Tedros Adhanom Ghebreyesus, Director General of the World Health Organization (WHO), speaks after Dr. Anthony Fauci, Director of the National Institute for Allergies and Infectious Diseases, during the 148th session of the Executive Board on the Coronavirus Disease (COVID-19) outbreak in Geneva, Switzerland, January 21, 2021.

Christopher Black | WHO | via Reuters

The World Health Organization announced on Friday that it is reviewing recent reports of blood clots in some people who have received the AstraZeneca Covid-19 vaccine, which has led some countries to stop introducing the shooting.

At least nine countries, including Denmark, Norway, Iceland and Thailand, have stopped using the vaccine for safety reasons. By Wednesday, around 5 million people in Europe had received the Oxford-AstraZeneca vaccine. Of this number, 30 so-called thromboembolic events were reported in recipients. These are blood clots that form in blood vessels and block blood flow.

AstraZeneca said in a statement Friday that there is “no evidence” that the vaccine causes an increased risk of developing blood clots.

WHO director-general Tedros Adhanom Ghebreyesus said Friday that the agency’s Global Advisory Committee on Vaccine Safety “is systematically reviewing safety signals and carefully evaluating recent reports on the AstraZeneca vaccine”.

“Once WHO has a full understanding of these events,” he added, “the results and changes to our current recommendations will be communicated to the public immediately.”

Dr. Mariangela Simao, WHO deputy director general for access to medicines and health products, added that the global health agency “is likely to have a statement this next week when investigations are complete”.

“The WHO is very much aligned with the position that we should continue immunization until we have cleared up the causal link,” she said.

Dr. Soumya Swaminathan, WHO’s chief scientist, said it was still unclear whether the vaccine was actually causing the clots. An AstraZeneca spokesperson noted that “the observed number of these types of events in vaccinated people is significantly lower than expected in the general population”.

“The adverse events reported after vaccination must be seen in the context of events that occur naturally in the population,” said Swaminathan. “Just because it’s reported after a vaccination doesn’t mean it’s the vaccination. It could be completely independent.”

The European Medicines Agency, the European Medicines Agency, has stressed that there is no evidence that the AstraZeneca shot caused blood clots and that the benefits of the vaccine “continue to outweigh the risks”.

“Reports of previously received blood clots are no greater than the numbers that would have occurred naturally in the vaccinated population,” said Dr. Phil Bryan, Vaccine Safety Director for the UK Medicines and Health Products Regulatory Agency.

“Public safety will always come first. We will continue to examine this issue carefully, but the evidence available does not confirm the vaccine is the cause. People should still get their COVID-19 vaccine when prompted become.” he added.

– CNBC’s Sam Meredith contributed to this report.