How was vaccinia invented

 　　Many adults have two or three circular or tic-tac-toe scars on the outside of their upper arms. This is the mark of vaccination to prevent smallpox.

　　Smallpox is a severe infectious disease caused by the smallpox virus (a type of poxvirus) infecting people. It is one of the oldest infectious diseases with the highest mortality rate. It has raged for more than 3,000 years and caused hundreds of millions of deaths. During the 100 years of the pandemic in the 18th century, 150 million people died of smallpox in Europe. The patients who survived by chance often leave permanent scars because of the abundant sebaceous glands on their faces that are invaded by the smallpox virus, commonly known as "numb face", and smallpox is also named after. This is a severe infectious disease with a fatality rate of more than 30%. It is called by historians "the largest genocide in human history". According to legend, the emperors of Shunzhi and Tongzhi of the Qing Dynasty died of smallpox, and the Emperor Kangxi had pockmarked his face due to smallpox.

　　For thousands of years, in the struggle against smallpox, humans have gradually discovered and mastered methods to treat and prevent smallpox. As early as the Tang Dynasty more than 1,000 years ago, the king of medicine Sun Simiao proposed the method of fighting poison with poison. He took the pus from the sore of the smallpox patient and applied the pus to the skin to prevent smallpox. But at the time it was difficult for people to accept it, and for fear of hiding, how could they still actively infect it? It was not until the Ming Dynasty that this kind of human pox vaccination was gradually accepted and became popular. In the Qing Dynasty, under the impetus of Emperor Kangxi, it was widely promoted. In 1742, the Qing government also ordered people to compile a large-scale medical series "Jinjian Jinjian: Essentials of the Heart Vaccination Method of Juvenile Vaccination", which introduced 4 methods of vaccination. The vaccination technique for vaccinia prevented the spread of smallpox in China to a certain extent. This method has also spread to Asian countries and Europe. However, the human pox vaccine, which is difficult to preserve, often fails during vaccination and may even become a source of infection and spread. In 1762, the smallpox outbreak in Paris originated from this. Human pox vaccination allows people to see the light at the same time, but it is also accompanied by danger; the haze is still looming.

　　It was not until the medical observations and experiments of the English country doctor Edward Jenner (1749-1823) that the eradication of smallpox led to the right path.

　　Around 1760, in the town of Thornbury, Gloucestershire, England, the milkmaid was hardly infected with smallpox. It was a "secret" that everyone knew, but no one was inquiring into the cause. While practicing medicine, Jenner investigated this phenomenon in depth and found that all milkmaid workers had been infected with cowpox (a relatively harmless pox virus in livestock). Inspired by this, he judged that the milkmaid had acquired immunity to smallpox virus because of vaccinia, and vaccinia might be able to prevent smallpox infection. In addition, Jenner's neighbor, the host, had smallpox, and the patient's wife was unable to take care of the patient because she had never had smallpox, so she hired a milkmaid to help take care of it. One month later, the neighbor recovered and the female worker did not get sick. This case strengthened his inference.

　　After more than ten years of careful research, Jenner began to experiment. On May 17, 1796, Jenner took a small amount of vaccinia herpes pus from the hand of the cowpox milking girl Nimes, then cut the arm of the 8-year-old boy James, and dripped the pus on the cut wound by James Vaccinated with vaccinia virus. Later, James developed a typical cowpox on the inoculation site of his arm. Six weeks later, Jenner inoculated James with smallpox pus again. After the observation period of more than 20 days, James was still alive and healthy. There was no sign of smallpox infection, which proved that he had developed immunity to smallpox.

　　This is the first time that humans have been vaccinated with vaccinia through a human trial, which proves that vaccinations can make people immune to variola virus. Jenner then conducted extensive experiments to prove that vaccination against smallpox can indeed prevent smallpox and is very safe. From then on, "Jenner's method of vaccination" was born, which is the famous "Vaccinium method". Napoleon called Jenner a "great man", respected him, and built a statue for him.

　　Cowpox vaccination gradually replaced the original human pox vaccination, which is safer and has less impact on the human body. Since then, a vaccinia mark has been added to human arms. As a result, Jenner created a new discipline for mankind-immunology, so he was called the "father of immunology." In China, the technique of vaccinia vaccination was introduced by British doctor Pearson in 1805. It began to spread in Guangzhou and gradually spread to other provinces.

　　Smallpox is the first infectious disease completely eliminated by humans. In 1977, the last naturally occurring smallpox patient on the planet was cured in Somalia. For this reason, on October 26, 1979, the World Health Organization officially announced that smallpox had been completely eliminated all over the world. This is the most glorious result achieved by human beings in the struggle against infectious diseases.