WATCH: Trump now says coronavirus vaccine by April – not Nov. 1 as he’s promised for weeks
President Donald Trump at a White House briefing (screengrab)

For months President Donald Trump and his top administration officials have been promising the coronavirus vaccine would be ready by November 1. White House chief of staff mark Meadows this week said "potentially" be the end of September. Trump, too, has pushed up the date, suggesting a vaccine could be ready in early October.

After CDC Director Robert Redfield testified before Congress on Wednesday that a vaccine would not be ready until early spring of 2021, or some time in the summer next year, Trump claimed he had been mistaken.

And then Trump went even further, promising not just that a coronavirus vaccine would be ready within weeks, but that timeline included "distribution" to Americans.

“I’m telling you, here’s the bottom line,” Trump said at Wednesday’s press conference, attacking a reporter. “Distribution’s going to be very rapid, he might not know that," Trump said of the CDC director,.

"Maybe he’s not aware of that, and maybe he’s not dealing with the military, etc., like I do. Distribution’s going to be very rapid.”

But on Friday Trump totally changed his prediction.

Calling it "historic progress we're making to deliver a safe and effective vaccine in record time," Trump announced "three vaccines are already in the final stage."

And then, Trump declared, "we expect to have enough vaccines for every American by April."

Not September, October, or November.

The president added, "We'll have manufactured at least 100 million vaccine doses before the end of the year, and likely much more than that. Hundreds of millions of doses will be available every month," he said.

Again, not September, October, or November.

But given all the important details, including testing, manufacturing the vaccine, manufacturing the delivery methods – meaning vials and syringes – and manufacturing the technology and infrastructure to transport vaccine at 70 degrees below zero, having at least 100 million vaccine doses before the end of the year, and being able to inoculate Americans are two very different things.

Trump also took false swipes at Vice President Joe Biden.