Blood clot case under investigation following Pfizer vaccine

The Therapeutic Goods Administration (TGA) and Queensland Health are investigating the case of a 40-year-old man who presented to hospital on Wednesday three days after receiving the Pfizer vaccine, but is not currently admitted.  
 
The policeman, who works in the state’s hotel quarantine system, has a history of clotting, having recently developed deep vein thrombosis after undergoing knee surgery.
 
‘It’s too early to say whether this incident is linked to the Pfizer vaccine,’ Queensland Deputy Premier Steven Miles said.
 
‘Our authorities will be looking into whether there is a link here ... and looking to see if it can help inform the vaccine rollout.’
 
To date, Australia has recorded three cases of thrombosis with thrombocytopenia syndrome (TTS) that have been linked to the AstraZeneca vaccine and led the Australian Technical Advisory Group on Immunisation (ATAGI) to change its guidance for people under 50, with a preference for Pfizer.
 
Leading epidemiologist Professor Mary–Louise McLaws has welcomed the Federal Government’s pivot, but says the move appears to be ‘highly precautious’ given the very low risk.
 
‘They’ll still have a problem with thrombocytopenia and thrombosis … because there still is a slight risk with Moderna and Pfizer,’ she told newsGP.
 
‘But [Pfizer is] faster to roll out, if you have the supply, and it’s got great efficacy.’
 
Recent research from Oxford University found that while recipients of AstraZeneca, Pfizer and Moderna have a risk of blood clots, the risk is up to 10 times higher from contracting COVID.
 
‘The COVID-19 risk is higher than seen with the current vaccines, even for those under 30; something that should be taken into account when considering the balances between risks and benefits for vaccination,’ co-lead author Professor Paul Harrison said.
 
Following ATAGI’s advice, the push for local manufacture of mRNA vaccines has gained momentum with the Victorian Government committing $50 million towards establishing a local facility.
 
‘It’s vital that we can develop and manufacture mRNA vaccines and treatments locally to ensure we have vaccine security here in Australia and across our region,’ Acting Victorian Premier James Merlino said.
 
While the mRNA vaccines currently in circulation are the first to be widely administered in humans, they are proving to be safe and highly effective, with a faster capacity to be adapted to new viral variants. 
 
The Federal Government has expressed its support to adapt current capacity to mRNA, but Department of Health Secretary Professor Brendan Murphy said local manufacture is ‘unlikely’ to assist with the primary vaccination program, given it could take up to 12 months to develop.
 
‘But we may need boosters in the future,’ he said. ‘If these are ongoing and necessary, these vaccines are of interest to the Government and we’ve been asked to provide options.’
 
But at present Australia is reliant on offshore supply.
 
So far Australia has received less than two million of the 40 million Pfizer doses it has contracted, with the majority expected to arrive in the final quarter of 2021.
 
Along with aged care, disability care residents are among those eligible to receive Pfizer under phase 1a, but fewer than 7% have received a dose so far – about 1500 out of 25,000 – with thousands now turning to GPs for the AstraZeneca vaccine.
 
To help address the shortage of Pfizer, some experts are calling for current supplies to be redirected from aged care to people aged under 50, namely healthcare workers under phases 1a and 1b.
 
Adjunct Professor Bill Bowtell, who is a strategic health policy expert, is among them.
 
‘There should be no more Pfizer given to people in aged care,’ he said.
 
‘That should be directed to people under 50, healthcare workers and their families, and the AstraZeneca … should now go to all people over 50 as quickly as possible.’
 
Professor McLaws believes that should have been the strategy from the start.
 
Despite the fact the majority of Australia’s COVID deaths – 685 out of the 910 – were aged care residents, she believes the approach to focus on older people is ‘very compassionate’ but contrary to the reality of how transmission unfolds in the community.
 
‘Ask yourself, epidemiologically, who gets COVID in Australia? It’s the 20-to-39-year-olds, and when you add that up to 49-year-olds, they represented 53% of all cases,’ Professor McLaws told newsGP.
 
‘So if you ring fence everybody within that [younger] age group, who acquired half the number of infections, you will be protecting anybody older than 50.’
 
This is the concept she put forward to the COVAX facility last year.
 
‘I was suggesting that we focus on the frontline health workers, then the 953,000 health workers [including GPs],’ she said.
 
‘And then … the 20–39-year-olds. They are most mobile, they are heavily in the workforce, maybe underemployed and having to do multiple jobs. They’ve also got kids at school, and so they see a lot of other people.
 
‘I wouldn’t be giving [Pfizer] to anybody in aged care. That would be my fourth group because they’re covered by the group looking after them, [most of whom] are under 50 anyway and we don’t have circulating virus. Then give them … AstraZeneca.’
 
Along with Pfizer’s high efficacy rate of 91.3% (or 97%, according to Israeli data), Professor McLaws says the candidate could also help Australia achieve faster coverage given there is only a 21-day window between the first and second dose, compared to the 12-week wait recommended for AstraZeneca.
 
‘Israel’s had a good experience with Pfizer for its protectiveness after one dose, but that’s after at least 10 days,’ Professor McLaws said. ‘So you’ve got a much better buffer for the elderly.’
 
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