J&J vaccine benefit outweighs "very rare" blood clot risk says EU regulator

The Johnson & Johnson single-shot COVID-19 vaccine can in very rare cases lead to unusual blood clots, the European Medicines Agency has concluded, though experts maintain the benefits outweigh the risks. It's the second coronavirus vaccine to be subject to extra warning labeling by the EU regulator, after AstraZeneca's drug was also linked to blood clotting issues.

Then, as now, the number of reported cases of those incidents was exceptionally low. Eight reports from the US of unusual blood clots associated with low levels of blood platelets were assessed by the EMA. One of those cases resulted in the individual dying.

Currently, the J&J one-shot COVID-19 vaccine is only in use in the US. Over 7 million people had been vaccinated with the drug as of April 13, 2021, the EMA pointed out.

All eight of the US cases occurred in people over 60 years of age, and the majority were women. All took place within three weeks of vaccination with the J&J Janssen drug. Beyond that, however, no specific risk factors have been confirmed, the EMA says.

According to PRAC, the EMA's safety committee, the blood clot cases were "very similar to the cases that occurred with the COVID-19 vaccine developed by AstraZeneca, Vaxzevria." Earlier in April, the EMA decided that Vaxzevria should be further labeled with blood clots as a very rare side effect, after 62 cases of blood clots in the brain (cerebral venous sinus thrombosis, or CVST) and 24 cases in the abdomen (splanchnic vein thrombosis) had been reported.

Of those cases among people immunized with AstraZeneca's drug, 18 proved fatal. The total immunized population with the drug was around 25 million at the time, the EMA said.

Just as then, the recommendation by the EMA is to continue deployment of Johnson & Johnson's vaccine. "The reported combination of blood clots and low blood platelets is very rare," it pointed out today, "and the overall benefits of COVID-19 Vaccine Janssen in preventing COVID-19 outweigh the risks of side effects."

Indeed, third-party research suggests that COVID-19 itself is a bigger contributor to risk of unusual blood clotting than the vaccines are.

"Healthcare professionals and people who will receive the vaccine should be aware of the possibility of very rare cases of blood clots combined with low levels of blood platelets occurring within three weeks of vaccination," the EMA recommends.

Those symptoms include shortness of breath, chest pain, leg swelling, persistent abdominal (belly) pain, neurological symptoms, such as severe and persistent headaches or blurred vision, and tiny blood spots under the skin beyond the site of the injection. Anybody observing those symptoms should seek emergency medical care.

The US FDA and CDC has recommended "a pause" in use of the J&J vaccine, as it reviews the data on the six cases of blood clotting. "This pause was recommended, in part, to ensure that the health care provider community is aware of the potential for these adverse events and can plan for proper recognition and management due to the unique treatment required with this type of blood clot," the FDA said in a statement.

Johnson & Johnson said today that, in light of the EMA's conclusions, it would resume shipments of its vaccine to the European Union (EU), Norway, and Iceland. "The safety and well-being of the people who use our products is our number one priority," Paul Stoffels, M.D., Vice Chairman of the Executive Committee and Chief Scientific Officer at Johnson & Johnson, said today in a statement. "We appreciate the rigorous review of the PRAC and share the goal of raising awareness of the signs and symptoms of this very rare event to ensure the correct diagnosis and appropriate treatment."