Figure 1. Map of Hyogo Prefecture and the six participating facilities. Hyogo Prefecture, with a population of ~5.4 million, is in the Kansai region of Japan and adjacent to Osaka, one of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) endemic areas in Japan.
Figure 2. Case distribution of all patients and positive patients by age. (a) Distribution of all cases (n = 10,377) by age. (b) Distribution of the positive cases on neutralizing activity assay (n = 16) by age.