摘要
In late December 2019,clinicians in Hubei Province noticed and reported to health authorities a cluster of cases of pneumonia of unknown etiology(PUE)that turned out to be the start of the coronavirus disease 2019(COVID-19)pandemic(1).By January 29,2020,all provincial-level administrative divisions(PLADs)across the country had launched their highest public health emergency responses(Level 1 responses)(2-3).
