Sending kids home again is unlikely to slow the virus.
Few pandemic decisions have become as destructively politicized as school closures. As a New Yorker article noted this week, whether schools are open depends more on a community’s support for Donald Trump than on its Covid-19 infection rate. And now a small resurgence of the virus in New York City has schools facing possible closure. An uptick this week has brought what’s called the positivity rate above 3% for the last several days. Under current policy, a seven-day average over 3% will trigger school closings. It’s not clear that 3% is the right cut-off for closing schools, though, or that re-closing the public schools would slow the pandemic. The positivity rate represents the percent of positive tests among all those tested in a given time period. Epidemiologists say it’s a measure that depends in part on how much testing is being done. If only the sickest people are getting tested, the rate is likely to be quite high. If lots of healthy people are added to the mix, the rates are likely to get lower. “Any increase in percent positivity represents an increase in the probability a test is used on a person who is infected. That might happen because tests are limited and used on those with clear symptoms, or because there are known outbreaks that are being actively investigated,” says Harvard University epidemiologist William Hanage via email. The positivity rate has in recent days gone from around 1% to around 3% in both New York City and Massachusetts, he says.
