Evaluation of the effect of the state of emergency for the first wave of COVID-19 in Japan

Toshikazu Kuniya

2020Infectious Disease Modelling51 citationsDOI Open Access PDF

Abstract

In this paper, we evaluate the effect of the state of emergency for the first wave of COVID-19 in Japan, 2020 from the viewpoint of mathematical modelling. In Japan, it was announced during the period of the state of emergency from April 7 to May 25, 2020 that the 80% reduction of the contact rate is needed to control the outbreak. By numerical simulation, we show that the reduction rate seems to have reached up to 86%. Moreover, we estimate the control reproduction number Rc during the period of the state of emergency as Rc=0.36 (95%CI, 0.34–0.39), and show that the effective reproduction number Re after the lifting of the state of emergency could be greater than 1. This result suggests us that the second wave of COVID-19 in Japan could possibly occur if any effective intervention will not be taken again.

Topics & Concepts

State of emergencyCoronavirus disease 2019 (COVID-19)Basic reproduction numberOutbreakSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2)2019-20 coronavirus outbreakReduction (mathematics)Emergency responseState (computer science)DemographyGeographyMedicineMedical emergencyOperations researchMathematicsEnvironmental healthPolitical scienceSociologyVirologyAlgorithmLawInternal medicineGeometryInfectious disease (medical specialty)DiseasePoliticsPopulationCOVID-19 epidemiological studiesMathematical and Theoretical Epidemiology and Ecology ModelsViral Infections and Outbreaks Research