AstraZeneca-OxfordEuropean Medicines Agency (EMA) official Marco Cavaleri said there was a link between AstraZeneca’s COVID-19 vaccine and rare reports of blood clots, including pulmonary embolism, deep vein thrombosis and thrombocytopenia, according to a Reuters report.

Two separate research groups in Europe had reached similar conclusions regarding the blood clots in March.

AstraZeneca had previously downplayed the possibility that its COVID-19 vaccine is linked to such events. The company did not immediately respond to a request for a comment.

The benefits of the vaccine, which was jointly developed by AstraZeneca and Oxford University, still outweigh the risks, said Marco Cavaleri, head of health threats and vaccine strategy, in an interview with Rome’s Il Messaggero paper.

EMA is poised to make a formal announcement regarding the subject, Cavaleri said.

The EMA press office itself notes that it “has not yet reached a conclusion, and the review is currently ongoing.”

Several countries have halted or constrained the use of the vaccine over the possibility that the vaccine could be linked to blood clot issues. Germany and the Netherlands have stopped using the vaccine in patients under the age of 60. The majority of patients with rare blood clot problems were between the ages of 25 and 65.

The AstraZeneca vaccine will likely be the fourth to win emergency use authorization in the U.S. The company is, however, searching for a contract manufacturer to produce the vaccine following allegations that its partner Emergent BioSolutions had quality control problems. The company refutes those claims.