Knowing how long to isolate is complicated.  Do you need a negative COVID test before you stop isolating?  When are you contagious?  

The guidelines from the Centers for Disease Control and Prevention are  a little confusing.  And the guidelines are always under review and being updated.  For example, CDC doesn't require a negative antigen test before you leave isolation, even though some infectious disease experts recommend it.  And, the guidelines can only provide a framework because every COVID case is unique.

The coronavirus is transmissible even before the infected person has symptoms. In general, peak contagion starts about a day or two before symptoms appear and continues two to three days after symptoms appear.   Experts advise that people continue to spread the virus for about eight days after testing positive and are unlikely to pass the virus to others  10 days after contagion. 

CDC recommends that infected individuals isolate for a minimum of five days.  If your symptoms have improved after five days, and you have not had a fever in the last 24-hours without fever-reducing medications,  you might be ready to quit isolation.   CDC has a calculator on its webpage to help people figure this out.

Day 1 of your isolation is the day after you start symptoms or test positive. After five-days of isolation, continue to wear a mask through Day 10 if you leave home.  If you test positive after five days of isolation, extend your isolation to ten days.

Read more at The Washington Post and at CDC