There is ‘no signal’ that the Oxford and AstraZeneca Covid vaccine is causing blood clots, scientists have said in response to scaremongering from European officials.
At least five EU countries and Thailand have stopped using the jab on members of the public after reports of people developing clots after having it in some nations.
But regulators and scientists say there’s no proof that the vaccine had anything to do with this or that blood clots are any more likely after having it.
AstraZeneca has reported just 37 blood clot-related events out of 17million people who have been vaccinated so far in the UK and EU. There had been 15 cases of deep vein thrombosis, usually affecting the legs, and 22 pulmonary embolisms in the lungs.
The chief medical officer at the firm said these numbers were actually lower than the ‘hundreds’ that would normally be expected in an average group that size.
And one scientist said countries ditching the vaccine were ‘reckless’ because Covid-19 is so dangerous.
Britain has used more doses of the AstraZeneca vaccine than anywhere else in the world – over 11million – and there has been no sign of a rise in blood clots.
Professor Anthony Harnden, from the UK’s official vaccination committee, said there was proof the vaccine would save lives from Covid but no proof it could lead to blood clots.
He said: ‘The risks of not having the Covid vaccination far outweigh the risks from the vaccinations.’
Oxford’s Professor Andrew Pollard, who helped develop the vaccine, said ‘a lot of stuff happens to people all the time… so, when you put a vaccination campaign on top of that, clearly those blood clots still happen.’
Professor Pollard said there are 3,000 blood clots every month in normal times so it wasn’t unusual to see people develop them. And people getting the first Covid vaccines are at higher than average risk of clots because they are older or unhealthy.
The AstraZeneca vaccine is one of the main jabs being used in the UK and scientists say they haven’t yet noticed an increase in the number of blood clots developing (stock image)
Oxford’s Professor Andrew Pollard (left) and the JCVI’s Professor Anthony Harnden (right) both said there is no evidence that the vaccine was causing blood clots, but there is evidence it is saving lives
Experts in the UK have leapt to the Oxford jab’s defence after countries in Europe said they wouldn’t use it while the blood clots were investigated.
Denmark, Norway, Iceland, Bulgaria, the Republic of Ireland and Thailand have all paused the use of the vaccine because of concerns about blood clots.
Although clots are very common they can be serious and even deadly, potentially triggering strokes, heart attacks or blockages in the lungs.
The European Medicines Agency has received 30 reports of people developing blood clots within days of having the vaccine, out of a total five million people.
It is carrying out a review of these cases to see if there is a link to the vaccine. But the numbers suggest that 4,999,970 out of the 5m did not get blood clots.
Fears about them were escalated when patients died with clot-related illnesses in Austria, Denmark and Italy.
Dr Simon Clarke, a microbiologist at the University of Reading, said it was ‘reckless’ to simply stop using the vaccine.
He said in a tweet: ‘I keep hearing the phrase “abundance of caution” being used in reference to countries pausing rollout of [the Oxford vaccine] but is it really caution?
‘Isn’t it actually reckless to expose your population to Covid-19 unnecessarily? Data needed or carry on vaccinating.’
British drugs regulator the Medicines and Healthcare products Regulatory Agency (MHRA) has insisted the vaccine is safe and said people should continue to take it.
Its vaccine safety chief Dr Phil Bryan said: ‘We are closely reviewing reports but given the large number of doses administered, and the frequency at which blood clots can occur naturally, the evidence available does not suggest the vaccine is the cause.
‘People should still go and get their Covid-19 vaccine when asked to do so.’
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The same message is being put out by the Joint Committee on Vaccination and Immunisation (JCVI), which advises the Government on its vaccine rollout.
Its deputy chairman Professor Anthony Harnden said on BBC Breakfast: ‘Safety is absolutely paramount and we monitor this data very carefully.
‘We have given 11million doses of the Oxford/AstraZeneca vaccine to date and there’s no demonstrable difference between the blood clots in those that have been vaccinated from those in the general population.
‘We have to remember that there are 3,000 blood clots a month on average in the general population and because we’re immunising so many people, we are bound to see blood clots at the same time as the vaccination, and that’s not because they are due to the vaccination. That’s because they occur naturally in the population.
‘One ought to also remember that Covid causes blood clots. So, the risks of not having the Covid vaccination far outweigh the risks from the vaccinations.’
And Professor Pollard, who ran the clinical trials of Oxford’s vaccine, added on BBC Radio 4: ‘A lot of stuff happens to people all the time in normal times and, in the case of blood clots here in the UK, we see about 3,000 cases of blood clots happening every month.
‘So, when you then put a vaccination campaign on top of that, clearly those blood clots still happen and you’ve got to then try and separate out whether – when they occur – they are at all related to the vaccine or not.’
He said it was ‘very clearly’ shown in MHRA reports that blood clots were not happening any more often than they normally would.
Professor Pollard added: ‘It’s absolutely critical that we don’t have a problem of not vaccinating people and have the balance of a huge risk – a known risk of Covid – against what appears so far from the data that we’ve got from the regulators – no signal of a problem.’
Professor David Spiegelhalter, a statistician at the University of Cambridge, said in a Guardian column that the links between the jabs and the blood clots could be ‘the basic and often creative urge to find patterns even where none exist’.
He said: ‘Deep vein thromboses (DVTs) happen to around one person per 1,000 each year, and probably more in the older population being vaccinated.
‘Working on the basis of these figures, out of 5 million people getting vaccinated, we would expect significantly more than 5,000 DVTs a year, or at least 100 every week. So it is not at all surprising that there have been 30 reports.’
And Professor Spiegelhalter added: ‘So far, these vaccines have shown themselves to be extraordinarily safe.
‘In fact, it’s perhaps surprising that we haven’t heard more stories of adverse effects.’