Healthy living

Vaccines, vaccination and immunisation

What is a vaccine?

A vaccine is the product made from killed or live, weakened strains of viruses or bacteria used to induce immunity against infectious diseases.

What is vaccination?

Vaccination refers to the act of giving a vaccine to a person. When a vaccine is given, it triggers an immune response in your body. This protects you if you come into contact with strains of that disease again in the natural environment.

How do vaccines work?

Vaccines help develop immunity by imitating an infection. We come into contact daily with people in many different settings, for example at schools and shopping centres, and during this contact it is easy for infectious diseases to be transmitted. The greater number of people vaccinated, the less risk of people becoming infected and spreading the disease to others.

What is immunisation?

Immunisation refers to the process of becoming immune to a disease as a result of a vaccine. Immunisation protects people against specific diseases by using the body’s natural defence mechanism – the immune response.

The World Health Organization considers immunisation to be the most effective medical intervention we have to prevent deaths and reduce disease in our communities.

In the short term, immunisation protects individuals from a specific infectious disease and its immediate complications. But immunisation may also have long-term protective effects – from cancer and other chronic conditions.

An important feature of immunisation is that it also benefits the entire community which is called herd immunity.

What is herd immunity?

When a significant proportion of people in a community have become immune to a specific disease through immunisation, people who are still susceptible to the disease are less likely to come into contact with someone who is carrying the infectious agent.

If enough people are immunised, it is possible to protect most of the community from the disease. This is called ‘herd immunity’. If you have good herd immunity (at least 95% are immunised), then even those who are not able to be immunised, for example very young infants, or people with medical conditions, are protected from the disease.

Where to learn more about immunisation


Acknowledgements
Public Health | Australian Academy of Science

This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.

Image: Young girl. Text: I'm protecting my whole family. Protect yourself and others. Get vaccinated for influenza.