Proponents of fully reopening schools got a major boost when the Centers for Disease Control and Prevention announced that elementary school students and some middle and high school students could be spaced three feet apart in classrooms.

The previous guidance of keeping most students six feet apart had in many school districts become a big obstacle to welcoming students back for full-time instruction because it severely limited capacity. Many experts now say a growing body of research shows that six feet is not much more protective than three, as long as other safety measures are in place, like mask wearing.