Vaccine safety experts from the World Health Organization (WHO) are meeting on Tuesday to review the Oxford-AstraZeneca jab, after a number of countries paused their rollouts, the BBC reports.
Countries including France and Germany said they were acting as a precaution amid reports of blood clots in some recipients in Europe.
The WHO says there is no evidence of a link between clots and vaccines.
It has urged countries not to pause their vaccinations.
The European Medicines Agency (EMA) – the European Union’s medicines regulator – is also meeting on Tuesday. It has previously said that people can continue receiving the vaccine.
AstraZeneca says a review of 17 million people who received doses in Europe found there were 37 cases of people who had developed blood clots.
Experts say the number of blood clots reported in vaccinated people is no higher than that seen in the general population.
A number of countries have temporarily suspended use of the vaccine, including Germany, France, Italy and Spain.
They said they were pausing the rollout following reports of blood clots in some recipients. Blood clots are solid clumps that form in the blood, which can be life threatening if not treated quickly. The countries stressed that it was a precautionary measure.