Some experts say they worry that producing more of AstraZeneca’s vaccine in the United States at this point will use up valuable raw materials that might be better directed overseas or to make other vaccines.
One federal official, speaking on condition of anonymity to discuss ongoing discussions, said the government is now renegotiating AstraZeneca’s contract, at least partly in order to shift production from Emergent to Catalent. That official estimated that Catalent could produce roughly 25 million to 35 million doses a month of AstraZeneca’s vaccine on its new line — similar to the output that was expected from Emergent.
Unlike Johnson & Johnson, Pfizer and Moderna, AstraZeneca has not sought authorization from the Food and Drug Administration to distribute its vaccine for emergency use here. Without an obvious or immediate need for the vaccine in the U.S., company officials are leaning against doing so according to people familiar with their thinking. AstraZeneca could still pursue licensure, a lengthier and more complicated process.
The AstraZeneca shot appears to be linked to a very rare, but sometimes fatal, blood clotting disorder, similar to the side effects that earlier led to a temporary pause on use of Johnson & Johnson’s vaccine in the United States. Many European countries temporarily stopped using the AstraZeneca vaccine earlier this year after a small number of clotting incidents, but they have largely restarted, in some cases with restrictions on what age groups should receive it. The vaccine is being used in 173 countries.
President Biden in late April committed to sharing 60 million doses of AstraZeneca’s vaccine. Jeffrey D. Zients, the White House’s Covid-19 response coordinator, said a month ago that 10 million of those doses could be released to other countries soon, with the rest ready to be shared within months, pending an F.D.A. review.
Mr. Biden later expanded his pledge, promising to also send 20 million doses of Covid-19 vaccines developed by other companies overseas. Samantha Power, who heads the federal Agency for International Development, told lawmakers last week that three-fourths of American excess supply would likely go to Covax, an international vaccine-sharing initiative, and the rest would be distributed through bilateral agreements.
Secretary of State Antony J. Blinken said this week that the administration will announce a plan to distribute vaccines overseas within two weeks.
Rebecca Robbins and Benjamin Mueller contributed reporting.