A trial of the Oxford-AstraZeneca COVID vaccine on children in the UK has been paused while the medicines regulator investigates a possible link between the jab and rare blood clots in adults.

A University of Oxford spokesperson stressed that there were “no safety concerns” with this specific study, but that further information was being awaited from the Medicines and Healthcare products Regulatory Agency (MHRA).

“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,” the statement said.

“Parents and children should continue to attend all scheduled visits and can contact the trial sites if they have any questions.”

A spokesperson for the department of health and social care said: “No decisions have been made on whether children should be offered vaccinations.

“We will be guided by the advice of our experts on these issues including the independent MHRA and Joint Committee on Vaccines and Immunisation.”

Over the weekend it was reported that there had been thirty blood clotting cases recorded by the MHRA out of the 18 million doses of the AstraZeneca shot administered.

The MHRA confirmed that of those 30 people, seven had died as of 24 March.

More from Covid-19

The European Medicines Agency’s (EMA) head of vaccine strategy has said it is “increasingly difficult” to say there is “no cause and effect relationship” between the Oxford-AstraZeneca jab and “rare cases of unusual blood clots”.

A press conference is expected from the European drug drug regulator either on Wednesday or Thursday this week, where its latest findings will be announced on the matter.

The World Health Organisation is also expected to report findings from an assessment this week.

SAGE adviser Professor Calum Semple told Channel 4: “”This has been done out of exceptional caution and the big story still is that for a middle-aged, slightly overweight man, such as myself, my risk of death is one in 13,000 – the risk of this rare clot, which might not even be associated with the vaccine, is probably one in a million.

“So I’m still going to say it’s better to get the vaccine than not get the vaccine and we can pause and take time to carefully consider the value for children because they’re not at risk of death from COVID.”

Adam Finn, a professor of paediatrics at the University of Bristol, said: “There is a lot that remains unclear about the cases of thrombosis and thrombocytopenia being intensively studied by regulators and widely reported in the media.

“We need to know more about the people affected and we need to understand exactly how the illnesses came about, while many other questions remain unanswered at this time.

“However, there are some things that are very clear. The first is that these cases are very rare indeed. The second is that the vaccines that are available and in use in the UK prevent COVID very effectively.”

He added: “In short, if you are currently being offered a dose of Oxford-AstraZeneca vaccine, your chances of remaining alive and well will go up if you take the vaccine and will go down if you don’t.”