After signaling that it was moving to a more nuanced COVID-19 policy, Shanghai — a city of 26 million — was pressured by the central government to lock down in late March, and has only just started to ease restrictions after one month. The official reason for this drastic policy shift is that citywide testing had revealed high infection rates. Yet one is left wondering why the authorities did not opt for a less costly alternative to a complete lockdown. After all, the Omicron variant of SARS-CoV-2, which now accounts for almost all new cases globally, has only mild effects on