People with COVID-19 are generally contagious from about 2-3 days before symptoms begin and remain contagious for about 8 to 10 days after symptoms start. The highest contagiousness usually occurs 1-2 days before symptom onset and the first few days after symptoms begin. For mild to moderate cases, people are likely no longer contagious after 10 days if symptoms have improved and there is no fever. However, those with severe illness or weakened immune systems may be contagious for longer, up to 20 days or more. Mask-wearing and isolation are recommended during the contagious period to prevent spread.

Key details about the contagious period for COVID-19:

• Contagious 2-3 days before symptoms appear.
• Most contagious 1-2 days before and shortly after symptoms start.
• Average contagious period is about 8 days, sometimes up to 10 days.
• Longer contagious duration for severe illness or immunocompromised individuals.
• Isolation and mask use advised until at least 24 hours fever-free with symptom improvement.
• Testing can help confirm when contagiousness has ended, especially before interacting with vulnerable people.

This outlines how long a person with COVID-19 is typically contagious and how precautions should be managed during that time.