The CDC’s New COVID Isolation Guidance Surprised Experts, Too

Experts welcomed the decision to shorten the isolation period to five days, but many are still concerned testing negative first hasn't been prioritized.

On the quiet Monday after the Christmas weekend, the CDC took many people by surprise — experts included — by releasing updated guidance for how long people with COVID-19 should isolate themselves.

The new guidance halves the number of days that people should self-isolate after testing positive from 10 to five, followed by an additional five days of wearing a mask when around others.

Crucially, the shorter isolation period only applies to people who are asymptomatic, meaning they are not exhibiting any COVID symptoms, such as a cough, fever, or fatigue. People who are still feeling sick, especially with a fever, should continue to isolate themselves.

Guidance also changed for people who have been exposed to someone with COVID. Now, in a signal that our understanding of “fully vaccinated” may be changing, only people who have had their booster shot can go without quarantining. A five-day quarantine, followed by another five days of mask use, is recommended following exposure for anyone else: people who are unvaccinated, who got an mRNA vaccine dose more than six months ago without a booster, or who got the Johnson & Johnson vaccine more than two months ago without a booster.

“I was not aware they were going to do that,” Georges Benjamin, executive director of the American Public Health Association (APHA), told BuzzFeed News on Tuesday. “But the essence of what they said is that as we get the science better, we have a better sense, even with Omicron, of what the exposure risks are.”

Amesh Adalja, an infectious diseases physician and senior scholar at the Johns Hopkins Center for Health Security, also welcomed the changes.

“It’s been clear for some time that a one-size-fits-all period for isolation did not fit the period of contagiousness,” Adalja said. “The updated guidance reflects the fact that this is going to be an endemic virus and the disruption of a case can be safely minimized based on the enhanced scientific understanding that has accumulated.”

The CDC stressed its new advice was “motivated by science” that demonstrates most transmission of the novel coronavirus occurs within the first few days before symptoms appear and then over the next two to three days.

The recommendations “balance what we know about the spread of the virus and the protection provided by vaccination and booster doses,” agency director Rochelle Walensky said. “These updates ensure people can safely continue their daily lives.”

Speaking to CNN on Monday afternoon, Anthony Fauci, the top medical adviser to President Joe Biden, said the new guidance had been discussed for some time and called the changes “very prudent” at this current stage of the pandemic.

Like Walensky, Fauci stressed that the recommendations would help the US continue to function as the country faces an unprecedented number of COVID cases in the weeks ahead due to the highly infectious Omicron variant.

“With the sheer volume of new cases that we are having and that we expect to continue with Omicron, one of the things we want to be careful of is we don’t have so many people out,” Fauci said.

“Obviously, if you have symptoms, you should not be out,” he added, “but if you are asymptomatic and you are infected, we want to get people back to the jobs, particularly those with essential jobs to keep our society running smoothly, so I think that was a very prudent and good choice on the part of the CDC.”

The APHA’s Benjamin said these new changes were aimed at avoiding yet more harsh lockdowns. “Without this, we go back to the total closures, which nobody has the stomach for right now,” he said. “The politics for that just aren’t there.”

The changes were announced four days after the CDC said asymptomatic medical workers could return to work after seven days if they test negative. That update was made out of concern that hospitals would be hamstrung by staff shortages as the Omicron variant spreads through medical facilities.

But experts contacted by BuzzFeed News said they were confused why the same negative test requirement, even via a rapid antigen test, was not made for the general public to exit isolation.

“I think finding ways to shorten isolation time is a great idea — 10 days is very disruptive — but with testing,” said virologist Angela Rasmussen, who called the CDC’s new changes “reckless.”

“Seems the CDC is now just letting big corporations suggest policy and they are saying, ‘Let’s go with it,’” she added. “But it’s not the scientists at the CDC. It’s Walensky and her bosses in Washington who are dictating it, I think.”

Epidemiologist Michael Mina also said that it was “reckless” to allow people to leave isolation without first testing negative, noting that he would not want to sit next to someone who tested positive five days ago.

“I am 100% for getting people to drop isolation early,” Mina wrote on Twitter. “But it was always with a negative test. What the heck are we doing here?”

Business leaders have been calling for changes to the isolation time for so-called breakthrough cases (vaccinated people who contract COVID) to minimize disruptions to the economy. Last week, before several thousand flights were canceled around the world partly due to sick crew members, Delta Air Lines CEO Ed Bastian asked Walensky to reduce the isolation time to five days for vaccinated people. He said the 10-day requirement “may significantly impact [the airline’s] workforce and operations.” But, according to Reuters, Bastian also said appropriate testing could play a role.

When asked Tuesday why a negative test was not made part of the updated guidance, CDC spokesperson Kristen Nordlund again emphasized that most transmission occurs early in the first five days of a COVID infection. She said that for the purpose of a diagnosis, both PCR and rapid antigen tests were best used early in the course of illness. “Some people may remain positive by PCR test beyond the period of expected infectiousness,” Nordlund said. “The importance of a positive antigen test late in the course of illness is unclear and does not necessarily mean a person can easily spread the virus.”

But experts contacted by BuzzFeed News said they suspected the lack of a testing requirement was due to more practical concerns: “You can’t get tested!” Benjamin said. “It would’ve been an interesting component of it, but you can’t get tests. People are lining up for hours to get tests.”

“I don’t know who to blame, but what I can say is we need to focus a hell of a lot more on testing, and that’s something we as a nation have not done well in,” he added. “I don’t know what the holdup is.”

The Biden administration has said it plans to send half a billion rapid COVID tests to Americans to try to meet the new demand, but those may take weeks to arrive, offering little help to people currently in isolation who may be struggling to get their hands on one.

Ashish Jha, dean of the Brown University School of Public Health, called the new guidelines “quite reasonable” but said that he too would have included a negative test as an exit requirement, as well as a recommendation for everyone to use better-quality masks, such as N95s.

“Do I wish they had added testing, better mask guidance, etc?” he wrote on Twitter. “Yup. But still a step in the right direction.”

Bob Wachter, chair of the Department of Medicine at the University of California, San Francisco, told BuzzFeed News that his preference would have been for the new guidance to only apply to vaccinated people and that negative tests be required on days four and five of the isolation period. But, he said, that could only exist “in a perfect world.”

“In the real world, shorting the isolation time is critical if we’re going to keep hospitals, airlines, and other essential services open, given the skyrocketing cases of Omicron,” Wachter said. “A testing requirement would have been impossible to operationalize given the shortage of tests, and a vaccine requirement would have been difficult to enforce.”

He added, “I think that the net benefit to society of bringing people back to work on Day 6 — assuming they mask on Days 6-10, as they’re supposed to — will exceed a relatively small number of infections caused by this strategy, particularly since Omicron is proving to be significantly less severe than prior variants.”

Scott Gottlieb, a former Food and Drug Administration commissioner who now sits on the board of Pfizer, told the Washington Post that the updated CDC guidance marked a new point in the pandemic.

“The new guidance reflects a growing reality that we’re going to have to learn to live with COVID as a persistent risk, and can’t let it shut down society,” Gottlieb said.

Benjamin said that as the world enters the third year of the pandemic, officials need to meet the moment with clear, calming communications, especially about the extremely low risk COVID poses to people who have had all their recommended vaccines.

“We need to come to a consensus — not just as a nation, but as a planet — as to what the new normal looks like,” he said, “and how we live as this matures to a more endemic version.”

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