Germans ‘SOLVE’ Covid vaccine blood clot puzzle: Scientists say rare side effect from AstraZeneca jabs is caused by cold virus used to deliver the jab into the body – and can be FIXED
German scientists say they have figured out why the Covid vaccines from AstraZeneca and Johnson & Johnson are linked to rare blood clots.
In a new pre-print, the team says the problem is with the adenovirus vector, a common cold virus used to get the body to induce an immune response.
They claim the vaccine is sent into the cell nucleus instead of surrounding fluid, where parts of it break off and create mutated versions of themselves.
The mutated versions then enter the body and trigger the rare blood clots.
Scientists say they can genetically adapt the vaccine to prevent the virus’s spike proteins, which it uses to enter cells, from splitting apart.
German scientists claim they have discovered why some coronavirus vaccines cause blood clots — and say jabs could be tweaked to stop the complication.
Two vaccines, one manufactured by Oxford-AstraZeneca and the other by Johnson & Johnson, have been linked to rare clotting disorders, particularly among women under the age of 50.
AstraZeneca’s has been linked to 309 clots and 56 deaths in the UK out of 33million shots. The J&J single-dose vaccine has been linked to 28 cases in the US out of more than 10.4million shots.
The clots — which can occur in the brain — are happening alongside abnormally low platelet levels, known as thrombocytopenia.
Now, researchers at Goethe-University of Frankfurt and Ulm University, in Helmholtz, say the problem lies in the adenovirus vector — a common cold virus used so both vaccines can enter the body.
They say the vaccines can be adapted to prevent the rare side effect from occurring, reported the Financial Times.
It comes after 18-year-old student Ellie Peacock, who suffered clots after receiving AstraZeneca’s jab in Australia, yesterday urged recipients to be aware and monitor any potential side effects.
German scientists say they have figured out why the Covid vaccines from AstraZeneca (left) and Johnson & Johnson (right) are linked to rare blood clots. In a new pre-print, the team says the problem is with the adenovirus vector, a common cold virus used to get the body to induce an immune response.
Scientists believe that in some people, the immune system sees the vaccine as a threat and over-produces antibodies to fight it. These lead to the formation of clumps in the blood, which can become deadly if the clots move towards vital organs and cut off supply.
The complication spooked some countries into turning their backs on AstraZeneca’s jab, with Denmark opting against using it in April.
Norway and Austria later followed suit.
Other countries have restricted its use to older adults.
UK health chiefs say under-40s should be offered other jabs because the risk of blood clots doesn’t clearly outweigh the benefits.
The decision was made because cases of Covid were plummeting, meaning the risk of catching the disease was tiny. On top of that, younger adults face little risk of falling seriously ill with Covid.
For older people who are at a genuine risk of dying if they catch Covid, the benefits of protection from the virus clearly outweigh any negative side effects, regulators say. The absolute risk of developing clots is around one in 100,000.
Some countries’ decision to stop using the jab and criticisms of it sparked a political row in Europe with EU leaders both demanding more supplies of the vaccine and at the same time claiming it didn’t work and was dangerous.
German ministers claimed the jab didn’t work at all old in people and France’s Emmanuel Macron called it ‘quasi-effective’ though real-world data prove it works.
Similar fears later emerged about the vaccine made by Johnson & Johnson after recipients in the US developed clots. That jab has been age-restricted in Europe, too.
The reason both have been linked to clotting is thought to be that they work in the same way – attaching part of the coronavirus to a damaged common cold bug called an adenovirus.
Russia’s Sputnik V vaccine works in the same way but there have not yet been reports of that jab causing blood clots.
Dr Rolf Marschalek, a biochemistry professor at Goethe University in Germany, told the Financial Times clots may be caused by the way vaccine enters the body.
The paper says the problem is ‘completely absent’ in mRNA vaccines like Pfizer’s and Moderna’s.
Dr Marschalek suggests that vaccine is delivered to the nucleus of the cell – a blob of DNA in the middle – rather than to the fluid around it that acts as a protein factory.
Bits of coronavirus proteins that get inside the nucleus can break up and the unusual fragments then get expelled out into the bloodstream, where they can trigger clotting in a tiny number of people, Dr Marschalek said.
The first clots to alarm people were ones appearing in veins near the brains of younger adults in a condition called CSVT (cerebral sinus venous thrombosis).
Since that, however, people have developed clots in other parts of their bodies and they are usually linked to low numbers of platelets, which is unusual because platelets are usually used by the immune system to build the clots.
In most cases people recover fully and the blockages are generally easy to treat if spotted early, but they can trigger strokes or heart or lung problems if unnoticed.
Dr Marschalek and colleagues think that the problem could be stopped if the genetic material in the vaccines is edited so that it doesn’t break up inside the cell nucleus.
This could be done in the labs producing the jabs, he said, and Johnson & Johnson has already approached the team for advice on how it can change its own vaccine – the study does not outline how this would be done.
“With the data we have in our hands we can tell the companies how to mutate these sequences, coding for the spike protein in a way that prevents unintended splice reactions,” Dr Marschalek told the FT.