Dozens of countries so far have suspended or limited the roll-out of AstraZeneca vaccines after isolated reports of recipients developing blood clots. However, the World Health Organization (WHO) said on Friday that there was no reason to stop using those vaccines, which were developed with the University of Oxford.
The WHO stressed that no causal link has been established between the vaccine and clotting. "We've reviewed the data on deaths. There has been no death, to date, proven to have been caused by vaccination," WHO spokeswoman Margaret Harris told reporters at a briefing in Geneva.
Early on Tuesday, Austria stopped using a batch of AstraZeneca vaccine while it investigated death from clotting and a case of pulmonary embolism.
Local media reported that a 49-year-old nurse in Zwettl, a town northwest of Vienna, died of severe coagulation disorders after receiving the vaccine. Another nurse, 35, from the same city, developed a pulmonary embolism after receiving a dose from the same batch. Currently, she is recovering.
Soon after reports of possible links between AstraZeneca shots and blood clotting and pulmonary embolism, several other countries including, Denmark, Norway, Iceland, Italy, Bulgaria, Romania, and Thailand suspended the use of that vaccine temporarily.
According to CNBC, at least five million people in Europe had received the Oxford-AstraZeneca vaccine as of Wednesday and of the figure, 30 cases of blood-clotting events have been reported.
In a statement on Thursday, AstraZeneca said it had found no evidence of an increased risk of pulmonary embolism or deep vein thrombosis in safety data from more than 10 million records.
"In fact, the observed number of these types of events are significantly lower in those vaccinated than what would be expected among the general population," a spokesperson for AstraZeneca said.
Europe's drug regulator, the European Medicines Agency, has also stressed on Thursday that there was no indication the vaccine was causing blood clots.
Despite the suspension by some countries, Germany, France, Australia, Canada, Mexico, and Poland, meanwhile, said they would continue using the AstraZeneca vaccine and have sought to reassure their citizens of the benefits of getting vaccinated.
The vaccine produced by AstraZeneca has not been authorized by the U.S. health regulator, but the White House on Friday said it will hold onto some doses so that once approval is obtained, they can be distributed quickly.