COVID-19 Outbreak Forecasting and Effects of Self-Restraint Against Excursions in Tokyo, Japan, as of the End of March, 2020, Before the Emergency Declaration on April 7, 2020
Yoshiyuki Sugishita*,, Junko Kurita**, Tamie Sugawara*, and Yasushi Ohkusa*
*National Institute of Infectious Diseases (NIID)
1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
**Department of Nursing, Tokiwa University, Ibaraki, Japan
In Tokyo, Japan, coronavirus disease 2019 (COVID-19) cases have been increasing gradually since late March 2020. This study was aimed to predict the effects of self-restraint against excursions in Tokyo before the emergency declaration of April 7, 2020. Data of symptomatic patients collected between January 14 and March 28, 2020, in Tokyo, were used to formulate a susceptible–infected–recovered (SIR) model using three age classes and estimate the basic reproduction number (R0). Based on the estimated R0, we inferred outbreak outcomes and medical burdens if self-restraint against excursions had not been enacted. Thereafter, we estimated the effects of self-restraint against excursions. The results suggested an R0 value of 2.86, with a 95% confidence interval of 2.73–2.97. It is likely that the exhaustion of medical resources could have occurred on April 28, 2020, if no self-restraint against excursions had occurred. If self-restraint against excursions had been enacted from April 6, 2020, and more than 60% of trips outside the home had been restricted voluntarily, medical care services would then have been predicted to be maintained. Our suggestion might have contributed to countermeasures against COVID-19 in Tokyo.
-  Japan Ministry of Health, Labour and Welfare, “Press Releases of Domestic Situation,” https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000121431_00086.html (in Japanese) [accessed March 31, 2020]
-  J. Kurita, Y. Sugishita, T. Sugawara, and Y. Ohkusa, “Estimation of protection for COVID-19 in children from epidemiological information and estimate effect of policy in Japan,” medRxiv, doi: https://doi.org/10.1101/2020.03.27.20045252, 2020.
-  Y. Sugishita, J. Kurita, T. Sugawara, and Y. Ohkusa, “Preliminary evaluation of voluntary event cancellation as a countermeasure against the COVID-19 outbreak in Japan as of 11 March, 2020,” medRxiv, doi: https://doi.org/10.1101/2020.03.12.20035220, 2020.
-  Y. Sugishita, J. Kurita, T. Sugawara, and Y. Ohkusa, “Effects of voluntary event cancellation and school closure as countermeasures against COVID-19 outbreak in Japan,” medRxiv, doi: https://doi.org/10.1101/2020.03.19.20037945, 2020.
-  P.-I. Lee, Y.-L. Hu, P.-Y. Chen, Y.-C. Huang, and P.-R. Hsueh, “Are children less susceptible to COVID-19?,” J. of Microbiology, Immunology and Infection, Vol.53, No.3, pp. 371-372, doi: 10.1016/j.jmii.2020.02.011, 2020.
-  Japan Ministry of Health, Labour and Welfare, “Press releases about chartered flight from Wuhan and cruise ship,” https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000121431_00108.html (in Japanese) [accessed May 13, 2020]
-  N. M. Ferguson, D. A. T. Cummings, S. Cauchemez, C. Fraser, S. Riley, A. Meeyai, S. Iamsirithaworn, and D. S. Burke, “Strategies for containing an emerging influenza pandemic in Southeast Asia,” Nature, Vol.437, No.7056, pp. 209-214. doi: 10.1038/nature04017, 2005.
-  N. M. Ferguson, D. A. Cummings, C. Fraser, J. C. Cajka, P. C. Cooley, and D. S. Burke, “Strategies for mitigating an influenza pandemic,” Nature, Vol.442, No.7101, pp. 448-452, doi: 10.1038/nature04795, 2006.
-  T. C. Germann, K. Kadau, I. M. Longini Jr., and C. A. Macken, “Mitigation strategies for pandemic influenza in the United States,” Proc. of the National Academy of Sciences of the United States of America, Vol.103, No.15, pp. 5935-5940, doi: 10.1073/pnas.0601266103, 2006.
-  I. M. Longini Jr., A. Nizam, S. Xu, K. Ungchusak, W. Hanshaoworakul, D. A. T. Cummings, and M. E. Halloran, “Containing pandemic influenza at the source,” Science, Vol.309, No.5737, pp. 1083-1087, doi: 10.1126/science.1115717, 2005.
-  Y. Ohkusa and T. Sugawara, “Simulation model of pandemic influenza in the whole of Japan,” Japanese J. of Infectious Diseases, Vol.62, No.2, pp. 98-106, 2009.
-  Y. Ibuka, Y. Ohkusa, T. Sugawara, G. B. Chapman, D. Yamin, K. E. Atkins, K. Taniguchi, N. Okabe, and A. P. Galvani, “Social contacts, vaccination decisions and influenza in Japan,” J. of Epidemiology and Community Health, Vol.70, No.2, pp. 162-167. doi: 10.1136/jech-2015-205777, 2016.
-  J. Kurita, T. Sugawara, and Y. Ohkusa, “Estimated effectiveness of school closure and voluntary event cancellation as COVID-19 countermeasures in Japan,” J. of Infection and Chemotherapy, Vol.27, No.1, pp. 62-64, doi: 10.1016/j.jiac.2020.08.012, 2020.
-  Y. Liu, A. A. Gayle, A. Wilder-Smith, and J. Rocklöv, “The reproductive number of COVID-19 is higher compared to SARS coronavirus,” J. of Travel Medicine, Vol.27, No.2, taaa021, doi: 10.1093/jtm/taaa021, 2020.
-  C.-C. Lai, T.-P. Shih, W.-C. Ko, H.-J. Tang, and P.-R. Hsueh, “Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges,” Int. J. of Antimicrobial Agents, Vol.55, No.3, 0105924, doi: 10.1016/j.ijantimicag.2020.105924, 2020.
-  S. Zhao, Q. Lin, J. Ran, S. S. Musa, G. Yang, W. Wang, Y. Lou, D. Gao, L. Yang, D. He, and M. H. Wang, “Preliminary estimation of the basic reproduction number of novel coronavirus (2019-nCoV) in China, from 2019 to 2020: A data-driven analysis in the early phase of the outbreak,” Int. J. of Infectious Diseases, Vol.92, pp. 214-217, doi: 10.1016/j.ijid.2020.01.050, 2020.
-  H. Nishiura, H. Oshitani, T. Kobayashi, T. Saito, T. Sunagawa, T. Wakita, MHLW COVID-19 Response Team, and M. Suzuki, “Closed environments facilitate secondary transmission of coronavirus disease 2019 (COVID-19),” medRxiv, doi: https://doi.org/10.1101/2020.02.28.20029272, 2020.
-  Y. Ohkusa and T. Sugawara, “Pandemic simulation: application of the mathematical model for infectious disease,” Gijutsu-Hyouron Co., Ltd., 2009 (in Japanese).
-  T. Sugawara, M. Sugiura, Y. Ohkusa, K. Taniguchi, and N. Okabe, “Survey of pandemic behavior: to stay at home or not,” The J. of the Japanese Association for Infectious Diseases (Kansenshogaku Zasshi), Vol.82, No.5, pp. 427-433, doi: 10.11150/kansenshogakuzasshi1970.82.427, 2008 (in Japanese).
-  Central Social Insurance Medical Council, “Survey on inpatient care,” 2017, https://www.mhlw.go.jp/file/05-Shingikai-12404000-Hokenkyoku-Iryouka/0000179720.pdf (in Japanese) [accessed March 31, 2020]
-  J. Kurita, T, Sugawara, and Y. Ohkusa, “Forecast of the COVID-19 outbreak and effects of self-restraint in going out in Tokyo, Japan,” medRxiv, doi: https://doi.org/10.1101/2020.04.02.20051490, 2020.