Extra edition2: Immunity

April 10, 2020

Continuing from the previous article, I would like to write about this blog about Covid-19, a new coronavirus. Covid-19 is now rampant on a global scale. As of April 9, the number of infected people worldwide has risen to about 1.5 million and the number of fatalities has reached 86,000. For those who have died unfortunately because of this virus, I would like to first give my deepest sympathies. And I would like to express my sincere respect to those who are dedicated to medical work day and night. Meanwhile, on the economic front, the situation is rapidly becoming more serious, damaging countries all over the world, surpassing the Lehman Shock. The chain of closure, bankruptcy and unemployment is expanding all over the world.

The last time I wrote a blog on March 16, the number of infected people worldwide was about 170,000 at the time, an increase of nearly nine times in just three weeks. The situation in Europe is particularly severe, and the number of infected people is increasing rapidly not only in Italy but also in countries other than Western Europe. In five major countries in Italy, Spain, Germany, France and the UK, the number of infected people was 12 times, about 44,000, and the number of fatalities was slightly more than 2,000, 23 times as many as 52,000. It is jumping. And, as predicted last time, the epidemic also spread to the United States, where the number of infected people, which was less than 2,000, has risen to nearly 400,000, and the number of fatalities has risen to more than 12,000.

In the meantime, the number of infected people in Japan increased from 814 to 4,768, and the number of fatalities increased from 24 to 85. It is true that it is increasing, but it is clearly different from other regions. The rapid expansion like in the United States and Europe has not occurred. Of course, we should stay alert. We don't know what will happen to Japan in the future. There is no guarantee that the rapid spread of infected people like in the West will not occur. The Japanese government has also issued a “Japanese style lockdown” under the name of “Emergency Declaration”, calling out to the public for avoiding unnecessary going out, recommending telework, refraining from sales at restaurant and bar, and social distancing, and increasing caution against the spread of infection.

A frequently cited issue recently is the Spanish flu that occurred about 100 years ago. The worst pandemic in history, said to have occurred in an American army camp, infected 500 million people, or about 30 percent of the world's population at that time, and killed 40 to 50 million people, close to 10% fatality rate. In Japan, 23 million people have been infected and 380,000 have died, which means the fatality rate was 1.7%, relatively low compared to other countries. Japan's low fatality rate is the same for Covid-19, which is 1.8% as of April 9th, while the rate was 6% worldwide and nearly 10% in Europe.

So why is Japan the only one with a relatively low fatality rate each time? What is the difference between Japan and other countries? And what is common at the time of the Spanish flu and now in Japan?

It is often called BCG, a vaccine for tuberculosis. Most Japanese have been inoculated with BCG to prevent tuberculosis when they were young. Some may say that it is also effective for Covid-19. Certainly, this time Covid-19 may be effective. However, 100 years before the Spanish flu outbreak, no BCG was available and tuberculosis was still an incurable disease for the common people. Therefore, BCG is not common to the Spanish flu. I think there are two major factors that have reduced the spread of infection during and after the Spanish cold. One is Japanese customs and behaviors, and the other is the spread of masks.

Japanese do not usually shake hands and hug, even if the government does not declare an emergency. They don't always talk face-to-face with each other, and rarely talk on the train. They are generally less sociable than Westerners. Whether the virus is present or not, wash their hands when they return from the outside. Even if they are outside, hand washing is indispensable in the toilet etc. This accumulation of habits and behaviors backed by introverted Japanese characteristics has helped prevent Covid-19 this time.

The other is wearing masks that have become very popular among Japanese people at the time of the Spanish flu. Whether corona is popular or not, half of the Japanese are wearing masks when they go outside, especially in winter. Recently, there has been momentum to reconsider masks in Europe and the United States, but in the United States and Europe, masks have not been encouraged for a long time, and many individuals have disliked masks at the individual level. However, the mask should not only prevent infecting others, but also certainly contribute to prevention in the sense of preventing the splashing of the virus that jump from mouth, and whether there are many or few people wearing this in public. It greatly affects the scale of the spread. In any case, I believe that the Japanese habits mentioned above and masks have reduced the spread of infections in Japan.

But this does not explain Japan's low fatality rate. No matter how small the number of infected people is, if there are no differences in the characteristics of the infected people, the significant differences in mortality rates between regions cannot be explained. So what is that "some difference"? I think it is a difference in immunity.

In the process of infecting a person and causing the virus to invade the body's cells, causing it to die, the human body makes immune cells to resist the virus. If you can successfully repel, it will not develop. Never die. Immunity can be strengthened by eating and drinking as well as ample sleep and moderate exercise. Ingredients that help improve immunity are rapidly gaining attention thanks to Covid-19, but the leading strains are yogurt and honey. However, there was no such food in Japan at the time of the Spanish flu. At least they didn't get into the common people. On the contrary, they were far less nutritious and did not have a sufficient diet to boost their immunity. But at that time and now, I believe that something that Japanese people often drink have helped boost immunity, which food lacks. It is green tea.

I believe that catechins in green tea are effective against both Spanish flu and Covid-19. Catechin is also found in tea and coffee, but green tea has a much higher catechin content. Most Westerners do not drink green tea. The benefits of catechins are limited. More recently, an Indian scholar has published a report stating that catechins can be effective in treating Covid-19. Of course, that's just the claim of the scholar so far, and catechin hasn't definitely proved to work with Covid-19. However, if the difference in immunity leads to a difference in lethality, and if the difference in immunity is due to normal dietary habits, the hypothesis is the frequent consumption of green tea that Japanese people are reducing the lethality. Nobody can deny that. I really want people all over the world to drink green tea.

The Spanish flu had two major waves of infection from late 1918 to early 1920. The death rate was higher in every area than in the first time. It is thought to be due to a mutation in the virus. I just hope Covid-19 doesn't last as long as the Spanish flu, but it's wise to strengthen your immunity now so that it's okay if that happens. As mentioned earlier, it involves good sleep and moderate exercise, a balanced diet, and drinking green tea. I would strongly recommend that people around the world drink green tea every day. If you can't get it, ask me. If you send a signal from the inquiry page of this website, I want to find a way to get it as soon as possible. In general, the antiviral effect of tea has been demonstrated. However, no effect on Covid-19 has been demonstrated, but It is better to try what is generally good and be luckily saved than wait for the effect to be proven and be unhappy.