Long before anybody understood anything about vaccination, it was noticed that, if people recovered from a disease, they didn’t get that particular disease again.

China in the 1500s

In the 1500s, the Chinese tried to prevent the deadly smallpox disease (which killed millions of people and is characterised by pus-filled blisters) by exposing uninfected people to the pus from the smallpox blisters (lesions). One method for doing this involved taking the pus and fluid from a lesion and using a needle to insert it under the skin of the healthy person to be protected. Sometimes a powder would be ground from the dried skin of the lesion, and this was either inhaled or injected straight into the person’s vein. This was known as variolation and is the earliest form of vaccination.

Turkey in the early 1700s

Mary Wortley Montagu, the wife of the British Ambassador to Turkey, observed variolation against smallpox in the early 1700s. She had the procedure administered to her two children, who recovered quickly.

Montagu brought the procedure back to England where the inoculation was trialled on condemned criminals. Once convinced that it worked, the royal family inoculated themselves, reassuring the English people it was safe. Although some people did die as a result of variolation, the overall effect was that the death rates from smallpox decreased.

England in the late 1700s

Perhaps the most famous person associated with vaccination is Edward Jenner (1749–1823). He experienced variolation as a child and survived. He went on to train as a doctor.

Jenner noticed that milkmaids (people who milked cows) who contracted cowpox from cows (similar to but less serious than smallpox) never contracted smallpox. They seemed to know they were protected. One milkmaid told Jenner she wouldn’t get smallpox because she’d had cowpox.

In 1796, Jenner decide to test the theory. Jenner took some infected cowpox matter and inserted it into a cut in a young boy’s arm. After the boy recovered from the cowpox illness, Jenner intentionally infected him with smallpox by injecting pus from a smallpox lesion directly under his skin. The boy remained healthy, and this became commonly known as the world’s first vaccine

The era of vaccinations

Jenner named his treatment vaccination – ‘vacca’ is the Latin word for cow. (Louis Pasteur – known for his work in causes and prevention of disease in 1800s – later adopted the word vaccination to mean immunisation against any disease). Initially, Jenner’s study was rejected. However, in time, it became clear that Jenner was right and soon thousands of people protected themselves from the deadly smallpox by intentionally infecting themselves with cowpox. Jenner is now credited as the Father of Immunology

The world’s last known case of naturally occurring smallpox was in 1977. The disease has since been eliminated from natural occurrences in the world, so the vaccine is no longer given. The smallpox virus is now only found in freezers in high-containment laboratories at the Centers for Disease Control and Prevention (CDC), Atlanta, in the United States and the State Research Center of Virology and Biotechnology VECTOR in Koltsovo, Russia.

Smallpox is the only major human disease to have been eradicated. Vaccinations for many different diseases are now commonplace. Children receive multiple vaccines. The result of vaccines has been a decrease in diseases across the globe.

Nature of Science

Some of the early scientific experiments (such as Jenner infecting a healthy boy with smallpox) would not be allowed today, yet it was often through these unorthodox methods that science advanced. It took time for Jenner’s ideas to be accepted.

Useful links

Cartoon version of the story of Edward Jenner.

    Published 2 November 2010