Admittedly I only skimmed this because I suspect politics by the teachers who want to keep up the fear and get govt. money for mask mandates. I'm confused by the timing of the "schoolyear" which is an integral part of their argument. That seems complicated by the fact that some schools have had no in-person classes for over a year. July was when pretty much everyone was back to school in person. This was when in general the delta variant was causing a surge, no surprise it would be affecting schools. Also by then many teachers were vaccinated, but only some older children. Where is that info? A further feature of our schools which hampers generalization is that there are so many charter schools and they all are on their own schedules and mask policies which don't necessarily coincide with the public system. No idea what their "school year" was last year.