Consider the actions taken in Italy. On Feb. 20, Italy reported three instances of infection and no known deaths. On Feb. 21, Italy had 20 cases and its first attributed death. Officials implemented interventions, including school closures, the following day and instituted a cordon sanitaire affecting 50,000 people. That’s aggressive, but it was too late. On Feb. 22, Italy reported 63 cases and a second death. A little more than a week later, there were 2,036 cases, with 140 patients in serious condition and 52 deaths. Today, the numbers continue to climb, with more than 9,100 cases and 460 dead, and on Monday the government expanded travel restrictions to the entire country.

By contrast, Hong Kong and Singapore acted immediately and are still holding the line, literally. Through isolation, quarantines, contact tracing, canceled gatherings and widespread surveillance, they have achieved linear growth of the virus, meaning a reproduction number close to one. What they are doing is working.

Working parents without child care have a legitimate concern, and we must find ways to help one another. But school closings can be the single most effective intervention. Amid an influenza pandemic, schools would be closed to protect the students themselves. Because children are not among the groups most vulnerable to coronavirus, schools should be closed in an effort to reduce community transmission and to protect the children’s parents and grandparents. How long? Epidemiologists suggest eight weeks might be needed to arrest this outbreak.