Europe, Canada and Australia, as a precaution, Hold Back Millions of doses of Johnson & Johnson’s Covid-19 vaccine produced by Emergent BioSolutions in Baltimore

WASHINGTON — Quality-control problems at a Baltimore plant manufacturing Covid-19 vaccines have led health officials on three continents to pause the distribution of millions of Johnson & Johnson doses, as the troubles of a politically connected U.S. contractor ripple across the world.

Doses made at the plant owned by Emergent BioSolutions have not been cleared by the Food and Drug Administration for use in the United States, and the Biden administration has repeatedly assured Americans that none of the Johnson & Johnson shots administered domestically were made there.

But millions of doses have been shipped abroad, including to Canada, the European Union and South Africa. Regulators in various countries are now working to ensure that those doses are safe after the disclosure in March that workers at the Baltimore plant accidentally contaminated a batch of Johnson & Johnson’s vaccine with the harmless virus used to manufacture AstraZeneca’s. Both vaccines were produced at the same site. The mistake forced Emergent to throw out up to 15 million Johnson & Johnson doses after tests showed that the batch failed to meet purity requirements.

E.U. officials, as well as those in Canada and South Africa, said there was no evidence that any of the doses they had received were tainted. But the problems identified in Baltimore have slowed their vaccination efforts while they perform additional quality assessments as a precaution.

Some doses from a single batch of the vaccine produced at Emergent are being administered in Europe, without problem, officials said. In addition, about six million to nine million more doses are now on hold there and in the other countries because they came from batches that were produced in the same manufacturing suite and over the same two-day period in late February when the contamination occurred, according to health officials familiar with the situation.

The F.D.A. has now called into question the equivalent of about 70 million doses from the plant, most of it intended for domestic use, and may decide that none of that vaccine can be released in the United States, those officials said.

One likely cause of the contamination is the failure of some employees to shower and change clothes as required when they moved between the factory zones dedicated to AstraZeneca and Johnson & Johnson, inspectors found.

Safety tests identified traces of AstraZeneca’s virus in one batch of Johnson & Johnson’s vaccine before it ever left the factory, but the F.D.A. is concerned that similar checks might have missed some lower-level contamination of the other batches that were produced simultaneously, according to a federal official who spoke on the condition of anonymity in order to describe internal discussions. ...