A trial testing the Oxford-AstraZeneca COVID-19 vaccine on children has temporarily been stopped while a possible link with rare blood clots in adults is investigated.
The research has been postponed while official bodies look into the potential association.
Meanwhile, Professor Andrew Pollard from the University of Oxford has told the BBC there were no safety concerns with the trial itself and Prime Minister Boris Johnson is continuing to urge people to have their vaccine when they are called up.
Professor Pollard said: “Whilst there are no safety concerns in the paediatric clinical trial, we await additional information from the MHRA on its review of rare cases of thrombosis/thrombocytopaenia that have been reported in adults, before giving any further vaccinations in the trial.”
Very rare cases of unusual blood clots among people who have had the vaccine is being looked into by the European Medicines Agency (EMA).
The organisation said it had “not yet reached a conclusion and the review is currently ongoing”.
The UK regulator the Medicines and Healthcare Products Regulatory Agency (MHRA) said so far 30 cases of rare blood clot events have been identified out of 18.1 million doses of the jab which have been administered up to and including 24 March. There have been seven deaths among the 30 cases.
Speaking to the BBC, the regulator’s chief executive Dr June Raine said: “People should continue to get their vaccine when invited to do so.
“Our thorough and detailed review is ongoing into reports of very rare and specific types of blood clots with low platelets [the cells involved in clotting] following the Covid-19 vaccine AstraZeneca. No decision has yet been made on any regulatory action.”