Parents gathered outside a primary school in Beijing late into the night on Monday, anxiously waiting for their children who were caught in a snap lockdown triggered by a teacher diagnosed hours earlier with Covid-19. The principal came out a little past midnight, telling them some of the kids would have to quarantine. Each could have one parent accompany them through the two weeks of isolation. For students whose test results hadn’t yet come back, parents were asked to bring quilts and pillows to spend the night at school. Perhaps nowhere in the world can a single Covid case trigger such extensive contact tracing and quarantine requirements as in Beijing, where officials are going to extraordinary lengths to halt transmission of the highly infectious delta variant. China’s […]