The Centers for Disease Control on Tuesday updated its week-old guidance for how long people should isolate after catching COVID-19, but did not include a negative-test recommendation as many had expected it would. Instead, the agency said that people with access to COVID testing could, if they wanted, also get tested near the end of their isolation period. It also clarified that its new isolation and quarantine guidelines applied to schools, and it released more information about its rationale for how and why it has reduced how long people with COVID should isolate themselves from others.
Last week, the CDC halved its recommended isolation time for people infected with COVID, as well as its recommended quarantine period for unvaccinated or unboosted people who have been exposed to COVID. The new isolation guidance said that anyone who either has or suspected they have COVID only needed to self-isolate for a least five days rather than ten, and then, if they aren’t experiencing symptoms, wear a “well-fitting” face mask when around other people for an additional five days. (Day zero is either the first day someone tests positive or the first day they experienced COVID symptoms, whichever came last.) The new guidelines came amid a skyrocketing rise in new COVID cases nationwide, likely fueled by the more transmissible Omicron variant, and widespread disruption across various industries as a result of those cases forcing people to isolate themselves from others.
Many scientists and public-health experts have criticized the new CDC policy for not recommending that people also test negative for COVID before leaving isolation, warning that doing so could result in people unknowingly spreading COVID. Until Tuesday, it wasn’t clear whether or not the CDC would change course as a result of the criticism. On Sunday, Dr. Anthony Fauci said in an interview that the CDC was “very well aware” of the pushback and that adding a testing requirement was “under consideration.” CDC director Rochelle Walensky, however, has repeatedly defended leaving out the negative test, suggesting that at-home rapid antigen tests were not reliable enough to use as a benchmark for ending isolation. (“We opted not to have the rapid test for isolation because we actually don’t know how our rapid tests perform and how well they predict whether you’re transmissible during the end of disease,” she told CNN last week.)
The CDC’s updated guidance stops short of recommending a negative test to leave isolation, but includes new guidelines for using a test in that situation. “If an individual has access to a test and wants to test, the best approach is to use an [FDA-authorized at-home rapid antigen test] towards the end of the five-day isolation period,” the agency said, advising collecting a test sample “only if you are fever-free for 24 hours without the use of fever-reducing medication and your other symptoms have improved.” If someone tests positive at this point, the CDC says they should isolate for the full ten days after they first developed symptoms. If they test negative, they can leave isolation but wear a mask around other people until ten days have elapsed since they first developed symptoms. The agency made a similar recommendation for people who have tested positive for COVID but have not experienced symptoms.
The CDC also clarified that its new guidelines for isolation and quarantine times applied to schools (which wasn’t clear last week), and added that people who have been infected with COVID should avoid anyplace where they cannot wear a mask, like restaurants, as well as any travel until after day ten.
Also on Tuesday, the CDC released more information about its rationale for these new guidelines. It said that studies have repeatedly indicated that COVID transmission is most likely during the early phase of the infection, and that early data has shown that infections from the Omicron variant may proceed faster than those from previous variants. The CDC also said that some research has suggested that only 25 to 30 percent of people had been isolating for the full ten days recommended by the agency’s earlier guidance.
The CDC also pointed out that “modeling data from the United Kingdom reinforce the importance of mask use; after the fifth day after a positive test, an estimated 31 percent of persons remain infectious.” But the CDC did not change its guidance on what kind of masks people should wear after isolation. Many critics have emphasized that cloth face masks, which the CDC continues to recommend as a viable option, do not provide anywhere near the same level of protection against transmission as high-filtration respirators like N95 or KN95 masks.
According to Politico, the limited availability of COVID testing throughout the country also factored into the CDC’s decision:
In meetings about whether to add a testing recommendation to the CDC guidelines, agency officials said they discussed the practicality of recommending individuals obtain a negative test before breaking isolation and quarantine. Americans across the country are still struggling to get a hold of COVID-19 tests, some waiting hours in lines for swabs. With limited supply, public-health officials worried about the ability of Americans finding a test to take before returning back to normal life on day six.
Scripps’s Dr. Eric Topol, who was one expert speaking out against the lack of a test-out in the CDC’s new isolation guidance, reiterated his frustration to the Associated Press on Tuesday: “We do need to come up with a strategy that limits isolation time, but we don’t want it to be one that’s adding to the spread of the virus and unwittingly leading to the virus circulating.” He also said in a tweet that the CDC’s updated guidance offered more confusion than clarity on whether or not people should test negative before leaving isolation. Brown-Lifespan Center for Digital Health director Dr. Megan Ranney similarly commented that the new guidance was “so convoluted” she was having trouble finding a succinct summary of what it was.