Vaccine development, testing and safety

During development, vaccines are tested on thousands of volunteers through a number of phased trials which are designed to assess the vaccine for safety and side effects and demonstrate:

  • how the vaccine works
  • that the vaccine prompts an effective immune response in different people
  • that the vaccine is effective in preventing the general population from getting the disease

No testing phase has been skipped during the development of the COVID-19 vaccines. Some of the testing phases have been combined or run at the same time to help test COVID-19 vaccines quickly and make them available as soon as possible.

Duration 00:02:15

This video describes how COVID-19 vaccines have been able to safely be developed and rolled out quicker than other vaccines.

Vaccines are an effective way to protect us from diseases like COVID-19, preventing death and serious illness.

Vaccines can take a long time to develop, because they must undergo multiple phases of clinical trials.

Researchers around the world have been working hard to develop COVID-19 vaccines from the very early stages of the pandemic.

They have been able to speed up development of vaccines without compromising safety and effectiveness.

Thanks to the collaboration between scientists, researchers, manufactuers and distributors, the development and implementation planning phases have been run side-by side, instead of one after the other.

Research into how to respond to a pandemic has been ongoing, long before COVID-19.

This research looks at data from previous coronaviruses such as SARS in 2002 and MERS in 2012, giving researchers a head start to build the COVID-19 vaccines.

Thanks to our community maintaining COVIDSafe behaviours like good hand hygiene and physical distancing, we have had more time to test vaccines for use in Australia while still keeping us safe from the virus.

Our scientists are still working quickly and have been able to deliver our first vaccine, but no corners have or will be cut.

In Australia, the Therapeutic Goods Administration, or the TGA, has been rigorously assessing the potential COVID-19 vaccines for safety, quality and effectiveness.

They will continue to do this with the remaining vaccines before they will be approved and made available to Australians this year.

Once approved, each batch must also be checked to make sure it meets the same quality standards.

All these steps are important before the vaccinations begin.

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The Australian Government requires robust scientific data and analysis before supporting a vaccine candidate. This is a critical part of the scientific process. We continue to follow our rigorous regulatory procedures to ensure that all vaccines supplied in Australia are effective and safe for use.

Advising the Government on COVID-19 vaccines are:

Long-term effects of COVID-19 vaccines

Like all medicines, COVID-19 vaccines do not last long in your body. The ingredients in vaccines degrade within a few days, and it takes a few weeks for your body’s immune response to develop. When there are rare, but serious side effects from vaccines, they occur within the first few weeks, while your immune system is being activated.

There is a very rare and serious risk of TTS with AstraZeneca (Vaxzevria) COVID-19 vaccine and myocarditis or pericarditis from Pfizer (Comirnaty) and Moderna (Spikevax) COVID-19 vaccines. It took a little longer to find out about them because they’re so rare. It’s important not to confuse “long-term” effects with “so rare it takes a long time to find.”

Immunity from vaccination is much less risky than immunity through exposure to a pathogen like the virus that causes COVID-19. We do not have long-term research on health outcomes of COVID-19, however we do know the virus can damage the lungs, heart and brain, even in mild cases, which increases the risk of long-term health problems.

Finding information about COVID-19 vaccines

Australians are encouraged to rely on reputable sources of information to help them make informed choices and stay up to date.

Information will be communicated through Government channels, as well as States and Territories and the health sector.

Reputable information about vaccines is available from: