Vaccines have a humble beginning. Smallpox was the first infection that people tried to prevent. For more than a thousand years, the Chinese practiced an ancient form of vaccination by first grinding up the scabs from a person infected with smallpox, then blowing the powder into the nose of an unexposed individual.

This practice is called variolation, and it originated from the observation that people who survived a previous smallpox infection somehow become resistant to getting the infection again. It was thought that by artificially infecting an unaffected person, the process could protect the individual from smallpox.

Ancient Chinese documents show that variolation was practiced in the Song dynasty in China (ad 960 to 1279). Legend has it that the Song emperor had lost his eldest son to smallpox, so he traveled deep into the forest of a high mountain and sought help from a reclusive nun. The woman was known as a holy healer, and she passed on the technique of variolation to save the ancient Chinese royal family.

The germ theory was unknown at the time when variolation was first invented, so the process of variolation was invented purely based on the intuition of a few observant people. However, the practice was not without risk. Virtually everyone variolated came down with a high fever. Getting variolated was a gamble.

The technique of variolation was passed on from ancient China to India and eventually made its way to the Middle East. The procedure was modified after hundreds of years, and the Turks practiced an alternative form of variolation. The Turkish procedure involved making a small cut on the skin and rubbing the drainage from a pustule of a person infected with smallpox into the small cut. Similar to the Chinese variolation process, the inoculated person would often get sick but almost always recovered with a lifelong immunity against smallpox.

Lady Mary Wortley Montagu was an English aristocrat who married a diplomat to Istanbul. She was famous for her extraordinary beauty and sharp wit, until her flawless facial features were tarnished by a bout with smallpox. Her brother also died from smallpox. She was the person credited for bringing the practice of variolation from the Middle East to Europe.

While living in Turkey with her husband, she witnessed the local Turks variolating each other to avoid getting the smallpox infection. She was impressed by the protective effect of variolation, and she had her five-year-old son and four-year-old daughter inoculated. Being a prominent figure in the political arena, she introduced the practice of variolation to the political elites back in Europe. When a smallpox epidemic swept through England, the royal family became anxious, but they were also hesitant to get variolated because it was such an unorthodox procedure.

To reassure themselves that the procedure was safe enough, they offered prisoners facing the death sentence a chance at redemption if they volunteered to receive variolation. Six prisoners offered to be guinea pigs for this medical experiment, and they all survived the variolation procedure. In addition, they did not get the smallpox infection when they were intentionally exposed to victims of smallpox.

After witnessing such success with variolation, the royal family was convinced and had their children variolated against smallpox. The royal family escaped the wrath of smallpox unscathed.

Ironically, the medical establishment at the time was the primary and most vocal opponent of variolation. It was an untested procedure, and it involved intentionally making healthy people sick. It was also well known that people died from variolation, and variolation was illegal in the American colonies. Only a few maverick doctors were brave enough to variolate people, and these doctors faced death threats from early vaccine opponents.

When variolation was first introduced during the smallpox epidemic of 1721 in Boston, it was viewed with skepticism and fear. Many in the Puritan town viewed the smallpox outbreak as divine judgment, and it would be heresy to thwart the will of God. People also feared the procedure, and with good reason, because the technique at the time — rubbing the pus from an infected person into a small cut on the arm or leg of a healthy individual — was indeed barbaric and crude. Finally, people had gotten extremely sick and even died from variolation, and the variolated person could transmit smallpox to other unvariolated people. There was good reason for people to hesitate about getting variolated.

While the controversy was brewing in the American colonies, Edward Jenner, an English physician, vastly reduced the side effects and danger of variolation by introducing the first modern vaccine. While working as an apprentice surgeon in rural England, he made the observation that while smallpox seemed to be rampant in the countryside, milkmaids generally were unaffected by this common infection. In fact, milkmaids were known for their uncanny fair complexion because their countenance was spared the scars of smallpox infections.

Dr. Jenner also realized that milkmaids were frequently afflicted with another condition called cowpox. This disease was uncommon in the general public, but it looked like a milder form of smallpox. In contrast with smallpox infection, cowpox infection did not leave its victim permanently scarred, and death was extremely rare. From these observations, Dr. Jenner hypothesized that by working closely with cows, milkmaids unintentionally became immune to smallpox infection by getting the cowpox infection first. He was also aware of the practice of variolation, and he subsequently derived his own technique of variolation.

Instead of using the pus or scab from a smallpox victim, he used material isolated from people infected with cowpox, a related infection that isn't nearly as deadly. When the body is exposed to cowpox, he surmised that the body then develops immunity against smallpox as well because the germ causing cowpox is so similar to smallpox. This practice is now known as vaccination, which is a significant improvement to variolation because the risks of serious side effects from smallpox vaccination are much smaller than smallpox variolation.

When Dr. Jenner first proposed the new technique of vaccination, his research paper went largely unnoticed. In fact, many of his colleagues ridiculed him for coming up with such a ludicrous idea of employing “alternative” medicine that originated from the Orient and Middle East. Cartoonists lampooned him and the process of vaccination, drawing caricatures of vaccinated individuals as having horns and hooves like cows.

To convince the public, he successfully performed the procedure on an eight-year-old boy named James Phipps. The material was isolated from the blisters of a milkmaid who had caught cowpox. Following his vaccination, James escaped an outbreak of smallpox in his town completely unaffected while other children perished. After his proven success with the vaccine, Dr. Jenner vaccinated his own son with the cowpox vaccine.

Beginning of Mass Immunization

By the late 1800s, Jenner's smallpox vaccine was more or less accepted by the public. A hundred years of experience using the vaccine had shown that vaccination can be safe and effective, but only the privileged few could afford vaccination. Smallpox outbreaks still occurred because the majority of the population was not vaccinated.

Scientists at the turn of the century were beginning to understand that germs were responsible for infectious diseases. A renewed effort saw the invention of additional vaccines to fight rampant outbreaks of diphtheria and whooping cough. At the time, diphtheria wreaked havoc in the communities, and the only treatment available was using antitoxin to combat the poison released by this bacteria.

The treatment was wrought with problems, even though it was quite effective in saving lives. The antitoxin was derived from horse serum. Consequently, many children who received the antitoxin serum developed severe and sometimes life-threatening allergic reactions. A better way was to prevent the infection in the first place rather than subject sick people to a dangerous treatment. As a result of this effort, the diphtheria vaccine was developed.

Shortly after the invention of the diphtheria vaccine, the tetanus vaccine became available, which was followed by the whooping cough vaccine. These vaccines were an important part of the war effort during World War II, and routine vaccination of soldiers played a major role in reducing casualties on the battlefield. The tetanus vaccine played an especially important role in reducing deaths from battle wounds.

During World War I, the leading cause of death from combat was tetanus. Even a relatively minor cut could trigger this almost fatal infection. Compared to the millions that perished from tetanus during the First World War, less than a handful died from tetanus during the Second World War. The difference was the tetanus vaccine.

HISTORICAL TIMELINE FOR CHILDHOOD IMMUNIZATION:

• 1796 - first vaccine for smallpox (no longer used in children)

• 1924 - first vaccine for tetanus

• 1924 - first vaccine for diphtheria

• 1926 - first vaccine for pertussis (whooping cough)

• 1945 - first vaccine for influenza

• 1954 - first vaccine for polio (injected Salk vaccine)

• 1964 - first vaccine for measles

• 1967 - first vaccine for mumps

• 1970 - first vaccine for rubella

• 1974 - first vaccine for chickenpox

• 1977 - first vaccine for pneumonia (Streptococcus pneumoniae)

• 1978 - first vaccine for meningitis (Neisseria meningitidis)

• 1981 - first vaccine for hepatitis B

• 1985 - first vaccine for Haemophilus influenzae type b (Hib)

• 1992 - first vaccine for hepatitis A

• 1998 - first vaccine for rotavirus

• 2006 - first vaccine for the human papilloma virus

The 1970s and 1980s witnessed an explosion in the development of new vaccines. Vaccines against measles, mumps, and rubella (German measles) came around in the 1970s, and the meningitis and hepatitis B vaccines rolled out in the 1980s. The introduction of so many vaccines in such a short period of time triggered much controversy. While scientists were busy coming up with new vaccines, the public felt overwhelmed and a backlash against the medical community ensued. Even though it was not the first time community activists took up arms against vaccination, it would later prove to be one of the most vocal and formidable social movements of our time.