Cities across China implemented stringent social distancing measures in early 2020 to curb coronavirus disease outbreaks. We estimated the speed with which these measures contained transmission in cities. A 1-day delay in implementing social distancing resulted in a containment delay of 2.41 (95% CI 0.97-3.86) days.
Keywords: COVID-19; SARS-CoV-2; coronavirus disease; epidemiology; nonpharmaceutical interventions; reproduction number; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.