The “trigger” behind extremely rare blood clot complications due to the Oxford/AstraZeneca vaccine may have been discovered, according to new research.
Scientists led by a team from Arizona State University and Cardiff University collaborated with AstraZeneca to investigate the causes of vaccine-induced immune thrombocytopenia (VITT) thrombosis.
TTS, in which blood clots form, is a life-threatening condition seen in a very small number of people after receiving the Oxford-AstraZeneca or Johnson & Johnson vaccines.
The scientists say they have now determined how a protein in the blood is attracted to an important part of the vaccine.
They think this starts a chain reaction involving the immune system, which can lead to dangerous clots.
The death of several people due to blood clots caused widespread concern about the AstraZeneca vaccine and affected the way countries distribute the vaccine.
In May, the UK’s drug safety regulator said there were 242 cases of clotting and 49 deaths, with 28.5 million doses of the vaccine administered.
It was therefore decided at the time that an alternative option would be offered to young people under 40.
Scientists and authorities have also argued that: the benefits of taking the vaccine outweigh the risk.
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The study, published in the journal scientific progress, found that the response could be traced to the way the adenovirus used by the vaccine to transport the genetic material of COVID into cells binds to a specific protein in the blood known as platelet factor four.
Professor Alan Parker, one of the researchers at Cardiff University, said the VITT only occurs in extremely rare cases because of a series of complex events that cause an extremely rare side effect.
He told BBC News: “The adenovirus has an extremely negative surface area and platelet factor four is extremely positive and the two things are a pretty good match.”
He added: “We have been able to prove the link between the main smoking weapons of adenoviruses and platelet factor four.
“What we have is the trigger, but there are still many steps to be taken.”