President Donald Trump announced Sunday that the Food and Drug Administration (FDA) has issued an emergency use authorization for convalescent plasma in treating patients with coronavirus, expanding access to a potentially lifesaving therapy.

“Today I’m pleased to make a truly historic announcement in our battle against the China virus that will save countless lives,” he told reporters gathered in the White House briefing room. “The FDA has issued an emergency use authorization and that’s such a powerful term, emergency use authorization for a treatment known as convalescent plasma.”

The treatment involves injecting coronavirus patients with the liquid portion of blood containing coronavirus antibodies, and Trump urged any Americans who were diagnosed with coronavirus “to go to Coronavirus.gov and sign up and donate plasma today.” (RELATED: What Happens If A Coronavirus Vaccine Is Deliverable Before The Election?)

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Health and Human Services Secretary Alex Azar noted that the therapy is most effective in patients recently diagnosed with coronavirus and that the treatment itself proved a 35% mortality rate reduction in patients under 80 who were not already using a ventilator.

“I just want to emphasize this point because I don’t want you to gloss over this number,” he reiterated. “We dream in drug development of something like a 35% mortality reduction. This is a major advance in the treatment of patients. This is a major advance.”

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Throughout the press conference, Trump and Azar both additionally talked about the progress the administration’s Operation Warp Speed has made toward developing vaccine candidates to combat coronavirus.