The EU’s drug watchdog said on Thursday it is still convinced the benefits of AstraZeneca’s Covid-19 vaccine outweigh the risks following an investigation into reports of blood disorders that prompted more than a dozen nations to suspend its use.

The news came as the European Medicines Agency (EMA) director Emer Cooke said the watchdog could not definitively rule out a link between blood clot incidents and the vaccine in its investigation into 30 cases of a rare blood clotting condition.

But she said in a briefing the “clear” conclusion of the review was that the vaccine “benefits in protecting people from Covid-19 with the associated risk of death or hospitalisation outweighs the possible risks”.

The agency will, however, update its guidance to include an explanation about the potential risks on both the patient leaflet and in the information for healthcare professionals, she said.

“This is a safe and effective vaccine,” said Cooke.

The agency has been under growing pressure to clear up safety concerns after a small number of reports in recent weeks of bleeding, blood clots and low platelet counts in people who have received the shot.

The agency’s review covering 5 million people, included 30 cases of unusual blood disorders in people in the European Economic Area , which links 30 European countries.

The EMA’s focus and primary concern has been on cases of blood clots in the head, a rare condition that’s difficult to treat called cerebral venous thrombosis (CVT) or a subform known as cerebral venous sinus thrombosis (CVST). More than 45 million of the shots have been administered across the EEA.

At least 13 European countries, including France, Germany and Italy, have stopped administering the shot pending the review.

Britain’s medicines regulator said on Thursday it was investigating five cases of CVST among people given AstraZeneca’s vaccine but it reaffirmed that the benefits of the shot far outweighed any possible risks.

The World Health Organisation also this week reaffirmed its support for the shot.

AstraZeneca has said a review covering more than 17 million people who had received its shots in the EU and Britain had found no evidence of an increased risk of blood clots. Many governments have said the decision to pause inoculations was out of an abundance of caution.

But experts have warned the political interference could undermine public confidence and hobble the bloc’s slow vaccination campaign as governments struggle to tame more infectious variants.