Smallpox, one of the most devastating diseases known to humanity, is a serious infectious disease caused by the variola virus. People who contracted smallpox developed a fever and a distinctive, progressive skin rash.
Most individuals who had smallpox recovered, however, about three out of 10 people with the illness died. Many survivors of smallpox had permanent scars over large areas of their bodies, particularly their faces. Some were also left blind.
Thanks to the success of vaccination, smallpox has been eradicated, and there have been no naturally occurring cases since 1977, with the World Health Assembly declaring the disease eradicated in 1980.
A person with smallpox goes through several stages as the disease progresses.Early symptoms include a sudden high fever, fatigue, severe back pain, and, less often, abdominal pain, and vomiting. Two to three days later, a widespread rash appears, starting on the face and hands before spreading to the rest of the body. The rash fills with pus, then a crust forms and eventually falls off.
About three out of 10 people with the disease died. Many people who survived smallpox were left with permanent scarring, especially on their faces, and some were left blind.
Human to human transmission of the virus occurs by inhalation of airborne droplets of saliva from an infected person. It mainly spread through close face-to-face contact with an infected person, or by contaminated clothing and bedding. Around 60 per cent of those who lived with a smallpox patient were likely to become infected.
Smallpox is a human disease and there is no evidence that it can be spread by insects or animals.
While some antiviral drugs may help treat smallpox disease, there is no treatment for smallpox that has been tested in people who are sick with the disease and proven effective. When smallpox was at its height the main treatment was cleaning wounds and reducing pain.
The only way to prevent and eradicate smallpox was via the vaccine, developed by British scientist Edward Jenner in 1796. Hearing that cowpox protected against smallpox he inoculated eight-year-old James Phipps with material from a cowpox sore from a milkmaid. He then twice exposed the boy to smallpox and he remained healthy. The vaccine was developed and then used to eradicate the disease.
Smallpox is believed to have originated at least 3,000 years ago, but its exact origins are unknown. Over thousands of years, smallpox killed hundreds of millions of people – 300 million of those deaths occurred in the 20th century alone. It was eradicated in Europe and the United States by the beginning of the 1900s but was still endemic in the rest of the world.
In 1967 the World Health Organization launched an eradication programme concentrating on countries hardest hit. Efforts included disease surveillance, case finding, contact tracing and mass communication campaigns – as well as vaccination. It was a joint effort led by the United States and Soviet Union at a time when the two superpowers were locked in the Cold War.
The last natural case of smallpox occurred in Somalia in 1977. However, the last ever victim was Janet Parker, a medical photographer in Birmingham, who died in 1978 after being infected in a laboratory accident.
Because of fears over the development of smallpox as a bioweapon, there are only two labs in the world that are approved to hold smallpox virus for research – the Centers for Disease Control and Prevention in the US and the Russian State Centre for Research on Virology and Biotechnology. Today the smallpox vaccine is used in the control of mpox as the two diseases are closely related.
who.int/history-of-smallpox-vaccination
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