COVID-19 vaccines: Frequently asked questions (FAQs)

Icon image: vaccine vial
Icon image: vaccine vial

Key points

  • COVID-19 is a disease caused by the SARS-CoV-2 virus. SARS-CoV-2 can change over time, leading to new variants of COVID-19.  
  • Older people and people with certain medical conditions – including infants and children – are at the highest risk of severe disease or death from COVID-19.  
  • COVID-19 vaccines are safe and effective and are available free of charge, even if you don’t have a Medicare card.
  • COVID-19 vaccine recommendations are based on several factors, including age, time since last dose and presence of certain medical conditions. New recommendations are made based on the changing COVID-19 situation.
  • Omicron XBB.1.5 variant vaccines are now preferred for all individuals who are recommended to receive a COVID-19 vaccine. 
  • An XBB.1.5 formulation for use in infants and children aged 6 months to less than 5 years has been approved for use but is not yet available. Availability is anticipated in 2024. 
  • COVID-19 vaccines can be co-administered with other vaccines in people aged 5 years and over, including influenza vaccines.
  • It is preferred that infants and children aged less than 5 years separate routine childhood vaccinations and COVID-19 vaccination by 7–14 days. If this is not practical, routine vaccinations can be given on the same day as a COVID-19 vaccine.

This page was last updated in March 2024 and includes the most recent Australian Technical Advisory Group on Immunisation (ATAGI) advice on the administration of COVID-19 vaccines in 2024.

COVID-19 vaccine recommendations will be reviewed annually – or earlier, if new evidence emerges or epidemiology changes. This resource will be updated to reflect new recommendations as they are issued.


Which COVID-19 vaccines are currently being used in Australia? 

There are two types of approved COVID-19 vaccines: 

  1. messenger RNA (mRNA) vaccines, including Comirnaty (Pfizer) and Spikevax (Moderna) 
  2. protein-based vaccines, including Nuvaxovid (Novavax). 

All COVID-19 vaccines available in Australia are expected to provide benefit to eligible people; however, the new monovalent Omicron XBB.1.5 variant mRNA vaccines are now preferred over other vaccines for all persons aged 5 years and over.

Nuvaxovid (Novavax) is not currently available in Australia.

Who is recommended to receive a COVID-19 vaccine?

At least 1 dose of COVID-19 vaccination is recommended for people aged 18 years and over.

Vaccination is also recommended for children aged 6 months to 18 years with severe immunocompromise or other medical conditions that may increase their risk of severe disease from COVID-19. See the Australian Immunisation Handbook for who is considered severely immunocompromised and a list of other medical conditions that may increase the risk of severe disease from COVID-19.

Which COVID-19 vaccines are approved for use in which age groups? 

Different COVID-19 vaccines are approved for use in different ages. Specifically:

  • Comirnaty (Pfizer) Original 6 months to <5 years formulation (maroon cap) is approved for children aged 6 months to less than 5 years. An XBB.1.5 formulation for use in infants and children aged 6 months to less than 5 years has been approved for use but is not yet available. The XBB.1.5 formulation will be the preferred vaccine for this age group when available in 2024. 
  • Comirnaty (Pfizer) Omicron XBB.1.5 5 to <12 years formulation (light blue cap) is preferred for children aged 5 years to less than 12 years. Comirnaty (Pfizer) Original 5 to <12 years formulation (orange cap) can also be used but is not preferred.
  • Comirnaty (Pfizer) Omicron XBB.1.5, ≥12 years formulation (dark grey cap) and Spikevax (Moderna) Omicron XBB.1.5 (pre-filled syringe) are preferred vaccines for adolescents and adults aged 12 years and over. Comirnaty (Pfizer) bivalent Original/Omicron BA.4/5 ≥12 years formulation (grey cap) can also be used in this age group but is not preferred.

A summary of all COVID-19 vaccines approved for use in Australia is available here

How do COVID-19 vaccines work?

COVID-19 vaccines work by ‘teaching’ and ‘reminding’ the immune system how to recognise SARS-CoV-2, the virus that causes COVID-19.

The Pfizer and Moderna COVID-19 vaccines are mRNA vaccines that contain the genetic code for a part of the SARS-CoV-2 virus called the spike protein. After getting the injection, your body ‘reads’ the genetic code and makes copies of the spike protein. Your immune system then detects these spike proteins and responds. The genetic code is quickly broken down and cleared away by the body.

Novavax is a protein-based vaccine. The proteins contained in the vaccine resemble the SARS-CoV-2 virus spike protein and trigger a response from your immune system. Like the mRNA vaccines, this vaccine does not contain any live component of the virus.

COVID-19 vaccines cannot cause COVID-19 disease.

What is the difference between the original COVID-19 vaccines and the vaccines that have recently been approved for use in Australia?  

The original COVID-19 vaccines – Pfizer, Moderna and Novavax – contain the original (ancestral) variant of SARS-CoV-2. The Pfizer bivalent vaccine contain both the original (ancestral) variant and the Omicron BA variants of the virus. The latest Omicron XBB.1.5 vaccines contain the more current Omicron XBB.1.5 variant.

Why have the new Omicron XBB.1.5 variant COVID-19 vaccines been developed?

These new vaccines target more current strains (or ‘subvariants’) of the Omicron variant. In Australia, Pfizer Omicron XBB.1.5 and Moderna Omicron XBB.1.5 vaccines are available and are now preferred over other available COVID-19 vaccines. 

What is meant by a ‘primary dose’ and a ‘primary course’ of COVID-19 vaccine?

Primary doses are the first doses of the COVID-19 vaccine given to an individual, to ‘introduce’ their immune system to the SARS-CoV-2 virus.

The full set of ‘introductory’ doses that an individual receives is known as the primary course.

How many primary doses of COVID-19 vaccines are recommended? 

The recommended schedule for COVID-19 vaccines depends on a person’s age and the presence of other medical conditions.

Most people need 1 primary dose of the COVID-19 vaccine. However, young children and some people whose immune systems are affected by medical conditions may need 2 or 3 COVID-19 primary doses.

Adults aged 18 years and over who have not previously received a COVID-19 vaccine are recommended a single primary dose.  

People with severe immunocompromise who have not previously received a COVID-19 vaccine are recommended to receive 2 primary doses and can consider a third dose based on a risk–benefit assessment.

Children and adolescents aged 5 years to less than 18 years with conditions that may increase the risk of severe COVID-19 and who have not previously received a dose of COVID-19 vaccine can receive a single primary dose. At-risk children aged 6 months to less than 5 years can receive 2 primary doses and can consider a third dose. 

Who should receive further COVID-19 vaccine doses after their primary course?

Some people who have completed their primary course are recommended to receive further doses of COVID-19 vaccine every 6 or 12 months.

Adults aged 75 years and over are recommended to receive a dose every 6 months.

ATAGI recommends the following groups to receive a dose of COVID-19 vaccine every 12 months. Individuals in these groups can consider receiving a dose every 6 months, based on a risk–benefit assessment: 

  • adults aged 65–74 years
  • adults aged 18–64 years with severe immunocompromise.

The following groups can consider receiving a COVID-19 vaccine every 12 months, based on a risk–benefit assessment:

  • all other adults aged 18—64 years
  • children and adolescents aged 5 years to less than 18 years with severe immunocompromise.

People with a history of COVID-19 can receive further doses of vaccine as recommended. Refer to ‘Can COVID-19 vaccines be given to people who have had COVID-19 in the past?’

What are the common side effects of COVID-19 vaccines?

The most common side effects of COVID-19 vaccines include pain at the injection site, tiredness, headache, muscle pain, chills, joint pain and fever. These symptoms are temporary and usually go away without treatment in 1–2 days. Paracetamol or ibuprofen can be taken to reduce side effects.

How can potential side effects after vaccination be reported?

Both individuals and their healthcare providers can report side effects to the relevant state or territory health authority or directly to the Therapeutic Goods Administration.

In some states and territories, it is mandatory for healthcare providers to report side effects after COVID-19 vaccines.

Reporting of side effects supports the TGA in detecting any safety concerns relating to the use of COVID-19 vaccines.

Can COVID-19 vaccines be co-administered with other vaccines (e.g. the influenza vaccine)?

Yes, in people aged 5 years and over, a COVID-19 vaccine can be co-administered with (i.e. given on the same day as) other vaccines, including the influenza vaccine, childhood and adolescent vaccines, and vaccines given later in life.

For children aged 6 months to less than 5 years who are recommended to receive a COVID-19 vaccine, it is preferable to separate administration from other vaccines by 7–14 days, given there is limited evidence on co-administration in this age group. If it is not practical to separate vaccines, routine vaccinations can be given on the same day as a COVID-19 vaccine.

Is there a maximum number of doses for older people or people who are at increased risk of severe COVID-19? 

There is no recommendation relating to the maximum number of doses for elderly people or people who are at increased risk of severe or complicated COVID-19. All people are recommended to have at least a primary course of COVID-19 vaccines and then follow the most current advice on further doses. 

Can COVID-19 vaccines be given to people who have had COVID-19 in the past?

Yes, COVID-19 vaccines can be given to people with a history of SARS-CoV-2 infection.

The immune response given from the combination of past infection(s) and vaccination (called ‘hybrid immunity’) provides important protection against severe COVID-19. 

COVID-19 testing rates have dropped, and some people may not know if they have had a recent COVID-19 infection. In these circumstances, it is best to go ahead with your next COVID-19 vaccine dose at the recommended time.

There is little benefit from having a COVID-19 vaccine dose in the first few months after a confirmed infection (i.e. one detected via a positive RAT or PCR test); however, having a vaccine dose after a recent COVID-19 infection is not harmful.

It can be helpful to think of a confirmed infection as a ‘dose of protection’ – just like a vaccine dose. The timing of further doses following infection would be based on current recommendations for your age and your medical background.

Are COVID-19 vaccines recommended for people who are immunocompromised? 

Yes. Immunocompromised people are at higher risk of severe COVID-19 disease and are encouraged to keep up to date with the number of vaccine doses recommended for them.

The level of immunocompromise and age of the person will determine the number of recommended doses.

Individuals receiving an immune system-weakening treatment, including chemotherapy, should discuss the timing of vaccination with their treating healthcare provider.

A summary of ATAGI’s recommendations on COVID-19 vaccination doses for individuals who are severely immunocompromised is available in the Australian Immunisation Handbook

Are COVID-19 vaccines recommended for women who are pregnant, breastfeeding or planning pregnancy? 

Yes, it is safe for COVID-19 vaccines to be administered during pregnancy, while breastfeeding or when planning pregnancy.

Unvaccinated pregnant women are at increased risk of severe disease from COVID-19. Pregnant women who have previously been vaccinated can discuss with their healthcare provider whether to have an additional dose during their pregnancy, based on an individual risk–benefit assessment.

mRNA vaccines are preferred in pregnancy, and ATAGI considers the latest XBB.1.5 variant mRNA vaccines equivalent to the other mRNA vaccines in terms of suitability and safety for pregnant women.

There are limited safety data on use of Novavax during pregnancy; however, it can be used if the benefits to the individual are judged to outweigh the risks.

Women who are breastfeeding do not need to stop breastfeeding after COVID-19 vaccination.

Women who are planning pregnancy do not need to delay pregnancy after COVID-19 vaccination. 

Are further COVID-19 vaccines recommended before travel? 

There is no specific recommendation to get a further COVID-19 vaccine prior to travel. 

However, individuals aged between 18 and 64 years can discuss the potential benefits of receiving a further dose before travelling with their healthcare provider, since this can reduce the risk of catching COVID-19 for a few months after receiving the vaccine. 

Can a recommended further dose be administered sooner than the recommended interval?

Individuals can receive further doses earlier than the recommended interval in certain circumstances, such as: 

  • before starting immunosuppressant therapy
  • before overseas travel
  • if they cannot reschedule vaccination easily, such as in an outreach vaccination program.

How effective are COVID-19 vaccines?

Several real-world studies of vaccination programs in countries including Australia, the US and the UK have shown COVID-19 vaccines provide strong protection against severe disease.

COVID-19 vaccines reduce the risk of severe disease by around 50–80% compared to someone who is not vaccinated. They provide the greatest benefit to people who remain at high risk of severe disease, such as older adults and people with certain medical conditions.

The protection provided by COVID-19 vaccines lessens (or ‘wanes’) over time, and so sometimes people are recommended further doses to restore protection.

Children and most adults aged less than 65 years are now well protected against severe COVID-19 disease, because previous vaccine doses, past infections and changes in the virus have reduced their risk to low levels. This is why they are recommended to receive fewer doses of vaccine than older adults and others at higher risk of severe disease.

Vaccines that use newer strains (or ‘subvariants’) provide marginally better protection against severe disease, but the original COVID-19 vaccines remain very effective.

COVID-19 vaccines are less effective against preventing sickness from COVID-19. They can reduce the risk of sickness by up to 40% compared to those who are not vaccinated. This protection ceases by 6 months after a dose.

How long does protection from a COVID-19 vaccine last?

While protection from COVID-19 vaccines reduces over time, many studies have shown protection against severe disease remains high at least 6 months after vaccination. Further COVID-19 doses are recommended for people at higher risk of serious illness to provide ongoing protection. 

What is long COVID? 

Long COVID (also known as ‘post-COVID-19 condition’) is a condition in which people with COVID-19 experience persistent symptoms for many months. Common symptoms include fatigue, shortness of breath and cognitive dysfunction (‘brain fog’). Symptoms can fluctuate or relapse (come back) over time.

Long COVID can affect both children and adults. It is not yet known how long symptoms last.

Treatment for long COVID depends on symptoms. A healthcare professional can outline the options available. 

Do COVID-19 vaccines protect against long COVID?

Yes – vaccines are effective at preventing COVID-19 infection and therefore reduce the risk of complications of COVID-19, such as long COVID.

There is some evidence that vaccinated people who develop a COVID-19 infection may be less likely to experience long COVID symptoms than unvaccinated people. If an individual is suffering from long COVID at the time of receiving a dose of the COVID-19 vaccine, it is unclear whether the vaccine will reduce the severity or duration of their long COVID symptoms.

What are myocarditis and pericarditis, and what is the risk of developing these conditions after receiving a COVID-19 vaccine?

Myocarditis and pericarditis are rare conditions where the heart muscle (myocarditis) or the lining around the heart (pericarditis) become inflamed. They can occur separately or concurrently. They can occur as a result of a range of different causes, including COVID-19 itself.

Myocarditis and pericarditis have been associated with COVID-19 vaccines. The risk is very small but is more likely after the second dose of mRNA vaccines (Moderna and Pfizer) in young males aged 15–40 years.

For individuals who have symptoms potentially consistent with myocarditis and/or pericarditis after a COVID-19 vaccine, assessment from a healthcare professional is required. ATAGI gives detailed advice on assessment, management and follow-up.

How is vaccine safety monitored after a COVID-19 vaccine is approved for use?

The TGA assesses the quality of every batch of vaccine before it is distributed in Australia. It also collects, analyses and reports data on vaccine side effects once a vaccine is in use. Individuals and healthcare providers can also report side effects directly to the TGA.

Additionally, programs such as AusVaxSafety collect information from individuals regarding side effects experienced after vaccination. Experts analyse this information to detect any safety issues as soon as possible. 

Can people have COVID-19 vaccines for free if they don’t have a Medicare card?

Yes, everyone in eligible age groups, including those without a Medicare card, can receive free COVID-19 vaccination. Further details about how to receive free COVID-19 vaccination can be found here.

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