Germany, France and Italy have halted rollouts of the Oxford-AstraZeneca vaccine, after a series of incidents in Europe involving blood clots.
They join several smaller European nations who have halted vaccinations as a precaution while checks are made.
The World Health Organization has said there is no evidence that the incidents are caused by the vaccine.
It said it was reviewing reports relating to the jab, but it was important vaccinations continued.
WHO adds it was good practice to investigate potential adverse events.
There have been a number of cases in Europe of blood clots developing after the vaccine was administered.
However, experts say the number of blood clots reported after the vaccine were no more than those typically reported within the general population.
AstraZeneca says about 17 million people in the EU and the UK have received a dose of the vaccine, with fewer than 40 cases of blood clots reported as of last week.
It said there was no evidence of an increased risk of clotting due to the vaccine.
[Source: BBC]
