It announced the decision on Tuesday after reports of clotting incidents led to a decision by US regulators to “pause” the single-dose shot, which has been developed by J&J’s pharmaceutical arm Janssen, being administered.
The Food and Drug Administration (FDA) said six cases in 6.8 million doses had been reported and it was acting “out of an abundance of caution”.
“We have been reviewing these cases with European health authorities,” J&J said, “and we have made the decision to proactively delay the rollout of our vaccine in Europe.”
Hundreds of thousands of doses of the vaccine were due to be shipped to Europe in the coming weeks.
In a joint statement, the FDA and the Centres for Disease Control and Prevention (CDC) said they were “reviewing data involving six reported US cases of a rare and severe type of blood clot in individuals after receiving the J&J vaccine”.
Six cases were in women aged between 18 and 48, with symptoms six to 13 days after vaccination, and the clotting presented as cerebral venous sinus thrombosis (CVST), the statement said.
When countries began pausing the rollout of AstraZeneca’s vaccine earlier this month, it was for the same condition. In the UK, of the 18 million people vaccinated with the Oxford-AstraZeneca jab, there have been 22 cases of CVST and eight others where – as in CVST – blood clots develop in association with low platelets in the blood.
Following investigations by both EU and UK regulators it was decided that the benefits of receiving the AstraZeneca jab outweighed the risk. In the UK, it has been advised that under-30s should be offered an alternative vaccine where necessary but experts stressed this was not a necessity and anyone offered an AstraZeneca shot should still take it.
The European Medicines Agency (EMA) said it has already started reviewing the J&J vaccine to assess the reports of blood clots in US citizens who received the shot.
“These reports point to a ‘safety signal’, but it is currently not clear whether there is a causal association between vaccination” with the J&J shot, the EMA said.
Experts were “investigating these cases and will decide whether regulatory action may be necessary,” it added.
Meanwhile, a German health ministry spokesman appeared to brush off rumours of J&J vaccines being halted across the EU before the decision was formally announced.
Hanno Kautz told reporters in Berlin there were no immediate plans to change the country’s inoculation schedule.
“I don’t currently have the date from which J&J will be administered,” he said. “But in principle, we naturally always take such warnings in an international context seriously and investigate them.”
The White House’s Covid coordinator, Jeff Zients, also released a statement to say the decision to halt J&J’s rollout would not slow the US vaccination programme.
“This announcement will not have a significant impact on our vaccination plan,” Mr Zients said, adding that the administration is on track to continue delivering some 3 million jabs per day and meeting Joe Biden’s goal of 200 million shots by his 100th day in office.
It was announced last week that the US had fully vaccinated just under 20 per cent of its population, with over 30 per cent of Americans thought to have been given a first dose, according to CDC data.
The same figures show that in the UK, just over 47 per cent of the population have been given a first dose while almost 10 per cent have received their second jabs.
J&J’s vaccine is single-dose, which at first made it favourable to its competitors – that and the fact it is 66 per cent effective overall at preventing moderate to severe Covid 28 days after vaccination, and 85 per cent effective in preventing severe disease.
The EU has signed a firm order for 200 million J&J doses, and an option for 200 million more, while the UK government has secured 30 million doses of the jab. However, it has yet to be authorised for use by the UK’s independent Medicines and Healthcare Products Regulatory Agency (MHRA).
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