COVID-19 vaccines explained

September 3, 2021

Let’s face it: it’s been a long road, this pandemic. Are you powering on, or just crawling along as best you can?

Either way, for most Australians there’s hope on the horizon. This hope comes in the form of a small vial and 2 jabs in the arm. As our vaccination rates increase, so does our hope that some of the burdens of this pandemic will lift.

What are the vaccines currently available to Australians? And what’s the difference between them?

Will these differences matter for you?

Find out the key facts here.

Covid Vaccines

Types of vaccines

Vaccines are a safe and effective way to help your immune system prepare its defence against deadly germs. We use vaccines to combat the health issues and spread of lots of major illnesses including:

  • measles
  • chickenpox
  • the seasonal flu

Vaccines are like the training run for the main event.  When you have a vaccine, your immune system will create antibodies, just as it does when it’s exposed to a disease.

However, vaccines contain only modified or weakened forms of germs. They do not cause disease.

At present, we have two vaccines in Australia to combat COVID-19, and some more on their way. They are safe and effective. But not they’re not identical.

Firstly, they have been developed using different technologies: mRNA technology, viral vector technology and protein-based technology.

mRNA vaccines

These types of vaccines use messenger-RNA (mRNA, a genetic code). The mRNA provokes cells in your body to produce a COVID-19-specific protein. This is the protein that your immune system will target and attack.

Messenger-RNA vaccines can’t alter or impact your DNA in any way. The Pfizer vaccine and Moderna vaccine are mRNA vaccines.

Viral vector vaccines

These types of vaccines use a harmless, weakened animal virus. This virus contains the genetic code for a protein unique to COVID-19. Your body will produce antibodies to this protein.

The AstraZeneca vaccine is a viral vector vaccine.

Protein-based vaccine

These types of vaccines are made from a non-infectious protein that mimics part of the virus. In the case of the coronavirus, this is the spike protein (which is on the surface of the virus).

Your body will produce antibodies to this protein.

The Novavax vaccine is a protein-based vaccine.

You can only get the COVID-19 from a live strain of the coronavirus. COVID-19 vaccines do not contain a live strain of the coronavirus. So you cannot get COVID-19 from a shot. 

In Australia, the:

  • Astra Zeneca vaccine is preferred for people over 60 years
  • Pfizer vaccine is the preferred vaccine for all other people aged 16 to 59.
  • Moderna vaccine is approved for people aged 18 years and older, and will join Australia’s COVID-19 vaccination program in the coming months.
  • Novovax vaccine is not yet approved by the Therapeutic Goods Administration (TGA).
  • COVID-19 vaccine Janssen — another viral vector vaccine — is approved but not included in Australia’s COVID-19 vaccination program.

For more information, see, Which COVID-19 vaccines are available in Australia?

What exactly does the covid vaccine do?

The research shows that these vaccines protect against COVID-19 symptoms and severe disease after 2 doses.

We don’t yet know if the COVID-19 vaccines reduce or stop the spread (transmission) of the virus. There is some evidence that it may.

The risks: in context

All vaccines have mild side effects, like a sore arm or mild fever. More serious side effects happen but are extremely rare.

You are most likely aware of the news concerning the AstraZeneca vaccine.

It’s linked to a very rare blood-clotting condition called thrombosis with thrombocytopenia syndrome (TTS). The very low risk of TTS appears to be higher in younger adults, which is why it’s preferred for people aged over 60.

However, if you are aged 18 to 59 you can have the AstraZeneca vaccine if you want to. You need to weigh up the benefits and the risks, and provide informed consent.

If you want to talk to a GP about having the AstraZeneca vaccine, InstantScripts doctors can help.

Talk to an InstantScripts GP about your vaccine options


You’ve probably lost count of the number of articles you’ve seen about COVID-19. We sure have.

But not all information is good information.

Make sure you source your information from trusted sites, such as the WHO or government websites. Find out more about sorting fact from fiction.

Fill 1 Like us on Facebook

Get the app