Vaccines work by training the immune system to recognise and fight off invading organisms. Although often used interchangeably, the terms vaccination and immunisation are not the same; vaccination is the process of receiving a vaccine, while immunisation is the process of receiving a vaccine and becoming immune to a disease as a result of being vaccinated.
In Australia, routine immunisation begins at birth and includes vaccines against a number of diseases, including measles, mumps, and whooping cough.
Herd immunity, also known as community immunity, occurs when a large portion of the population is immunised, making it difficult for a disease to spread. Herd immunity helps protect people who are more vulnerable – such as those who are too young or medically unable to get vaccinated. High immunisation rates, at about 95%, are required to achieve herd immunity for many infectious diseases.
When are children immunised?
As of June 2025, the Australian Government provides funded vaccines against 18 diseases to eligible people through the National Immunisation Program (NIP). Australian children are expected to have received specific vaccinations by the ages of 1, 2 and 5. The immunisation rates at all 3 ages are above 90%. The rate for Aboriginal and Torres Strait Islander (First Nations) children is slightly lower than the rate for all children at the ages of 1 and 2, but by the time First Nations children are 5 years old they are more likely than all children to be fully immunised.
The NIP also provides funded vaccines for adolescents, older people and others at high risk. For example, the influenza vaccine is available to pregnant women, First Nations people in most age groups, people aged 65 and over, and people who are medically at risk. A national human papillomavirus (HPV) vaccination program is also available for Australian girls and boys, aged up to 19. Vaccinations are routinely given in school-based programs when children are aged 12–13.
Australia has relatively high levels of immunisation, however, vaccination rates vary by where a child lives.
