If you have been exposed to COVID-19 after attending a holiday gathering, you must immediately quarantine yourself to avoid further spread. 

The Centers for Disease Control and Prevention (CDC) highly encourages to sick individuals to:

• Stay home for 10 days if you think you have been exposed to someone who has COVID-19. Do not wait for COVID-19 symptoms to appear and stay at home if possible. 
• Observe any possible COVID-19 symptoms especially a fever (100.4°F or higher), cough, shortness of breath, and loss of taste and smell 

See also: What COVID-19 symptoms appear first?

• Continue social distancing and avoid seeing/visiting immunocompromised individuals
• If available, get tested for COVID-19 at least 3 to 5 days after exposure. 
• Avoid any non-essential travels

If unable to self isolate for 10 days:

• Practice social distancing (i.e. keeping at least 6 feet distance from others)
• Wear facial coverings especially indoors and when around other people or animals, including pets (even at home)

See also: What is the best type of face mask to use?

• Continue hand hygiene practices (e.g. hand washing with soap and water for at least 20 seconds. Use alcohol-based sanitizer is soap and water is not available)

See also: How should I wash my hands to prevent getting COVID-19?

• Monitor your entire household for COVID-19 symptoms 
• Reach out to your healthcare provider if you are feeling sick with COVID-19 symptoms and get tested 
• If you test positive for COVID-19, immediately notify your family relatives and other individuals you have been exposed to during a gathering

Visit the CDC website for more guidance on holiday gatherings.