"Given the strong portfolio of vaccines that the United States has already authorized and that is available in large quantities, including two two-dose vaccines and one one-dose vaccine, and given that AstraZeneca is not authorized for use in the United States, we do not need to use AstraZeneca in our fight against Covid over the next few months", Psaki said.
The U.S. has also been under mounting pressure in recent weeks to share more of its vaccine supply with the world, as countries like India experience devastating surges of the virus and others struggle to access doses needed to protect their most vulnerable populations.
Announcing on Monday, April 26, its decision to take the company to court, a commission spokesman said the legal claim had been made as "some terms of the contract have not been respected and the company has not been in the position to come up with a reliable strategy to ensure timely delivery of doses".
AstraZeneca is no longer making vaccine at that plant after a batch of Johnson & Johnson's vaccine was ruined by contamination with ingredients from the AstraZeneca shot. Upto 18 EU countries stopped using the vaccine following incidents of blood clots, though later, the Union's drug regulator said the benefits of the shot outweighed the risks. But on March 12, AstraZeneca said in a statement that it would aim to deliver only one-third, or 10 crore vaccines, by June-end, and seven crore of it in the second quarter, according to Reuters.
Political concerns have also weighed on officials, who are wary of sending doses overseas before every American can access them.
"This is not just a crisis for India, it's a global crisis and India has become the epicenter. Many people here were reminded of the Cold War era when the United States was not seen as a reliable partner", Arun Singh, former Indian ambassador to the United States, told ThePrint.
"Given that there is not enough of the supply for the entire global manufacturing effort and in light of the current crisis, we, the United States, are diverting our order to India", the official added.
Another category of assistance that the U.S. will provide to India are therapeutics, personal protective equipment and tests. While vaccine doses were not included, the U.S.is sending a supply of remdesivir, an anti-viral drug used to treat hospitalized Covid-19 patients, a senior administration official said.
The aid package includes oxygen and related supplies, with the USA looking at sending oxygen generation systems. A team of experts from the Centers for Disease Control and Prevention is being sent to India to assist public-health officials there as well, the White House said.
"Right now we have zero doses available of AstraZeneca", Psaki said, noting that USA regulators still need to review the quality of those already produced.
"I think we can safely say that the issue of doses of vaccine, particularly the AZ vaccine, are certainly under active discussion".
The World Health Organisation expects to decide whether to give emergency approval for China's two main Covid-19 vaccines in the next two weeks.
An AstraZeneca spokeswoman could not comment on specifics of the arrangement, but said the doses were part of its supply commitments to the USA government.
During the conference on Monday, Slavitt said the AstraZeneca vaccine is highly safe and effective, but that the US has enough doses of vaccines already approved by the FDA without the 300 million ordered from the UK.
Biden signaled last week that the USA was considering loaning more, but said that won't happen until there is enough supply.