Faculty of Science and Technology, Keio University
Projected number of positive cases in the short term
If the 4th state of emergency continues to have the same effect as the current situation, the number of positive cases will peak in mid-September. On the other hand, it will be difficult to reduce the number of positive cases by September unless there is stronger restraint on human flow than at present.
Projected number of seriously ill patients in the short term
If the 4th state of emergency continues to have the same effect as the current situation, the number of seriously ill patients is assumed to increase until September.
Projected number of infected people in the mid-term
Expanding the current (4th) state of emergency to nationwide would help suppress the spread of infections quickly. At this point in time, when the effects of vaccination have yet to be fully realized, measures equivalent to a lockdown should be implemented, such as refraining from long-distance travel, raising the rate of remote work, and taking summer vacation for the entire month of August at the earliest.
Projected number of seriously ill patients in the mid-term
As with the projected number of positive cases on the previous page, extending the scope of the state of emergency to nationwide at an early stage is expected to curb the number of seriously ill patients.
By an analysis of Twitter tweets, it was found that a greater number of tweets expressing feelings of scared led to behavioral inhibition. The number of tweets expressing feelings of scared increased after the 4th state of emergency, which may be related to some decrease in human flow in Tokyo.
Number of COVID-19 related posts
Emotional component values of COVID-19 related posts
SNS sentiment analysis (Data during 2021/4/1~7/31) ※Reposting document dated 8/3
Mobile Spatial Statistics (Population Change)
During the 4th state of emergency and priority measures to prevent the spread of infectious disease, we have confirmed some decrease in human flow in all regions.
・Mobile spatial statistics were used to identify changes in the population flow in downtown areas within the region where the state of emergency was declared.
・During past state of emergency, we have seen a significant reduction in human flow in each of the areas where the state of emergency was declared. The effect (reduction in the number of people in the region) was strongest at the time of the 1st declaration, with no significant difference in effect between the 2nd and 3rd.
・After the 4th state of emergency was declared, a decrease in human flow in downtown areas was observed, although not as drastic as during previous declarations.
・In areas where the priority measures has been newly declared, the same decrease in the human flow has been confirmed.