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Biden administration announces additional purchase of 500,000 AstraZeneca Covid-19 treatment courses

(CNN) The Biden administration announced Wednesday the purchase of additional courses of a Covid-19 treatment manufactured by drugmaker AstraZeneca.

The White House is "in the process of ordering another half-million courses of AstraZeneca's preventive therapy for immunocompromised individuals," Covid-19 response coordinator Jeff Zients said at Wednesday's Covid-19 briefing.

"The federal government was instrumental in the research and development of this product -- and our latest order will also bring us to over one million doses available through end of March," Zients said.

The US Food and Drug Administration authorized AstraZeneca's Evusheld, a drug aimed at helping immune-compromised people from getting infected with the coronavirus, in December. The Covid-19 vaccines worked well for many -- but not all -- people with suppressed immune systems, leaving them vulnerable to the virus. Evusheld is a monoclonal antibody, and doctors hoped to give it to their immune-compromised patients because it works in a different way than the vaccines.

About 7 million adults in the US are immune-compromised and could benefit from Evusheld, according to AstraZeneca. The federal government, which is the sole distributor of the drug, contracted for only enough doses to treat 700,000 people in December, and Wednesday's announcement will build on that initial purchase.

Zients also touted the previously announced purchase of 20 million courses of Pfizer's antiviral pill, with the first 10 million courses expected to be delivered by the end of June 2022, as part of the administration's "diverse portfolio" of Covid-19 treatments.

Additionally, he noted that the US has completed the purchase of 600,000 additional treatment courses of GlaxoSmithKline's monoclonal antibody treatment for more than 1 million total treatment courses that will become available through the end of March.

"We have more courses of effective treatment now than at any other point during the pandemic. This is the direct result of the Biden administration's focus from day one to stock our nation's medicine cabinet with a diverse set of treatments and the aggressive actions we have taken to expedite research, development, manufacturing and procurement," he said.

The administration spent much of the past year focused on manufacturing and scaling vaccine supply. But as the Omicron variant continues to spread, with surging cases and hospitalizations, some experts have warned current efforts to surge supply of therapeutics for those who do contract the virus are not enough.

Therapeutics aren't just being hampered by small supply. Some doctors are warning CNN they are also hampered by lack of testing to get test results in a timely enough fashion to actually administer doses in the proper window. Pfizer's Paxlovid treatment needs to be administered within five days of symptoms, and GlaxoSmithKline's Sotrovimab monoclonal antibody treatment needs to be administered within seven days. Additionally, some hospitals also say there is simply not enough hospital staff to administer enough monoclonal antibody infusions because of staffing shortages.

This story has been updated with additional reporting.

CNN's Elizabeth Cohen contributed to this report.