AstraZeneca: thromboses considered as "rare side effects" of the vaccine, EMA says

Published by Laurent P., Manon C. · Published on 7 April 2021 at 16h49
After the Medicines Agency confirmed the existence of a "rare" risk of atypical thrombosis, this Tuesday April 6, the European Medicines Agency declares there is indeed a link between the vaccine and the creation of blood clots. The day after, on Wednesday April 7, the European regulator announced in a press brief they list blood clots as one of vaccine rare adverse effects.

And what if cases of thromboses were indeed related to the AstraZeneca vaccine? While a recent Norwegian study proved the link between the vaccine and the blood clots, the European Medicines Agency invited to keep on vaccinating, even though, they confirmed this Tuesday April 6 - via a representative of the institution - there is a link between the vaccine and cases of thrombosis reported in France and Europe.

"We can say it now, it is clear there is a link with the vaccine … But we still do not know what causes this reaction. [...] In the next few hours, we will say that there is a connection, but we still have to understand how this happens" -  EMA head of vaccines Marco Cavaleri told Italy's Il Messaggero newspaper. He goes on: "We are trying to get a precise picture of what is happening, to define in detail this syndrome due to the vaccine. [...] Among the vaccinated, there are more cases of cerebral thrombosis … among young people than we would expect".

A link the European regulator officially addresses on Wednesday April 7 explaining in a press brief a "possibility of very rare cases of blood clots combined with low levels of blood platelets" was now established, after tempering Cavaleri's statement this very same day, stating in a release the EMA had "not yet reached a conclusion and the review is currently ongoing". The Agency is expected to host a press brief as soon as review is completed.

This Wednesday, still during the briefing, they added "unusual blood clots with low blood platelets should be listed as very rare side effects". They concluded: "People who have received the vaccine should seek medical assistance immediately if they develop symptoms of this combination of blood clots and low blood platelets".

In France, even though vaccination resumed, people are worried about the growing cases. “Two days ago, there were about six cases” of thrombosis in France, Haute Autorité de santé (HAS) president Dominique Le Guludec announced this Thursday March25 on France Info. She goes on saying they are enough to “sound the alarm”. Concerns encouraged the French regulator to approve vaccinating only people over 55 years of age with this product.

She gives some precision: “a type of very peculiar pathologies has been noticed. These are not pulmonary embolisms, there are not phlebitis, these are not heart attack. This is a very special coagulation failure that led us to focus on the use of this vaccine. We opened it to people over 65 and there, waiting for more details on the nature of these rare but severe accidents, we rather limit it to 55 years old”.

Le Guludec also added people developing severe reactions are “rather young people, and this is concerning”. She concludes, “as we mostly vaccinate elderly people, there are few young people given the vaccine. So, we still need additional explanation”. As to know if people under 55 can get their second dose, “it is being though about. We have time to answer, because the second dose is only given in the third month. And to reassure the French, I would say the longer they wait, the more effective the vaccine is”, the HAS President explains.

This Friday March 26, 2021 The Agence du Médicament (ANSM) has confirmed there is a "rare" risk of atypical thrombosis related to the AstraZeneca vaccine. "Nine cases of deep vein thrombosis, atypical due to their location (mostly in the brain, but also in the stomach), likely to be associated with thrombocytopenia or coagulation failure have been reported", the ANSM states in a release. "The very atypical character of these thromboses, their close clinical pattern, and the even time before occurence lead the follow-up committee to confirm the very rare occurence of this thrombotic risk in people vaccinated with AstraZeneca vaccine", they go on.

Yet, the Agence du Médicament highlights AstraZeneca vaccine's benefit/risk equation remains "favorable", concluding there is a "likely link with the two very rare forms of blood clots (disseminated intravascular coagulation (CID), and cerebral venous sinus thrombosis) associated to blood platelet failure cannot be excluded at that point", reminding a group of experts is currently studying "the action mechanism, likely underlying risk factors, and any additional data to explain events reported".

The issue is taken seriously then, while waiting for results from other studies on the matter.

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