Covid 19 coronavirus: AstraZeneca vaccine and blood clots link 'clear', says top health official

A health worker prepares a dose of the Astrazeneca vaccine. Photo / AP

A health chief from the European Medicines Agency (EMA) has said that there is a link between AstraZeneca's Covid-19 vaccine and blood clots.

"In my opinion, we can say it now, it is clear there is a link with the vaccine," said the EMA's head of vaccines Marco Cavaleri in an interview with Italy's Il Messaggero newspaper.

Cavaleri indicated that the EMA would confirm this view, adding, "in the next few hours, we will say that there is a connection, but we still have to understand how this happens".

He said that "we still do not know what causes this reaction", as reports accumulate of people across the world experiencing blood clots after receiving the jab developed by British-Swedish drug company AstraZeneca and Oxford University.

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

"Among the vaccinated, there are more cases of cerebral thrombosis among young people than we would expect."

Investigations are under way to determine if the rare syndrome is a side effect from the AstraZeneca vaccine or just a coincidence.

The EMA last week recommended that countries should keep using the AstraZeneca vaccine because the benefits outweighed the risks, as countries including Italy suspended their rollout of the jab.

The agency said that a "causal link with the vaccine is not proven but is possible, and further analysis is continuing". It is expected to provide an updated assessment this week.

The EMA said the vaccine was not associated with an increase in the overall risk of blood clots, but may be associated with clots linked to thromocytopenia, a very rare condition involving low levels of blood platelets.

Australian health officials have said they are taking the "potential risk very seriously", after the country recorded its first case of a blood clot following the vaccine.

A 44-year-old Melbourne man who received the jab on March 22 was found to have abdominal clots and low platelet levels on Friday. The Australian Health Protection Principal Committee and Therapeutic Goods Administration vaccine safety investigation group held emergency meetings on Saturday to look into the case.