Oxford pauses dosing in trial of AstraZeneca COVID-19 vaccine in children, teenagers

The University of Oxford has paused administering doses of the COVID-19 vaccine it developed with AstraZeneca PLC in a small U.K. study to test the shot in children and teenagers, pending further information about rare blood-clotting issues in adults who have received it, the Wall Street Journal reported on Tuesday.

An Oxford spokesman told the Journal that no safety issues have arisen in the trial itself, but broader concerns about rare clotting problems in adults have triggered further regulatory reviews in the U.K. and Europe to investigate any potential link with the vaccine.

A senior official for the European Medicines Agency (EMA) said in an interview today that there is a link between AstraZeneca’s COVID-19 vaccine and very rare blood clots in the brain but the possible causes are still unknown.

However, the EMA later said in a statement that its review of the vaccine was ongoing and it expected to announce its findings on Wednesday or Thursday. An AstraZeneca spokesman declined to comment on the matter.

“In my opinion, we can now say it, it is clear that there is an association (of the brain blood clots) with the vaccine. However, we still do not know what causes this reaction,” Marco Cavaleri, chair of the vaccine evaulation team at the EMA, told Italian daily Il Messagero.

Cavaleri provided no evidence to support his comment.

The EMA has repeatedly said the benefits of the AstraZeneca shot outweigh the risks as it investigates 44 reports of an extremely rare brain clotting ailment known as cerebral venous sinus thrombosis (CVST) out of 9.2 million people in the European Economic Area who have received the vaccine.