Smallpox was a serious, contagious infectious disease caused by the Variola virus, which in some cases could lead to death. There was no treatment for smallpox, and the only preventive measures were inoculation or vaccination.

The name "smallpox" comes from the Latin word variŭs (meaning varied or spotted).

According to the World Health Organization (WHO), smallpox has been completely eradicated, making it one of only two diseases, alongside rinderpest, to be fully eradicated by humans.

It is believed that smallpox appeared in human populations around 10,000 B.C.

The mortality rate of smallpox could reach as high as 30% of infected patients.

Smallpox was highly devastating in 18th-century Europe, killing millions of people.

Smallpox is classified into two forms:

• Major smallpox
• Minor smallpox

The disease was transmitted through direct and prolonged contact, face-to-face. It could also be spread through infected bodily fluids or contaminated objects, such as sheets, pillowcases, or clothing.