Here’s what it could look like if schools reopened today

Here’s what it could look like if schools reopened today.

The novel coronavirus is spreading uncontrolled in more than 20 states. Let’s say that the prevalence of the virus in a community is 1 in 100. A school with 1,000 students could have 10 people walk in on day one who are unknowingly infecting others.

Many who favor on-time reopening cite a recent large study from South Korea that found that children younger than 10 are half as likely to spread the coronavirus as adults. But half of a lot...