Why the CDC Reduced COVID-19 Isolation to 10 Days

The Centers for Disease Control and Prevention (CDC) has updated its guidelines on when it’s considered safe for someone who has COVID-19 to end isolation, suggesting the virus is no longer contagious 10 days after symptom onset.

"It seems that virus loads drop when people actually start feeling sick. By the end of 10 days, there should be minimal virus left to infect others," David Cennimo, MD, assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School, tells Verywell.

In the past, the CDC recommended that people try to be tested again after their symptoms—including fever—improved. Earlier guidelines recommended that someone have two negative tests for the virus, taken 24 hours apart, before leaving isolation. As of July 22, the CDC lessened the emphasis on re-testing, instead recommending that people leave isolation after they meet specific criteria.

The CDC also changed its guidelines on leaving isolation based on a person’s fever. Previously, the organization recommended that someone be fever-free without the use of fever-reducing medications for three days before ending isolation. Now, the organization has dropped that timeline to one day without a fever.

It can be confusing to keep track of all of the changes, and to try to understand why they’re in place. Here’s what you need to know.

Current Guidelines for Leaving Isolation

The CDC says people with a confirmed case of COVID-19 can leave isolation when they meet the following criteria:

• It’s been at least 10 days since you first had symptoms.
• You haven’t had a fever in 24 hours without the use of fever-reducing medication.
• Your symptoms have improved.

If you tested positive for COVID-19 but had no symptoms, the CDC says you can leave isolation 10 days after your test was taken.

Symptoms May Not Totally Resolve

When it comes to evaluating symptom improvement, Cennimo recommends looking for "significant improvement" but notes that patients may not feel completely better.

"There are a growing number of papers showing prolonged symptoms after COVID-19, with patients complaining of things like fatigue for weeks after infection," he says. "We also know that cough after viral infection can linger for weeks; especially in patients who have a history of respiratory ailments."

Why Have the Recommendations Changed?

The 10-day recommendation is based on recent research cited by the CDC that shows people with mild to moderate forms of COVID-19 are not infectious after 10 days. However, people with more severe forms of the virus may be infectious up to 20 days after they first developed symptoms, the CDC says.

“The 10 days is based on making sure that someone who is not infectious can get back into society,” Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo, tells Verywell.

A contact tracing study published in JAMA Internal Medicine in May also found that people who were exposed to a COVID-19 patient were less likely to contract the virus if they came into contact with the patient six days after they first started showing symptoms.

The lesser emphasis on re-testing is likely based on a few factors, Russo says. Testing delays are an issue in the country right now, with some areas taking as long as two weeks to get results to patients. According to Russo, waiting on the results of two tests can unnecessarily prolong the amount of time someone is in isolation.

Additionally, research shows that fragments of SARS-CoV-2 viral RNA can show up in swab tests for up to 7 weeks, even after someone is no longer considered infectious. This means a person could test positive for the virus even when they’re no longer able to infect others, unnecessarily prolonging their isolation.

The CDC didn’t explain the change that patients should be fever-free for 24 hours before ending isolation. However, this is more in line with what doctors generally suggest with other infections, David Cutler, MD, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, California, tells Verywell.

“Traditionally, that has been our recommendation when people have strep throat or the flu; they’re most likely not contagious after 24 hours without a fever,” he says.

Why Is Isolation So Important?

Isolation is used to separate people who are infected with SARS-CoV-2, the virus that causes COVID-19, from people who are not infected. The goal is to prevent further infection. People who are in isolation should stay home and be separated from other people in their household as much as possible, the CDC says.

The CDC specifically recommends that people in isolation do the following:

• Monitor your symptoms.
• Stay in a separate room from other household members, if possible.
• Use a separate bathroom, if possible.
• Avoid contact with other members of the household, including pets.
• Avoid sharing personal household items, like cups, towels, and utensils.
• Wear a cloth face covering when you need to be around other people.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.