Background and Overview
■In some areas such as Tokyo, the capacity of the medical system has been tightened. Due to insufficient number of hospital beds, there are patients with moderate or more serious illness who are not able to be hospitalized.
■The effect of stronger behavioral restrictions on infection control and the changes in the number of severely ill and inapparent infected people in the community are investigated by simulation.
■If behavior restrictions are weak, the ratios may reach the following levels during the peak seasons (mid-Sept/Oct):
Table: Simulation results for weak behavior restrictions
Simulation
■The simulator is extended to record the change in the number of seriously ill patients.
■The number of agents is 1 million. From the 64 trials from December 22 last year to August 14 this year, 4 trials are selected that are close to the actual data. As a continuation of these, we ran subsequent simulations to see the average and standard deviation.
■Assume that the meeting frequency and movement frequency are reduced to 20~80% from August 23, and maintained.
■#1 Change in number of new positive cases (page 3)
■#2 Change in number of infected people (page 4)
■#3 Change in number of seriously ill patients (page 5) - The criteria for severity of illness in the simulator are adjusted based on the changes in Tokyo.
■#4 Change in number of inapparent infected people (asymptomatic and untested) (page 6)
Simulation Result #1 Change in number of new positive cases
■The average number of positive patients during the peak period is 0.056〜 0.069% of the population, about 7,800〜9,600 if applied to the population of Tokyo.
■The number of infected people declines from late August to mid September, but high levels of infection will persist after November.
Simulation Result #2 Change in number of infected people
■The average number of infected people during the peak period is 0.99〜1.23% of the population, about 140,000〜170,000 if applied to the population of Tokyo.
■The number of infected people declines from late August to mid September, but high levels of infection will persist after November.
Simulation Result #3 Change in number of seriously ill patients (Tokyo standard)
■The average number of seriously ill patients during the peak period is 0.0026〜0.0031% of the population, about 360〜430 if applied to the population of Tokyo.
■The number of infected people declines from late September to early October, but high levels of infection will persist after November.
Simulation Result #4 Change in number of inapparent infected people
■The average number of infected people who are asymptomatic and untested during the peak period is 0.44〜0.53% of the population. 1 in 190〜226 people, which translates to approx. 62,000-74,000 for population in Tokyo.
■It peaks from the end of August to early September, and then decreases.
Insights from the simulation
■Depending on the severity of behavioral restrictions, the peak will be from the end of August to early October. The effectiveness of vaccination will then reduce the number of infections.
■If behavior restrictions are weak, the ratios may reach the following levels during the peak seasons (mid-Sept/Oct):
Table: Simulation results for weak behavior restrictions
■The decline in immune response over time may sustain a high number of infected individuals.
Subjects
Supplemental information: Assumptions in the simulation and how to interpret the graph
