In Australia, Comirnaty (Pfizer COVID-19 vaccine) is the preferred vaccine for adults aged under 50 years and COVID-19 Vaccine AstraZeneca is recommended for adults aged 50 years and over.
This recommendation is based on:
- the increasing risk of severe outcomes from COVID-19 in older adults (and hence a higher benefit from vaccination), and
- a potentially increased risk of thrombosis with thrombocytopenia (TTS) following AstraZeneca vaccine in those under 50 years.
Both vaccines are highly effective at preventing severe disease, hospitalisation and death, and vaccination is the best way to protect yourself, your family and our communities from severe COVID-19 illness.
Understandably, people want to know if there are exceptions to these recommendations.
Current clinical advice
At the time of writing, under the current clinical guidance on use of COVID-19 vaccine in Australia, the only absolute contraindications to a COVID-19 vaccine are:
- anaphylaxis after a previous dose of the same vaccine
- anaphylaxis to any component of the vaccine, including:
- anaphylaxis to polyethylene glycol (PEG) for Comirnaty
- anaphylaxis to polysorbate 80 for COVID-19 Vaccine AstraZeneca
There are also some precautions for consideration and these are outlined in the clinical guidance on use of COVID-19 vaccine in Australia (page 14).
In summary, the Australian Technical Advisory Group on Immunisation (ATAGI) recommends the following:
- Comirnaty (Pfizer vaccine) is preferred over COVID-19 Vaccine AstraZeneca in adults aged under 50 years.
- The AstraZeneca vaccine can still be given to adults under 50 years if vaccine benefits are likely to outweigh the risk and the patient has provided informed consent.
- If the first dose of AstraZeneca vaccine has already been given with no serious adverse events, such as TTS or anaphylaxis, AstraZeneca vaccine can be given as the second dose.
- Comirnaty (Pfizer) is the preferred vaccine for people with a past history of cerebral venous sinus thrombosis or heparin-induced thrombocytopenia. This is precautionary advice, based on a theoretical concern that these patients may have an increased risk of TTS, however, there is no evidence yet to suggest this is the case.
- There is no evidence that people with any other previous thromboembolic disorders or other clotting tendencies have an increased risk of this unique thrombosis with thrombocytopenia after vaccination. AstraZeneca vaccine can be given to such patients.
This advice may be revised as more information becomes available, or if the epidemiological situation of COVID-19 in Australia changes.
For more information see:
- Mid and North Coast COVID-19 Vaccination HealthPathways
- Username: manchealth
- Password: conn3ct3d
- ATAGI: Clinical guidance on use of COVID-19 vaccine in Australia in 2021 V3.0
- COVID-19 vaccination provider resources
- Information on Thrombosis with Thrombocytopenia Syndrome following COVID-19 vaccination
- NCIRS: FAQ COVID-19 vaccines
Top tip: the best way for people to find out when and where they can get vaccinated is using the vaccine eligibility checker or calling the COVID-19 vaccine hotline on 1800 020 080.