Find out more about the Pfizer COVID-19 vaccine, including how it works, who it's recommended for and potential side effects.
Approval for use in Australia
The Comirnaty (Pfizer) vaccine is currently available as a:
- first and second dose for people aged 5 years and over
- third dose for people aged 5 years and over with severe immunocompromise
- booster dose for people aged 16 years and over.
The primary course of Pfizer COVID-19 vaccine for most people is 2 doses, 8 weeks apart.
Children aged 5-11 years will receive Pfizer for children. This is a different formulation of the Pfizer vaccine with a smaller dose.
It is preferable to have the first two doses 8 weeks apart, but the interval between doses can be reduced to 3 weeks. A shorter interval may be recommended for people at higher risk of severe COVID-19 (including older adults and people with underlying medical conditions), in an outbreak setting, or prior to international travel.
Booster doses of Pfizer are available to everyone 16 years and over who have had their primary course of a COVID-19 vaccine at least 3 months ago.
You may not be fully protected against COVID-19 until 7 to 14 days after your second dose or booster.
Staying up to date
To be considered up to date with COVID-19 vaccination, you must have completed all the doses recommended for your age and health status.
Find out about how to stay up to date with COVID-19 vaccines.
What's in the Pfizer vaccine
Pfizer is a messenger RNA (mRNA) vaccine. This type of vaccine uses a genetic code called RNA to make your body's cells produce the coronavirus’ specific spike protein.
Your immune system cells then recognise the spike protein as a threat and begin building an immune response against it. The RNA from the vaccine does not change your DNA in any way, and your body quickly breaks it down.
Pfizer does not contain any live virus and it cannot give you COVID-19.
This video from John Hopkins Bloomberg School of Public Health explains how mRNA vaccines work.
You can read the full Cominarty (Pfizer) Consumer Medicine Information document on the TGA site for more details (click 'I accept' to see the PDF).
Pfizer vaccine for 5 to 11 year olds
On 5 December 2021, the Therapeutic Goods Administration (TGA) provisionally approved the Comirnaty (Pfizer) vaccine for children aged 5 to 11 years .
The TGA’s provisional approval of Pfizer for children was based on a careful evaluation of available data to support its safety and efficacy among this age group.
Vaccinating children can help protect children from getting COVID-19. It can also help prevent children passing the virus onto younger siblings, parents, grandparents and the wider community.
The paediatric vaccine dose of Pfizer for children is one third of the dose for people aged 12 and over.
Children aged 5 to 11 years will receive a 2-dose primary course of vaccination, given 8 weeks apart.
Parents, carers and guardians can book appointments through the Vaccine Clinic Finder. If you can’t find an appropriate appointment, please check back regularly as more appointments will become available.
Note that not all vaccine providers will administer Pfizer to children aged 5 to 11 years.
Common side effects
As with any vaccine, you may have some temporary side effects after receiving Pfizer. This shows your immune system is working.
Common side effects after Pfizer include:
- injection site pain or swelling
- muscle or joint pain
- fever and chills.
Most side effects are mild and go away within 1 to 2 days. AusVaxSafety data shows that side effects are more common after the second dose.
Rare side effects
Myocarditis or pericarditis in young people
In rare cases, myocarditis (inflammation of the heart) and pericarditis (inflammation of the membrane around the heart) can develop after vaccination with Pfizer.
Most cases have mild symptoms and recover well.
The TGA reports that these rare effects on the heart typically occur:
- within 10 days of vaccination
- after the second dose
- more often in men aged under 30.
Contact a doctor or go to hospital immediately if you develop any of the following symptoms after a Pfizer vaccination:
- chest pain
- pressure or discomfort in the chest
- irregular, skipped heartbeats or ‘fluttering’
- shortness of breath
- pain when breathing.
Low risk of developing myocarditis or pericarditis
The risk of developing myocarditis or pericarditis is very low.
In the US, reported rates in males were 10 cases per million after first doses, and 67 cases per million after second doses. The TGA is monitoring the risk in the Australian population.
The risk in children aged 5 to 11 years is not yet known. The clinical trial in children aged 5 to 11 years did not have enough participants to assess rates of myocarditis or pericarditis following the Pfizer COVID-19 vaccine, but no specific safety concerns have been identified so far from millions of doses of this vaccine administered overseas to children aged 5 to 11 years. The benefits of vaccination outweigh this very rare risk, and vaccination is still recommended for all eligible age groups.
You can find out more about myocarditis and pericarditis and COVID-19 vaccines here.
We have printable guidance on myocarditis and pericarditis after mRNA COVID-19 vaccines.
The Melbourne Vaccine Education Centre has a page on myocarditis and pericarditis that includes an explanatory video.
Injection technique unlikely to cause myocarditis
The Australian Technical Advisory Group on Immunisation (ATAGI) does not consider injection technique to cause adverse events because most myocarditis cases occur after the second dose. If accidentally injecting into a blood vessel was a factor, cases would occur equally after both doses.
Risks and benefits
The benefits of vaccination with Pfizer greatly outweigh the risk of side effects.
People who are not recommended to have the Pfizer vaccine
It's not recommended that you have the Pfizer vaccine if you have had:
- a severe allergic reaction (anaphylaxis) to a previous dose of the vaccine
- anaphylaxis after exposure to any component of the vaccine, including polyethylene glycol (PEG)
- myocarditis and/or pericarditis attributed to a previous dose of the vaccine
- any other serious adverse event attributed to a previous dose of the vaccine.
Our patient resources include fact sheets about Pfizer and what to expect after your shot.