The World Health Organization (WHO) said Friday there was no reason to stop using AstraZeneca’s COVID-19 vaccine after several European countries suspended the roll-out over blood clot fears.

The WHO said its vaccines advisory committee was currently looking at safety data and stressed that no causal link had been established between the vaccine and clotting.

Denmark, Norway, Iceland, Italy and Romania postponed or limited the rollout of AstraZeneca vaccines after isolated reports of recipients developing blood clots.

“AstraZeneca is an excellent vaccine, as are the other vaccines that are being used,” WHO spokesperson Margaret Harris told reporters at a briefing in Geneva.

“We’ve reviewed the data on deaths. There has been no death, to date, proven to have be caused by vaccination,” she said.

“Yes, we should continue using the AstraZeneca vaccine,” she added, stressing though that “any safety signal must be investigated.”

“We must always ensure that we look for any safety signals when we roll out vaccines, and we must review them,” she said.

“But there is no indication to not use it.”