‘No change’ in risk profile with second blood clot case linked to AstraZeneca

Anastasia Tsirtsakis

13/04/2021 5:04:56 PM

Two cases of clotting in 700,000 administered doses does not indicate an increased level of risk, experts have said.

AstraZeneca vaccine.
The risk of developing the very rare syndrome in Australia is currently one per 350,000.

The news undeniably sounds bad.
The Therapeutic Goods Administration (TGA) has confirmed another Australian case of thrombosis with thrombocytopenia syndrome (TSS) that is likely linked to AstraZeneca’s coronavirus vaccine.
But given it is the second reported case of TTS out of 700,000 doses so far administered in Australia, it represents a risk of one per 350,000.
‘Your chances of winning lotto are much higher,’ TGA Deputy-Secretary Professor John Skerritt told reporters.
The latest Australian case was confirmed on Tuesday after the TGA met with the vaccine safety investigation group on Monday evening, noting similarities with blood clot cases reported in the UK and Europe.
About a fortnight after receiving the vaccine in mid-March, the woman, aged in her 40s, was transferred to Royal Darwin Hospital, where she is in a stable condition in intensive care.

The case comes less than a week after the Australian Government’s decision to revise its use of AstraZeneca, following a recommendation from the Australian Technical Advisory Group on Immunisation (ATAGI) that preferenced the use of the Pfizer vaccine in people under 50.
But Associate Professor Charlotte Hespe, Chair of RACGP NSW&ACT and member of the college’s COVID Working Group, told newsGP while the second case reinforces ATAGI’s findings, it in no way indicates an increased risk.
‘If you look at the numbers there is no change in the risk and no increased risk in Australia than was reported for it to be,’ she said.
‘To put it into perspective for medical procedures which people do every day, there’s a higher risk of things going wrong with people having colonoscopies than there is of [blood clots related to the AstraZeneca vaccine].
‘I don’t really know of any of my patients who would not go ahead with a colonoscopy, because for them the benefit of what the test gives them easily outweighs the risk.’
The sudden change to Australia’s vaccination strategy has created challenges for GPs. Many have reported appointment cancellations from concerned patients over the age of 50, while others have expressed concern over issues of legal liability.
Some practices have even decided to pull out of the vaccination program altogether, citing frustrations over a lack of funding for the longer consultation times required to conduct a risk–benefit analysis with patients to allay any concerns.
‘It’s just the extra amount of time trying to explain to people what the risk is, and why we’re proceeding with the AstraZeneca vaccine,’ Associate Professor Hespe said.
‘What a lot of people don’t understand is that we manage risk all the time, there’s a risk associated with everything. It’s just that this has been so extraordinarily public, of course, [with] the vaccine being new and there being different ones on the market.
‘If you look at the numbers that we’ve vaccinated, it actually aligns with the expected number of cases; in fact, we’re still lower than the expected number.’
Federal Health Minister Greg Hunt on Tuesday acknowledged there had been ‘a couple of hesitations at a practice level’, but noted that national data suggests vaccine uptake remains steady, with 56,000 doses administered in a 24-hour period – 40,000 of which have been delivered across primary care and aged care.
Associate Professor Hespe says while the second case of blood clotting may lead to further apprehension among patients, it reaffirms the need for GPs to look into and understand the information around TTS to help patients make an informed decision.  
‘The interesting thing is that although it is similar to what was described with the Heparin, it is actually a completely separate entity and there is no risk associated with a second dose of AstraZeneca,’ she said.
‘So if people have had the first dose and are afraid of having the second dose, they’ve in fact already been through their “risky” phase and are safe to have the second one – and that the risk remains ridiculously low.
‘Also, by knowing about it and warning people … we’re hopeful that it will actually decrease the mortality associated with it because we’ve got more of an understanding about what’s going on and how to manage it.’
While GPs are well-accustomed to talking through the notion of risk versus benefit with patients, Associate Professor Hespe acknowledges that Australia’s successful response against the virus means talking about the immediate benefits of vaccine can be challenging.
‘Quite honestly, for us in Australia that’s the hardest selling point because we don’t have COVID in our community … whereas there is now this one-in-350,000 risk of developing this rare thrombosis thrombocytopenia syndrome,’ she said.
But as was seen with the rapid escalation of Victoria’s second wave last year, it is important people remember just how quickly that risk level can change.
‘We want to go back to normal and there’s a big push from business, in particular, for us to be opening up our borders and to lower our quarantine regulations,’ Associate Professor Hespe said.
‘Well, the minute you do that, we’re going to have COVID in our community.
‘In fact, we are going to have COVID in our community next year once a large number of people are vaccinated [and borders open up], so then the risk for every individual will actually change – and it may well change this winter if we have another outbreak like we did in Melbourne last year.’
And GPs have a crucial role to play. But Associate Professor Hespe says adequate funding is needed to ensure they feel supported.
‘We need the Government to recognise that this is a very difficult issue, and that GPs need to be financially remunerated for what they’re expecting us to do as part of this,’ she said.
‘At the moment, the payment for doing this has been extraordinarily small and we’re doing it because that’s our business. But it would be nice if the Government actually recognised that it’s a much more complicated rollout than was anticipated.’
Professor Skerritt said on Tuesday that there do not appear to be any other clotting cases related to the vaccine and encouraged GPs to report any suspected cases.
‘When you have an issue like this, we want people to err on the side of caution. Tell us if there is any funny thing happening with clotting,’ he said.
‘Most of the time, it’s coincidental because clotting disorders are common. But when I left my office, there were none that look highly suspicious. That could change in the next 10 minutes, we don’t know.
‘We are encouraging as many doctors [as possible] to report anything suspicious.’
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Dr Duncan MacWalter   14/04/2021 6:38:45 AM

This is most unhelpful. The chance of winning lotto are about 1:8,000,000. So nearly two orders of magnitude greater than the vaccine. If the ATAGI professor can't articulate risk well, what hope do we have? They're had been no legislative change to afford increased legal protection from GPs, and any lawyer would easily argue we have a false risk profile if we used 'winning the lotto' as an analogy.

Dr Stewart James Jackson   14/04/2021 6:48:22 AM

We have vaccinated 10% of Our rural area so far. People understand risk better than the media believe and our clinics are full. How did we ever win a war?

Dr Michael Lucas Bailey   14/04/2021 7:34:55 AM

It’s been a while since I had to calculate the chances of winning lotto in high school maths. It used to be less than 1 in 8 000 000. We should expect more from the TGA Deputy Secretary. Also comparing risk of side effects for a colonoscopy as an investigative/therapeutic procedure with fairly strict guidelines on indication with mass vaccination is inappropriate.

Dr Andrew Robert Jackson   14/04/2021 9:49:48 AM

Substantially increasing after hours VSAS Medicare rebates would be a start.

Our clinic has no interest in running after hours clinics to help the government with its vaccine rollout problem, given the costs involved and the unsociable-hours inconvenience.

Dr Slavko Doslo   14/04/2021 1:27:57 PM

This is try odds Professor, I hope that you can read our comments.
But we poor GP we have to put money from time to time to win something to survive after Medicare/ MBS and politicians slaughter GP's and reimbursements
Thank you for not reading
The following prize divisions can be won (cumulative probability refers to the probability of winning that division or a higher division, thus the chance of winning any prize is 1 in 85):

Division Winning Numbers Required Probability (Single Game) Cumulative Probability (Single Game)
1st Division 6 1 in 8,145,060 1 in 8,145,060
2nd Division 5 + supplementary 1 in 678,755 1 in 626,543
3rd Division 5 1 in 36,689 1 in 34,659
4th Division 4 1 in 733 1 in 718
5th Division 3 + one or both supplementary 1 in 297 1 in 210
6th Division 1 or 2 + 2 supplementary numbers 1 in 144 1 in 85

Dr Robert William Micallef   15/04/2021 12:38:12 AM

1st prize in oz lotto is 1 in 43,000,000. The two cases are the result of far fewer than 700,00 doses as 1. Not all were astra Zeneca. Many were Pfizer. And 2. Both cases arose from doses given to mid March. Far fewer than 700,000. Taking this into account the risk of a major thrombotic event is more like 1 in 100,000.

Dr Robert William Micallef   15/04/2021 6:36:35 AM

Overnight Germany is quoting 1 in 100,000 (which as my previous comment suggests is much closer to the real Australian risk) and Denmark 1 in 40,000 for serious complications of astra Zeneca. If the TGA want to maintain public confidence they need to stop fudging the numbers so blatantly.

Dr Raymond Yeow, BA MBBS FIAA   15/04/2021 12:18:44 PM

There are 200,000 tickets in the $5 Lottery, and 270,000 tickets in the $2 lottery. So the chances of winning first prize is 1:200000 and 1:270,000 respectively for the $5 and $ 2 lotteries.

NSW has a population of 8.1million people; even if there are ten Infections per day (asymptomatic or mild or moderate or severe) ; This is a probability of 1:810,000 of being infected.
If a person buys a $5 lottery every day, the person will have a better chance of winning first prize in the Lottery vs catching an infection which can be asymptomatic or mild or moderate or severe .