Seven people have died since developing blood clots after receiving the Oxford-AstraZeneca vaccine, according to the United Kingdom medical regulator.
The news of deaths in the UK comes as many European countries have suspended the use of the AstraZeneca vaccine due to a possible connection to blood clots, reports NDTV.
"Out of the 30 reports up to and including 24 March, sadly 7 have died," the UK's Medicines and Healthcare Products Regulatory Agency said in a statement.
After five new cases among women, one of whom died, the Netherlands halted vaccinations with the AstraZeneca jab for people under the age of 60 on Friday.
Earlier this week, Germany made a similar decision.
On 7 April, the European Medicines Agency (EMA), which, like the World Health Organization, previously declared the AstraZeneca vaccine safe, will provide updated advice on the matter.
The EMA reiterated on Wednesday that it believes the vaccine is safe and that no particular risk factors, such as age, gender, or medical history, have been reported.
The 30 reports of thrombosis, which were sent by physicians or members of the public via a government website, came after 18.1 million doses of the vaccine had been administered in the UK, according to the UK regulator.
Most of the cases (22) were cerebral venous sinus thrombosis, a rare condition when a blood clot forms in the brain.
Eight other cases saw people suffer thrombosis and low levels of blood platelets, which help blood clot.
There were no reports of blood clots from the Pfizer/BioNTech vaccine it said, adding that "our thorough review into these reports is ongoing."
The regulator's website says that on the basis of current data, the benefits of the vaccines against COVID-19 "continue to outweigh any risks".
AstraZeneca said last month following US efficiency trials that its vaccine is 79 percent effective at preventing the disease and does not increase the risk of blood clots.
The UK has administered more than 31 million first vaccine doses, using both the Oxford-AstraZeneca and the Pfizer-BioNTech jabs. People cannot choose which one they get.
The UK in June 2020 ordered 100 million doses of the Oxford-AstraZeneca vaccine and supported its development. It also ordered 30 million doses of the Pfizer-BioNTech vaccine the same year