People with COVID-19 are generally contagious starting about 2-3 days before symptoms begin and remain contagious for about 9 to 10 days after symptom onset. You are likely not contagious about nine days after symptoms start, especially if your symptoms have improved and you have been fever-free for at least 24 hours without fever-reducing medication. Even after isolation ends, it is recommended to wear a high-quality mask for 5 additional days to reduce the risk of transmission. People with severe illness or weakened immune systems may be contagious longer and should consult a healthcare provider for guidance on when it’s safe to end isolation. Testing can help confirm contagiousness if needed.

Key points on contagiousness:

• Contagious from about 2-3 days before symptoms and up to 9-10 days after symptom onset.
• Isolation can end if symptoms improve and no fever for at least 24 hours.
• Continue wearing a mask for 5 days after isolation.
• Severe illness or immunocompromised individuals may be contagious longer.
• Rapid antigen tests are less likely to detect contagious virus after 9 days.
• PCR tests can detect viral RNA much longer but do not indicate contagiousness.

This provides a guideline for when a person with COVID-19 is no longer contagious and can safely end isolation while protecting others.