How COVID-19 vaccines work

Find out how the COVID-19 vaccines work, how they are approved, how we decide how to use them, and where to go for credible information.

COVID-19 vaccines in Australia

We are using 3 COVID-19 vaccines in our national vaccine rollout:

  1. Vaxzevria (AstraZeneca)
  2. Comirnaty (Pfizer)
  3. Spikevax (Moderna)

How the vaccines work

These vaccines will protect you from getting severely ill or dying if you get COVID-19. 

The vaccines train your immune system to recognise and clear out the virus, before it makes you seriously ill. Your body's immune system builds this protection over time.

You are best protected 7 to 14 days after your second dose. Your booster dose helps restore and extends this protection.

The virus that causes COVID-19 (called SARS-CoV-2) has spikes of protein on each viral particle. These spike proteins allow the virus to attach to cells and cause disease.

The vaccines help the body to:

  • recognise these spike proteins as a threat
  • fight the coronavirus that has these proteins.


Most people need 2 doses of the same vaccine to be fully vaccinated. 

Find out more about booster doses for people aged 18 years and older and third doses for people with severe immunocompromise.

Types of vaccines

There are 2 types of approved vaccines:

The Therapeutic Goods Association (TGA) has provisionally approved a third type of vaccine – a protein vaccine called Novavax

For details of how the approved vaccines work, see our pages on each one:

Learn more about the science of immunisation.  

How vaccines are approved

The Therapeutic Goods Administration (TGA) approves vaccines for use in Australia after a careful evaluation process

The COVID-19 vaccines have provisional approval. This means they can be legally used in Australia because the need for early access outweighs the risks. The manufacturers continue to collect data on vaccine safety and efficacy and will apply for full approval later.

The TGA also continuously monitors vaccine safety and side effects

Vaccination recommendations

The Australian Technical Advisory Group on Immunisation (ATAGI) advises the Australian Government about the medical administration of vaccines, including COVID-19 vaccines. 

They make recommendations on the use of each COVID-19 vaccine based on research and medical advice. This includes which vaccines are recommended for people in different age groups.

The Australian Government considers ATAGI’s advice when it makes policy decisions about vaccines.

Authoritative vaccine information

There is a lot of information – and misinformation – out there about coronavirus and the COVID-19 vaccines. 

We encourage you to rely on reputable sources to help you make informed choices and stay up to date.

Reputable information about COVID-19 vaccines is available from:

Last updated: 
21 January 2022

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