What are the CDC’s new quarantine recommendations, and why are they shorter?

On December 2nd, the CDC updated their recommendations on quarantine duration after exposure to a person with known or suspected COVID infection.  Prior to this, the recommendation was to quarantine for 14 days (see our prior FAQ on this).  

The new recommendations include options to reduce quarantine based on modeled outcomes that show these strategies can reduce burden while continuing to minimize risk (though admittedly not as much as the full 14-day quarantine minimizes risk).  These are not meant to replace the 14-day quarantine recommendation, but rather to allow for some flexibility. The CDC states, “Reducing the length of quarantine may make it easier for people to quarantine by reducing the time they cannot work. A shorter quarantine period also can lessen stress on the public health system, especially when new infections are rapidly rising.”

Local public health authorities make the final decisions about how long quarantine should last, based on local conditions and needs. But the new options the CDC now encourages them to consider include stopping quarantine

• After day 10 without testing
• After day 7 after receiving a negative test result (test must occur on day 5 or later)

After stopping quarantine, you should

• Watch for symptoms until 14 days after exposure.
• If you have symptoms, immediately self-isolate and contact your local public health authority or healthcare provider.
• Wear a mask, stay at least 6 feet from others, wash their hands, avoid crowds, and take other steps to prevent the spread of COVID-19.

CDC scientists modeled the residual post-quarantine transmission risk, expressed as a percent of total transmission, per day of quarantine if quarantine were discontinued that day. Without testing, after 7 days of quarantine, there is still 10-20% transmission risk.  After 10 days of quarantine, this decreases to 0.1-11%, and after 14 days this decreases to 0-3%.  By adding PCR testing within 48 hours of discontinuation of quarantine, transmission risk after quarantine was reduced to 2-9% at day 7, 0-2% at day 10 and 0-1% at day 14.  You can see more information about the CDC modeling with very helpful graphs here.

The CDC states they continue to endorse quarantine for 14 days and recognize that “any quarantine shorter than 14 days balances reduced burden against a small possibility of spreading the virus.” When considering pursuing the updated guidelines we recommend taking into consideration the level of risk for severe disease around you and the number of people you will come in contact with, given the persistent (though small) risk of transmission in the subsequent days after quarantine. If you will be spending time around high-risk individuals or those who might then spread disease to high-risk individuals, consider modifying your plans or taking the 14-day quarantine route to be safe.

Jennifer Abrams, MD, December 8, 2020