ROME (Reuters) – There is a link between AstraZeneca’s COVID-19 vaccine and very rare blood clots in the brain, but possible causes are still unknown, a senior official at the European Medicines Agency (EMA) said in an interview. posted on Tuesday.
“In my opinion now we can say it, it is clear that there is an association with the vaccine. However, we still do not know what causes this reaction, ”Marco Cavaleri, president of the EMA’s vaccine evaluation team, told the Italian newspaper Il Messaggero when asked about the possible relationship between the injection of AstraZeneca and the cases of clots. of blood in the brain.
Cavaleri added that the EMA would say there is a link, although the regulator is likely not in a position this week to give an indication of the age of people who should be given the AstraZeneca injection.
He did not provide evidence to back up his comments.
AstraZeneca was not immediately available for comment. He has previously said that his studies have not found an increased risk of clots from the vaccine.
The regulator has consistently said the benefits outweigh the risks as it investigates 44 reports of an extremely rare brain clotting disease known as cerebral venous sinus thrombosis (CVST) from 9.2 million people in the European Economic Area who have received the AstraZeneca vaccine.
The World Health Organization has also endorsed the vaccine.
The EMA said last week that its review thus far had not identified any specific risk factors, such as age, gender or a prior medical history of bleeding disorders, for these rare events. A causal link with the vaccine has not been proven, but it is possible and testing is continuing, the agency said.
A high proportion of reported cases affected young and middle-aged women, but that did not lead the EMA to conclude that this cohort was particularly at risk from the AstraZeneca injection.
The EMA is expected to give an update on its investigation on Wednesday.
Some countries, including France, Germany and the Netherlands, have suspended use of the vaccine in younger people while research continues.
Scientists are exploring several possibilities that could explain the extremely rare brain blood clots that occurred in individuals in the days and weeks after receiving the AstraZeneca vaccine.
European researchers have proposed a theory that the vaccine triggers an unusual antibody in some rare cases; others are trying to understand whether the cases are related to birth control pills.
But many scientists say there is no definitive evidence and it is unclear whether or why the AstraZeneca vaccine would cause a problem not shared by other vaccines that target a similar part of the coronavirus.
In a separate interview, Armando Genazzani, a member of the EMA’s Committee for Medicinal Products for Human Use (CHMP), told La Stampa newspaper that it was “plausible” that the blood clots were correlated with the AstraZeneca vaccine.
Report by Giulia Segreti; Giles Elgood Editing