Citing new evidence and an “acceptable risk” of transmission, the agency hopes reducing the 14-day quarantine will increase overall compliance and improve public health and economic constraints.
The agency also suggested people postpone travel during the upcoming winter holidays and stay home because of the pandemic.
Thesedo not replace initial CDC guidance. “CDC continues to recommend quarantining for 14 days as the best way to reduce risk for spreading COVID-19,” said Henry Walke, MD, MPH, the CDC’s COVID-19 incident manager, during a media briefing on Wednesday.
However, “after reviewing and analyzing new research and data, CDC has identified two acceptable alternative quarantine periods.”
People can now quarantine for 10 days without a COVID-19 test if they have no symptoms. Alternatively, a quarantine can end after 7 days for someone with a negative test and no symptoms. The agency recommends a polymerase chain reaction test or an antigen assay within 48 hours before the end of a quarantine.
The agency also suggests people still monitor for symptoms for a full 14 days.
Reducing the length of quarantine “may make it easier for people to take this critical public health action, by reducing the economic hardship associated with a longer period, especially if they cannot work during that time,” Dr. Walke said. “In addition, a shorter quarantine period can lessen stress on the public health system and communities, especially when new infections are rapidly rising.”
The federal guidance leaves flexibility for local jurisdictions to make their own quarantine recommendations, as warranted, he added.
An ‘acceptable risk’ calculation
Modeling by the CDC and academic and public health partners led to the new quarantine recommendations, said John Brooks, MD, chief medical officer for the CDC’s COVID-19 response. Multiple studies “point in the same direction, which is that we can safely reduce the length of quarantine but accept there is a small residual risk that a person who is leaving quarantine early could transmit to someone else.”
The residual risk is approximately 1%, with an upper limit of 10%, when people quarantine for 10 days. A 7-day quarantine carries a residual risk of about 5% and an upper limit of 12%.
“Ten days is where the risk got into a sweet spot we like, at about 1%,” Dr. Brooks said. “That is a very acceptable risk, I think, for many people.”
Although it remains unknown what proportion of people spending 14 days in quarantine leave early, “we are hearing anecdotally from our partners in public health that many people are discontinuing quarantine ahead of time because there is pressure to go back to work, to get people back into school – and it imposes a burden on the individual,” Dr. Brooks said.
“One of our hopes is that ... if we reduce the amount of time they have to spend in quarantine, people will be more compliant,” he added.
A reporter asked why the CDC is shortening quarantines when the pandemic numbers are increasing nationwide. The timing has to do with capacity, Dr. Brooks said. “We are in situation where the number of cases is rising, the number of contacts is rising and the number of people who require quarantine is rising. That is a lot of burden, not just on the people who have to quarantine, but on public health.”