Cowpox to the mild form of smallpox and the observation that dairy farmers were immune from smallpox inspired the first smallpox vaccine, created and administered by English physician Edward Jenner. The word “vaccination,” coined by Jenner in 1796, is derived from the Latin root "vaccinus", meaning of or from the cow. Once vaccinated, a patient develops antibodies that make them immune to cowpox, but they also develop immunity to the smallpox virus, or "Variola virus". The cowpox vaccinations and later incarnations proved so successful that in 1980, the World Health Organization announced that smallpox was the first disease to be eradicated
Smallpox vaccine in Somalia, in October 1977. A Global Commission for the Certification of Smallpox Eradication chaired by Frank Fenner examined the evidence from, and visited where necessary, all countries where smallpox had been endemic. In December 1979 they concluded that smallpox had been eradicated; a conclusion endorsed by the WHO General Assembly in May 1980. However, even as the disease was being eradicated there still remained stocks of smallpox virus in many laboratories. Accelerated by two cases of smallpox in 1978, one fatal (Janet Parker), caused by an accidental and unexplained containment breach at a laboratory at the University of Birmingham