Feds call halt to Johnson & Johnson COVID-19 vaccine rollout after 'extremely rare' blood clot cases

After drug regulators on both sides of the Atlantic revealed safety probes into Johnson & Johnson’s COVID-19 vaccine, U.S. officials are calling for an immediate pause to the rollout.

Since the vaccine’s late February emergency use authorization in the U.S., nearly 7 million people have received the shot. Six recipients of the vaccine—all women between 18 and 48—were diagnosed with rare blood clots afterward, the FDA says. One died and one is in critical condition.

The FDA on Tuesday said it’s “recommending a pause in the use of this vaccine out of an abundance of caution.”

Speaking with reporters on Tuesday, FDA acting commissioner Janet Woodcock said she expects the pause to last a “matter of days.” While the FDA and CDC investigate, officials also want to flag symptoms of the rare clots and treatment recommendations for them.

The rare blood clots need to be treated differently than typical clots, officials said. In fact, standard treatments can worsen a patient's condition.

The cases all surfaced about one to three weeks after vaccination, FDA vaccine official Peter Marks said on the call. Warning signs include severe headache, abdominal pain, leg pain and shortness of breath. The FDA plans to revise the J&J vaccine fact sheet to include the updated information.

RELATED: FDA joins Europe in probing rare blood clots after Johnson & Johnson's COVID-19 vaccine

The pause represents a setback for the J&J vaccine as the U.S. pushes ahead with the mRNA shots from Pfizer and Moderna. AstraZeneca's COVID-19 vaccine—which, like J&J's, is adenovirus-based—has also raised rare blood clot concerns, and that has led to a sporadic vaccination effort in Europe, where individual countries are setting vaccine policy.

The CDC’s Advisory Committee on Immunization Practices—which reviews data and makes vaccination recommendations for the U.S.—will meet Wednesday to discuss the data. The FDA is investigating the rare clotting cases and will review the committee’s analysis.

J&J is "aware of an extremely rare disorder involving people with blood clots in combination with low platelets" in a small number of people after vaccination, the company said in a statement

"We have been working closely with medical experts and health authorities, and we strongly support the open communication of this information to healthcare professionals and the public," the company added.

While the news is “unfortunate,” it’s also the “right step,” Ashish Jha, dean of the Brown University School of Public Health, wrote on Twitter. 

No drug or vaccine is perfect, he noted, but “confidence is built on having a system that takes adverse events seriously, investigates them” and then makes “data-driven decisions.” That’s the process the agencies are following, Jha said. 

The news comes after the FDA and European Medicines Agency (EMA) late last week acknowledged they were investigating the vaccine after cases of rare blood clots. At the time, the FDA said it had not "found a causal relationship with vaccination." 

RELATED: Johnson & Johnson's COVID-19 vaccine under scrutiny at EMA after 4 'serious cases' of unusual blood clots

So far, 190 million COVID-19 vaccine doses have been administered in the U.S. J&J is delaying its vaccine rollout in Europe as the investigation proceeds, the company said.