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CDC: Some COVID-19 Transmission May Occur After 7- to 10-Day Quarantine

Woman in quarantine wearing a face mask.

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Key Takeaways

  • Data from the Centers for Disease Control and Prevention shows that if a person with COVID-19 leaves quarantine early, they might still be able to spread the virus to others.
  • The CDC initially advised a 14-day quarantine. The updated 7- to 10-day shortened quarantine period was meant to help more people comply.
  • If you test positive for COVID-19, know that ending your quarantine sooner than 14 days can put others at risk. Continue to wear a face mask and stay at least 6 feet away from others.

In early December 2020, the Centers for Disease Control and Prevention (CDC) shortened its COVID-19 quarantine period from 14 days to as low as seven days with a negative test result, “based on local circumstances and resources.”

However, new CDC data suggests that ending quarantine as soon as one week may carry the risk of transmitting the virus to others.

What This Means For You

If you test positive for COVID-19 and end your quarantine sooner than 14 days, be mindful that you could still spread COVID-19. Wear a face mask and stay at least six feet apart from others.

The Data

The new report, which was published in the CDC’s Morbidity and Mortality Weekly Report, analyzed data from 185 household contacts of people who had COVID-19.

Of the contacts,109 (59%) had detectable levels of SARS-CoV-2, the virus that causes COVID-19, at any time. Of the household contacts who tested positive, 76% had positive test results within seven days of exposure, while 86% tested positive within 10 days after the original patient became sick.

Among the household contacts who had a negative SARS-CoV-2 test and no symptoms through day seven, there was an 81% chance that they would stay asymptomatic and test negative for the virus through 14 days. That likelihood increased to 93% for household members who had no symptoms and tested negative for the virus through day 10.

Overall, among people exposed to COVID-19 at home who had no symptoms and negative test results seven days after being exposed, 19% had symptoms or received positive test results within the following week.

Therefore, people might leave quarantine not realizing that they have COVID-19 and are capable of spreading it.

The CDC researchers concluded that “although SARS-CoV-2 quarantine periods shorter than 14 days might be easier to adhere to, there is a potential for onward transmission from household contacts released before day 14."

Current CDC Guidance for Ending Quarantine

The CDC previously recommended that people with COVID-19 and members of their household quarantine at home for 14 days. However, on December 2, 2020, the CDC updated its guidance to give households two options:

  • Quarantine can end after day 10 without testing and if no symptoms have been reported during daily monitoring. According to the CDC, the risk of transmitting COVID-19 after quarantine is anywhere from 1% to 10% using this strategy.
  • Quarantine can end after day seven if the person tests negative and does not have symptoms. The testing specimen can be collected and tested within 48 hours before day seven, but quarantine cannot end until at least a week has passed. The CDC says that the risk of spreading COVID-19 after quarantine is between 5% to 12% with this strategy.

With either approach, the CDC says that people with COVID-19 should continue to monitor their symptoms and wear masks through day 14.

What To Do When Leaving Quarantine

Stacey Rose, MD, assistant professor of medicine in infectious diseases at the Baylor College of Medicine in Texas, tells Verywell that the ability of people to spread the virus after leaving quarantine is not surprising.

“The initial recommendation from the CDC for a 14-day quarantine period was based on the upper bounds of the COVID-19 incubation period—the period between exposure to an infection and the appearance of the first symptoms,” Rose says. “So, although most people develop symptoms within 10 days of exposure, it is still possible to develop symptoms up to 14 days after exposure to an infected person.”

Richard Watkins, MD, an infectious disease physician and a professor of internal medicine at the Northeast Ohio Medical University, tells Verywell that he's also not surprised by the findings. "We are still learning about the novel coronavirus."

Rose says that the latest data is an “important reminder of the longer potential window for infection"—which is unique to COVID-19. “Different infections have different incubation periods,” Rose says. “For the flu, the incubation period is shorter—usually transmission occurs within four days of exposure to an infected person. Other infections have even longer incubation periods. For pertussis, the upper limit is around six weeks.”

If someone in your household develops COVID-19, Rose says that “every effort” should be made to lower the risk of spreading it to other household members.

“Ideally, you should stay home for 10 to 14 days after your last exposure to the infected person,” Rose says. “Even once the quarantine period is over—particularly if you are using the shortened quarantine period—you should monitor yourself for symptoms and immediately isolate yourself if you develop any symptoms.”

The CDC specifically states in its report that people released from quarantine before 14 days “should continue to avoid close contact and wear masks when around others until 14 days after their last exposure.” Watkins adds that frequently washing your hands is also a good idea.

“We continue to see high rates of spread of COVID-19,” says Rose. “We must all continue to do our part to reduce the spread of this potentially deadly virus.”

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Article Sources
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  1. Centers for Disease Control and Prevention (CDC). Options to Reduce Quarantine for Contacts of Persons with SARS-CoV-2 Infection Using Symptom Monitoring and Diagnostic Testing. Updated December 2, 2020.

  2. Rolfes MA, Grijalva CG, Zhu Y, McLean HQ, Hansen KE, Belongia EA, et al. Implications of shortened quarantine among household contacts of index patients with confirmed SARS-CoV-2 infection — Tennessee and Wisconsin, April–September 2020MMWR Morbidity and Mortality Weekly Report. 2021;69(5152):1633-1637. doi:10.15585/mmwr.mm695152a1

  3. Centers for Disease Control and Prevention (CDC). COVID-19: When to Quarantine. Updated December 10, 2020.