The trigger that causes the – rare – blood clots to form is a protein in the blood.
Work carried out by British and American researchers to identify what would cause thrombosis in some people after they were vaccinated with AstraZeneca was published on December 1 by Science Advanced.
It is important to remember that even though production had been stopped in France and in other countries, cases of thrombosis linked to the AstraZeneca vaccine were rare.
The British government funded an emergency program to understand why the AstraZeneca vaccine caused thrombosis.
Scientists were joined by those who developed the vaccine after the first research results were published.
A blood protein attracted like a magnet to a vaccine component
Scientists would have arrived at isolate a trigger of the formation of these blood clots after injection with the vaccine, as reported by the BBC.
A protein present in the blood would be “attracted” by a component of the vaccine. It would therefore be a “trigger” as the researchers qualify it.
The researchers focused on two elements for their work.
First of all, the risk of thrombosis has been identified with the AstraZeneca vaccine. So we had to study the components of this vaccine to understand what made the people vaccinated with this serum react.
In addition, patients who developed blood clots presented with special antibodies that attacked a protein in their blood.
Based on these two observations and postulates, all that remained was to understand the mechanism which linked the two elements.
The area of the specific adenovirus involved
AstraZeneca vaccine is an adenovirus vaccine, also called a viral vector vaccine, which uses a non-pathogenic virus to elicit an immune response.
And researchers have shown that the surface area of the adenovirus used in AstraZeneca attracts protein like a magnet.
They therefore demonstrated what triggers the formation of the clot, but as they specify: “It is believed that the body begins to attack the platelet factor identified after mistaking it for part of the foreign adenovirus to which it is stuck. Thus, antibody are released into the blood, which clump together and trigger the formation of dangerous blood clots. “
But for this to happen there need to be a number of factors. This is what explains why thrombosis has been so rare.
The director of this research specifies: “You could never have predicted that this would have happened and the chances are extremely low, so we have to remember the big picture of how many lives this vaccine has saved. “
This initial research is therefore very interesting for the future.
And for good reason, a spokesperson for AstraZeneca explained after the publication: “Although the research is not definitive, it offers interesting information and AstraZeneca is exploring ways to exploit these findings as part of our efforts to suppress this extremely rare side effect. “
