Trump was asked about a timeline for a vaccine during the Cabinet Room meeting with pharmaceutical executives and members of his task force.
"I don't know what the time will be. I've heard very quick numbers, that of months. And I've heard pretty much a year would be an outside number. So I think that's not a bad range. But if you're talking about three to four months in a couple of cases, a year in other cases," Trump said.
But Dr. Antony Fauci, the head of the National Institute of Allergy and Infectious Diseases, immediately corrected the President: "Let me make sure you get the ... information. A vaccine that you make and start testing in a year is not a vaccine that's deployable."
As Fauci explained the timeline, Trump folded his arms.
Fauci said: "So he's asking the question -- when is it going to be deployable? And that is going to be, at the earliest, a year to a year and a half, no matter how fast you go."
"Do you think that's right?" Trump asked the pharmaceutical executives at the table, just as Fauci finished speaking. "Well, I think treatment in many ways might be more exciting."
The pushback didn't come just from Fauci.
Throughout the meeting, Trump was hyperfocused on pressing industry leaders in the room for a timeline for a coronavirus vaccine and treatment. But experts at the table -- from the administration and the pharmaceutical industry -- repeatedly emphasized that a vaccine can't be rushed to market before it's been declared safe for the public.
"So you're talking over the next few months, you could have a vaccine?" Trump later asked Stéphane Bancel, the CEO of Moderna, a biotechnology company.
"Correct, (for) phase two (testing)," Bancel answered.
Fauci interjected: "He wouldn't have a vaccine. He'd have a vaccine to go into testing."
Trump said: "Oh, so you're talking in about a year."
Fauci said: "A year to a year and a half."
The President said that one executive was "talking about two months."
But Health and Human Services Secretary Alex Azar clarified that Regeneron, a biotechnology company that was represented in the room, would be ready for phase one testing for a vaccine in two months.
Leonard Schleifer, the CEO of Regeneron Pharmaceuticals, then underscored that "vaccines have to be tested because there's precedent for vaccines to actually make diseases worse. ... You don't want to rush and treat a million people and find out you're making 900,000 of them worse."
"That's a good idea," Trump said.
The President also said he agrees that any coronavirus vaccine has to be safe in order for it to be made widely available, but added: "Get it done. We need it. We want it fast."
Inovio CEO J. Joseph Kim, who was in the meeting, told CNN that Trump told the executives to contact him directly if they encountered holdups within the federal government.
A source familiar with the administration's response said the scientists and experts gathered for the meeting were able to convince Trump that it will likely take a year or longer for an effective vaccine to be on the market.
"I think he's got it now," the source said.