Johnson & Johnson delays vaccine roll-out in Europe after US suspension
All six cases of cerebral thrombosis involved women aged 18 to 48.
The clots developed between six and 13 days after inoculation.
US federal health agencies made their recommendation on Tuesday after six blood clot cases were reported among the nearly 7 million people who have received the jab in the country.
All six cases of cerebral thrombosis involved women aged 18 to 48. The clots developed between six and 13 days after inoculation, the agencies said.
Three women also developed thrombocytopenia, a lack of blood platelets.
The US Food and Drug Administration and the Centers for Disease Control said use of the vaccine should be suspended while the data is examined, prompting many states to announce the doses would be shelved.
The single-shot Johnson & Johnson vaccine has been used in the United States since last month and has been administered to more than 6.8 million people.
Jeff Zients, the White House Covid-19 coordinator, said the announcement would "not have a significant impact" on the US vaccination plan, noting the jab has made up less than 5% of all shots and that the country has secured enough doses from Pfizer/BioNTech and Moderna to be given to 300 million Americans.
Roll-out in Europe 'delayed'
Shortly after the shots were put on ice in the US, Johnson & Johnson announced that it would "proactively delay" the roll-out of the vaccine in Europe as investigations were under way.
The European Union started receiving its very first deliveries of Johnson & Johnson's jab only on Monday, one month after it was given the green light for use in the bloc's 27 member states.
Last week, the European Medicines Agency (EMA) announced it was investigating four reported incidents of potentially deadly internal blood clots following vaccinations with Johnson & Johnson, without changing its recommendation status.
Earlier, EMA had identified a similar possible link between thrombosis and British-Swedish drugmaker AstraZeneca's shot in very rare cases, but upheld its backing for the jab. The benefits very much outweighed risks, according to the EU regulator.
Many EU countries have limited the use of the AstraZeneca shot to people in older age groups.
The suspension of the Johnson & Johnson jab is sure to compound the the vaccine problems of the EU, which has struggled to accelerate its inoculation drive even as several countries are in the midst of a third wave of rising coronavirus cases.