CDC Updates COVID-19 Isolation Guidance to Include a Section on Antigen Tests

Agency doesn't expressly recommend antigen tests but provides guidance should people choose to test
By Mimi Nguyen Ly
Mimi Nguyen Ly
Mimi Nguyen Ly
Mimi Nguyen Ly covers world news with a focus on U.S. news. Contact her at
January 4, 2022 Updated: January 5, 2022

The Centers for Disease Control and Prevention (CDC) updated its guidelines for COVID-19 isolation on Jan. 4 to include a section on rapid antigen tests, in which it provides guidance for cases where people wanted to take a test.

The updated CDC guidance doesn’t state that isolated people have to test negative before emerging from isolation, but states that if people want to take a test, “the best approach is to use an antigen test towards the end of the 5-day isolation period.”

The move comes shortly after the CDC shortened the isolation period from 10 days to five days for people with confirmed or suspected COVID-19 who are asymptomatic or are recovering from their symptoms. Isolation is followed by five days of wearing a mask when around other people, the CDC stated.

White House pandemic adviser Dr. Anthony Fauci recently said federal officials were considering amending COVID-19 isolation guidance for people who test positive for COVID-19.

“There has been some concern about why we don’t ask people at that five-day period to get tested. That is something that is now under consideration,” he said. “The CDC is very well aware that there has been some pushback about that.”

Per the updated CDC guidelines, if the person does choose to take a test and the antigen test result is positive, the person should continue to isolate until day 10. If the test result is negative, the person can end isolation, but continue to wear a mask around others at home and in public until day 10.

rapid antigen test
Two test cassettes used in an antigen rapid test for the coronavirus (COVID-19) at a testing center in Berlin on Feb. 17, 2021. (John MacDougall/AFP via Getty Images)

“Collect the test sample only if you are fever-free for 24 hours without the use of fever-reducing medication and your other symptoms have improved,” the CDC stated, referring to the antigen test.

Even if a person chooses not to test, isolation “should only end if a person has been fever-free for at least 24 hours without the use of fever-reducing medication and other symptoms have resolved,” the CDC said in a statement.

The agency noted that loss of taste and smell “may persist for weeks or months after recovery and need not delay the end of isolation.”

People who develop symptoms of COVID-19 are most contagious two days prior and about three days after, the CDC stated on Dec. 27, 2021. CDC Director Dr. Rochelle Walensky said 85 to 90 percent of transmission happens during this time.

In a White House briefing last week, Walensky said the CDC isn’t requiring people to get tested before leaving isolation, in part because PCR tests can yield COVID-19 positive results for up to three months after a person contracts the illness—long after they’re infectious.

“We know that PCR testing would not be helpful in this setting, as people can remain PCR-positive for up to 12 weeks after infection and long after they are transmissible and infectious,” she said at the time. Antigen tests may not “give a good indication of transmissibility” by day five.

CDC recommendations on ending isolation are slightly different for people who were severely ill with COVID-19 or have a weakened immune system—they “might need to isolate at home longer” and “may also require testing with a viral test to determine when they can be around others,” the CDC stated in its guidance.

“CDC recommends an isolation period of at least 10 and up to 20 days for people who were severely ill with COVID-19 and for people with weakened immune systems,” the guidance states. “Consult with your healthcare provider about when you can resume being around other people.”

Mimi Nguyen Ly
Mimi Nguyen Ly covers world news with a focus on U.S. news. Contact her at