Advice on COVID-19 AstraZeneca vaccine

Following a review of the use of the COVID-19 AstraZeneca vaccine by the Australian Technical Advisory Group on Immunisation (ATAGI) and the Therapeutic Goods Administration, the following recommendations have been made and accepted by the Australian Government:

  • ATAGI recommends that the COVID-19 vaccine by Pfizer is preferred over COVID-19 Vaccine AstraZeneca in adults aged under 50 years. This recommendation is based on the increasing risk of severe outcomes from COVID-19 in older adults, and a potentially increased risk of thrombosis with thrombocytopenia following AstraZeneca vaccine in those under 50 years.
  • People who have had the first dose of COVID-19 Vaccine AstraZeneca without any serious adverse effects can be given the second dose, including adults under 50 years.

Read the statement from the Department of Health Secretary and Chief Medical Officer.

What is this new side effect?

The clotting syndrome that has been linked to the AstraZeneca vaccine is extremely rare.

Thrombosis is the formation of a blood clot, which prevents blood flowing normally through the body.

Thrombocytopenia is a condition in which you have a low blood platelet count. Platelets (thrombocytes) are blood cells that help blood clot. Platelets stop bleeding by clumping and forming plugs in blood vessel injuries.

Thrombosis with Thrombocytopenia Syndrome (TTS) is a rare and new syndrome which involves blood clots (occurring in body sites like the brain or abdomen) together with low platelet levels.

Why has ATAGI made this recommendation?

When balanced with the fact that older people have a higher risk of complications from COVID-19, and potentially a lower of risk of developing this extremely rare clotting syndrome, ATAGI is recommending that people over 50 should still receive the AstraZeneca vaccine.

For people under 50, the Pfizer vaccine is recommended over the AstraZeneca vaccine.

The Pfizer COVID-19 vaccine does not appear to carry a risk of causing the clotting syndrome.

Is the AstraZeneca vaccine safe?

Yes. The individual benefit-to-risk balance of vaccination with the AstraZeneca COVID-19 vaccine varies with age. This balance is based on factors including the increased risk of complications from COVID-19 with increasing age and the potential lower risk of this very rare, but serious, adverse event with increasing age.

ATAGI has advised the AstraZeneca vaccine remains safe and is recommended to be given to people aged 50 years and over.

I’ve had an AstraZeneca vaccine within the last three weeks – what should I do?

The clotting syndrome that has been linked to the AstraZeneca vaccine is extremely rare.

You may experience some side effects following vaccination. Most side effects last no more than a couple of days and you will recover without any problems.

Common reactions to vaccination include pain, redness and/or swelling where you received the needle, mild fever, headache and flu-like symptoms.

Serious reactions such as allergic reactions are extremely rare.

Use the COVID-19 vaccine side effects symptom checker if you have concerns about any symptoms after your vaccine. The checker is also available through the National Coronavirus Helpline on 1800 020 080, 24 hours a day.

People should seek medical attention immediately if they experience any of the following symptoms:

  • shortness of breath
  • chest pain
  • swelling in your leg
  • persistent abdominal (belly) pain
  • neurological symptoms, including severe and persistent headaches or blurred vision
  • tiny blood spots under the skin beyond the site of injection.

If you go to your GP or a hospital with any concerns, please let them know that you have recently had the AstraZeneca vaccine.

If you’ve had your first dose of the AstraZeneca vaccine without developing this condition, then you can safely receive your second dose regardless of your age.

I’ve had my first dose of AstraZeneca, can I switch to Pfizer for my second dose?

To be fully vaccinated against COVID-19 you must have two doses of the same vaccine.
If you’ve had your first dose of the AstraZeneca vaccine without developing Thrombosis with Thrombocytopenia Syndrome (TTS) or experiencing another serious adverse event, then you can safely receive your second dose regardless of your age.

What if I don’t want my second dose of AstraZeneca?

Getting vaccinated is not mandatory. However, we strongly encourage you to get vaccinated as COVID-19 can cause serious ongoing health conditions, and sometimes death.

To be fully vaccinated against COVID-19 you must have two doses of the same vaccine.

If you’ve had your first dose of the AstraZeneca vaccine without developing Thrombosis with Thrombocytopenia Syndrome (TTS) or experiencing another serious adverse event, then you can safely receive your second dose regardless of your age.

What is a serious adverse event?

A serious adverse event after a vaccination:

  • is life-threatening
  • requires in-patient hospitalisation or prolongs existing hospitalisation
  • results in persistent or significant disability/incapacity
  • requires intervention to prevent one of the outcomes above.

If you think you’ve experienced a serious adverse event, please speak to your GP or vaccine provider.

Why is AstraZeneca still recommended for people over 50?

It is important to note the AstraZeneca vaccine remains highly effective at preventing death and severe illness among people who have contracted COVID-19 – and that the incidence of the blood-clotting syndrome is very rare.

ATAGI has advised the AstraZeneca vaccine remains safe and is recommended to be given to people aged 50 years and over, and may be given to people aged 50 years and over.

While Australia currently has very low or no community transmission of COVID-19, this could change. The risk of serious disease and death in Australia remains, even as border controls and other measures continue.

The individual benefit-to-risk balance of vaccination with the AstraZeneca COVID-19 vaccine varies with age. This balance is based on factors including the increased risk of complications from COVID-19 with increasing age and the potential lower risk of this very rare, but serious, adverse event with increasing age.

If I’m on the pill or already susceptible to blood clots for another reason, am I at a higher risk of developing TTS?

So far no specific biological risk factors or pre-existing medical conditions have been found to modify (i.e. increase or decrease) the risk of Thrombosis with Thrombocytopenia Syndrome TTS occurring after AstraZeneca vaccine. However, if you have any concerns, you should discuss them with your doctor.

While there have been more reports of TTS in women in some settings, this may be because more vaccine doses have been given to women. In one country the reported rate of TTS (number of cases adjusted for the number of men and women vaccinated) was similar in men and women.

ATAGI recommends that vaccination with any COVID-19 vaccine should be deferred for people who have a confirmed medical history of :

  • cerebral venous sinus thrombosis (CVST)
  • heparin induced thrombocytopenia (HIT)
  • idiopathic splanchnic (mesenteric, portal and splenic) venous thrombosis
  • anti-phospholipid syndrome with thrombosis.

Why is the advice different to other countries?

Each country’s advice has been informed by the local risk for COVID-19, how much of the population has already been vaccinated and in what age groups, and whether they have an alternative supply of vaccines.

Australia currently has very low or no community transmission of COVID-19, but this could change. The risk of serious disease and death in Australia remains, even as border controls and other measures continue.

The risk-versus-benefit assessment for the use of AstraZeneca COVID-19 vaccine is different for Australia compared to other countries, such as those with widespread transmission. This includes countries in our region such as those currently experiencing very serious outbreaks of COVID-19, such as Timor Leste, Papua New Guinea and others.

Who can I speak to if I have concerns?

If you’d like to speak to someone, you can call National Coronavirus Helpline 1800 020 080, your GP or your vaccine provider if you’ve already been vaccinated or have an appointment to be vaccinated.