AstraZeneca/Janssen: thromboses explained by German searchers

Published by Laurent P. · Updated on 28 May 2021 at 10h30 · Published on 28 May 2021 at 09h37
German scientists are said to have discovered where thromboses caused by the AstraZeneca and Janssen vaccines come from, explaining they are caused by the vector used, the adenovirus. Keep reading to find out more.

Rare thrombosis cases after injection of the AstraZeneca and Janssen vaccines soon to be a bad memory? This is what German scientists hope after they have found - accoridng to Financial Times - the origin of the creation of blood clots. The reason might be adenovirus. "The problem sat with the adenovirus vectors that both vaccines use to deliver the genetic instructions for the spike protein of the Sars-Cov-2 virus into the body", the magazine reads, stating scientists based their first studies on the matter.

The latter explained "once inside the cell nucleus, certain parts of the spike protein splice, or split apart, creating mutant versions, which are unable to bind to the cell membrane where important immunization takes place". Then follows an over-reaction creating clots. An issue scientists have found a solution to, epxlaining they can neutralize the risk of thromboses: "if the vaccine developers can modify the gene sequence that codes for the spike protein to prevent it splitting apart", Pr. Rolf Marschalek running the study says, to our peers from Financial Times. He continues and says his team is already in touch with Johnson & Johnson producing the Janssen vaccine to set things right.

Cases of thrombosis, an injection-related mistake?

Many scientists tried to explain how the creation of blood clots could be explained, such as French doctors and scientists from Du côté de la science group have a few early explanations. They think thromboses are not directly caused by the vaccine itself, but a poor injection. Thromboses could be cause by injecting intravenously - instead of intramuscular - leading to a "discordant immune response". Strasbourg immuno-oncology scientist Eric Billy says: "Patients with thrombosis may have had tendencies, and the intravenous injection may have led to an escalating".

Despite precautions taken to target the deltoid muscle, the injection mistake could lead to the formation of thromboses: "the presence of the adenovirus within the blood flow activaes the individula's local immune defense in an intense way to limit the spread of adenovirus", Dr. Florian Zores explains as he is also member of the group working on that matter. He goes on: "this excessive immune reaction might in some ways lead to the activation of platelets that will do what they are here for: creating blood clots".

An auto-immune reaction that cannot occur intramuscularously, unless a vein has been hit: "In the event of intravenous injection, adenovirus is found in the blood, while intracellular, it would have infected muscle cells and would not have been in the blood flow", Billy continues. He goes on: "in the blood, it is found with other cells, that rule the blood flow, the veins' permeability, all-thing blood homeostasis and therefore thrombotic ability".

How to know if the intramuscular injection worked or not? A very simple manipulation, when back from the injection, the group recommends to "check for the absence of blood flow during vaccination".

Rare blood clots past the injection

This Tuesday March 30, immunology lecturer and Head of the vaccinal strategy guidance committee Alain Fischer told our peers from France Inter about what could explain the creation of blood clots: "Several European teams - including Germans - have highlighted people who developed, five to fifteen days later, complications as thrombosis, a small decrease in platelets, and coagulation failure, what we call disseminated intravascular coagulation", he said.

He went on: "they found self-antibodies causing the platelets to stick together. This is what causes the abnormal formation of clot". He concluded: "This antibody probably is a marker of this complication, but we have left to see if there is a causal link with the vaccine".

As for the study thoroughly conducted in Norway after a young and health caretaker died ten days after being vaccinated with AstraZeneca, to brain hemorrhage, without clear link between her situation and the inoculation of the vaccine. As for the European regulator, the investigation goes on anyway. During a press brief on Thursday March 18, the EMA also stated that even though vaccinations were allowed to resume, it was required to show on leaflets given to people recently vaccinated that thromboses were likely to occur.

In France, AstraZeneca vaccination has resumed but remains limited to people over 55 years of age.

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