The death of a NSW woman who developed blood clots in her arteries and veins was ‘likely’ linked to the AstraZeneca vaccine, health authorities have confirmed.
But Australians have been told people are eight times more likely to develop blood clots from catching the coronavirus itself than from getting the AstraZeneca jab.
The Therapeutic Goods Association (TGA) met on Friday afternoon to review the case of the 48-year-old woman the ABC has identified as Genene Norris, from the NSW Central Coast.
The TGA’s early finding was her death “is likely to be linked to vaccination”.
Ms Morris, who was a diabetic and had several chronic health issues, was admitted to hospital four days after her jab and was the third person in Australia to present with thrombosis (blood clots in the arteries and veins) and low platelet count (thrombocytopenia).
She reportedly received her jab on the same day the federal government announced AstraZeneca would no longer be the preferred option for Australians under 50.
As an investigation continues into the woman’s death, medical authorities are calling on Australians not to cancel their bookings, saying the risk of blood clots is higher from the disease itself.
Chief Medical Officer Paul Kelly quoted a new Oxford University study which found the risk of developing blood clots in the brain is eight to ten times more likely after a COVID-19 infection than a vaccine.
“Clotting is a feature of COVID,” Prof Kelly said.
“It also happens to be a feature, very rarely, of the AstraZeneca vaccine.
“But the benefit absolutely, and particularly for those over the age of 50, outweighs significantly the risk.”
The Oxford University study, which is yet to be peer reviewed, found the virus itself is still far more dangerous, with the risk of blood clots up to 10 times higher than the Pfizer and Moderna jabs and eight times higher than AstraZeneca.
Researchers examined and compared over 500,000 coronavirus diagnoses and more than 480,000 recipients of a mRNA vaccine – either the Pfizer or Moderna jab.
Based on US data, it found blood clotting in the brain – cerebral venous thrombosis or CVT – occurs in 39 people per million diagnosed with COVID-19, compared with 4.1 people per million who have received the Pfizer or Moderna vaccine.
The study notes the European Medicines Agency estimates that 5 per million people who receive the AstraZeneca vaccine develop CVT.
On those numbers, a person is 10 times more likely to develop a blood clot in the brain after contracting COVID-19 than after receiving a mRNA vaccine.
The risk posed by COVID-19 infection is eight times that of the AstraZeneca vaccine.
However Dr Daryl Cheng, the medical lead of the Melbourne Vaccine Education Centre, pointed out the study focused on CVT, which is only part of the syndrome linked to the AstraZeneca vaccine.
The thrombotic thrombocytopenia syndrome is characterised not just by clots in the brain and abdomen but in other areas of the body and also causes low platelet counts.
“Comparing isolated CVT with … the syndrome of interest following COVID-19 AstraZeneca vaccine means we actually may be comparing two separate entities and drawing conclusions that are not entirely accurate,” he said.
“With a low incidence of COVID-19 disease in Australia, and hence an absence of this increased risk of thrombosis, this study does not directly impact or should not change our approach to a COVID-19 vaccine rollout,” he said.
Infectious disease doctor Michelle Ananda-Rajah agreed the scope of the study was a concern.
“Vaccine induced thrombotic thrombocytopenia has a higher published mortality of 55 to 60 per cent … compared to the 18 to 20 per cent described in this report,” she said.
However Griffith University Associate Professor of Haematology Dr Indu Singh said she believed vaccinations should continue in earnest in regions with community transmission.
“More evidence is required, and quickly, to make a conclusive statement but in the meantime, some protection is better than nothing,” she said.