Center of Biomedical Physics and Information Technology
１．Predict the number of new positive cases from the Japanese situation considering the impact of the variant (no definition of the vaccination rate)
２． Learned and corrected the data of other countries to consider the impact of vaccination in more detail
*:Reduce the need for Model 2 in predicting the number of newly infected people (similar accuracy with Model 1 alone)
Model of the infection-prevention effect of vaccination
Based on the medium model (infection-prevention effects of the 1st and 2nd vaccinations: 65% and 75%, respectively) and the report of 10/5, it is assumed that the prevention effect of the 3rd vaccination is 95% and the attenuation rate of the prevention effects of the 1st and 2nd vaccinations of half a year later are 35% and 55% (decrease linearly). The vaccination effect is assumed to keep its peak for 14 days after vaccination and then attenuate (Reference:https://doi.org/10.1038/d41586-021-02261-8）.
・Second vaccination rate up to the end of the year: 80%
・Start timing of the third vaccination: Early December (Dec 1)
・Daily number of people of the third vaccination: Assume 1/3 of the peak (25,000) (from healthcare workers, etc.)
Flows of people
Made a calculation assuming that flows of people would return to the level before the coronavirus catastrophe at the end of March, referring to flows of people of the last year (dotted line)
The implementation of countermeasures against infection is assumed.
※The standard for people flows is the medican value by day of the week for 5 weeks from Jan. 3 – Feb. 6, 2020.
(Last year, the declaration of a state of emergency was issued between January 7 and March 21 for Tokyo and between January 13 and February 28 for Osaka and Aichi)
Prediction of the numbers of new positive cases and seriously ill patients in Tokyo
Prediction of the numbers of new positive cases and seriously ill patients in Osaka
Prediction of the numbers of new positive cases and seriously ill patients in Aichi
Summary and consideration of the current situation
Smaller peak than before in around mid-January in Tokyo, Osaka, and Aichi (continue countermeasures against infection).
・Decrease in the effective proportion of infection-prevention vaccination per capita
・ Effect of year-end behaviors
The vaccination rate of the working generations is about 0.1–0.15 (considering the incubation period)
Prospect for the period after the start of the third vaccination and issues with modeling
Issue 1: How to keep the prevention effect of vaccination per capita (lower left)
○Temporal attenuation effect of the infection-prevention effect of vaccination for Japanese people (especially the third vaccination)
○ Need to keep the prevention effect of vaccination for the working generations above a certain level
(0.2–0.3 if countermeasures are kept)
Issue 2: Temporal attenuation effect of the aggravation prevention effect (there are few analysis examples)
○ Need for case analysis of Israel, etc.
Issue 3: Prediction of Japan in the case of overseas appearance of a new variant
○Improvement to the accuracy of prediction by reading the proportion of the variant, etc. (Description of the periodicity?)