World Immunization Day | Why is the best medicine in the human body?

Do you have any medicine?

Capsules, fish oil, melatonin, liver protection pills, swallow a few "tendon and bone strengthening" pills for breakfast, supplement a dose of "all-round nutrients" for lunch, and fall asleep with "sleeping pills" at night... These health products that are popular among young and middle-aged people today may all do more harm than good - because all medicines are poisonous.

Some doctors may tell you who are in sub-health: "I have no medicine, to be honest. The best "medicine" is in your body, which is the human immune system."

The story of the immune system

We have to start from 100 years ago in 1918. A global flu infected one-third of the world's population in two years, killing at least 30 million people. Faced with this disaster, the human immune system failed miserably.

So, what exactly is the immune system? It is the body's loyal guardian, patrolling the body day and night. Once it finds foreign matter such as bacteria and viruses, it immediately starts fighting. Neutrophils, macrophages and other immune cells will try their best to devour foreigners. This process is called "nonspecific immunity." At this time, the immune cells do not know what kind of virus they are fighting.

This kind of battle is like a chaotic war, sometimes you can win, sometimes you can't. At this time, you need to activate "specific immunity" through "reinforcement" to let B cells and T cells come to support. B cells can differentiate into effector B cells, produce antibodies, mark viruses, and let other immune cells concentrate their firepower to attack virus-infected cells. The "killer T cells" in T cells secrete "perforin", which causes the infected cells to perforate and die, thereby eliminating the virus inside.

Not only that, B cells can also differentiate into memory cells to remember the invading virus. If the virus returns, the memory cells will quickly differentiate into effector B cells, produce antibodies, and launch a fierce attack in advance.

The birth of vaccines

After understanding the working principles of the immune system, humans began to think: Is it possible for the human body to directly initiate specific immunity and nip the danger in the bud?

That’s the story of vaccines.

The first time people used this principle to form a vaccine was to fight against the smallpox virus. Doctors took serum from the pox of cows infected with cowpox or patients infected with cowpox and inoculated it under the forearm of healthy people to prevent smallpox. The serum contained a large amount of smallpox virus, which infected healthy people through skin contact, thereby triggering an immune response. Because the patient's immune system is also at work, the activity of the virus is low, which can both evoke specific immunity and not be fatal.

Later, scientists improved this method and made safer vaccines. Today's vaccines include attenuated vaccines and inactivated vaccines. Inactivated vaccines are made with inactivated viruses that can still cause an immune response after being injected into the body. Attenuated vaccines reduce the activity of the virus and make vaccines.

The importance of strengthening immunity

It has become common sense to use vaccines to strengthen one's own immune system. People will take the initiative to get vaccinated during the peak period of influenza. The genes of influenza viruses are very easy to mutate. Although they are all influenza viruses, the antigenic determinants on the surface have also changed. Therefore, influenza vaccines are not a one-time solution and need to be selected according to the specific type of prevalent virus.

December 15th of every year is World Immunization Day. This day was originally established by the United Nations to eradicate polio, and later gradually developed into an important day to remind people to strengthen immunization.

In recent years, my country has made great progress in strengthening the immunity of its citizens. For example, since 2010, the country has called on children of appropriate age to be vaccinated against measles, and through the establishment of an information management system for children's vaccination, the incidence of measles in the country has continued to decline. At the same time, through methods such as the popularization of vaccines, my country has successfully reduced the prevalence of hepatitis B virus. From 1992 to 2019, China has prevented about 50 million cases of chronic hepatitis B virus infection.

It can be seen that vaccines are the number one contributor to enhanced immunity.

However, vaccines alone are not enough for individuals. We need to improve our immunity in our daily lives to resist various pathogenic bacteria or viruses.

How to improve immunity?

There are many ways to enhance immunity, such as a reasonable diet, adequate sleep, and moderate exercise...

Finally, don't forget your mental health. No matter how stressed you are, you must learn to relieve it. When you are stressed, your immune system will be under even greater pressure. Remember, our weak spot is our immune system, which is the best "medicine" we carry with us to defeat diseases.

This article is a work supported by the Science Popularization China Creation Cultivation Program

Author: Dongdongmiao Popular Science

Reviewer: Tao Ning, Associate Researcher, Institute of Biophysics, Chinese Academy of Sciences

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.