NEW YORK (AP) — U.S. health officials are endorsing “test-to-stay” policies that allow close contacts of students infected with the coronavirus to remain in classrooms if they test negative.

The Centers for Disease Control and Prevention on Friday decided to more firmly embrace the approach, after research of such policies in the Chicago and Los Angeles areas found COVID-19 infections did not increase when schools switched to test-to-stay.

CDC had recommended that when someone in a school tests positive for COVID-19, those who were deemed to be in close contact with them should stay out of school for 10 days.