Reyhan Harmanci is feeling better. After cycling through an illness she thinks was COVID-19, with headache, fever, and nausea, her symptoms started to subside. But she lives in Brooklyn, New York with her husband, who’s still sick, and her young kids — and it’s getting harder to schedule a grocery delivery.

There’s a store around the corner, but Harmanci says she’s still struggling to figure out when it’s safe for her to leave the house without infecting other people. “Everyone has a doctor friend or doctor relative who is going to tell you different things,” she says. She’s heard that she should wait seven days without fever, or seven days without any symptoms, or even as long as 40 days.

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Right now, the Centers for Disease Control and Prevention (CDC) says that people can stop isolating if they’ve been fever-free for 72 hours, their other symptoms have improved, and it’s been at least seven days since they first felt sick. The limited information available about how patients recover seems to support those guidelines, says James Hudspeth, the COVID response inpatient floor lead at Boston Medical Center.

But patients like Harmanci are still facing conflicting advice, in part because there’s still no clear data showing just how long people who get COVID-19 are contagious. “There are a lot of questions left unanswered,” says Hudspeth.

One study out of Germany, that hasn’t been peer-reviewed, showed that people who had COVID-19 but weren’t hospitalized had high levels of the novel coronavirus in their respiratory tract early on in their illness. The levels dropped off after four or five days of symptoms, and by the tenth day after they got sick, there was hardly any virus left. A study of hospitalized patients in China, though, found that the virus was detectable for up to 20 days after symptoms started — but levels also dropped off when the symptoms did.

“There are a lot of questions left unanswered”

Doctors still don’t know how much of the virus is enough to infect someone else. But Hudspeth says they generally feel that if people have lower levels of the virus, the chances that they’re contagious is lower, as well.

“That data has made us feel more assured about the CDC guidelines,” he says. “It’s reasonable that they will capture most cases, and make sure most patients are cleared to a reasonable degree.”

Alexei Wagner, assistant director of adult emergency medicine at the Stanford Department of Emergency Medicine, also says he’s largely following CDC guidelines, with some exceptions. “Sometimes it’s easier to just tell people seven days since their last symptom,” he says. “That’s a more conservative interpretation of the guidelines.”

Relying on symptoms can be challenging, because the illness caused by this coronavirus can come and go. Harmanci says her fever would go away and come back a few days later, and that she continued to develop new symptoms. “The shapeshifting nature of the illness makes it hard to track how you’re doing,” she says. “It adds another layer of confusion about when it’s ok to leave the house.”

“The shapeshifting nature of the illness makes it hard to track how you’re doing”

COVID-19 can also cause a wide range of symptoms, Hudspeth says — and doctor’s don’t have great answers about when or why certain symptoms appear. “We know some patients feel better, and then have more cough and shortness of breath again,” he says. Waiting three days, though, should usually give people enough time to see if they’re actually improving, he says.

In some cases, people might be able to get tested after their symptoms improve to get a better sense of if they’ve cleared their infection — the CDC has a second set of guidelines saying that they can leave isolation if they have two negative tests in a row, 24 hours apart. US citizens with COVID-19 who were repatriated from the Diamond Princess were tested before they were allowed to leave isolation, for example. But it’s still challenging for most people to get tested to confirm they’re sick, and there aren’t enough tests to make it standard practice after recovery. “If we had unlimited tests, I’d recommend people get tested again to confirm,” Hudspeth says.

Using testing as a criteria for letting people emerge form isolation comes with its own issues: the standard test checks to see if a patient has any amount of the novel coronavirus in their respiratory system, either by swabbing their nose or throat. But just because someone still has the virus in their system doesn’t necessarily mean they still have an active infection, Wagner says. Residual virus left over could still return a positive test, even if it’s not enough to be infectious.

Scientists keep learning more about the novel coronavirus and COVID-19, and as they do, guidelines around recovery will continue to change. “Does viral detection mean you’re infectious? Maybe, maybe not,” Wagner says.

For now, people like Harmanci — and the tens of thousands of others in the US who are sick and waiting at home — are left to make decisions based on the guidelines they have right now. The anxiety around that is understandable, Hudspeth says. Until there’s more information available, being cautious makes sense. “No one wants to be the person that infects their loved ones,” he says.