Federal regulators have asked Emergent BioSolutions to suspend making materials for COVID-19 vaccines until inspectors examine a plant that ruined millions of doses of Johnson & Johnson's coronavirus shot.

The Food and Drug Administration requested that Emergent halt producing the vaccine's active ingredient at its plant in Baltimore, the company said in a regulatory filing Monday.

Emergent was contracted to manufacture bulk drug substances for various coronavirus vaccine candidates at its Bayview facility in Maryland.

The company said the FDA inspected the facility last week.

"At the request of the FDA, Emergent agreed not to initiate the manufacturing of any new material ... and to quarantine existing material manufactured at the Bayview facility," Emergent said in the filing.

The FDA began inspections after Johnson & Johnson learned that Emergent workers had conflated ingredients for its one-shot COVID-19 vaccine with ingredients for the vaccine developed by AstraZeneca, which has not yet been approved for use in the United States.

The discovery led to Johnson & Johnson installing its own experts and technicians to oversee the production of its vaccine at the Emergent facility. AstraZeneca removed production of its vaccine from the Emergent plant altogether.

Johnson & Johnson said about 15 million doses affected by the mix-up were never distributed.

"We acknowledge that there are improvements we must make to meet the high standards we have set for ourselves and to restore confidence in our quality systems and manufacturing processes," Emergent said, according to Politico.

Last week, federal regulators recommended a pause in administration of the Johnson & Johnson vaccine over a possible link to a few cases of blood clotting in recipients. The inspections at the Emergent plant is unrelated to the pause.

Copyright 2021 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent., source US Top News