).
- Keep cool by not overdressing.
- Sponge down with lukewarm water.
- Cold baths or showers are not recommended.
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Irritability, decreased appetite, sleepiness
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- These symptoms are common in children and usually disappear over 24 to 48 hours. It does not usually require any specific treatment.
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Vomiting and diarrhoea
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- Continue to breastfeed, giving small frequent feeds.
- Wash hands thoroughly after changing soiled nappies to prevent any spread.
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A small lump may appear at the injection site
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- No treatment is usually required and it will disappear in a few weeks.
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Fainting (uncommon, however this may sometimes occur)
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- Anyone experiencing light-headedness before or after vaccination is advised to lie down until symptoms subside.
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Read more about side effects for specific vaccines used in the National Immunisation Program (external site).
Managing common side effects
Pain relief
The routine use of paracetamol at the time of vaccination is no longer recommended as today’s vaccines have fewer side effects.
You can use paracetamol to help with pain and fever after a vaccination, remembering to carefully follow the instructions on the packet.
Never give aspirin to a child or adolescent under 16. It can cause a rare, but severe illness called Reye’s Syndrome.
You can ease the soreness at the injection site by placing a wet cloth over it.
Fainting
This is mainly seen in adolescents and adults. If you feel light-headed or dizzy before or after a vaccination you should lie down until you feel better.
Vomiting and diarrhoea
See your doctor if these symptoms are severe or persistent.
Irritability, loss of appetite, sleepiness
These are common symptoms and do not require any treatment. These symptoms usually disappear after 24 to 48 hours – if they don’t, see your doctor.
Your child may need extra comforting after vaccination.
Fever
If you develop a fever higher than 38.5 °C after a vaccination take paracetamol (not aspirin) as directed depending on your weight and age. Make sure you drink extra fluids and wear light-weight, loose clothing.
If your child has a fever:
- take their temperature regularly. If your child has a persistent high temperature, see your doctor.
- give them extra fluids (for example more breast feeds or more water)
- dress them in light clothing
- do not give them a bath in cool water. This can cause shivering, which can increase the body’s core temperature.
Rare and serious side effects
Any medication, including vaccines, may have potentially serious side effects including a severe allergic reaction, such as anaphylaxis.
The risk of developing severe reactions after receiving a vaccine is extremely rare.
You should seek emergency medical care immediately by calling 000 if you think you are having an allergic reaction, such as difficulty breathing, wheezing, a fast heartbeat or collapsing.
Some rare and serious side effects could include the following:
- Thrombosis with thrombocytopenia syndrome – There has been a link between the AstraZeneca COVID-19 vaccine and a very rare condition called thrombosis with thrombocytopenia syndrome (TTS) which appears to be more common in younger adults. Learn more about TTS (external site).
- Seizure (also known as convulsion or fit) – some children are more prone to seizures when experiencing a high fever. The seizure usually lasts approximately 20 seconds and very rarely more than 2 minutes. If you or your child has a seizure after a vaccination you should call 000 for an ambulance. You should always make sure your child sees a doctor if they have a seizure. There is usually no long-term damage from seizures in young children, but they should be checked by your doctor.
- Intussusception (relates to rotavirus) – this is an uncommon form of bowel obstruction where one segment of the bowel slides into the next, much like the pieces of a telescope. There is a very small risk of this occurring in a baby in the first 1 to 7 days after receiving the first dose of rotavirus vaccine, and a smaller risk after the second dose of rotavirus vaccine. The baby may have bouts of crying, look pale, get very irritable and pull his or her legs up to the abdomen (stomach) because of pain.
- Anaphylaxis – a severe allergic reaction which occurs suddenly, usually within 15 minutes of vaccination, however anaphylaxis can occur within hours of vaccine administration. Early signs of anaphylaxis include: redness and/or itching of the skin, swelling (hives), breathing difficulties and a sense of distress. Hence, it is important for you to wait at the place you have received your vaccination so that you can be observed for any reaction.
Where to get help
Seek medical advice immediately by:
- calling healthdirect (external site) on 1800 022 222, who will advise you on what to do next,the advice may include calling an ambulance by dialling triple zero (000) to get immediate assistance
- seeing your family doctor (GP)
- contacting your vaccine provider for advice
Acknowledgements
Public Health
This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.