On October 26th, 1977, a hospital cook in Somalia named Ali Maow Maalin was diagnosed with smallpox. What makes this so remarkable is that no naturally-occurring cases of smallpox have been diagnosed in the 32 years since.
The global eradication of smallpox was certified, based on intense verification activities in countries, by a commission of eminent scientists on 9 December 1979 and subsequently endorsed by the World Health Assembly on 8 May 1980 as Resolution WHA33.3. The first two sentences of the resolution read: “Having considered the development and results of the global program on smallpox eradication initiated by WHO in 1958 and intensified since 1967 … Declares solemnly that the world and its peoples have won freedom from smallpox, which was a most devastating disease sweeping in epidemic form through many countries since earliest time, leaving death, blindness and disfigurement in its wake and which only a decade ago was rampant in Africa, Asia and South America.”
Smallpox once killed millions of people every year, and may have been responsible for up to 500 million deaths in the 20th century. National vaccination programs began in the early 1800s, but it was a global push by the World Health Organization begun in 1958 that finally led to the eradication of the disease worldwide.