Fauci, who is one of the public health officials on the administration’s coronavirus task force, said such a system is one of several options they are discussing.

“That’s possible,” he said on CNN’s “New Day.”

“It’s one of those things that we talk about when we want to make sure who the vulnerable people are and not,” Fauci added. “This is something that’s being discussed, I think it might actually have some merit.”

The director of the National Institute of Allergy and Infectious Diseases also said that within a period of “a week or so” there will be a large number of new antibody tests, which allow users to discover whether they possess a unique immune response to the virus.

“As soon as they get validated, they’ll be out there for people to use,” Fauci said. “It’s very likely that there are a large number of people out there that have been infected, have been asymptomatic and did not know.”

There are more than 475,000 cases of the coronavirus in the U.S. and nearly 18,000 deaths.

Federal officials have expressed interest in trying to reopen the American economy next month, but health experts warn that doing so too soon could result in a second surge of COVID-19.