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Australian authorities update side effect advice on AstraZeneca vaccine
The ATAGI release confirms most over-50s can receive the vaccine, and that the rare blood clotting linked to AstraZeneca can be treated effectively.
The outcome and prognosis of the majority of people who experience thrombosis with thrombocytopenia syndrome has improved since it was first identified. (Image: AAP)
Almost anyone over the age of 50 can safely receive the AstraZeneca AZD1222 COVID vaccine, new advice from the Australian Technical Advisory Group on Immunisation (ATAGI) states.
It also clarifies that the rare blood clotting condition that has been linked with the use of AstraZeneca’s vaccine in some groups – thrombosis with thrombocytopenia syndrome (TTS) – can now be treated effectively.
Australia’s Chief Medical Officer Professor Paul Kelly recently wrote to doctors informing them of the updated advice, and has urged anyone eligible to ‘not hesitate’ and arrange a time with their GP to discuss getting vaccinated against COVID.
‘There are very few contraindications [and] that’s been narrowed down significantly,’ he told reporters earlier this week. ‘Most people over 50 can have the AstraZeneca vaccine.’
Professor Kelly has warned that cases of TTS are likely to increase as Australia’s COVID vaccination rollout continues to ramp up, but also said treatments for the condition have improved dramatically since it first emerged.
‘As we increase the numbers of vaccines, we do expect to have more cases of this disorder, but there’s [been] 25 so far [out of more than 2.1 million administered doses],’ he said.
‘We had one unfortunate death … [but] of the others, there’s only two remaining in hospital. All the others have gone home.
‘That’s really a testament to the information that has gone out to all doctors and to people that are having the AstraZeneca vaccine about what symptoms to watch out for, to get looked at quickly, to be diagnosed properly, and to be treated properly.’
The most recent ATAGI release confirms that the risk of TTS is not likely to be increased in people with the following conditions (and that over-50s in these groups can still get vaccinated with AstraZeneca):
- History of blood clots in typical sites
- Increased clotting tendency that is not immune mediated
- Family history of blood clots
- History of ischaemic heart disease or stroke
- Current or past thrombocytopenia (low platelet count)
- Those receiving anticoagulation therapy
Additionally, ATAGI reports that
UK data suggest the risk of TTS is much lower following a second dose, with only 15 cases reported to date out of nine million administered, translating to an estimated rate of 1.7 cases per million doses.
However, the list of conditions for which Pfizer is the preferred vaccine has also been expanded to include:
- past history of idiopathic splanchnic (mesenteric, portal, splenic) vein thrombosis
- antiphospholipid syndrome with thrombosis.
This list is in addition to previously identified conditions, namely:
- a past history of cerebral venous sinus thrombosis (CVST)
- a past history of heparin-induced thrombocytopenia (HIT)
- people with contraindications to the AstraZeneca vaccine, ie
- anaphylaxis to a previous dose, or to an ingredient of the vaccine
- TTS occurring after the first dose
- other serious adverse events attributed to the first dose.
The information, released jointly with the Thrombosis and Haemostasis Society of Australia and New Zealand (THANZ), is the first ATAGI update since April and clarifies that TTS can now be treated ‘very effectively’.
Critically, Professor Kelly said Australia has been able to observe what has happened in the rest of the world and learn from their experiences with TTS.
‘The key issue there is to not use the type of medicine we usually use for clots, which is called heparin, because that can make things worse,’ he said.
‘Some of the early unfortunate events and higher death rates in Europe in particular were because people had received that medicine, which actually inadvertently made the situation worse.
‘Due to better awareness, early diagnosis and appropriate treatment, the outcome and prognosis of the majority of those who have experienced this syndrome is good.’
Haematologists Dr Danny Hsu and Dr Vivien Chen will provide a review of Australian cases of TTS, discuss the newly-released guidelines, and look at how to address patient concerns in a webinar at 7.00 pm (AEST) on 31 May. Register on the RACGP website.
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