Chief coronavirus task force medical advisor Dr. Anthony Fauci said Friday that Americans may soon have to carry a certificate of immunity to the coronavirus.

Fauci was asked if he could “imagine a time where Americans carry certificates of immunity” on CNN’s “New Day.”

“You know, that’s possible. It’s one of those things that we talk about when we want to make sure that we know who the vulnerable people are and not — this is something that’s being discussed. I think it might actually have some merit under certain circumstances,” said the director of the National Institute of Allergy and Infectious Diseases.

Fauci, has said that it is more difficult to predict the spread of a virus in the United States because of the sheer size of the country. “If you go now to the United States, we’re a big country and there are different patterns. Remember weeks ago, the hardest hit part was in Washington State. And that was a cluster of nursing homes, extended care homes … ”

Coronavirus Response Coordinator Dr. Deborah Birx (R) speaks with US President Donald Trump and Director of the National Institute of Allergy and Infectious Diseases Dr. Anthony Fauci during a Coronavirus Task Force press briefing in the Rose Garden of the White House in Washington, DC, on March 29, 2020. (Photo by JIM WATSON/AFP via Getty Images)

The doctor has also warned people during his daily appearances at the president’s coronavirus task force news conferences that life in America might never quite get “back to normal.”

“If back to normal means acting like there was never a coronavirus problem, I don’t think that’s going to happen until we do have a situation where you can completely protect the population,” Fauci said.