Key facts
- Vaccines must pass 3 clinical trial phases before they can be approved for use.
- Every batch of vaccine is assessed before supply in Australia.
- Most vaccine side effects are minor. Serious reactions are rare.
Developing vaccines for safety
It can take many years to develop a new vaccine. They go through several stages:
- research – identifying vaccine ideas
- discovery – identifying the most promising vaccine ideas
- pre-clinical testing – testing in the lab
- clinical trials – testing with people
- approval – from the Therapeutic Goods Administration (TGA).
Every vaccine in Australia must pass 3 clinical trial phases before it can be submitted for approval.
| Trial phase | Participants | What the phase assesses |
|---|---|---|
| Phase 1 | Small number of people |
|
| Phase 2 | Hundreds of people |
|
| Phase 3 | Thousands of people |
|
Approving vaccines for use
The TGA assesses the safety and quality of every vaccine before approving its use in Australia.
This includes assessing:
- clinical trial data
- ingredients
- how the vaccine is made
- the quality of the manufacturing process.
The TGA will only approve vaccines if:
- the manufacturing process and the vaccine meet high standards
- there is evidence that the benefits of the vaccine greatly outweigh the risks.
The TGA also ensures there is independent quality assessment for every batch of vaccine before it can be supplied in Australia.
Monitoring vaccines for safety
After vaccines are given to people, AusVaxSafety and the TGA monitor them for safety.
Australia uses 2 ways to monitor vaccine safety. Some systems follow up with people after vaccination, while others rely on reports from the public, health professionals and vaccine suppliers. Together, these systems help identify and investigate potential safety issues as quickly as possible.
The TGA also ensures there is independent quality testing done for every batch of vaccine before it can be supplied in Australia.
AusVaxSafety survey
AusVaxSafety is a safety surveillance system. AusVaxSafety clinics send a survey to people after they get vaccines, so they can report any side effects.
Independent experts analyse the responses to make sure any safety issues are found quickly.
View the vaccine safety data from AusVaxSafety. The data shows what to expect after a range of vaccines, including the free National Immunisation Program (NIP) vaccines.
Reports to the TGA
The TGA receives reports of adverse events or safety problems. These can be from:
- the general public
- health professionals
- vaccine suppliers
- state and territory health departments.
These reports help experts investigate potential safety concerns and monitor vaccine safety over time.
Search the Database of Adverse Event Notifications (DAEN).
Vaccine ingredients
Vaccines usually have 6 main ingredients. Each ingredient:
- serves a specific purpose
- is tested for safety in the manufacturing process.
Ingredients vary depending on what the vaccine is for. They can include:
- a small dose of a live (but weakened) virus
- dead viruses
- dead bacteria
- small parts of bacteria
- a small dose of a modified toxin produced by bacteria
- a bit of mRNA or DNA from the virus
- a small amount of preservative
- a small amount of an antibiotic to preserve the vaccine.
None of the free vaccines on the NIP contain mercury (thiomersal).
Search for product information for vaccines and their ingredients on the TGA website.
Possible side effects of vaccines
Common side effects include pain and redness where the needle went in. Most side effects do not last for long.
Common side effects can be a sign that your body is building protection against disease.
A person may experience a severe reaction, but this is rare.
You are more likely to get serious health problems from a disease than from the vaccine for that disease.
Find out more about the possible side effects of vaccination. You can also compare the effects of diseases and vaccines in the Australian Immunisation Handbook.
Symptoms not caused by vaccines
Studies show that vaccines do not always cause common symptoms. They can happen at the same time by chance.
Symptoms such as fever and rashes are common, especially among children.
It can be hard to know whether a vaccine caused these symptoms, because they can happen naturally in many people of the same age.
This leads some people to incorrectly link vaccines to medical conditions with unknown causes.
One example is the false claim that vaccines cause autism. Extensive research has found no evidence that vaccines cause autism.
Next steps
Find out about:
More information
It’s normal to have questions about vaccine safety.
Information shared online and on social media is not always accurate. If you have questions or concerns about vaccines, talk to a health professional and use trusted sources of information like:
- Questions about vaccination booklet
- The Science of Immunisation: Questions and Answers page on the Australian Academy of Science website
- Sharing Knowledge About Immunisation (SKAI) website
- National Centre for Immunisation Research and Surveillance (NCIRS) website.
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