NYC schools were actually closed because of citywide COVID positive rates, not school COVID positive rates. The school positivity rate was practically nonexistent-something like 0.2%. But the citywide COVID positivity rate was at least an order of magnitude higher, and unfortunately that’s what the reopening deal with the teacher’s union had been tied to.

TBH, it might be better to have testing in the schools. I think testing at schools pretty much any place in America would show much lower positivity rates at school than in the general community, due to the age of students. It could potentially provide a barrier to closing schools because some 50+ year olds in the community are testing positive.