Japan may see more deaths among the younger generation from the vaccination than from the natural COVID-19

(This post is based on the information as of 26 Jan 2021. If the information changes, my view will be changed accordingly.)

Two in twenties died after the first month of U.S. COVID-19 vaccination. Wait! There are only two deaths in twenties from COVID-19 in Japan in a year. 

I was astonished by the number of deaths reported on the U.S. Vaccine Adverse Event Report as of Jan 15, 2021.* I did not get surprised by the number of deaths in the elderly but by the number of deaths in the younger generation.** Two deaths among 18-29 years?!

* As The U.S. vaccinated around 5 million by the early Jan, 148 deaths come from 5M 1st-dose vaccination. The Vaccine Fatality Rate is around 0.003%. I don't know if this is high or not as a vaccine.  
** I fully understand these adverse events do not necessarily mean a causal relationship. However, how COVID-19 deaths are counted are as same as this adverse event report. So, I think we can compare the number of adverse event deaths and COVID-19 deaths.

For young Japanese, COVID-19 is a cold, not a life-threatening disease. This is the number of deaths by age groups in Japan as of Dec 2020. You can see that there are only two deaths among 20 to 29 years in a year.

Source: https://www.statista.com/statistics/1105162/japan-patients-detail-novel-coronavirus-covid-19-cases-by-age-and-gender/

5 million 1st-dose vaccination in one month in the U.S. may have caused the same number of deaths in the twenties the real COVID-19 caused in a year in Japan?? What happens if Japan vaccinates as the U.S. does?? What is the relative risk of the new vaccines to the younger Japanese? 

The world's first analysis of IFR by age group between the countries; the U.S. and Japan: Japanese immunity against COVID-19 is 10+ years younger than American immunity

These questions made me look into the U.S. and Japan COVID-19 data by age groups in detail. I already knew that Japan IFR (Infection Fatality Rate) is lower than the U.S. as Prof Ioannidis at Stanford has already analyzed in the paper below.

John P A Ioannidis, Infection fatality rate of COVID-19 inferred from seroprevalence data

https://www.who.int/bulletin/online_first/BLT.20.265892.pdf

But, I had never seen an IFR comparison between the countries and I could find it by Googling (actually I use DuckDuckGo these days). So, I did it by myself.

Here are the results in tables.

Here are some findings from the tables;

• The absolute numbers of deaths are quite different. The U.S. people may not be surprised by the number of adverse event deaths but you can see that the Japanese will be surprised to see the number of adverse event deaths especially because there are almost zero deaths among the younger generation in Japan.
• The U.S. population is 2.6 times the Japan population, but the population fatality rates are very different.
• Interestingly, the infection fatality rates and case fatality rates for each age group are quite different, too.

Let's visualize and compare CFR, IFR, PFR by age groups between the U.S. and Japan, using the same y-axis.

Did you notice anything? Yes, the CFR/IFR of a Japanese age group is around the same CFR/IFR of a U.S. +10 years age group. In other words, when infected, Japanese immunity against COVID-19 is around 10+ years younger than American immunity. This is a simple but great finding, isn't it? And this would be another evidence of the BCG vaccination hypothesis.

Looking at the tables above, we can say that if someone gets 10 years older, he/she will increase his/her IFR/CFR by 3 to 5 times and Japanese IFR/CFR in a particular age group is one-third to one-fifth of American IFR/CFR in the same age group.

Japan may see more deaths among the younger generation from the vaccination than from the natural COVID-19

Let's go back to the vaccination. As the vaccination starts from high-priority/risk segments, we cannot simply multiply the current figures for the whole population but should look at the vaccination target plan. The U.S. has a phased plan of vaccination and the highest priority; Phase 1a covers the following population.

It seems that we can assume that the same profile population will be vaccinated by reaching 24 million. So, I created a table simply multiplying the actual number as of Jan 15.

How does this look?

Comparing with the U.S. COVID-19 death figure, this can be called "marginal". But if you compare it with Japan COVID-19 death figure, can you call this "marginal"? Japan may see more deaths among the younger generation from the vaccination than from the natural COVID-19. Adverse event deaths in Japan can be much smaller thanks to the strong immunity or even worse but we don't know it.

Though we don't know how the vaccination fatality rate differs by age, the current vaccination fatality rate 0.003% is higher than the IFR of 5-17 years old in the U.S. and the IFR of 20-29 years old in Japan. With the current information, it is unethical to recommend the vaccination to those younger generations. 

Let me use an earthquake metaphor.

• The scale of disaster differs by country significantly
• The U.S. is experiencing an earthquake with an intensity of 7.
• Japan is experiencing an earthquake with an intensity of 1.
• There comes a massive solution to reduce the earthquake intensity by 90% at a cost of 0.1 intensity earthquake.
• The U.S. can reduce the earthquake intensity from 7 to 0.7 at the cost of 0.1.
• Japan can reduce the earthquake intensity from 1 to 0.1 at the cost of 0.1.

I think the vaccination worths trying for the U.S. but I don't know if it worths the risk and price in Japan.

It is better to be humble about an uncertain/unforeseeable future

Through this pandemic, I have read many medical papers and found that we don't know much about our immunity or viruses yet.

Do you know that inactivated influenza vaccination seems to increase the likelihood of catching common colds including the coronavirus one? I don't believe anyone developed inactivated influenza vaccine thought of this possibility when developing or doing trials.

Source: Increased Risk of Noninfluenza Respiratory Virus Infections Associated With Receipt of Inactivated Influenza Vaccine https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404712/

People are saying that those who don't take the new vaccines are illiterate or can't do the math. That may be true if nothing happens outside the trial scopes. It's also better to be humble about an uncertain/unforeseeable future. For example, what happens to "Factor X" of Japanese (or I would say "the BCG vaccination effect") after this vaccination? No one knows or tries to investigate.

As I am an entrepreneur, I like taking risks (and returns😀). The risks can be divided into foreseeable risks and unforeseeable uncertainty. I take an unforeseeable risk when there can be a high return.

Sources for the U.S. figures:

• https://covid.cdc.gov/covid-data-tracker/#demographics
• Though the site says "CDC | Updated: Jan 26, 2021, 12:16PM", the number seems to be a month old, maybe December numbers.
• https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/burden.html
• https://www2.census.gov/programs-surveys/demo/tables/age-and-sex/2019/age-sex-composition/2019gender_table1.xlsx

Sources and assumptions for Japan figures:

• https://toyokeizai.net/sp/visual/tko/covid19/
• https://www.populationpyramid.net/japan/
• Estimated infections are estimated using the ratio of cases to estimated infections in the U.S. as the positive rates of testing of both countries are in the same range.