Vaccination is a hot-button issue – and that's not a new thing. By the 18th century, smallpox was a disease that had been ravaging Europe for centuries, and a man named Edward Jenner set out to eradicate the deadly disease that killed one third of its victims.
In 1796, Edward Jenner, a country doctor, discovered a way to vaccinate (a term he himself coined) people against smallpox using the cowpox virus, a disease found in cows that could be transferred to humans – but that was much less harmful than smallpox. Jenner's cowpox vaccine and his insistence on the powers of the vaccination, despite ridicule from others (similar to the anti-vaxxer movement today), led to the complete eradication of smallpox in Europe.
On May 14, 1796, Edward Jenner injected an eight-year-old boy with cowpox he took from lesions on a milkmaid's hand. Jenner's test didn't just come to him from out of the blue; he knew that dairymaids seemed to be protected from smallpox, and he theorized that their near-constant exposure to cowpox must be the reason for this. The boy, James Phipps, developed a slight fever and discomfort, and after a week's time, he felt cold and had lost his appetite. It was a small price to pay for immunity to a deadly disease. Two months later, when Jenner bravely (or foolishly) injected Phipps with live smallpox, the boy did not contract the disease at all. He was entirely immune, and Jenner had laid the foundation for modern vaccination.
Jenner wasn't entirely sure why this worked, and in order to prove it wasn't a fluke, he continued his experiments... on more children.
Before vaccination, people protected themselves against smallpox using a method called inoculation. This involved placing pus from the disease into a small cut on the limb of someone not immune to smallpox – they would get a less lethal form of the disease and then be immune to it going forward. Inoculation, also known as variolation, was practiced all over the world, and in the 18th century, an aristocrat named Lady Mary Wortley Montague became responsible for introducing the practice to England.
In 1715, Lady Montague came down with a mild case of smallpox, which permanently scarred her once beautiful face. When, on a trip to Istanbul with her husband, she noticed the use of variolation at the Ottoman Court, she decided to inoculate her five-year-old son in Istanbul. She did so to her four-year-old daughter years later in front of the court physicians back in England.
After numerous tests on prisoners and orphans (because this was 18th century England, after all), the practice was deemed safe and soon spread rapidly across Europe.
On the surface, inoculation and vaccination seem quite similar. They both involve infecting a healthy person with the disease they are trying to become immune to. However, the reason vaccination is much safer and more effective than inoculation has to do with the disease you are infecting a person with.
Inoculation involved infecting the patient with actual smallpox, usually by rubbing powdered smallpox scabs or pus from a smallpox pustule into a small scratch made on the healthy person's skin. The person would then develop a less-severe disease, and henceforth be immune to smallpox. However, inoculation came with the danger of the patient actually developing full-blown smallpox, or other transmittable diseases such as syphilis.
Vaccination, on the other hand, involved injecting a patient with a completely different disease than the one they were trying to protect against. Jenner discovered cowpox provided complete immunity against smallpox.
One of the most well known traits of smallpox was that, if you were lucky enough to survive getting the disease, you were completely immune for the rest of your life. In 11th-century China, people inoculated others by blowing the dust from a smallpox scab up the nose of a healthy patient. As early as 430 BCE, smallpox survivors were the ones who nursed the newly infected. Before it reached Europe in the 18th century, inoculation was practiced in Africa, India, and China, proving that the disease truly was a worldwide epidemic.