The impact of declaring the state of emergency on human mobility during COVID-19 pandemic in Japan

Daisuke Nakamoto; Shuko Nojiri; Chie Taguchi; Yuta Kawakami; Satoshi Miyazawa; Manabu Kuroki; Yuji Nishizaki

doi:10.1016/j.cegh.2022.101149

The impact of declaring the state of emergency on human mobility during COVID-19 pandemic in Japan

Clin Epidemiol Glob Health. 2022 Sep-Oct:17:101149. doi: 10.1016/j.cegh.2022.101149. Epub 2022 Oct 6.

Authors

Daisuke Nakamoto¹, Shuko Nojiri^{1

2}, Chie Taguchi³, Yuta Kawakami^{4

3}, Satoshi Miyazawa⁵, Manabu Kuroki³, Yuji Nishizaki^{1

4

2}

Affiliations

¹ Clinical Translational Science, Juntendo University Graduate School of Medicine, Tokyo, Japan.
² Medical Technology Innovation Center, Juntendo University, Tokyo, Japan.
³ Graduate School of Engineering Science, Yokohama National University, Kanagawa, Japan.
⁴ Clinical Research and Trial Center, Juntendo University, Tokyo, Japan.
⁵ LocationMind Inc, Tokyo, Japan.

Abstract

Background/objectives: Japan has responded to the spread of COVID-19 through declaration of a state of emergency to regulate human mobility. Although the declaration was enforced by the government for prefectures, there is limited evidence as to whether the public complied with requests for voluntary stay at home. In this study, we evaluated the impact of declaring a state of emergency on human mobility during the COVID-19 pandemic in Japan.

Methods: We utilized daily human mobility data for 47 prefectures in Japan. Data were collected via mobile phone from February 1, 2020 to April 30, 2021. Difference-in-difference analysis was utilized to estimate the effects of the declaration of a state of emergency on prefectures in the Tokyo Metropolitan Area (Tokyo, Kanagawa, Saitama, and Chiba) in comparison to other prefectures where the state of emergency was first lifted (Osaka, Hyogo, Fukuoka, and Aichi).

Results: Human mobility was suppressed during the second state of emergency, from January 8 to March 21, 2021. However, the impact was weaker for the second state of emergency compared to the first.

Conclusion: In Japan, government requests for stay at home, such as the declaration of a state of emergency, were temporarily able to control human mobility. However, the second state of emergency was not as effective as the first. If additional need to regulate human mobility arises, self-restraint with stronger enforcement should be considered.

Keywords: Coronavirus; Difference-in-difference; Infection control; Isolation.