recommended that inoculations with the Johnson & Johnson Covid-19 vaccine be halted while researchers investigated six reports of unusual blood clots out of 6.8 million people who had received it.
Top federal officials said in interviews with The New York Times that they had found a few additional cases of the rare blood clots, but would not specify how many. They said that the overall rate did not appear to have changed significantly since last week.
The committee could recommend that Johnson & Johnson add a formal warning label about the side effect, as the company has done in the European Union. Roughly 10 million doses or more of the vaccine, produced at the company’s factory in the Netherlands, are sitting on shelves across the United States and could be deployed immediately.
The meeting comes as the federal government is also investigating problems at a Baltimore factory that was slated to help satisfy the country’s demand. Emergent BioSolutions, the plant’s operator, has produced tens of millions of doses of Johnson & Johnson’s vaccine, but they cannot be distributed until regulators certify the plant.
After Emergent had to discard up to 15 million possibly contaminated doses of the vaccine last month, federal regulators conducted an inspection that found a series of problems, including the risk that other batches could have been contaminated.
Last week’s pause followed reports of six women who experienced a rare type of blood clot in the brain within three weeks of getting the Johnson & Johnson vaccine. The clots were accompanied by an unusual drop in platelets, components of the blood that normally help heal wounds.
On Thursday, the Oregon health authorities reported that a death was being investigated for a possible connection to the Johnson & Johnson vaccine. The woman who died was in her 50s and had symptoms consistent with the blood clotting cases identified in eight other Johnson & Johnson recipients in the U.S. Dr. Shimi Sharief, the state health authority’s senior health adviser, emphasized that it was not known whether the woman’s death was related to the vaccine.
The C.D.C. committee met the day after the initial pause, and a representative from Johnson & Johnson provided details on the six cases, along with two others. Rather than voting, the panel decided to hold a second meeting the following week, giving them time to better assess the data.
European regulators, who have also been scrutinizing the shots, said on Tuesday that they would allow these vaccinations to resume with the addition of a formal warning label.