The World Health Organization 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, Romania and Bulgaria postponed or limited the rollout of AstraZeneca vaccines after isolated reports of recipients developing blood clots.

Thailand also abruptly delayed its rollout of the AstraZeneca Covid-19 vaccine on Friday, stopping Premier Prayut Chan-O-Cha from getting the first jab.

France will continue to use AstraZeneca's Covid vaccine, the health minister said Thursday. France is scrambling to boost its vaccination rollout in the hope of avoiding a third lockdown.

Luxembourg, meanwhile, put some doses on hold following the reports of blood clots in other countries.

'Excellent vaccine'

"AstraZeneca is an excellent vaccine, as are the other vaccines that are being used," WHO spokeswoman 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."

Europe's medicines regulator said on Thursday that the blood-clot risk is 'no higher' in vaccinated people, adding that it will continue to review reports of thromboembolic events that occur around the time people receive the vaccine.