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COVID-19: GP Alert (9 April 2021)

April 09, 2021

Important update - use of vaccines in patients under 50

The Australian Technical Advisory Group on Immunisation (ATAGI) has provided new advice on immunisation, in light of the evolving evidence of a rare but serious side effect involving thrombosis with thrombocytopenia following receipt of the AstraZeneca vaccine.

This ‘thrombosis with thrombocytopenia syndrome’ (TTS) is a newly described serious condition, with unusual blood clots in the brain (cerebral venous sinus thrombosis) or in other parts of the body, associated with low platelet levels and can cause serious long term disability or death.

The evidence that connects TTS to receipt of the AstraZeneca vaccine has been reviewed by ATAGI and the Therapeutic Goods Administration (TGA) and subsequently, ATAGI has recommended new changes to the Australian COVID-19 Vaccine Program including a preference for the use of the Comirnaty (Pfizer) vaccine in adults aged under 50 years.

Below is a summary of the new advice:


  • ATAGI notes further evidence of a rare but serious side effect involving thrombosis (clotting) with thrombocytopenia (low blood platelet count) following receipt of COVID-19 Vaccine AstraZeneca.
  • ATAGI recommends that the COVID-19 vaccine by Pfizer (Comirnaty) 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 hence a higher benefit from vaccination) and a potentially increased risk of thrombosis with thrombocytopenia following AstraZeneca vaccine in those under 50 years.
  • COVID-19 Vaccine AstraZeneca can be used in adults aged under 50 years where the benefits are likely to outweigh the risks for that individual and the person has made an informed decision based on an understanding of the risks and benefits.
  • 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 full statement here

Advice for vaccine providers: Prof Paul Kelly, CMO, Australian Government Department of Health

The Australian Government Department of Health's Chief Medical Officer, Professor Paul Kelly, has provided advice to vaccination providers. This includes, in the short term, and in line with ATAGI’s recommendations, that practices may want to contact any patients under 50 who are currently booked to receive their first dose of the AstraZeneca COVID19 vaccine and cancel in cases where the benefit clearly does not outweigh the risk. Read the statement here

ATAGI advice for healthcare providers: the warning signs of thrombosis

As per the previous ATAGI statement on April 2, 2021, please remain alert for warning signs of TTS.

Scripts for general practices to assist with patient inquiries

The Australian Government Department of Health has provided a script to assist with inquiries from patients about the new advice relating to the AstraZeneca vaccine.

TGA advice

The Therapeutic Goods Administration has provided updated safety advice for the AstraZeneca vaccine. Read the advice here

Joint statement on COVID-19 AstraZeneca vaccine advice

Read the joint statement from Professor Brendan Murphy, Department of Health Secretary and Professor Paul Kelly, Australian Government Chief Medical Officer.