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Culture & Society
On May 8, 1980, the WHO declared smallpox eradicated, ending a disease that killed 300 million in the 20th century alone.
On May 8, 1980, the World Health Organization officially declared smallpox eradicated—a disease that had plagued humanity for 3,000 years and killed an estimated 300 million people in the 20th century alone. It remains the only human infectious disease ever completely wiped out.
Two virus strains cause smallpox: Variola major, the deadlier form with fatality rates between 20% and 40% (reaching 90% in severe outbreaks), and Variola minor, with a 1% to 3% death rate. Symptoms include fever, headache, lower back and limb pain, vomiting, and a distinctive rash on the skin and mucous membranes. Survivors often bear permanent pitted scars known as pockmarks.
The virus spreads through airborne droplets from coughing, sneezing, or talking, as well as direct contact with contaminated surfaces like bedding and clothing. Incubation typically lasts 8 to 14 days but can extend to 19. In the 20th century alone, smallpox killed between 300 and 500 million people worldwide. Roughly half of survivors suffered vision problems, sometimes leading to total blindness, and most retained extensive scarring.
Evidence suggests smallpox may have killed several rulers of ancient Egypt during the New Kingdom period (16th to 11th centuries BCE), as distinctive lesions appear on the skin of some mummies. In the 16th century, the disease reached the Americas from Europe, wiping out millions of indigenous people and annihilating entire tribes.
In 1796, English physician Edward Jenner demonstrated that infection with cowpox—a similar but milder virus—conferred natural immunity to smallpox. The global eradication program began in 1958 when the World Health Assembly adopted a resolution initiated by the Soviet Union. By 1936, the USSR had already eliminated smallpox within its borders through mandatory vaccination and regular revaccination.
The last naturally occurring case was recorded in Somalia in 1977. In December 1979, scientists concluded the disease had been fully eradicated, and the World Health Assembly officially confirmed this at its 33rd session in May 1980.
Among history's worst smallpox epidemics: an 8th-century outbreak killed up to one-third of Japan's population. Another, following the Franco-Prussian War (1870–1875), claimed 500,000 lives as the virus spread from French prisoners of war to civilians in Germany and beyond. In India, between 1868 and 1907, roughly 4.7 million people died; from 1926 to 1930, 979,738 cases were reported with a 42.3% fatality rate.
Today, smallpox virus survives only in two high-security laboratories: the State Research Center of Virology and Biotechnology in Novosibirsk, Russia, and the U.S. Centers for Disease Control and Prevention in Atlanta, Georgia.
