Seven people have died from unusual blood clots after getting the Oxford-AstraZeneca vaccine in the UK.
The UK's medicines regulator has confirmed to the BBC that in total, 30 people out of 18 million vaccinated by 24 March had these clots.
BBC News reports it is still not clear if they are just a coincidence or a genuine side effect of the vaccine.
The UK's Medicines and Healthcare Products Regulatory Agency says the benefits continue to outweigh any risk.
However, concern has led other countries including Germany, France, the Netherlands and Canada to restrict the vaccine's use only to older people.
The data released on Friday in the UK showed 22 cases of cerebral venous sinus thrombosis (CVST) which is a type of blood clot in the brain.
These were accompanied by low levels of platelets - which help form blood clots, in the body.
BBC News reports investigations are underway to determine if the AstraZeneca vaccine is causing very rare blood clots.
Earlier this week, the European Medicines Agency said it was "not proven, but is possible".
[Source: BBC]
