This 29 September 2020 video from the USA says about itself:
Translated from Dutch NOS radio, 29 September:
Coronavirus infections have been detected in more than 350 schools. According to the Schools Reporting Point, part of Coronavirus Locator Netherlands (CLN), schools in large cities are mainly affected. “We receive so many reports that it can hardly be kept up to date”, a spokesperson told daily De Telegraaf.
According to CLN, more than half of the current coronavirus clusters originated in education. “Because it is discouraged to have children tested, the question is whether we have all the trouble spots in the picture.”