CHICAGO (CBS) — It was a powerful and memorable day Monday for the medical community as the COVID-19 vaccine arrived in Illinois – with several saying this is a “once-in-a-lifetime” experiment and result doesn’t quite capture it.

“In this pandemic, everybody is like: ‘Are we at the end or the beginning? Are we in the middle?” Dr. Emily Landon of the University of Chicago Medical Center told CBS 2’s Chris Tye. “This is the beginning of the end.”

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In boxes loaded with dry ice and frozen vaccine, a day chiseled in history unfolded in Illinois on Monday.

“I think you’ll think of this day like you think of the Vietnam War ending, or someone being assassinated, or the end of World War II – things like that,” said Dr. Richard Freeman, chief medical officer at Loyola University Medical Center. “I mean, this is one of those kind of days, I think, for most people.”

Indeed, for Freeman, this day – Monday, Dec. 14, 2020 – makes that short list.

“Personally, you remember certain things – your first patient, your first patient death, things like that,” he said. “For those of us that have been in medicine for a while, it’s one of two, three things I think we’ll all remember.”

Others measure it increments longer than lifetimes.

“It’s a once-in-a-millennium type of an event,” Landon said.

Landon said bluntly that removing the risk of death is equal parts powerful and emotional.

“The peace of mind of knowing that you are likely not going to die of COVID-19 no matter what is a really huge thing,” she said.

A huge thing as well as a fast one. Just three months ago, the vaccine timetable from Dr. Robert Redfield, head of the Centers for Disease Control and Prevention, was far less optimistic.

“We’re probably looking at late second quarter, third quarter 2021,” Redfield said at the time.

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He wasn’t alone.

“I think most people would have told you 12 to 24 months,” Freeman said.

In the end, it took less than a year.

“This is the first time in history that we are going to stop a pandemic in its tracks with a vaccine,” Landon said.

And unlike other iconic moments in history such as the moon landing in 1969, this one is not captured on grainy film reels. It is far more modern – but no less seismic.

The experts believe the virus has met its match.

“This is an unprecedented day – a sort of triumph of medicine,” Landon said.

The medical experts who talked with Tye said the process involved to “generate, manufacture, test, and distribute” the vaccine speedily and safely represents a singular moment in time in the medical profession – light years faster than what was seen with polio and HIV – the latter of which now has treatments, but still no vaccine.

Meanwhile, experts remind everyone that even after getting a second shot of the Pfizer vaccine, it will take another month to achieve peak immunity.

Much of the success in getting the vaccine to market so safely and quickly can be credited to slow-building improvements in the medical community over the last 10 years or so.

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