The CDC updated its guidance around isolation on Tuesday, declining to add a clear testing recommendation while saying that people can take a test if they have "access" and "want to." 

The new guidelines come as millions of Americans wait in hours-long lines to get tested during a record-breaking surge in cases. 

The agency halved its recommended isolation and quarantine time last week, saying that a person infected with COVID-19 can leave isolation after five days if they're asymptomatic, followed by five days of wearing a mask. 

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Medical experts pushed back on that recommendation, saying that it may result in people leaving isolation while they're still infectious. 

"The best science … still points back to the fact that we should be testing our way out of isolation with antigen tests, but we know that the federal government has not been able to provide those antigen tests," former surgeon general Dr. Jerome Adams told Fox News Digital last week. 

City residents wait on line for COVID-19 tests in Philadelphia

City residents wait in a line extending around the block to receive free at-home rapid COVID-19 test kits in Philadelphia, Monday, Dec. 20, 2021.   (AP Photo/Matt Rourke)

After receiving some criticism, Dr. Anthony Fauci hinted on Sunday that a testing recommendation may be added. 

"There has been some concern about why we don’t ask people at that five-day period to get tested," Fauci told ABC. "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."

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Despite that, the CDC declined to add a testing recommendation in the updated guidance, saying people can take a test if they can find one. 

"If an individual has access to a test and wants to test, the best approach is to use an antigen test towards the end of the 5-day isolation period," the CDC wrote in its new guidelines. 

Pfizer COVID-19 vaccine at children's hospital in Chicago

Lurie Children's hospital registered nurse Carolyn Ruyle prepares a dose of a Pfizer COVID-19 vaccine at Lurie Children's hospital Friday, Nov. 5, 2021, in Chicago. (AP Photo/Nam Y. Huh)  (AP Photo/Nam Y. Huh)

The agency said that tests "are best used early in the course of illness to diagnose COVID-19" and are not authorized to "evaluate duration of infectiousness."

"Data, including a review of 113 studies from 17 countries, show that most SARS-CoV-2 transmission occurs early in the course of infection," the CDC wrote in its explanation. 

Individuals 18 and older who are not boosted should still quarantine for five days if they are exposed to someone, followed by a test and five days of wearing a mask if possible. 

Close up of entrance sign for Centers for Disease Control and Prevention. (iStock)

Close up of entrance sign for Centers for Disease Control and Prevention. (iStock)

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In explaining the new guidelines, the CDC said it took the "societal impact" of the isolation and quarantine periods into account. 

"Spread of the Omicron variant has the potential to worsen staffing shortages and increase supply chain challenges, which jeopardize industry, education, and other systems that are essential to maintain a functioning society and economy," the CDC wrote