ABSTRACT
As of Feb. 2021, COVID-19 is still spreading. To overcome this infectious disease, COVID-19 vaccines are being developed around the world. In Japan, inoculation of COVID-19 vaccines to people will be starting soon (as of Feb. 2021). However, desirable vaccination strategies are not clear. Therefore, we investigate the relationship between vaccination strategies and COVID-19 spreading using positive-case data in Japan. The method is SIRVD (Susceptible Infected Recovered Vaccination Death) model, which can represent vaccinated persons. Moreover, we discuss desirable vaccination strategies based on the results. © 2022 Japan Industrial Management Association. All rights reserved.
ABSTRACT
In the end of 2019, the emergence of COVID-19 was reported and confirmed for the first time, and it triggered an international pandemic. In Japan, the strong tendency to spread of infection is still continuing. The Japanese Government has been raised two concepts to overcome this difficulty. One is the thorough measures to control of the spread of infection and the other is the economic recovery. The government has carried out the corresponding two policies: the use of COVID-19 Contact-Confirming Application (COCOA) and the application of “GoTo Travel Campaign”. We focus on these two policies and study an ideal situation, which enables us to balance more economic recovery and control of the spread of infection. To pursue this goal, we propose a mathematical model to estimate these policies’s effects and conduct simulations of 28 scenarios. In addition, we analyze each result of the simulation and investigate characteristics of each situation. As a result, we clearly find that it required that not only the increasing the using rate of COCOA but also a positive change of people’s behaviors and awareness. © 2021 Institute of Physics Publishing. All rights reserved.
ABSTRACT
As of November 2020, the COVID-19 pandemic continues to rage across the world. One of the measures that has been taken to curb the spread of the virus is blanket stay-at-home orders. Staying at home significantly limits close contact with others and can, thus, decrease the number of new cases. However, if people refrain from going out, this will cause significant economic damage. For this reason, some people think that these orders should be revoked after a short period of time, and people should get out more often. However, if blanket stay-at-home restrictions are lifted before a significant decrease is seen in the number of new cases, the number of infected people is likely to increase within a short period. This will, in turn, hasten the next round of blanket stay-at-home orders and lead to a further reduction in people who can leave their home. Against this backdrop, this study examines below phenomena, through a multi-agent simulation. The early removal strategies of stay-at-home orders for increasing the number of people leaving their homes have the effect of both increasing and decreasing the number of such people. Therefore, we consider the strategies do not lead to a sufficient increase in the overall number of people leaving their homes. To examine these phenomena, we conducted the simulations that consist of six scenarios with the different removal condition of stay-at-home orders. As a result, we could confirm that when more removal conditions of stay-at-home orders were eased, the tendencies of more number of infected people and death people were increasing with some exceptions. In contrast, there were almost no differences among the numbers of people leaving their home of these scenarios. Based on the results, we also examined the possibility of a strategy that covers both infected people and the number of people allowed to leave their homes.