The United States has put Johnson and Johnson in charge of a plant that ruined 15 million doses of its Covid-19 vaccine and has stopped British drugmaker AstraZeneca Plc from using the facility, a senior health official said on Saturday.

J&J said it was "assuming full responsibility" of the Emergent BioSolutions facility in Baltimore, reiterating that it will deliver 100 million doses to the government by the end of May.

In a separate statement late Sunday, Emergent said it expects to align with the US government and AstraZeneca to ramp down...