%0 Journal Article
%@ 2291-5222
%I JMIR Publications
%V 9
%N 5
%P e27342
%T On-site Dining in Tokyo During the COVID-19 Pandemic: Time Series Analysis Using Mobile Phone Location Data
%A Nakanishi,Miharu
%A Shibasaki,Ryosuke
%A Yamasaki,Syudo
%A Miyazawa,Satoshi
%A Usami,Satoshi
%A Nishiura,Hiroshi
%A Nishida,Atsushi
%+ Research Center for Social Science & Medicine, Tokyo Metopolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan, 81 3 6834 2292, mnakanishi-tky@umin.ac.jp
%K COVID-19
%K mobility data
%K on-site dining
%K public health and social measures
%K public health
%K mobile phone
%K mobility
%K protection
%K time series
%K location
%K infectious disease
%K transmission
%D 2021
%7 11.5.2021
%9 Original Paper
%J JMIR Mhealth Uhealth
%G English
%X Background: During the second wave of COVID-19 in August 2020, the Tokyo Metropolitan Government implemented public health and social measures to reduce on-site dining. Assessing the associations between human behavior, infection, and social measures is essential to understand achievable reductions in cases and identify the factors driving changes in social dynamics. Objective: The aim of this study was to investigate the association between nighttime population volumes, the COVID-19 epidemic, and the implementation of public health and social measures in Tokyo. Methods: We used mobile phone location data to estimate populations between 10 PM and midnight in seven Tokyo metropolitan areas. Mobile phone trajectories were used to distinguish and extract on-site dining from stay-at-work and stay-at-home behaviors. Numbers of new cases and symptom onsets were obtained. Weekly mobility and infection data from March 1 to November 14, 2020, were analyzed using a vector autoregression model. Results: An increase in the number of symptom onsets was observed 1 week after the nighttime population volume increased (coefficient=0.60, 95% CI 0.28 to 0.92). The effective reproduction number significantly increased 3 weeks after the nighttime population volume increased (coefficient=1.30, 95% CI 0.72 to 1.89). The nighttime population volume increased significantly following reports of decreasing numbers of confirmed cases (coefficient=–0.44, 95% CI –0.73 to –0.15). Implementation of social measures to restaurants and bars was not significantly associated with nighttime population volume (coefficient=0.004, 95% CI –0.07 to 0.08). Conclusions: The nighttime population started to increase after decreasing incidence of COVID-19 was announced. Considering time lags between infection and behavior changes, social measures should be planned in advance of the surge of an epidemic, sufficiently informed by mobility data. 
%M 33886486
%R 10.2196/27342
%U https://mhealth.jmir.org/2021/5/e27342
%U https://doi.org/10.2196/27342
%U http://www.ncbi.nlm.nih.gov/pubmed/33886486