Short answers, pulled from the story.
The World Health Organization certified the global eradication of smallpox in 1980, with a commission of scientists certifying it on the 9th of December 1979 and the World Health Assembly endorsing it on the 8th of May 1980. It is the only human disease to have been eradicated.
Smallpox began with fever and vomiting, followed by ulcers in the mouth and a skin rash. The rash turned into fluid-filled blisters with a dent in the center, which scabbed over and fell off, leaving scars, and some survivors were left blind.
Smallpox had a risk of death of about 30 percent, with higher rates among babies. The hemorrhagic and flat forms were nearly always fatal, while the milder variola minor killed about 1 percent or less of those infected.
The last naturally occurring case of indigenous smallpox was diagnosed in Ali Maow Maalin, a hospital cook in Merca, Somalia, on the 26th of October 1977. The final fatal case occurred in 1978 in a laboratory in the United Kingdom, where medical photographer Janet Parker died on the 11th of September 1978.
In 1796, Edward Jenner, a doctor in Berkeley, Gloucestershire, introduced the modern smallpox vaccine after discovering that material from a cowpox lesion produced immunity. He named the material vaccine, from vacca, the Latin word for cow.
Smallpox was eradicated through a WHO campaign that intensified in 1967 using ring vaccination, which isolated each outbreak and vaccinated everyone nearby. It succeeded because humans were the only reservoir for the virus and no asymptomatic carrier state existed.
Two live samples of variola major virus remain, one at the CDC in Atlanta and one at the Vector Institute in Koltsovo, Russia. Research with them is tightly controlled and each proposal must be approved by the WHO and the World Health Assembly.