On March 11, 2020, Italy imposed a national lockdown to curtail the spread of severe acute respiratory syndrome coronavirus 2. We estimate that, 14 days after lockdown, the net reproduction number had dropped below 1 and remained stable at »0.76 (95% CI 0.67-0.85) in all regions for >3 of the following weeks.
Keywords: COVID-19; Italy; SARS; SARS-CoV-2; coronavirus disease; lockdown; reproduction number; respiratory infections; severe acute respiratory syndrome; severe acute respiratory syndrome coronavirus 2; transmissibility; viruses; zoonoses.