"It is increasingly difficult to talk about the absence of a causal relationship between AstraZeneca vaccination and extremely rare cases of blood clots due to low blood platelet count. It is clear that there is a link," Cavaleri said, referring to cases recorded mostly in women under 55 years of age.
The expert stressed that the investigation was far from over and "we still have to understand how this happens."
Following the news, several European states halted the use of AstraZeneca as a precautionary measure until further investigations into the drug's safety were made.
On March 18, the EMA announced that there was no conclusive evidence that AstraZeneca shots could be linked to higher risks of thromboembolic complications.