As the COVID-19 omicron variant surges across the United States, top federal health officials are looking to add a negative test along with its five-day isolation restrictions for asymptomatic Americans who catch the coronavirus, the White House's top medical adviser said Sunday.

Dr. Anthony Fauci said the Centers for Disease Control and Prevention is now considering including the negative test as part of its guidance after getting significant "pushback" on its updated recommendations last week. 

Under that December 27 guidance, isolation restrictions for people infected with COVID-19 were shortened from 10 days to five days if they are no longer feeling symptoms or running a fever. After that period, they are asked to spend the following five days wearing a mask when around others.

The guidelines have since received criticism from many health professionals for not specifying a negative antigen test as a requirement for leaving isolation.

"There has been some concern about why we don't ask people at that five-day period to get tested," Fauci said. "Looking at it again, there may be an option in that, that testing could be a part of that, and I think we're going to be hearing more about that in the next day or so from the CDC.”

Fauci, the nation's top infectious diseases expert, said the U.S. has been seeing almost a "vertical increase" of new cases, now averaging 400,000 cases a day, with hospitalizations also up.

"We are definitely in the middle of a very severe surge and uptick in cases," he said. "The acceleration of cases that we've seen is unprecedented, gone well beyond anything we've seen before.”

Fauci said he's concerned that the omicron variant is overwhelming the health care system and causing a "major disruption" on other essential services.

"When I say major disruption, you're certainly going to see stresses on the system and the system being people with any kind of jobs...particularly with critical jobs to keep society functioning normally," Fauci said. 

"We already know that there are reports from fire departments, from police departments in different cities that 10, 20, 25 and sometimes 30 percent of the people are ill. And that's something that we need to be concerned about because we want to make sure that we don't have such an impact on society that there really is a disruption. I hope that doesn't happen,” he noted.

(With input from AP)