The UK’s MHRA announced on Friday it has seen 30 brain clot cases in 18.1million AstraZeneca-vaccinated people – around one in every 600,000 people (0.00017 per cent).
But there are fears that while the benefit of elderly people being vaccinated far outweighs the risk, use of the Oxford-made jab in younger people is ‘more complicated’.
If a ban on under 30s having the jab is confirmed by the MHRA, this would be the first restriction of its kind in the UK and could slow the next stage of the rollout.
Two senior sources told Channel 4 News that while the data is still unclear there are growing arguments to justify offering younger people – below the age of 30 at the very least – a different vaccine.
Both sources however emphasised their support for the Oxford jab and their concerns that any restriction of its rollout could damage public confidence in it.
He said older and middle-aged groups should ‘very much’ get the vaccine because the threat of coronavirus far outweighs the risk of the clots, thought to affect just one in 600,000 people given the jab (0.00017 per cent).
But the SAGE epidemiologist, 53, who himself has had AstraZeneca’s jab, said the balance of risk is ‘slightly more complicated’ when younger people who are less vulnerable to the virus are considered. The risk of blood clots from the vaccine may prove to be higher in younger age groups.
British scientists say the risk of dying of Covid for 25 to 44-year-olds is 0.04 per cent, and 0.01 per cent for people aged 15 to 24. For comparison, the rate is up to 6 per cent in elderly age groups.
It comes after several European countries – including Germany, Spain and Norway – suspended the British-made vaccine after dozens of vaccinated people suffered a rare brain clot, known as CVST, or cerebral venous sinus thrombosis.
The UK’s medical regulator has seen 30 similar cases, of which seven people have died. But it insists its analysis has still not found any evidence the vaccine is causing the clots, a finding which has also been echoed by the EU’s medical watchdog.
Professor Ferguson told the BBC Radio 4 Today Programme: ‘In terms of the data at the moment, there is increasing evidence that there is a rare risk associated, particularly with the AstraZeneca vaccine.
‘But it may be associated at a lower level with other vaccines, of these unusual blood clots with low platelet counts. It appears that risk is age related, it may possibly be – but the data is weaker on this – related to sex.
The risk of dying from Covid-19 is significantly higher than the rate of CSVT blood clots, which haven’t even been definitively linked to the vaccines (Based on fatality estimates from Cambridge University and CSVT occurrences in Germany)
At least 10 countries in Europe, joined by Germany last night, have put some kind of restriction on the use of AstraZeneca’s jab, mostly opting to give it only to over-60s because the CSVT cases seem to be happening in younger adults
‘And so the older you are, the less the risk is and also the higher the risk is of Covid so the risk-benefit equation really points very much towards being vaccinated.
‘I think it becomes slightly more complicated when you get to younger age groups where the risk-benefit equation is more complicated.’
Because health experts aren’t sure how common CVST normally is in the wider population, they are still uncertain if it is occurring more in vaccinated people than it otherwise would.
CVST, or cerebral venous sinus thrombosis, is a blockage in a vein that carries blood away from the brain and it can lead to strokes or bleeding inside the skull.
A TIMELINE OF THE ASTRAZENECA BLOOD CLOT SAGA
March 7: Austria suspended the use of one batch of the vaccine after a woman, 49, who had been given it died of a ‘severe coagulation disorder’ and a 35-year-old developed a blood clot in her lung.
March 11: Authorities in Denmark, Norway and Iceland suspended all use of the vaccine following a 60-year-old woman in Denmark died of a blood clot after the reports emerged in Austria. Danish health minister Magnus Heunicke said: ‘It is currently not possible to conclude whether there is a link.’
March 11: European Medicines Agency’s safety committee began an investigation into the cases. It confirms 30 cases of ‘thromboembolic events’ – clots – were reported after five million vaccines in the EEA.
March 12: Thailand suspended the use of the vaccine off the back of European worries. Bulgaria also stops using it.
March 12: The European Medicines Agency, Britain’s Medicines and Healthcare products Regulatory Agency, Health Canada, the World Health Organization and AstraZeneca itself, all spoke out to defend the vaccine and say there is no proof it’s linked to blood clots.
March 13: The Netherlands, Italy and Ireland temporarily stopped using the vaccine as fears about the cases in Austria and Denmark snowballed.
March 14: Germany and France suspended the vaccine.
March 15: Spain, Portugal and Slovenia suspended use of the jab.
March 15: Professor Andrew Pollard, the Oxford expert who ran the clinical trials of the jab, insisted safety data are ‘reassuring’ and said ‘clearly those blood clots still happen’ as often as they would in unvaccinated people.
March 16: World Health Organization officials met to discuss the issue. European Medicines Agency is still investigating.
March 17: Scientists accuse governments of banning the jab on political grouns. AstraZeneca’s vaccine has been a flashpoint in the past.
March 18: European Medicines Agency holds a press conference on its investigation and rules that the vaccine is ‘safe and effective’. It said there wasn’t enough evidence to rule out a link to blood clots, but also not enough to prove one. On balance, it would be safer for countries to keep using the vaccine to stop Covid. The investigation would continue.
March 18: Germany, France and Italy resume use of the jab after the EMA’s conclusion.
March 19: Finland suspends the jab after finding blood clot cases in its own population.
March 19: Bulgaria, Cyprus, Ireland, Latvia, Lithuania, Netherlands and Spain all confirm they will start using the jab again. Scandinavian countries did not follow suit and kept the ban in place.
March 22: A study is published that found public trust in the AstraZeneca vaccine collapsed in Europe at the time of the blood clot saga. A YouGov survey found more than half of people in Germany, France, Italy and Spain believed the jab was unsafe.
March 30: Germany bans the vaccine for people under the age of 60 after officials said they had found 31 cases of CSVT after 2.7million vaccinations.
April 2: UK regulators announce a total of 30 blood clots, 22 in the brain, have now been discovered in Britons vaccinated with the AZ jab.
Scientists say it’s morally complicated to jab children because they have almost zero risk of dying or falling seriously ill from the disease, and would only be vaccinated to protect older people. It is still unknown, however, how long Covid may affect them.
Leaked Government plans last month suggested ministers wanted to start getting jabs to millions of under-18s by August to try to achieve herd immunity — when the virus can’t spread because so many people are protected.
The UK’s MHRA regulator announced on Friday it has seen 30 brain clot cases in 18.1million AstraZeneca-vaccinated people – around one in every 600,000 people (0.00017 per cent).
The UK’s health watchdog said it hadn’t seen CVST cases in people who got the Pfizer jab but there was still no proof the AstraZeneca vaccine is raising the risk. This may be because different groups of people are getting different vaccines.
Germany last month went against the European regulator’s advice and banned the AstraZeneca jab for under-60s because it fears a link to the condition.
Scientists say the balance of risk is ‘very straightforward’ and clearly in favour of vaccination because of the ‘extreme rarity’ of CVST cases.
Officials in Frankfurt recorded 31 cases of the condition among 2.7million people to have been given the AstraZeneca jab and have been alarmed by the number. But this is a rate of just 0.0012 per cent.
By comparison, Cambridge University experts estimate the risk of dying of Covid for 25 to 44-year-olds is 0.04 per cent – 33 times higher.
For 15 to 24-year-olds the Covid death risk is 0.005 per cent, making it four times more likely.
Forty under-20s have died in England, out of 86,351 in total, along with 598 20 to 40-year-olds.
And the main benefit of giving the vaccine to younger people is that it protects elderly members of society, whose risk of death is much higher, and therefore allows ministers to loosen lockdown rules.
If young people shun, or aren’t offered, AstraZeneca’s vaccine as the roll-out moves down the ages, it could pose problems for the inoculation drive.
Britain is currently reliant on the jab for dishing out first doses, with supply of Pfizer’s having been reserved to dish out 10million top-ups. Moderna’s vaccine is set to come on stream this week – but the campaign has yet to officially move to under-50s and it won’t be delivered in large enough quantities to be used as the main option.
Johnson and Johnson’s single-dose jab could be ready to use by July, Government sources say. No10 has bought 30million doses but it is unclear when the UK will receive them.
Professor Adam Finn, a University of Bristol researcher and government adviser on vaccines, said: ‘The extreme rarity of these events in the context of the many millions of vaccine doses that have been administered means that the risk-benefit decision facing people who are invited to receive Covid vaccines is very straight forward: receiving the vaccine is by far the safest choice in terms of minimising individual risk of serious illness or death.’
Comparing the rates of CVST to coronavirus death is tricky for a number of reasons, including that it’s so rare data aren’t clear, and that more people will get a jab than catch coronavirus.
Regulators also don’t break down the CVST cases by age, although they are thought to be more common among young adult women.
And the fatality rates for coronavirus, estimated by Cambridge University experts only include people who get the virus.
This means the average person’s actual risk of dying from coronavirus is significantly lower than the estimate because not everyone catches it – although if nobody took the vaccine, the likelihood of them catching it one day is far higher.
Most recent calculations by the Cambridge team suggest the risk of dying of Covid is lowest for toddlers and babies, at 0.00039 per cent, around one in 256,000.
It’s highest for over-75s, at 6.9 per cent, or one in 14. And overall, the risk is around 0.3 per cent, meaning that across the whole population around three in every thousand infected people die.
Another complication is that there is no proof the coronavirus vaccine causes CVST, meaning the cases that happen may have occurred anyway.
If this is the case, the risk caused by the vaccine is effectively zero and the jab is infinitely safer than being unvaccinated.
But even if a link is established, it will be difficult to know how many cases are triggered by the jab in people who would not otherwise have developed CVST.
And CVST is more often survived than it is fatal. Medics say if it’s spotted in time – before it blocks the vein – it can be simple to treat with blood thinners.
Johns Hopkins University in Baltimore, US, estimates that one in every 200,000 people of all ages develop CVST each year.
The European Medicines Agency said last week, echoing data from Germany, that the risk appears to be one in 100,000 in under-60s who have had the AstraZeneca vaccine.
But much of the data comes from Germany’s AstraZeneca vaccine patients, who are mostly young female adults, and young female adults are statistically more likely to get CSVT even when there is no vaccine around.
EMA director Emer Cooke said cases in women usually outnumber those in men by 10 to one.
WHAT IS CVST?
Cerebral venous sinus thrombosis (CVST) is an extremely rare type of blood clot in the brain.
It occurs when the vein that drains blood from the brain is blocked by a blood clot, resulting in potentially deadly bleeding on the brain.
Symptoms can quickly deteriorate from a headache, blurred vision and faintness to complete loss of control over movement and seizures.
John Hopkins University estimates it affects five in a million people in the US every year, which would suggest 330 patients in Britain suffer from the condition annually.
According to the university, it can affect patients with low blood pressure, cancer, vascular diseases and those prone to blood clotting. Head injuries can also trigger the condition.
Britain’s regulator said CVST is so rare they aren’t even sure how common it is in the general population.
The contraceptive pill and smoking may be risk factors for this – scientists are investigating the links.
In the wake of EU scare stories over the AstraZeneca jab, which came amid a row over supplies, the MHRA last month said there had only been five cases of CVST among 11million administered doses.
In last week’s update, which took into account all adverse reactions recorded up until March 24, it put the count at 22.
The watchdog also revealed it had eight reports of other serious clotting events associated with low blood platelets.
The MHRA said: ‘Our rigorous review into the UK reports of a rare and specific type of blood clot is ongoing.
‘On the basis of this ongoing review, the benefits of the vaccines against Covid continue to outweigh any risks and you should continue to get your vaccine when invited to do so.’
The tenuous links between the vaccine and CVST are still mired in confusion because experts in Germany and other countries where the jab has been halted claim the condition is most common in women.
But all five of the original cases in the UK were among men.
The MHRA did not offer any more details about the new 25 cases.
Until recently, Germany had banned the AZ jab for over-60s due to initial fears about blood clots.
Other major European countries have also restricted the jab to certain age groups, even though they have seen significantly fewer CVST cases despite vaccinating more people.
If the same rate of CVST in Germany had appeared in the UK, almost 200 people would have been diagnosed with it already because six times as many jabs have been used.