Figure 3

Violin plot showing Z-scores from the Before Omicron (April 8, 2020 to November 28, 2021), Early Omicron (November 29, 2021 to July 9, 2022), and Late Omicron (July 10, 2022 to January 31, 2023) periods. The asterisk (*) indicates significant difference in Z-score values between two groups (Mann–Whitney test; p < 0.05). Red dotted lines indicate median Z-score values, and the black dashed lines indicate the interquartile range.