We analyzed 3,184 cases of coronavirus disease in Japan and identified 61 case-clusters in healthcare and other care facilities, restaurants and bars, workplaces, and music events. We also identified 22 probable primary case-patients for the clusters; most were 20-39 years of age and presymptomatic or asymptomatic at virus transmission.
Keywords: 2019 novel coronavirus disease; COVID-19; Japan; SARS; SARS-CoV-2; coronavirus; epidemiology; respiratory infections; severe acute respiratory syndrome coronavirus 2; transmission; viruses; zoonoses.