Question Number: 175
PDR Number: SQ22-000165
Date Submitted: 24/02/2022
Department or Body: Department of Health

The Senator’s assertion is not backed up by Australian or global experience – safety monitoring does not indicate that the risk of adverse events increases after a booster.

To 27 February 2022, approximately 11.4 million boosters or third doses have been administered in Australia. The Therapeutic Goods Administration (TGA) has received approximately 4,100 reports of suspected adverse events following a third or booster dose. The pattern of adverse events is similar to those for first and second vaccine doses and does not suggest any emerging safety concerns or increased risk of side effects following a third or booster dose.

In fact, myocarditis has been reported less frequently after a booster dose than a second dose in Australia, the United States and the United Kingdom. To 10 March 2022, myocarditis has been reported in less than one in every 100,000 people after a booster or third dose in Australia. The TGA publishes information about the reporting rate of myocarditis after a booster or third dose in its weekly COVID-19 vaccine safety report.

Thrombosis with thrombocytopenia syndrome (TTS) is a rare but serious adverse event linked to the Vaxzevria (AstraZeneca) vaccine. People with TTS have blood clots and low blood platelets. The rate of reporting of TTS after a second dose of Vaxzevria is much lower than after the first dose (2.1 reports per 100,000 first doses versus 0.3 reports per 100,000 second doses); and as of 6 March 2022, no cases of TTS have been reported in Australia following a booster dose of this vaccine.