Why do I need a booster?

Not all vaccines give us life-long immunity, so we have boosters as a ‘top up’. For example, it’s recommended that we get flu shots every year around winter, because that’s when our risk of flu exposure increases. There are also other vaccines, like tetanus and polio vaccines, that have recommended boosters depending on your risk of exposure. COVID-19 is still active in our community, and we’re all still at risk of being exposed to it, so getting boosters is one key way we can stay protected and reduce our chances of getting seriously sick.

The first doses of the COVID-19 vaccine teach your body how to make antibodies to fight COVID-19, but over time your body will decrease the number of antibodies it makes. This is called waning immunity.

Boosters work in a similar way to the original vaccines: they trigger your body to make more antibodies again, which also keeps you more protected against new COVID variants. That’s why boosters are recommended to top up the strength of your immune system.

You can expect your body to respond to a booster in a similar way to how you felt after your last COVID vaccinations. However, if you experience anything unexpected, you can read about when to seek help or use the COVID-19 Vaccine Side Effect Checker to help you decide what to do.

Note: Some immunocompromised people will have had three doses to receive the same level of protection as everyone else. In this case, the third dose is not the same as a booster, so eligible immunocompromised people will still need a booster (i.e. a fourth dose) three or more months after their last shot. If this applies to you, you can consult with your health professional for more information about what a booster means for your personal health situation.

I've had my COVID booster shot

Do I need to get a booster if I’ve had COVID-19?

Research shows that the natural immunity people get after having COVID-19 can be short-lived. Reinfection is possible in as little as three months, and it’s also important to protect yourself from new variants.

ATAGI’s latest advice is to get a booster as soon as possible after three months have passed since a COVID infection. This reflects the fact that immunity from the Omicron variant in the three-month period after infection is quite strong. ATAGI notes that this advice might change if we get another COVID variant in the future. 

People with long COVID can still get a booster too – discuss with a doctor if you have questions about this. If were hospitalised for COVID-19 received any specialised treatments, talk to your doctor first.

This advice only applies to COVID-19 vaccines. ATAGI notes that it’s still fine to go ahead as usual with other vaccines (for example, flu shots).

Who can get a booster?

In Victoria, you are eligible for a booster if you’re 16 years old or older, and your last shot to get fully vaccinated was three or more months ago. You’re also eligible if you finished getting fully vaccinated at 15 years old and are now 16.

  • If you got your last shot in February 2022 or earlier, your booster is due ASAP
  • If you got your last shot in March 2022, your booster is due in June 2022
  • If you got your last shot in April 2021, your booster is due in July 2022
  • If you got your last shot in May 2022, your booster is due in August 2022

As of 4 February 2022, ATAGI is still reviewing booster shots for people under 16, so it does not currently recommend boosters for this age group.

What options are available?

In Australia, people who are 16 and 17 years old are only able to get Pfizer as a booster (as at 4 February 2022). People in this age group who experienced pericarditis or myocarditis after having Pfizer or Moderna (i.e. mRNA vaccines) should speak to a cardiologist or their regular doctor before deciding if they should get a booster.

For people who are 18 years and older, the Pfizer and Moderna vaccines are currently recommended as booster doses. Alternatively for this age group, AstraZeneca boosters are available to people who:

  • Had AstraZeneca for their primary course of vaccination
  • Have had an adverse reaction to the Pfizer or Moderna vaccines.

Nurse putting a bandaid on a young person's upper arm

How do I get a booster?

Booster shots are available in all the same ways the primary course of vaccines has been, and you can book them in the same way. The only difference is that you will only need a single dose. See our booking guide find a vaccination close to you that suits your needs.

What happens to my COVID-19 vaccine certificate?

Your booster dose will automatically be uploaded to your Australian Immunisation Record. It will also appear automatically on your COVID-19 digital certificate.

As at 28 January 2022, you are still considered fully vaccinated with two doses, and your digital certificate is still valid without a booster. Updates on your digital certificate can be used as evidence for those who work in sectors where you’re required to have a booster (or a medical exemption) to be able to continue working onsite.

What should I do if I have more questions?

If you have specific questions about what the booster will mean for your personal health, it’s always a great idea to talk to a health professional.

Stay up to date with the booster rollout via the Victorian Government Coronavirus Vaccine website. YACVic also posts breakdowns of the latest updates on our Instagram, TikTok, Twitter, Facebook and newsletter.


Australian Technical Advisory Group on Immunisation, ‘Australian Technical Advisory Group on Immunisation (ATAGI) recommendations on the use of Spikevax (Moderna) as a COVID-19 booster vaccine’, 12 December 2021.

Australian Technical Advisory Group on Immunisation, ‘ATAGI Statement on the Omicron variant and the timing of COVID-19 booster vaccination’, 24 December 2021.

Australian Technical Advisory Group on Immunisation, ‘ATAGI recommendations for use of Pfizer COVID-19 vaccine as a booster dose in adolescents aged 16-17 years’, 3 February 2022.

Better Health, ‘Immunisations - catch-ups and boosters’, 7 August 2020.

Matt Woodley, newsGP, ‘COVID immunity following natural infection likely short-lived: Study’, 21 October 2021.

Victorian Government, ‘COVID-19 vaccine third dose’, 19 January 2022.

Victorian Government, ‘Who can get vaccinated against COVID-19’, 27 January 2022.

Last update: 6 May 2022