■The number of closed childcare centers, etc.(*) increased rapidly during the 6th wave.
■During the 7th wave, the number of closed childcare centers, etc. against the number of infected people decreased significantly compared to the 6th wave.The following are considered to be the factors in this decrease.
■The shortening of isolation periods for close contacts
■The policy of not tracking close contacts (Tokyo)
■Estimates of the number of closed childcare centers, etc.:We estimated the number of new closures based on the state of child infections and the trend in the number of days of childcare center closures. The data used at the time of estimating are as follows:
■Most recent number of newly infected people
■Proportion of infected people less than 10 years of age
■Number of days of closure of childcare centers, etc.
■Estimated number of childcare centers, etc., closed as of July 28, 2022: 32 (forecast width: 0 to 84)
*“Childcare centers, etc.” means licensed childcare centers, childcare center-type licensed daycare centers, community-based childcare businesses and remote area childcare centers
Trend in the number of new positive cases and the number of closed childcare centers, etc. nationwide
Source: Ministry of Health, Labour and Welfare “State of closure of childcare centers, etc. due to COVID-19” (municipality statistics as of 14:00, July 21, 2022 (Thursday)) https://www.mhlw.go.jp/content/11920000/000897067.pdf
Model for estimating the number of newly closed childcare centers, etc.
■Assuming that the number of days closed follows the exponential distribution of the average d(t) days, the number of newly closed childcare centers, etc. at a certain point in time t is estimated using the following model.
■N(t) = N(t-1) + ΔN(t) - 7/d(t)* N(t-1)
■N(t) : Number of closures at time t
■ΔN(t) : Number of new closures at time t
■d(t) : Number of days of closure at time t (P.5)
Definition of number of days of closure in the estimation model
■There are no regulations on the number of days of closure of childcare centers, etc.
■The number of days for the temporary closure of schools*1 established by the Ministry of Education, Culture, Sports, Science and Technology is linked to the isolation period*2 for general close contacts.
■In these estimates, the number of days of closure of childcare centers, etc. is defined based on data at the municipal level.
(Mostly linked to the isolation period for general close contacts)
Estimated average number of new closures (all periods)* Since 2021
■OLS estimates based on a regression model using the number of positive cases*3 among children less than 10 years of age nationwide as an explanatory variable showed a strong correlation between the average number of new closures of childcare centers, etc., and the number of positive cases among children less than 10 years of age.
Estimates of the average number of new closures of childcare centers, etc. (since May 2022)
■OLS estimates based on a regression model using the number of positive cases*3 among children less than 10 years of age nationwide as an explanatory variable showed a strong correlation between the average number of new closures of childcare centers, etc., and the number of positive cases among children less than 10 years of age.
■Estimated number of childcare centers, etc. closed as of July 28, 2022: 32 (forecast width: 0 to 84)
Outlook for the average number of positive cases to late August 2022: forecast by scenario
Based on the latest state of infections, three scenarios were set for the outlook for the future average number of positive cases (less than 10 years of age).
Outlook to late August 2022: Number of closures of childcare centers, etc.
■If infections are brought under control in the future, the number of closed childcare centers, etc. will decrease rapidly.
■If it takes time to bring infections under control, the pace of decline in the number of closed childcare centers will be slow.
■The most recent increase in the positivity rate (51% as of July 29) suggests that the number of people testing positive may not reflect the state of infections correctly.*4
