From Variolation to Vaccination: Humanity's Hard-Won Victory Over Smallpox

Smallpox was once an epidemic that swept across every country on earth; wave after wave of smallpox pandemics caused massive death tolls.

Smallpox is caused by the variola virus. Smallpox has existed in human history for a very long time; observations of the mummy of Pharaoh Ramses V, who died in 1156 BCE, suggest that Ramses V may have contracted smallpox in his lifetime.

Smallpox is a highly virulent infectious disease with a mortality rate as high as 80–90%; in regions with multiple outbreaks, mortality can still reach 15–30%. In the 2nd–3rd centuries CE, smallpox epidemics contributed to the decline of the Roman Empire. When Europeans discovered the New World, they brought the variola virus to the Americas; because indigenous American tribes had no immunity to smallpox, outbreaks caused near "genocidal" disasters, which was also an important reason Native Americans were defeated by invaders whose numbers were far smaller.

Smallpox was introduced into China around the 1st century CE, when China was at war with Western Regions states; prisoners of war from the Western Regions transmitted smallpox to China, which is why smallpox was initially called "captile sores" in China. It is also said that Ma Yuan brought smallpox into China during his southern campaign against Jiaozhi.

In ancient China smallpox was also called "pox rash" or "pox sores"; Chinese religions even had a "Pox Rash Goddess" and a "Pox God," and people prayed to deities to avoid smallpox. Smallpox killed not only ordinary people but also royalty and nobility; several European monarchs died of smallpox, and China's Emperor Kangxi also contracted it.

TCM has a large number of monographs on treating pox rashes, but these are now useless because smallpox is believed to have been completely eradicated. In May 1980, the WHO declared that humanity had completely defeated smallpox. Currently, live variola virus for research purposes is stored in only two laboratories, in the United States and Russia.

The weapon humanity used to defeat smallpox was the vaccine; it was precisely because of the smallpox vaccine that immunology arose in modern medicine.

The earliest smallpox vaccine appeared in China; at that time, vaccinating ordinary people against smallpox was called "planting pox," and there were专门的 "pox planters" who did it.

Some scholars believe that as early as the Kaiyuan period of the Tang dynasty, the Zhao clan in the Jiangnan region already had a method of variolation (Dong Yushan's

Niudou Xinshu

, published 1884). Other scholars record that during the Northern Song Zhenzong period, Wang Su, the young son of Prime Minister Wang Dan, was variolated by a "divine physician" from Mount Emei and never contracted smallpox thereafter (Zhu Chunxi's

Douzhen Linduan

, published 1713).

But the above accounts are isolated pieces of evidence; the more reliable account is that during the Longqing period of the Ming dynasty, when smallpox raged in Taiping County, Ningguo Prefecture, locals adopted variolation for immunization. Later, pox planting became a specialized profession, mostly practiced by people from Ningguo; in the late Qing there was even a dedicated Pox Planters' Bureau.

Early variolation involved pricking a smallpox pustule on the body of a patient who had recovered from smallpox, extracting some serous fluid, dipping a bit of cotton in it, and inserting it into the nostril of the recipient. The recipient would develop mild smallpox symptoms; most would develop immunity and not be infected during a smallpox outbreak. However, about 2% of recipients would contract smallpox from the procedure and die, so variolation was still a very risky undertaking. But during large smallpox epidemics, many were still willing to take the risk to avoid the plague.

The serum of recovered patients contains antitoxins; the virus in the pox sores of recovered patients was already equivalent to today's attenuated vaccine and could help recipients produce antibodies. Although this immunization method looks primitive today, it saved many lives in history.

Chinese variolation spread to other countries very early; as early as the 17th century, Japanese and Koreans learned variolation from the Chinese. The Japanese Ikeda Masatada, after learning variolation from the Chinese, established a specialized pox department in Japan, and his descendants practiced it as a family profession.

In 1688, Russian physicians came to Beijing to learn variolation; it then spread through Russia and onward to Turkey and Northern Europe. It was then brought to Britain by Lady Mary Wortley Montagu, wife of the British ambassador to Turkey, and from there spread across continental Europe.

However, when variolation first entered Europe it also caused great controversy; many Europeans did not believe in it. The British did not accept variolation until, more than forty years after learning of it, they were forced to during a smallpox outbreak — showing how difficult social prejudice is to overcome.

Later the English physician Edward Jenner accidentally discovered that milkmaids who had contracted cowpox did not contract human smallpox.

Jenner had previously given people human variolation; inspired by the Chinese method, he tried inoculating people with cowpox. The results showed that cowpox inoculation was a much safer and effective immunization method than variolation; almost no one died from cowpox inoculation.

In 1840, the British Parliament passed an act recognizing cowpox vaccine as the safer method of preventing smallpox, and human variolation was replaced by cowpox vaccination.

Of course, after the cowpox vaccine appeared, rumors spread through society: some said people vaccinated with cowpox might grow cow horns and their noses might turn into cow's noses. All sorts of rumors born of ignorance and prejudice hindered the spread of cowpox, but in the end fact triumphed over prejudice, and cowpox began to spread across Europe.

As cowpox spread through Europe, it also began to be introduced into China through some employees of the East India Company. The Englishman Pearson专门 wrote a Chinese-language book,

Yingjili Guo Xin Chu Zhongdou Qishu

, to teach Jenner's cowpox technique in China. But the Chinese were not receptive to this novelty. Pearson's Chinese assistant Qiu Xi, in order to make the Chinese accept cowpox, packaged the technique using traditional TCM theory and wrote a book called

Yindou Lüe

introducing cowpox vaccine; only then did cowpox gradually become accepted by the Chinese.

With the development of industrial civilization, cold-chain technology for smallpox vaccines also made breakthrough progress. In the late 1960s, coordinated by the WHO, countries around the world launched an all-out campaign against the variola virus. By October 1979, the WHO announced victory in that campaign in Kenya, Africa, and held a celebration ceremony.

In May 1980, the WHO formally declared that humanity had defeated the variola virus. To prevent its recurrence, 200 million doses of smallpox vaccine are currently stockpiled worldwide. American and Russian scientists are also observing and studying the natural evolution of the variola virus through laboratory samples, so that humanity will not be caught off guard if smallpox outbreaks again.

Humanity's victory over smallpox was hard-won, and its eradication greatly boosted human confidence. But not every virus can be defeated like smallpox; HIV has been discovered for 40 years, and despite billions of dollars invested in developing an AIDS vaccine, we have not succeeded. Like HIV, many of the viruses we have discovered still have no vaccine.

Meanwhile, dozens of new pathogenic microorganisms have appeared in recent years, and humanity has remained surrounded by all kinds of infectious diseases. Although our sanitary conditions have improved considerably, we are still far from defeating infectious diseases.

Because of ecological factors, the tropical rainforests of Africa, Yunnan in China, and the Ganges basin in India have been important foci of infection since ancient times. From time to time infectious diseases emerge in these places and then rapidly affect the whole world. These regions are relatively poor and backward, with poor sanitary conditions and weak public-health awareness, so weaknesses remain in preventing outbreaks.

Therefore, to defeat infectious diseases, we must first defeat poverty and backwardness and correct regional imbalances. Only by developing the economy and education can we raise the literacy of residents in backward areas and improve their living habits and sanitary conditions. These are major challenges for human society; we still have a long way to go before completely escaping infectious diseases.