BOSTON (CBS) — A new study published by the CDC finds that the spread of COVID-19 within households is more common than previously thought.

Researchers followed 101 people infected with COVID-19 and the people in their homes. They found that just over half of the household contacts became infected within a week, usually within just five days of the initial patient developing symptoms, regardless of whether it was an adult or child.

It was also clear that people without symptoms could pass the virus to others in the home. This underscores the need to promptly isolate people who could be infected within the home, even before they get tested, and to wear masks in common spaces.

Those who are elderly or immunocompromised may want to separate themselves within the home to avoid unnecessary contact with people who could be infected, even if they don’t have symptoms.