In a collaborative study between Duke University and the University of North Carolina-Chapel Hill, researchers discovered that among 11 school districts with nearly 100,000 staff and students, there were no instances of children passing the coronavirus to adults during in-person instruction. Researchers found just 32 cases of either kid-to-kid or adult-to-adult coronavirus transmission over nine weeks.

The study also slammed school policies that ask individuals to self-quarantine if they come within six feet of a person infected with coronavirus for more than 15 minutes, even if both individuals wore masks. The study calls the policy “counter-productive,” as transmission of the coronavirus when properly wearing a mask is “uncommon” in school settings. Researchers also said the policy sends a mixed message to the public on the benefit of face coverings.

The study concluded that “schools can stay open safely in communities with widespread community transmission.”