Take a good look at all the inclines to the wave of the COVID-19 and it's variants. Which incline going up is steeper? Yes, that is correct, the current one. The winter of 2020 into 2021 has the steepest decline, but, the current Delta Variant spreads faster, infects the host, and rampages through the body faster damaging the ONLY SET OF LUNGS A PERSON HAS.
What is the latest census of people with COPD, asthma, and emphysema? It would be easy to track escalations in lung disease because the inhalers are being sold at a higher rate than before.
Then take a look at the demand for other medications, like heart disease medications, mental health medications, appointments for rehabilitation after hospitalizations. There are ways of deciding what the exact toll is of these viruses and whether there were adequate precautions by state governors.
With this graph alone there is reason to keep schools closed. Then add the nightmare scenario of IGNORANT parents and children that contract the viruses and there is even more reason to keep the children enrolled in distant learning and home. That is especially true for the children of minority parents.