Johnson & Johnson has said it is delaying the roll out of its coronavirus vaccine in Europe amid a US probe into rare blood clots.
The company announced the decision on Tuesday after regulators in the United States said they were recommending a “pause” in administration of the single-dose vaccine to investigate reports of potentially dangerous blood clots.
“We have been reviewing these cases with European health authorities,” the company said.
“We have made the decision to proactively delay the roll out of our vaccine in Europe.”
Hundreds of thousands of doses of the vaccine were due to be shipped to Europe in the coming weeks.
Earlier, the US recommended a “pause” in administration of the vaccine to investigate reports of potentially dangerous blood clots.
In a joint statement, the Centres for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) said they were investigating clots in six women that occurred six to 13 days after vaccination.
The clots occurred in veins that drain blood from the brain and occurred together with low platelets.
All six cases were in women between the ages of 18 and 48.
More than 6.8 million doses of the J&J vaccine have been administered in the US, the vast majority with no or mild side effects.
US federal distribution channels, including mass vaccination sites, will pause the use of the J&J vaccine, and states and other providers are expected to follow.
The other two authorised vaccines, from Moderna and Pfizer, make up the vast share of Covid-19 jabs administered in the US and are not affected by the pause.
US health authorities cautioned doctors against using a typical clot treatment, the blood-thinner heparin.
“In this setting, administration of heparin may be dangerous and alternative treatments need to be given,” the FDA and CDC said.
European authorities investigating the AstraZeneca cases have concluded clots appear to be similar to a very rare abnormal immune response that sometimes strikes people treated with heparin, leading to a temporary clotting disorder.
Officials say they also want to educate vaccine providers and health professionals about the “unique treatment” required for this type of clot.
Johnson & Johnson said it was aware of the reports of “thromboembolic events”, or blood clots, but that no link to its vaccine had been established.
“We are aware that thromboembolic events including those with thrombocytopenia have been reported with Covid-19 vaccines,” said Johnson & Johnson in a statement.
“At present, no clear causal relationship has been established between these rare events and the Janssen Covid-19 vaccine.”
The J&J vaccine received emergency use authorisation from the FDA in late February with great fanfare, with hopes that its single-dose and relatively simple storage requirements would speed up vaccinations across the country.
Yet the shot only makes up a small fraction of the doses administered in the US as J&J has been plagued by production delays and manufacturing errors at the Baltimore plant of a contractor.
Last week the firm took over the facility to scale up production in the hopes of meeting its commitment to the US government of providing about 100 million doses by the end of May.
Until now, concern about the unusual blood clots has centred on the vaccine from AstraZeneca, which has not yet received authorisation in the US.
