EU regulator backs use of Johnson & Johnson COVID-19 vaccine despite finding possible link to blood clots

Europe's drug regulator has found a possible link between Johnson & Johnson's COVID-19 vaccine and rare blood clotting issues in adults who received doses in the United States, but backed its overall benefits against any risks.

The European Medicines Agency (EMA) said on Tuesday its safety committee had concluded that a warning about unusual blood clots with low platelets must be added to the vaccine's labels, just as it has also required of rival vaccine maker AstraZeneca-Oxford.

The findings are a blow to the European Union, which is battling major hurdles to its immunization campaign after several nations suspended or limited the use of AstraZeneca's vaccine over possible blood clots. 

The EMA found that all instances of clotting had occurred in adults under 60, mostly women, within three weeks of vaccination with Johnson & Johnson's single shot.

It said all available evidence, including eight U.S. reports of cases, had formed part of its assessment.

The watchdog also said that most clots had occurred in the brain and abdomen, as was the case with AstraZeneca's shot, which is also being studied for similar blood clotting problems.

"One plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin," the EMA said.

U.S. had recommended Johnson & Johnson pause

The U.S. health regulator last week recommended pausing the use of the Johnson & Johnson single-dose shot after six women under the age of 50 developed rare blood clots after receiving it, in a fresh setback to global efforts to tackle the pandemic.

The cases were reported out of more than seven million doses administered in the United States as of April 13, the EMA said.

Johnson & Johnson, which recorded $100 million in COVID-19 vaccine sales, has delayed rolling out the vaccine to Europe, but is prepared to resume the deployment. It has said it would aim to deliver 55 million doses to the EU, as contracted, by the end of June.

Johnson & Johnson's vaccine, developed by its Janssen unit, is one of four COVID-19 vaccines authorized for use in Europe.

It's also among the four vaccines approved here in Canada, with a first shipment expected later this month, alongside the AstraZeneca shot, which has been a source of controversy amid changing recommendations tied to the blood clot concerns.

As CBC News reported on Monday, Canada's National Advisory Committee on Immunization previously recommended that provinces pause the use of the vaccine in those under the age of 55 due to safety concerns, but new documents show it will now recommend expanding the use of the AstraZeneca vaccine to younger age groups under specific conditions.

Multiple provinces have already shifted to a lower age cut-off for the vaccine, which Health Canada maintains is safe for use.