Germany, France, Italy and Spain are suspending use of the Oxford-AstraZeneca coronavirus vaccine as EU regulators investigate reports some people developed blood clots after having the jab.
The German health ministry, the Italian medicines authority and French President Emmanuel Macron said the measure was a “precaution” while the European Medicines Agency (EMA) looks into the matter.
Mr Macron said EU regulators were expected to give guidance on Tuesday afternoon.
Spain joined the group early on Monday evening, with a pause in its use of the vaccine to last at least two weeks, and Slovenia has also temporarily halted its rollout of the jab.
The countries are the latest European nations to stop administering the AstraZeneca vaccine amid concerns over possible links to the clots.
Professor Andrew Pollard, director of the Oxford vaccine group which developed the jab, has said there is “very reassuring evidence there is no increase in a blood clot phenomenon here in the UK, where most of the doses in Europe have been given so far”.
AstraZeneca has said there is no cause for concern, and Boris Johnson also insisted the jab was safe.
The prime minister said: “In the MHRA (Medicines and Healthcare products Regulatory Agency) we have one of the toughest and most experienced regulators in the world.
“They see no reason at all to discontinue the vaccination programme… for either of the vaccines that we’re currently using.”
The agency’s vaccines safety lead, Dr Phil Bryan, said: “We are closely reviewing reports but the evidence available does not suggest the vaccine is the cause.
“Blood clots can occur naturally and are not uncommon. More than 11 million doses of the AZ vaccine have now been administered across the UK, and the number of blood clots reported after having the vaccine is not greater than the number that would have occurred naturally in the vaccinated population.”
AstraZeneca said it had conducted a review covering more than 17 million people vaccinated in the EU and the UK which had shown no evidence of an increased risk of blood clots.
The European Medicines Agency has insisted the benefits of the vaccine outweigh potential side effects, adding the number of thromboembolic events (blood clots) in people inoculated does not seem higher than among the general population.
It said as of 10 March, a total of 30 cases of blood clotting had been reported among almost five million people vaccinated with the AstraZeneca shot in the European Economic Area, which links 30 European countries.
An EMA statement on Monday said: “Events involving blood clots, some with unusual features such as low numbers of platelets, have occurred in a very small number of people who received the vaccine.
“Many thousands of people develop blood clots annually in the EU for different reasons. The number of thromboembolic events overall in vaccinated people seems not to be higher than that seen in the general population.”
An Oxford University spokesperson said: “Thromboembolic disease – not related to vaccines – is reasonably common in the UK general population, occurring in one in every 1,000 people.
“The UK Medicines and Healthcare products Regulatory Agency (MHRA) are monitoring these and have indicated that they are not seeing an increase from this baseline level as part of the vaccine rollout, which reassures us that it is unlikely to be a problem, which is supported by further data from the Finnish health authorities.”
The World Health Organisation has appealed to countries not to suspend vaccinations against a disease that has caused more than 2.7 million deaths worldwide.
“As of today, there is no evidence that the incidents are caused by the vaccine and it is important that vaccination campaigns continue so that we can save lives and stem severe disease from the virus,” said WHO spokesman Christian Lindmeier.
In a statement, the German health ministry said its decision to suspend the jab was taken on the advice of national vaccine regulator, the Paul Ehrlich Institute (PEI).
The PEI has called for further investigation into seven reported cases of clots in the brains of people who had been vaccinated.
German health minister Jens Spahn said his country’s decision to stop using the vaccine was not political and while the risk of blood clots is low it cannot be ruled out.
Mr Macron said he hopes “we can resume quickly” administering the vaccine “if the EMA gives the green light”.
He added: “We are therefore suspending its use until tomorrow afternoon.”
On Sunday, Ireland temporarily suspended the shot “out of an abundance of caution” after reports from Norway of serious blood clotting in some recipients there.
Three health workers in Norway who recently received the AstraZeneca vaccine were being treated in hospital for bleeding, blood clots and a low count of blood platelets, its health authorities said on Saturday.
Irish authorities received some reports of clotting similar to those seen in mainland Europe last week but nothing as serious as the Norwegian cases, according to Deputy Chief Medical Officer Ronan Glynn.
Denmark, Norway and Iceland have suspended the use of the vaccine over reported clotting issues.
Other countries temporarily halting its use include the Netherlands, Congo and Bulgaria.
Authorities in Italy’s northern region of Piedmont said on Sunday they would stop using a batch of AstraZeneca vaccines after a 57-year-old teacher died following his vaccination a day earlier.
Post-mortem examinations have been ordered into his death, as well as several other fatalities last week in Italy of people who had received the vaccine.
The EMA has said there was no evidence so far linking the vaccine to illnesses in two people who received it in Austria, one of whom died 10 days after being inoculated.
Austria halted using a particular batch last week.