In updated coronavirus guidelines, the Centers for Disease Control and Prevention (CDC) made a shift to a symptom-based strategy, rather than a test-based strategy, in deciding when to stop isolation and resume normal activities. The updates are intended to prevent unnecessarily long isolation and excessive use of lab tests.
Most people can stop isolation and precautions 10 days after COVID-19 symptom onset, and after a break in fever for at least 24 hours without the use of fever-reducing medications. This marks a change from a prior recommendation of waiting 72 hours after a fever breaks without using fever-reducing medications. It is important to note that the CDC still recommends 14 days of quarantine after exposure, based on the time it takes to develop illness if infected.
People who are severely immunocompromised or have more serious illness should isolate for 20 days, and likely aren’t infectious after that point, the CDC said.
There was also a change in language from “improvement in respiratory symptoms” to “improvement in symptoms” to address the expanding list of symptoms associated with COVID-19.
Sometimes the virus is persistent in detectable levels up to 12 weeks after infection, but likely isn't infectious. For this reason, people previously diagnosed with symptomatic COVID-19 who are asymptomatic after recovery shouldn't undergo virus testing within three months after the date of symptom onset for the initial infection.
The cause of this persistence of detectable virus has yet to be determined.
In six months since the virus emerged, the CDC said “there have been no confirmed cases of SARS-CoV-2 reinfection.”
Finally, the CDC advised against using serologic testing to establish the presence or absence of SARS-CoV-2 infection or reinfection.