CDC shortens Covid-19 quarantine period: 7 days after exposure with a negative test or 10 days minus symptoms
The number of days that Americans need to quarantine after coronavirus exposure can be as short as seven to 10 days, the US Centers for Disease Control and Prevention (CDC) has announced in new guidelines. Previously, the agency recommended that close contacts quarantine for 14 days after exposure. The agency, however, maintains that a 14-day quarantine after coronavirus exposure remains the safest option and is the best way to reduce the risk of spreading the virus.
Quarantine is used to keep someone who might have been exposed to Covid-19 away from others. It helps prevent the spread of the disease that can occur before a person knows they are sick or if they are infected with the virus without feeling symptoms. According to the latest guidance, two acceptable alternative quarantine periods have been identified. Under these options, quarantine can end after 10 days without a Covid-19 test if the person has reported no symptoms or after seven days with a negative test if the person has no symptoms.
The CDC had earlier said that it is currently reviewing evidence about how long people should quarantine after potential exposure to Covid-19 and the agency may soon shorten the length of the self-quarantine period. Dr John Brooks, the chief medical officer for the CDC’s Covid-19 response, explained during a briefing that extensive modeling by public health experts point to the same direction: which is that “we can safely reduce” the length of quarantine. He, however, accepted there is a “small residual risk” that a person who is leaving quarantine early can transmit to someone else if they became infectious. It is estimated that a person stopping at day 10 has about a 1% risk of spreading the virus, while someone exiting at day 7 with a negative test has a 5% risk.
“Local public health authorities determine and establish the quarantine options for their jurisdictions. CDC currently recommends a quarantine period of 14 days. However, based on local circumstances and resources, the following options to shorten quarantine are acceptable alternatives. Quarantine can end after day 10 without testing and if no symptoms have been reported during daily monitoring. With this strategy, residual post-quarantine transmission risk is estimated to be about 1% with an upper limit of about 10%,” the agency notes.
“When diagnostic testing resources are sufficient and available, then quarantine can end after day 7 if a diagnostic specimen tests negative and if no symptoms were reported during daily monitoring. The specimen may be collected and tested within 48 hours before the time of planned quarantine discontinuation (for example, in anticipation of testing delays), but quarantine cannot be discontinued earlier than after Day 7. With this strategy, the residual post-quarantine transmission risk is estimated to be about 5% with an upper limit of about 12%,” the advisory states.
In both cases, additional criteria such as continued symptom monitoring and masking through day 14 must be met, suggest experts. “People should still watch for symptoms during quarantine for a full 14 days after exposure, especially if quarantine is discontinued early,” recommended Dr Henry Walke, the CDC’s Covid-19 incident manager.
The incubation period for coronavirus is thought to extend to 14 days, with a median time of 4 to 5 days from exposure to symptoms onset. However, the CDC had earlier said that about 40% of people with Covid-19 are asymptomatic. Health experts emphasize that the recommendations are based on the best information available in November 2020 and “reflect the realities of an evolving pandemic.” “CDC will continue to closely monitor the evolving science for information that would warrant reconsideration of these recommendations,” they add.
Dr Walke informed that the CDC is sharing these alternatives with public health agencies across the country so that they can determine how long the quarantine periods should last in their jurisdictions based on local conditions and needs. “Everyone should follow the specific guidance from their local public health authorities about how long they should quarantine,” he added.
Why did the CDC decide to change guidelines?
According to the agency, a 14-day quarantine can impose personal burdens that may affect physical and mental health as well as cause economic hardship that may reduce compliance. Implementing quarantines can also pose additional burdens on public health systems and communities, especially during periods when new infections and consequently the number of contacts needing to quarantine, are rapidly rising.
The prospect of quarantine may dissuade recently diagnosed persons from naming contacts and may dissuade contacts from responding to contact tracer outreach if they perceive the length of quarantine as ‘onerous,” explain researchers.
“Reducing the length of quarantine will reduce the burden and may increase community compliance. Shortening quarantine may increase willingness to adhere to public health recommendations but will require evaluation, not only in terms of compliance with quarantine and contact tracing activities but also for any potential negative impacts such as post-quarantine transmission,” the CDC notes.