Background
■If we would like to consider how to respond to the sixth wave from the perspective of “balancing infectious disease control and socioeconomic activities,” it is important to predict the rate of serious illness during the sixth wave.
■A guideline is to “continue social, economic, cultural, and educational activities as much as possible while avoiding a strain on the medical system.”
■Accurate prediction of the serious illness rate will lead to accurate prediction of when straining on medical system is likely to occur.
■Note that there is also a guideline that “a relative emphasis on infection control is good for the economy in the medium to long term.”
■Fujii-Nakata analysis before the start of vaccination: https://covid19outputjapan.github.io/JP/resources.html
■Note that while this could be said under a variety of conditions before vaccination began, it is not necessarily a robust guideline in the situation after the second vaccination has been completed.
■Post-vaccination world: Long-term Outlook for COVID-19 Infection and Economic Activity
■https://covid19outputjapan.github.io/JP/files/FujiiNakata_LongTermOutlook_20210831.pdf
Analysis
■This document quantitatively summarizes the determinants of the rate of serious illness in the sixth wave.
■Estimate how the following 4 factors contribute to the “average rate of serious illness.”
■Percentage of positive cases who received 2 vaccinations
■Percentage of elderly among those who are tested positive
■Prevention rate of serious illness from Omicron variant for those who received 2 vaccinations
■Intrinsic rate of serious illness of Omicron variant
■Monitor how much the rate of serious illness decreases during the sixth wave compared to the fifth wave.
■3 scenarios are presented
■Performed similar analysis for mortality rate
Results (serious illness rate)
■Contribution (Tokyo, basic scenario)
■Fifth wave: 0.66%
■+ Percentage of people who received 2 vaccinations: 0.36% (-45%)
■+ Percentage of elderly people: 0.42% (+17%)
■+ Intrinsic rate of serious illness of Omicron variant: 0.13% (-70%)
■+ 2 vaccinations to prevent serious illness (= sixth wave): 0.15% (+16%)
Results (mortality rate)
■Contribution (Tokyo, basic scenario)
■Fifth wave: 0.31%
■+ Percentage of people who received 2 vaccinations: 0.19% (-40%)
■+ Percentage of elderly people: 0.27% (+43%)
■+ Intrinsic mortality rate of Omicron variant: 0.081% (-70%)
■+ 2 vaccinations to prevent mortality (= sixth wave): 0.094% (+16%)
Percentage of positive cases who received 2 vaccinations
Percentage of elderly among those who are tested positive
Efficacy of 2 vaccinations in preventing serious illness: Tokyo
Serious illness rates were calculated for the 2 groups of aged under 60 (aged 30s and under as well as 40s and 50s) and aged 60 and over dividing the number of positive cases by the number of seriously ill patients based on the table on slide p.5. The efficacy of preventing serious illness from the Delta variant was assumed to be 30% based on data from Osaka Prefecture.
Efficacy of 2 vaccinations in preventing serious illness: Osaka
After 2 groups of those aged under 60 (aged 20s-30s as well as 40s-50s) and aged 60 and over are divided into those who had received 2 vaccinations and those who have not received yet, serious illness rates were calculated for each group dividing the number of positive cases by the number of seriously ill patients based on the table on slide p.6.
Percentage of positive cases who received 2 vaccinations
Percentage of elderly among those who are tested positive
Intrinsic rate of serious illness of Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
Efficacy of 2 vaccinations in preventing mortality: Tokyo
Mortality rates were calculated for the 2 groups of aged under 60 (aged 30s and under as well as 40s and 50s) and aged 60 and over dividing the number of positive cases by the number of mortalities based on the table on slide p.26. The efficacy of preventing mortality from the Delta variant was assumed to be 30% based on data from Osaka Prefecture.
Efficacy of 2 vaccinations in preventing mortality: Osaka
After 2 groups of those aged under 60 (aged 20s-30s as well as 40s-50s) and aged 60 and over are divided into those who had received 2 vaccinations and those who have not received yet, mortality rates were calculated for each group dividing the number of positive cases by the number of mortalities based on the table on slide p.6.
Efficacy of 2 vaccinations in preventing mortality from Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
Efficacy of 2 vaccinations in preventing serious illness from Omicron variant
