YOU'RE up to ten times more at risk of getting a blood clot from Covid-19 than the AstraZeneca vaccine, scientists say.
A study looked at the odds of getting a brain blood clot, called CVST, in people who had been diagnosed with Covid compared with those who had a vaccine.
🔵 Read our coronavirus live blog for the latest updatesThe risk of a brain blood clot, CVST, in different groups of people. It shows the risk and the range in brackets
It showed the risk of a brain blood clot after the AstraZeneca vaccine was five in a million, and four in a million after vaccines from Pfizer or Moderna
For people who had Covid, the risk was almost 40 in a million.
Researchers at Oxford - the same university that created the AstraZeneca vaccine - said either after the coronavirus or a jab, the risk of a brain blood clot in the following two weeks was very rare.
But comparing the two, they said the risk was "substantially and significantly higher" after Covid - which is largely avoidable with a vaccine.
The team also looked at rates of clotting in people who had the flu, which was zero.
And they said the risks of CVST after Covid was "many-fold" higher than in the general population, perhaps up to 100 times higher.
A similar pattern was seen for another serious clotting disorder, portal vein thrombosis, which affects blood supply to the liver. The condition has not been flagged by regulators.
But the team cautioned their results, which haven't yet been published in a medical journal, had some limitations.You're up to ten times more at risk of getting a blood clot from Covid-19 than the AstraZeneca vaccine, scientists sayCredit: AFP
Not all cases studied had CVST with the addition of low blood platelets, called thrombocytopenia.
It is this "unusual combination" of conditions that the AZ jab has been linked to, and not CVST alone.
The researchers said therefore that their findings "cannot contribute" to the debate around the AstraZeneca vaccine and its links to unusual blood clot events.
It may also explain why the risk of CVST was similar between the AstraZeneca jab, and those from Pfizer and Moderna.
The latter two jabs have not been linked to the concerning cases of CVST with low blood platelets.
UK regulators say this risk of CVST and low blood platelets is about four in a million, the equivalent of 0.000095 per cent of people who get the jab, or the risk of taking a long haul flight.
The Oxford researchers suggested the key takeaway of their study was the risks of catching Covid and suffering serious complications outweighed the risks of getting a jab.
After all, the study was designed to look at the risk of CVST caused by coronavirus infection, with comparison to the jabs as extra element.
It echoes the reassurances from regulators in both Europe and the UK, that people should feel safe to get the jab because the benefits are so much greater than any potential, and extremely rare, risk.
What are the risks of a brain blood clot?
According to the Oxford study:
Covid: 39 in a million (using 500,000 Covid patients)
AstraZeneca/Oxford vaccine: 5 in a million (using 34 million recipients)
Pfizer or Moderna mRNA vaccines: 4 in a million (using 480,000 recipients)
Flu: Zero (using 173,000 participants)
Compared to the mRNA vaccines, the risk of a CVST from Covid is about 10 times greater.
Compared to the AstraZeneca/Oxford vaccine, the risk of a CVT from Covid is about eight times greater.