The World Health Organisation's advisory vaccine safety panel said on Wednesday a causal link between the AstraZeneca Covid-19 vaccine and rare cases of blood clots with low platelets is "considered plausible but is not confirmed".
The independent experts, in a statement issued after a review of the latest global data, said that specialised studies were needed to fully understand the potential relationship between vaccination and possible risk factors.
"It is important to note that whilst concerning, the events under assessment are very rare, with low numbers reported among the almost 200 million individuals who have received the AstraZeneca Covid-19 vaccine around the world," the panel said.
It added that it would meet against next week to review additional data.