"You have to be realistic," Fauci told CNN's Chris Cuomo on "Prime Time."
"And you have to understand that you're not making the timeline, the virus is making the timeline. So you have to respond to what you see happening. And if you continue to see this acceleration, it doesn't matter what you say. One week, two weeks, three weeks – you have to keep up with the situation on the ground. "
Fauci said in reference to slowing the rate of the outbreak, "you can see for a relatively shorter period, when you see the flush of the flush and come down." But you know, you can't make an arbitrary decision until you see what you have to do with. You need the data. "
The dynamics were in full swing when Trump was asked earlier this month for a vaccine timeline during a White House meeting opened to journalists.
"I don't know what time it will be. I've heard very fast numbers, that from months. And I've heard pretty much that a year would be an external number. So I guess that's no bad range. But if you talk about three to four months in a couple of cases, one year in other cases, "Trump said.
Fauci, who was in the room, immediately corrected the president: "Let me make sure you get … the information. A vaccine you make and start testing in a year is not a vaccine that can be implemented."