I’ve noticed that many people including journalists are often using the words “isolation” and “quarantine” interchangeably. They are words that are referring to different things and they refer to different kinds of recommended actions.
Isolation refers to separating sick people with a contagious disease from people who aren’t sick. So, for example, if you have been diagnosed with COVID-19 disease, then you should isolate yourself from other people until you’re no longer infectious. When a person is in Isolation they separate themselves from people who aren’t infected to prevent spread of the communicable disease. Isolation for public health purposes may be voluntary or compelled by federal, state, or local public health order.
Quarantine refers to separating and restricting the movement of people who were exposed to a contagious disease to see if they become sick. So, this is the word that you would use if you have been exposed to someone with COVID-19 disease but you yourself aren’t sick. When a person is in quarantine they separate themselves from people who haven’t been exposed to prevent the possible spread of the communicable disease.
For example, my daughter and niece came back to Arizona after having been living in NYC. They have been exposed to people in the last couple of weeks that have tested positive for the virus but my daughter and niece aren’t sick. They are quarantining together, but neither of them are in isolation, because they aren’t sick. If one of them comes down with symptoms, that person will go into isolation. If neither get sick in the next 14 days then they can come home with our family.