Key facts
- Immunisation trains your body to recognise and quickly fight diseases.
- You may still get sick, but it will be less serious and you’ll recover faster.
- High immunisation rates protect people who are too unwell to get vaccines.
What is immunisation
Immunisation is the process of becoming immune to a disease after getting vaccinated. This takes about 7 to 21 days.
Being immune to a disease means your body can recognise and fight it.
Vaccination is when you receive a vaccine. Immunisation is the protection your body develops after vaccination.
What vaccines do in your body
Vaccines trigger an immune response in your body without making you ill. They contain parts of dead or weakened viruses or germs that train your immune system to recognise and fight disease.
When you get a vaccine, your immune system:
- makes antibodies to protect you against the disease
- creates memory cells to remember the virus or germ.
Vaccines strengthen your immune system by training it to recognise and respond quickly to specific diseases.
All vaccines used in Australia are carefully tested and monitored to ensure they are safe and effective.
For further information, you can read the The science of immunisation page on the Australian Academy of Science website.
How immunisation protects you
If you come across the virus or germ in the future, your immune system quickly makes antibodies to destroy it.
A small number of people may still get a less serious form of the disease. Their stronger immune system:
- protects them from the more serious effects
- reduces the risk of hospitalisation
- helps them to recover faster.
How immunisation protects the community
When you get vaccinated, you also help to protect our community.
If enough people are immunised against a disease, it becomes harder for that disease to spread. This is known as ‘herd immunity’. In some cases, herd immunity can stop a disease spreading from person to person and may even eliminate it from a community.
Herd immunity helps protect people who are unable to be vaccinated, including those who are too young or too unwell to receive vaccines.
For many infectious diseases, we need 95% of people to get immunised to get herd immunity.
The World Health Organization (WHO) considers immunisation one of the most effective public health measures for preventing disease and saving lives.
Immunisation prevents 3.5 to 5 million deaths around the world every year.
Natural immunity
Natural immunity develops when someone gets a disease and becomes immune to it in the future.
Some people believe natural immunity is better than immunity from vaccines. However, the risks are much higher. Some infectious diseases can lead to severe illness or even death.
Vaccines provide protection without the risks of getting the disease itself.
Why we need immunisation
Some vaccine-preventable diseases, like polio, diphtheria and measles, can cause serious illness and complications. These diseases are now rare in Australia because of the success of our immunisation programs.
If our vaccination rates fall:
- the few cases we get would spread more quickly
- more people would get sick, have serious complications, be hospitalised or die
- our defences against diseases brought into Australia by international travel would weaken.
Benefits and risks
Like any medicine, vaccines can cause side effects. Most side effects are mild and short-lived.
Benefits of vaccination include:
- reducing your risk of getting a disease
- protects against serious illness, complications, hospitalisation and death
- protects your family and community
- protects people who cannot be vaccinated
- reduces the risk of long-term health complications from infections.
For example, human papillomavirus (HPV) vaccination helps prevent some cancers, and chickenpox vaccination can help reduce the risk of shingles later in life.
Risks include:
- minor side effects, such as soreness at the injection site
- low risk of still getting the disease, but will usually be less serious
- serious side effects, which are very rare.
Overall, the risks of vaccination are much lower than the risks of the diseases they help prevent.
Next steps
Find out about:
More information
Contact
