why 14 day quarantine?

How long does someone need to isolate after first COVID-19 symptom onset?
People who are severely ill with COVID-19 might need to stay home longer than 10 days and up to 20 days after symptoms first appeared. Persons who are severely immunocompromised may require testing to determine when they can be around others. Mar 12, 2021
Full answer in: www.cdc.gov
What is the purpose of quarantine during the COVID-19 pandemic?
Quarantine is used to separate someone who might have been exposed to COVID-19 and may develop illness away from other people. Quarantine helps prevent spread of disease that can occur before a person knows they have the virus. CDC recognizes that any quarantine shorter than 14 days balances reduced burden against a small possibility of increasing the spread of the virus. Dec 2, 2020
Full answer in: www.cdc.gov
Why do you have to quarantine for 14 days after travel during the COVID-19 pandemic?
You may have been exposed to COVID-19 on your travels. You may feel well and not have any symptoms, but you can be contagious without symptoms and spread the virus to others. You and your travel companions (including children) pose a risk to your family, friends, and community for 14 days after you travel. May 3, 2021
Full answer in: www.cdc.gov