• Immunisation keeps us safe from many infectious diseases, but, just like any medication, we may experience side effects after our vaccinations.
  • Side effects after immunisation are mostly mild and usually last one to two days. 
  • The most common side effects are fever (that is, a temperature over 38.5°C), and redness, swelling and tenderness around the area where the needle went in to the skin.
  • Babies may be unsettled or sleepy after immunisation.
  • Millions of people – many of them babies and young children – are immunised every year, with no side effects.

Immunisation keeps us safe from many infectious diseases, but, just like any medication, we may experience side effects after our vaccinations. These side effects can affect between one and 10 in every 100 people being immunised, depending on the vaccine. They are mostly mild and usually last one to two days.  

Common side effects after immunisation

The most common side effects of immunisations are:

  • fever (that is, a temperature over 38.5°C)
  • redness, swelling and tenderness around the area where the needle went in
  • babies may be unsettled or sleepy
  • sometimes, a small, hard lump (nodule) at the injection site may persist for some weeks or months. This should not be of concern and requires no treatment.

Managing common side effects 

A number of treatment options can reduce the side effects of the vaccine including:

  • Give extra fluids to drink.
  • Do not overdress children or babies if they are hot.
  • Put a cold wet cloth on the injection site to ease discomfort.
  • Although routine use of paracetamol after vaccination is not recommended, if fever or pain at the injection site is present, paracetamol can be given. Check the label for the correct dose or speak with your pharmacist, (especially when giving paracetamol to children).

Concerns about immunisation side effects

If a reaction following immunisation is unexpected, persistent or severe, or if you are worried, see your GP (doctor).

It is also important to seek medical advice if you (or someone in your care) is unwell, as this may be due to an illness rather than because of the immunisation.

Adverse events that occur following immunisation may be reported to the Victorian Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC) Line. SAEFVIC is the central reporting service in Victoria for any significant adverse events following immunisations. You can discuss with your immunisation provider how to report adverse events in other states or territories.

Uncommon or rare immunisation side effects

There is a very small chance of experiencing a serious reaction after immunisation. A serious reaction is an unwanted and unexpected symptom or sign associated with the immunisation. This is why you are advised to stay at the clinic or medical surgery for at least 15 minutes after receiving a vaccine in case further treatment is required.

Examples of uncommon or rare reactions are:

  • anaphylaxis – an immediate allergic reaction. This is dramatic but rare (fewer than one in a million people will have anaphylaxis after a vaccination), and it is completely reversible if treated quickly.
  • febrile seizure – this seizure usually lasts one or two minutes. It can be frightening and usually does not cause permanent harm or have lasting effects. It is caused when the child’s fever rises quickly.
  • bowel blockage (intussusception) – this occurs in the seven days following the first and second dose of rotavirus vaccine. This is a rare side effect for about 1 in 17,000 babies. 

If any other reactions are severe and persistent, or if you are worried, contact your GP (doctor) immediately or dial 000.

Safety testing and re-testing of immunisations 

Millions of people  – many of them babies and young children – are immunised every year, with no side effects. 

Other people may experience mild common side effects. 

You can be sure the immunisations used in Australia are safe. Did you know it can take up to 10 years for a vaccine to be approved in Australia? There are rigorous safety research and testing processes that all new vaccines must pass before they’re registered. Every vaccine is manufactured and tested according to strict safety guidelines.

And, we keep monitoring vaccines, even after they’re registered and being used. The Therapeutic Goods Administration (TGA) conducts  detailed surveillance  to make sure vaccines stay safe and effective. 

If the TGA has any concerns about a vaccine, it revokes the vaccine’s registration and withdraws it from the market. 

The bottom line

Think of it this way – a vaccine is a medicine that we use to stop ourselves and those in our care from getting sick. We are much less likely to get an illness if we are immunised. 

Immunisations are medicine. Like any medicine, they can cause mild side effects. In  rare cases, they can cause more serious side effects, but the chance of an immunisation seriously harming us is rare. 

Deciding not to be immunised puts you, loved ones and the community at risk of unnecessarily catching an infectious disease that can be very serious and even deadly. 

Do you have all the information you need?

There’s a lot of information available about immunisation, and it’s easy for us to feel overwhelmed or not know where to start. 

If you have questions, a good first step is to talk to your GP (doctor). If you have young children, maternal and child health nurses, or paediatricians can also help. They can explain how vaccines work, discuss the benefits of immunisation and the risks of disease, and outline your options. 

Before you agree to any vaccines, your immunisation provider has to give you all the information you need to make an informed decision. Your consent must be voluntary, without any pressure, coercion or manipulation. And you do not have to give your consent until your immunisation provider has explained the risks and benefits. 

Remember, you can take your time before making a decision about immunisation. You don’t have to decide on the spot. You can always make another appointment, to ask more questions or to go ahead with the immunisation. 

Where can I get more information about immunisation?

Find out more about immunisation by speaking with your health professional. The best place to start is with your GP. You can also ask your clinic nurse or specialist.

There is also lots of information online. If you would like to know more about immunisation, check out the Australian Government’s information on frequently asked questions, the safety of vaccines and immunisation myths. 

When looking for immunisation information, stick to reliable information providers, such as:

Where to get help


More information


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Immunisation basics

Timing and schedules

Immunisation throughout life

A-Z of immunisations and vaccines

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This page has been produced in consultation with and approved by: Department of Health and Human Services - RHP&R - Health Protection - Communicable Disease Prevention and Control Unit

Last updated: April 2018

Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health & Human Services shall not bear any liability for reliance by any user on the materials contained on this website.