https://www.npr.org/2020/06/24/882316641/what-parents-can-learn-from-child-care-centers-that-stayed-open-during-lockdowns
The Y says that during the lockdowns it cared for up to 40,000 children between the ages of 1 and 14 at 1,100 separate sites, often in partnership with local and state governments. And in New York City, the pandemic's national epicenter in March and April, the city's Department of Education reports that it cared for more than 10,000 children at 170 sites.
Working in early days, and on very short notice, these two organizations followed safety guidance that closely resembles what's now been officially put out by the Centers for Disease Control and Prevention. The Y says a few staff members and parents at sites around the country did test positive, but there are no records of having more than one case at a site. This, among a population of essential workers.