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Are vaccines safe?

Health professionals

Find information that will help you deliver your service to your patients

Vaccine testing

Research and testing is an essential part of developing safe and effective vaccines.

In Australia, vaccines must pass strict safety testing before the Therapeutic Goods Administration (TGA) will register them for use. Approval of vaccines can take up to 10 years.

Before vaccines become available to the public, large clinical trials test them on thousands of people.

    How are vaccines shown to be safe? fact sheet

    A fact sheet about how vaccines are shown to be safe, noting how all vaccines are carefully tested.

    Vaccine ingredients

    Vaccine ingredients vary depending on what the vaccine is for. They may contain:

    • a very small dose of a live (but weakened) virus
    • killed viruses
    • killed bacteria
    • small parts of bacteria
    • a small dose of a modified toxin produced by bacteria
    • a small amount of preservative
    • a small amount of an antibiotic to preserve the vaccine

    What is in vaccines? fact sheet

    Fact sheet about vaccine ingredients, noting that all ingredients are tested for safety.

    You can also search the TGA's product information for more detail about each vaccine and its specific ingredients.

    Vaccine side effects

    You may experience minor side effects following vaccination. Most side effects last no more than a couple of days and you will recover without any problems.

    Common reactions to vaccination include:

    • pain, redness and/or swelling where you received the needle
    • mild fever

    Serious reactions like allergic reactions are extremely rare. If your body reacts in an unexpected way, seek medical advice straight away. 

    If you have any concerns about potential side effects of vaccines, talk to your doctor or nurse.

    Vaccine safety monitoring

    The TGA and the manufacturer closely monitor how well a vaccine is working and how safe it is. 

    After the TGA approves vaccines, we monitor and test them in a number of ways:

    • further clinical trials
    • national surveillance
    • monitoring serious side effects

    AusVaxSafety is a national system for monitoring vaccine safety in Australia. The National Centre for Immunisation Research and Surveillance leads this system. The Australian Government Department of Health funds it. 

    The AusVaxSafety system involves a range of collaborators around Australia. 

    AusVaxSafety tracks vaccine safety through following up vaccinated children and adults and asking if they reacted to vaccines.

    The first annual report from AusVaxSafety summarises information from parents and carers about vaccine reactions. The parents and carers had responded to an SMS about their child's health a few days after receiving a vaccine at routine National Immunisation Program schedule points in 2016–17.

    You can report adverse events directly to the TGA online using:

    The TGA reviews these reports on a regular basis. The TGA can refer the reports as required to expert committees, such as the Advisory Committee on Vaccines (ACV). This ensures there is ongoing safety assessment of vaccines.

    You can report side-effects of vaccines by calling 1300 134 237. A pharmacist from NPS MedicineWise will provide advice on how to manage the side effect and lodge a report.

    You can also report vaccine reactions to your state or territory health service.

    Mercury is no longer used in vaccines

    Thiomersal, which contains mercury, was previously used as a preservative in some vaccines in very small amounts. Manufacturers removed thiomersal from all vaccines on Australia’s National Immunisation Program in 2000.

    There is no scientific evidence that these small amounts of thiomersal caused any harmful effects in children or adults.

    No established link between vaccines and autism

    High-quality studies over many years have compared the health of large numbers of vaccinated and unvaccinated children. Medical information from nearly 1.5 million children around the world have confirmed that vaccination does not cause autism.

    People first became concerned about autism and immunisation after the medical journal The Lancet published a paper in 1998. This paper claimed there was a link between the measles, mumps, rubella (MMR) vaccine and autism. Since then, scientists have completely discredited this paper. The Lancet withdrew it in 2010 and printed an apology. The UK’s General Medical Council struck the author off the medical register for misconduct and dishonesty.

    Vaccination and autism fact sheet

    This fact sheet explains how we know vaccination does not cause autism and where the misunderstanding came from.

    Further information

    You can find more information on vaccine safety in the following resources:

    Last updated: 
    1 May 2019