Premiers and territory leaders raised concerns in April about whether it was safe to give AstraZeneca jabs to Australians aged 50 and over during a national cabinet deliberation mulling expert health advice.
The Morrison government on 8 April announced it had accepted expert advice that Pfizer be the preferred vaccine for under 50s and AstraZeneca the preferred Covid inoculation for Australians over 50.
That announcement by Scott Morrison followed accumulating evidence that the AstraZeneca jab was associated with extremely rare but potentially deadly blood clots.
Guardian Australia can reveal during a national cabinet discussion the next day, the Queensland premier, Annastacia Palaszczuk, raised a number of questions about whether the line should be drawn at 60 years of age rather than 50, citing publicly available advice from the Therapeutic Goods Administration about blood clots found in other jurisdictions in women under 60.
The TGA advice the Queensland premier referred to referenced findings from the European Medicines Agency that most reports of the rare blood clots possibly linked to the AstraZeneca vaccine were in women aged under 60 – although that advice noted “an association with gender has not been firmly established”.
Guardian Australia understands other leaders also raised concerns and asked a number of questions during a discussion exploring whether there were different views between the TGA and the expert Australian Technical Advisory Group on Immunisation (Atagi) over whether the cut-off for AstraZeneca should be 50 or 60.
At one point during the discussion, the New South Wales premier, Gladys Berejiklian, said communications around the decision needed to be clear in order to avoid supercharging vaccine hesitancy.
The TGA was not represented at the national cabinet meeting on 9 April but Prof Allen Cheng, who is the co-chair of Atagi, gave a detailed presentation to the leaders outlining the advice informing the recommendation that AstraZeneca only be given to Australians over 50.
The national cabinet meeting resolved to accept the health advice from Atagi which was the formal recommendation of the commonwealth.
Cheng said publicly after the meeting that health advisers, in making the determination, were balancing the risks of a negative side-effect due to vaccination and the benefit of a reduced risk of Covid.
The Atagi advice published on 8 April also made it very clear the recommendations could be revised “as more information becomes available or if the epidemiological situation changes, particularly if there is, or is likely to be significant community transmission”.
Atagi changed its advice on Thursday.
More than 2 million people aged 50-59 who were previously advised to take AstraZeneca vaccine are now being told to take the Pfizer jab – a decision that experts warn will further strain supplies and could lead to a spike in vaccine hesitancy.
“Sixty people have had this rare clotting syndrome over the past 10 weeks in Australia,” Atagi co-chair Associate Prof Christopher Blyth told ABC’s 7.30 program on Thursday. “We’re very keen to make sure that we have a program that can instill confidence and deliver vaccines safely.”
Australia’s chief medical officer, Prof Paul Kelly, said the “risk benefit equation” had now changed for the over 50s because of the reported incidence of the rare blood clotting condition known as thrombosis with thrombocytopenia syndrome (TTS).
The TGA said on Thursday there were a further 12 reports of blood clots and low blood platelets assessed to be confirmed or probable cases of TTS linked to the AstraZeneca vaccine in the past week. Of those, seven were aged in their 50s.
The three confirmed cases were two Victorian women aged 55 and 65 and a 53-year-old woman from NSW.
It takes the total Australian reports of TTS following the AstraZeneca vaccine to 37 confirmed and 23 probable cases. There have been two deaths.
The estimated risk of TTS following the first dose is 3.1 per 100,000 for people under 50, 2.7 for people between 50 and 59, 1.4 for people between 60 and 69, 1.8 for people 70 to 79, and 1.9 for people over 80 years of age.
The chief medical officer said on Thursday that Australians over 50 who had followed the previous health advisory and had their first AstraZeneca jab should proceed and have the second shot.
Kelly said if people had not experienced problems after the first jab they should “feel very confident to have their second dose and should keep that booking”. He cited data from Britain showing the incidence after the second dose was one in 1.5m.
The federal health minister, Greg Hunt, made it clear on Thursday the shift followed a change in the medical advice and the government had followed the advice of experts throughout the pandemic.
