Smallpox is a disease caused by a pox virus that is transmitted from person to person that causes high fever, and rashes, and may kill about one-third of those infected. Smallpox (also called variola) is the only disease that has been completely wiped out throughout the world.

The origin of smallpox is unknown. The finding of smallpox-like rashes on Egyptian mummies suggests that smallpox has existed for almost  3,000 years. The earliest written description of a disease like smallpox appeared in China in the 4th century CE. Early written descriptions also appeared in India in the 7th century.

An estimated 300 million people died from smallpox in the 20th century alone. This virulent disease, which kills a third of those it infects, is known to have coexisted with human beings for thousands of years.

In 1777, people used a method called Variolation to achieve immunity from the virus. It was a method where the blisters of an infected person would be cut open and whatever puss like fluid came out, would be dried, powdered and put into a cut on the arm of a healthy person. This gave them a less potent form of the virus which made it easier for their body to fight against it. Since smallpox was contagious, anyone who had been variolated, had to be quarantined so that he/she didn’t spread it. This method was flawed as, not only could the patient die from the procedure but the mild form of the disease which the patient contracted could spread, causing an epidemic. Victims of variolation could be found at all levels of society; King George III lost a son to the procedure as did many others.

In 1796, a young boy named Edward Jenner heard something from a group of milkmaids which stuck with him forever. They were speaking about how they were affected by cowpox so they were now immune to smallpox. When he grew up, he created the first vaccination in the world by thinking about what the milkmaids said. He realized that cowpox wasn't as virulent as smallpox and someone who got cowpox can’t get smallpox. He used a similar method to variolation but used cowpox instead of smallpox in order to vaccinate people. He called it Variolae vaccinae which meant smallpox of the cow.

Although his method worked, many people objected to it. People in India believed it was unholy because it would require them to take it from a cow, which Hindus consider holy animals. Some people weren't able to execute the procedure properly due to contamination and people got other diseases while getting vaccinated. Many people believed that the process of  vaccination was flawed whereas it was just not performed in a clean and safe environment.

After many protests against vaccination, eventually in 1959, the WHO (world health organisation) created a plan to completely eradicate smallpox from the world. They provided vaccines to people throughout the world and eventually by 1980, smallpox became the 1st disease to be completely eradicated from the world.