Top EMA official says EU regulator to confirm link between AstraZeneca’s vaccine and deadly blood clots

The head of vaccines at the European Medicines Agency (EMA) says the body may soon officially confirm a connection between Vaxzevria – AstraZeneca’s vaccine against Covid-19 – and cases of deadly cerebral venous thrombosis.

“In my opinion, we can say now, it is clear there is a link between the vaccine” and rare cases of potentially deadly blood clots affecting people’s brains, Marco Cavaleri told Italian newspaper Il Messaggero.

He said the agency’s investigation has not established the exact mechanism causing the thrombosis. If the problem is with the vector – Vaxzevria uses a rhesus chimpanzee adenovirus to deliver proteins from the SARS-CoV-2 coronavirus to train the immune system to defeat it – medics may need to reevaluate other vaccines using the same technique, the newspaper wrote.

The EMA’s vaccine safety assessment committee PRAC is holding a conference this week. Updated guidelines for the use of Vaxzevria, which acknowledge the link, may come from the committee within hours, the official suggested.

Some EU countries have restricted use of the vaccine to people over 60, since the blood clotting side effects were mostly reported among younger people. Britain, which is relying heavily on the Oxford-developed vaccine to immunize its population, is reportedly considering a similar restriction for under 30s.

The producer of the vaccine assured last month that its product’s safety was backed by scientific research, and that its review of data for vaccinations in the EU found no evidence of increased risk of blood clots.

Overall, the drug regulators which authorized Vaxzevria for emergency use believe that the benefits it offers far outweigh the risks of side effects. The number of reported blood clotting cases that developed after a Vaxzevria jab is measured in the dozens per tens of millions of vaccinated people.