April 8, 2021: -A senior official at Europe’s medicines regulator has said a clear “association” between AstraZeneca’s Covid-19 vaccine and rare blood clots in the brain. However, the direct cause of the lumps is still unknown.
The European Medical Agency (EMA) said that it was still conducting a review of the vaccine and expected to announce its findings Wednesday or Thursday.
“In my opinion, we can now say it, and it is clear that there is an association with the vaccine. However, we still do not know what causes this reaction,” Cavaleri said, without giving evidence to support his comments.
The EMA has said the AstraZeneca shot benefits outweigh any risks, and the World Health Organization has backed the vaccine. AstraZeneca has said previously that its studies have found no higher risk of clots because of its vaccine.
The EMA investigates 44 reports of an extremely rare brain clot known as cerebral venous sinus thrombosis out of 9.2 million people who have received the vaccine in the European Economic Area, which comprises European Union member states Iceland, Liechtenstein, and Norway.
Cavaleri said the EMA would say in its review that there is a link but was not likely to indicate this week on which age groups should or should not get the AstraZeneca shot.
Some countries, including France, Germany, and the Netherlands, have suspended the vaccine’s use in younger people while the investigations continue.
A high proportion of the reported cases are in young or middle-aged women, but that has not led the EMA to conclude this group is at particular risk.
Scientists are exploring several possibilities that might explain the rare brain blood clots. One theory suggests the vaccine triggers an unusual antibody in some rare cases; other investigators are looking into a possible link with birth control pills.
But many experts say there is no definitive evidence, and it is not clear whether or why AstraZeneca’s vaccine would cause a problem not shared by other vaccines that target a similar part of the coronavirus.