AstraZeneca's Covid vaccine may not be suitable for young people if its link to blood clots is proven to be true, says Britain's 'Professor Lockdown'

 

  • SAGE adviser said older and middle-aged people should 'very much' get AZ jab 
  • But the balance of risk becomes 'slightly more complicated' in younger groups
  • UK has spotted 30 cases of brain clots in AZ-jabbed people, of which seven died

AstraZeneca's coronavirus vaccine may not be suitable for young people if its link to blood clots is proven to be true, one of No10's top scientific advisers suggested today.

'Professor Lockdown' Neil Ferguson 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.

'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. 

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 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)

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

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

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.

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.

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.  

Neil Ferguson: AstraZeneca jab may not be suitable for young people
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