The Critical Variable in Keeping Coronavirus in Check

In U.S. and Europe, Covid-19 illness is starting to retreat, but relaxation of containment measures will be fraught

Countries are experimenting with both high- and low-tech ways to enforce lockdowns or self-quarantines. WSJ reporters in Rome, New York and Hong Kong compare their isolation experiences to show how some governments are willing to impose stricter measures to stop the virus. Photo illustration: Crystal Tai

28365365体育投注Governments across Europe and in the U.S. say they have driven down a key variable to levels that suggest that the lockdowns that plunged their economies into the deep freeze are succeeding in containing the spread of the deadly new coronavirus.

28365365体育投注 The variable measures the average number of other people each carrier of the new coronavirus infects. This infection ratio will be avidly watched as policy makers calibrate the task of rolling back measures that have kept hundreds of millions of people at home.