Retesting for COVID-19 is not recommended for individuals who have tested positive in the past 3 months. Available data indicates that individuals with mild-to-moderate COVID-19 are no longer infectious 10 days after symptoms start. Individuals with severe or critical illness, as well as those who have a weakened immune system, may remain infectious for up to 20 days after symptoms start. Individuals who have recovered may have detectable virus in their samples for up to 3 months after the start of infection, but may not be infectious during that time. If you have questions, contact your healthcare provider for additional information.