CDC halves COVID isolation recommendation for people without symptoms

The Centers for Disease Control and Prevention (CDC) is shortening its recommended isolation period for people who test positive for COVID-19 from 10 days to five, provided they are asymptomatic or have been without a fever for 24 hours.

In a December 27 statement, the CDC said the updated guidance is based on scientific evidence showing that most COVID-19 transmissions occur early in the course of the illness, either one to two days before the onset of symptoms or two to three days after. The guidelines also recommend that people with COVID-19 wear masks for five days when around others to minimize the risk of spreading infection, regardless of vaccination status.

The new guidance comes even as the COVID-19 Omicron variant continues to spread rapidly, with an average of more than 401,000 cases being reported daily in the U.S. according to a New York Times database, triple the level of two weeks ago.

Some physicians and infectious disease experts have questioned why the new guidelines don’t include testing during the second five-day period. Speaking on CNN on January 2, Anthony Fauci, MD, President Biden’s chief medical adviser, said he felt such testing is “a reasonable thing to do.”

“I believe that the CDC soon will be coming out with more clarification of that,” Fauci added.

The CDC also is shortening its recommended quarantine period for people exposed to COVID-19 and who are unvaccinated or more than six months out from their second mRNA dose (or more than two months after getting the Johnson & Johnson vaccine) and not yet boosted. For these people, the CDC recommends a five-day quarantine period followed by five days of strict mask use.

If a five-day quarantine is not feasible, the CDC statement says it is “imperative” for exposed people to wear a well-fitting mask for when around other people for 10 days following exposure. Those who’ve gotten a booster shot don’t need to quarantine following an exposure but should wear a mask for 10 days following the exposure. In addition, the guidelines state, best practice for anyone exposed to COVID-19 is to test for it at day five after exposure.

CDC Director Rochelle Walensky, MD, MPH, said in the statement: “CDC’s updated recommendations for isolation and quarantine balance what we know about the spread of the virus and the protection provided by vaccination and booster doses. These updates ensure people can safely continue their daily lives.”