Figure 1.

Epidemiological curves for COVID-19 by date of report, along with trends of Google mobility and temperature in Tokyo, Osaka, Aichi, and Hokkaido, Japan.

The number of COVID-19 cases by date of report (yellow bars) from March 15, 2020 to January 12, 2021 in the four training data prefectures of Japan: (A) Tokyo, (B) Osaka, (C) Aichi, and (D) Hokkaido. Red lines indicate trends of changes in human mobility patterns (the ‘retail and recreation’ category in Google community mobility reports) compared with those in the pre-pandemic period (January 3 to February 6, 2020). Blue lines show trends for the daily temperature in each region; both mobility and temperature were smoothed using 7-day moving averages. In each figure, two red-shaded areas indicate the time periods for the first and second nationwide states of emergency, respectively, while purple-shaded areas show the time periods when stringent restrictions on bars and restaurants were implemented by each prefectural government right before the second state of emergency.