What You Should Know About the CDC’s New Quarantine Guidance

A shorter quarantine will reduce people’s burden and hopefully improve adherence, while still preventing spread of the virus

Photo by Noah on Unsplash

The U.S. Centers for Disease Control and Prevention (CDC) has updated their quarantine recommendations, offering people the options to isolate for seven or 10 days instead of two weeks after a potential exposure to the coronavirus. The shorter timelines require that people have no symptoms and continue to wear a mask for the full 14 days. The one-week quarantine also hinges on a negative test after at least five days post-exposure.

The new guidelines aim to improve adherence by reducing the time frame burden on people while balancing a small increase in the risk of spreading the virus. Modeling performed by CDC scientists estimates that a 10-day quarantine carries a 1% risk of transmission in the following days, while a seven-day quarantine with a negative test has a 5% transmission risk.

The CDC states, “These recommendations for quarantine options shorter than 14 days balance reduced burden against a small but non-zero risk of post-quarantine infection that is informed by new and emerging science.”

The point of quarantine is to prevent people from spreading the disease before they know they are infected. Previous research has shown that 50% of people develop symptoms five days after exposure to the virus, and 97.5% of infected people will be symptomatic by day 11. People are typically most contagious two to three days before symptoms emerge and for five days after. However, anywhere from 20% to 40% of people may be asymptomatically infected but still contagious. The incubation time frame for SARS-CoV-2 is presumed to be the same regardless of whether or not people are symptomatic. The new guidelines — particularly with a test on day five, six, or seven — will catch the vast majority of even asymptomatically or pre-symptomatically infected people.

Two models by scientists at Yale University and the London School of Hygiene and Tropical Medicine recently came to a similar conclusion, stating that an eight-day quarantine with a test on day seven would be sufficient to prevent the spread of the virus.

In an interview with the Washington Post, infectious disease experts said they supported the new guidelines.

“Behind the scenes, many of us had been urging the CDC to move forward with this because I think it’s in the best interest of public health, and it’s in the best interest of the economy, and it’s in the best interest of the mental health of people who have to be quarantined,” said William Schaffner, a professor of infectious-disease at the Vanderbilt University Medical Center. “This is a win all around.”



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Dana G Smith

Dana G Smith


Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental