How to make sense of the CDC's new quarantine guidance

The US Centers for Disease Control and Prevention sparked confusion and criticism recently when it loosened its recommendations for what you should do if you test positive for COVID-19.

The agency shortened the isolation period from 10 days to five, as long as someone is asymptomatic or has "improving" symptoms, which includes being fever-free for at least 24 hours (without taking medicine that brings fevers down, such as ibuprofen). The new recommendations don't require someone to test negative before they're given the OK to be around others or return to work.

The new guidance has inspired some internet satire as well, with people riffing on making bad decisions just because the "CDC said it's OK." This points to a larger problem the agency has wrestled with since the beginning of the pandemic (and likely before, too), which is clearly communicating its public health recommendations, and the decision-making that goes into them.

If you're confused about how long to stay home if you have COVID or have been exposed, keep reading for a breakdown of the CDC's new guidance and why these changes were made now.

Why did the CDC make these changes?

"The messaging around prevention is never easy, and this really is putting that prevention message in an international spotlight," says Brian Labus, an assistant professor in the School of Public Health at the University of Las Vegas who studies communicable disease surveillance.

The change in isolation guidance is based on science, Labus says, that shows that up to 85 to 90% of disease transmission occurs in the one to two days before symptoms appear, and two to three days after. CDC Director Dr. Rochelle Walensky reiterated this reasoning at a recent White House COVID-19 response briefing. But even if the science is sound (some argue it's not), the CDC's problem is communicating that science to the public in a way that's transparent, and reflective of a public health effort, rather than a succession to the pressures of the US economy. 

"I don't think that the CDC guidelines were significantly wrong," Dr. Tom Frieden, the agency's director under former President Barack Obama, told The New York Times. But, "I think the way they were released was very problematic."

How long should I isolate if I have COVID-19? What does the guidance mean?

To "quarantine" means to stay away from other people after you were exposed to someone who has COVID-19, and "isolating" means staying away from others when you have COVID-19.

According to the CDC's guidance, people with COVID-19 should isolate and stay home for at least five days. This is the case regardless of whether you've been vaccinated. "Day one" is the first full day after your symptoms began, or after you received your positive test if you don't have symptoms. If after five days you either don't have symptoms anymore or your symptoms have improved (this includes being fever-free for at least 24 hours, without having taken medicine that brings fevers down, such as Tylenol), you can leave your house. 

However, there are some additional "don'ts" for what not to do during the following five days -- the remainder of the agency's old 10-day isolation guidance. Don't go anywhere without a mask, don't hang out with friends, family or anyone who would be at high risk for severe COVID-19, don't eat around other people and try not to travel. 

For example: Suppose you wake up Monday with a headache and fever, you happen to have a rapid COVID-19 test on hand and it comes back positive. Tuesday will be day one of your isolation, and you'll be able to leave home on Sunday (wearing a mask), if your fever goes down naturally before Saturday. 

If you still have a fever after five days, or you feel just as crummy as you did earlier in the week, you should stay home for the full 10 days, according to the CDC.

Read more: When COVID-19 is no longer a pandemic: How our reality changes

What if I've been exposed to COVID-19? 

The CDC also tweaked its recommendations for whether you need to quarantine after you've had close contact with someone with COVID-19 (been within 6 feet of someone for 15 minutes). The changes are mostly based on the CDC's consideration of who's "up to date" on their vaccinations. You're considered up to date if you've gotten your booster shot after becoming eligible, or if you're immunocompromised and have received your recommended additional dose (the definition of fully vaccinated hasn't changed). You're also up to date if you are fully vaccinated but aren't yet eligible for a vaccine (within five months of the second dose for people who got Pfizer's or Moderna's vaccine; within two months for people who got Johnson & Johnson's vaccine). 

If you're up to date on COVID-19 shots and are exposed to COVID-19, you don't need to quarantine. You also don't need to quarantine if you've had a positive COVID-19 test within 90 days. 

However, if you're unvaccinated or aren't up to date on your booster shots, you should quarantine and stay home for five days following your exposure.

Regardless of how many shots you've had, you should avoid hanging out with people at high risk for COVID-19 for 10 days following your exposure, and you should also avoid travel and mask up during that time. And regardless of your symptoms or your vaccination status, you should get tested for COVID-19 at least five days after you had an exposure.

Read more: How to find an at-home COVID-19 test today

Why did the CDC change its guidance? 

In a Dec. 28 interview with NPR, Walensky said the CDC's isolation guidance changed because of newly discovered science about the virus that causes COVID-19, and because of the need to keep the "critical functions of society" operating as the US faces a tsunami of COVID-19 cases caused by the extremely contagious omicron variant.

Labus called the CDC's decision to shorten its isolation period for people with mild or asymptomatic COVID-19 "not completely out of left field," given what scientists know now about the contagious period of COVID-19 and other common respiratory illnesses. But some have also accused the CDC of giving into the pressure from politicians and big industries to get people back to work at the expense of public health. Notably, Delta Air Lines wrote the CDC a letter asking the agency to shorten its isolation guidance six days before the agency announced its changes. 

The American Medical Association has also criticized the CDC guidance, in part, for not recommending a negative COVID-19 test, acknowledging a present "dearth" of tests and calling on the administration to "pull all available levers" to distribute tests. (The CDC made a small clarification to its guidance that gives people testing instructions if someone "wants" to test and "has access" to a test.) Shortly before the CDC changed its isolation recommendations for the general public, it changed them for health care workers.

Another factor in the CDC's guidance change might be people's willingness to stay home when they're sick. Labus notes that this isn't the first time the CDC has updated its isolation guidance – earlier in the pandemic, the recommendation was to isolate for 10 days and quarantine for 14 if you were exposed to COVID-19. And people just weren't following it. In an explanation posted Jan. 4, the CDC noted the mental health effects of the pandemic in its decision to change its guidance, in addition to "adherence to prevention interventions."

"Some of it's about trying to get the best compliance with these things, because we're relying on people," Labus says. 

In her interview with NPR, Walensky said that the CDC is trusting people to get tested for COVID-19 in the first place, and also trusting them to attest to their symptoms and follow public health practices accordingly.

Labus says that public health messaging has always been a problem.

"We know that smoking is bad, we know that seat belts save lives," he says. "But people still smoke and don't wear their seat belts. This is nothing new, and even people who do those behaviors know those things."

Sometimes, the issue of staying home when you're sick has little to do with what the CDC recommends and everything to do with whether you can afford it, or if you'll lose your job by staying home. Since long before COVID-19, Labus says, people have been forced to work when sick (anyone who's worked at a restaurant or in retail can attest to the urgency of getting your shift covered last-minute, unpaid, if it's covered at all). There is also the idea that we are indispensable in our jobs, in bad health and in good, in what Labus calls "presenteeism." This feeling of a need to show up no matter what has driven a lot of illnesses, he says. 

"People don't have sick time, they don't have the ability to miss work when they need to, and this is something that public health guidance can't address," Labus says.

Read more: The pandemic changed health care, and there's no going back

The CDC's communication problem 

Before health officials make big recommendations to the public, a lot happens behind the scenes. With vaccines, for example, an independent committee of scientists, doctors and other experts meet to go over safety and effectiveness data with a fine-tooth comb before guidance is issued to the public. These meetings, which have grappled with such important decisions as, for example, the use of Pfizer's COVID-19 vaccine in kids, are technically open to the public but they're not easy to track down unless you know exactly where to look. 

The advice that comes out of these meetings, too, can be hard to parse, as with the CDC's confusing early booster guidance and its new isolation guidance. 

"Public health creates guidance for our populations," Labus notes. "It just is difficult to message these things -- we don't always make the same recommendations for everybody."

But given the criticism the CDC faced in its execution and delivery of the new isolation guidelines, it's likely an issue the agency will address. In fact, as NPR reported, the CDC has expressed interest in doing more media telebriefings, outside of Walensky's regular appearances on the White House COVID-19 Response team briefings, which were infrequent during 2021. 

But the public scrutiny of the CDC's latest isolation guidance did not go unheard by Walensky. 

"I hear that you are interested in hearing from the CDC independently," Walensky said at a press briefing Friday, in response to a reporter that asked about the CDC's public messaging. "And we are eager to answer your questions, and I will continue to engage with you." 

CNET has reached out to the CDC and Delta Air Lines for comment.