One possibility that I don't see discussed is that the pandemic caused a reduction in childhood physical activity. Not saying this was the link, but it seems w

One possibility that I don't see discussed is that the pandemic caused a reduction in childhood physical activity. Not saying this was the link, but it seems worth investigating. The mentioned seasonality of normal rates also suggests either a link to physical activity or exposure to sunlight. The resumption of normal school attendance in 2022 will test this theory anyway; it would be nice if it showed it going back down.