Available data indicate that persons with mild to moderate COVID-19 remain infectious no longer than 10 days after symptom begin.
Persons with weakened immune system likely remain infectious no longer than 20 days after symptom begin.
Recovered persons can continue to have traces of virus for up to 3 months after illness begins however, infectiousness is unlikely.
To reassure our patient’s possibility of transmission of infection is even lower, we assure the patient has not only been fever-free for at least 24 hours, but at least 72-hours without the use of fever-reducing medications AND symptoms have been improving or resolved for at least 10 days.
This means we might keep some of our positive COVID-19 patients under isolation for an extended amount of time that extends more than 10 days. Rest assure, we will provide clearance letters with all the pertinent information for schools/employers.
Source: https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/end-home-isolation.html; https://www.cdc.gov/coronavirus/2019-ncov/hcp/duration