A top official of the European Medicines Agency on Tuesday declared that there was a link between the AstraZeneca coronavirus vaccine and blood clots.

EMA head of vaccines, Marco Cavaleri told Italy’s Il Messaggero newspaper that he has identified a link between the two.

“In my opinion, we can say 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,” he said.

Persistent questions on whether rare but serious blood clots among those getting the AstraZeneca jab against COVID-19 are more frequent than in the general population have undermined confidence in the beleaguered vaccine.

After several countries suspended the use of the jab – including Italy – the EMA declared that the benefits outweigh the risks and it should remain in use.

The agency has said that a causal link between clots and the vaccine is possible, and is expected to provide an updated assessment this week.

“We are trying to get a precise picture of what is happening, to define in detail this syndrome due to the vaccine,” Cavaleri said.

He added: “Among the vaccinated, there are more cases of cerebral thrombosis… among young people than we would expect.”