The European Union's drug regulator said blood clots with low platelets should be listed as "very rare side effects" of the Johnson & Johnson COVID-19 vaccine, but stressed that the overall benefits of the shot outweigh the risk.  
"There is a possible link between the occurrence of these blood clots combined with the low levels of blood platelets, thrombocytopenia, and the vaccination with the COVID-19 vaccine," Sabine Straus, Chair of the European Medicines Agency's safety committee PRAC, said on Tuesday.  

 

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The blood clots, which the safety committee emphasized were "very rare," have all occurred in the U.S.. Out of the roughly 7 million doses administered, eight cases were reported in people under the age of 60, the majority of whom were women. One person died. The European Medicines Agency (EMA) said it found no specific risk factors or a clear cause of the clotting.

No cases have been reported in Europe, although the vaccine's roll-out has been very limited.  

"The benefits of the vaccine continue to outweigh these risks and we now have detailed information in the labeling that alerts to these risks, we have detailed information for the healthcare professionals in case there are any issues," EMA Executive Director Emer Cooke said during a press conference.  

J&J halted the European roll-out of its COVID-19 vaccine last week after the U.S. Food and Drug Administration recommended the use of the jab be paused while the cases were examined. U.S. health regulators are expected to issue their recommendation on Friday. 

It's now up to individual member states to decide on how and if to use the J&J vaccine. France already indicated it would stick to its plan of only using the jab for people over 55 years of age.  

Ahead of the EMA's announcement, a top executive at J&J said the company was "very confident" in its COVID-19 vaccine.  

"We remain very confident and very hopeful that the benefit-risk profile will play out," Joseph Wolk, J&J Chief Financial Officer, told CNBC.

J&J/AstraZeneca link? 

EMA said the J&J cases were "very similar" to the cases that occurred with the COVID-19 vaccine developed by AstraZeneca, now called Vaxzevria. Both vaccines use adenoviral vectors to deliver immunity instructions to the body, although Straus said "there was still no way of telling" whether clotting occurs more or less frequently with the AstraZeneca jab.  

Pfizer and Moderna use mRNA technology for their shots, although the EMA said cases of clotting had been reported in people who had received those vaccines as well.

There are worries the pause could further damage vaccine confidence and hamper the global ramp-up of immunization. The J&J jab was once seen as the potential backbone of global immunization. A one-dose shot that can be stored in a refrigerator, it could easily be transported to remote areas and poorer countries. It was also seen as ideal for younger populations who may skip second doses.   

Clotting concerns over the AstraZeneca vaccine prompted many European countries to restrict the shot's use to older age groups. Denmark dropped administering the jab altogether, while Sweden on Tuesday said it would give people aged under 65 who had received a dose of the AstraZeneca vaccine an alternative jab for their second dose.