Despite various other 'pox' affecting a range of animals - many can be passed to humans: zoonosis - we (mankind) are the only known hosts of the variola virus. It has killed billions, literally, and is thought to have been the cause of death of 300 - 500 million people in the last century before eradication alone.
Recorded instances of variolation (innoculation with variola - smallpox) began as early as the 10th century through intranasal insufflation of dried crusts of smallpox lesions...hmmm, nice...enjoying your sandwich? In 18th-century Europe, brought to England by Lady Mary Wortley Montagu (oh yes!...not a commoner she) from her experiences in Turkey, the method consisted of subcutaneous injection of fluid from smallpox pustules or scabs (like some mustard on that sandwich?) Variolation caused a mild form of smallpox, but prevented more significant problems...like death. There was a certain amount of prejudice from the medical world despite Lady Mary having her daughter treated in front of 'physicians of the Royal Court'. Experiments followed on prisoners and then orphans (hahaha...imagine that today!) until finally acceptance followed the successful treatment of the two daughters of the Prince of Wales.
Religous powers were equally sceptical as they believed the 'providence of life should be in God's hands' (see image of Gentleman's Magazine 1750 - courtesy of the ILEJ, Internet Library of Early Journals click image to enlarge); they got even more irate when variolation became Satan's tools...or vaccination as we know it. Vaccination from vacca, the Latin for cow (cowpox...) throughout England there was a popular concept that dairy maids who had caught cowpox were thereafter immune to smallpox.
Despite Edward Jenner being the man famous for 'inventing' vaccination, there has been a growing recognition of Benjamin Jesty as the first to vaccinate against smallpox . "The breakthrough in vaccination came in 1774 with a Dorset farmer, Benjamin Jesty... [he would have been] aware of the rural 'myths' that people who had earlier caught the mild disease of cowpox did not catch the normally fatal disease of smallpox. Furthermore country people had noticed for some time that dairymaids caught the much milder cowpox from their cows but never smallpox. In fact dairymaids were renown for their pure complexions and Jesty’s milkmaids had previously caught cowpox, nursed family members with smallpox yet still had not caught smallpox.
This was the first recorded vaccination and it took place not in the context of established medical procedure by medical experts but on a farm in rural Dorset." (IBMS Institute of BioMedical Science - history zone). The Jestys freely admitted that they were probably not the first with vaccination, but he was the "first person (known) that introduced the Cow Pox by inoculation"...that's their gravestone inscription. Also there are those none-too-happy that Jenner didn't give credit to previous work and 'much of his correspondence was deliberately destroyed leaving enough gaps to wonder how much he knew about Jesty’s experiment which was known about in medical circles.' Some go further, in 1995, Richard Horton, now editor of The Lancet) said:
Jesty became convinced that cowpox somehow protected against smallpox and during a smallpox outbreak in the summer of 1774 took his family to a farm where there was an outbreak of cowpox. He took infected pus from the udder of a cow and used the sharp point of a stocking needle to scratch his wife and his sons’ arms just below the elbow where he inserted the pus.
Oooer...not happy at all. That said, it shouldn't lessen our appreciation of Jenner's accomplishments, indeed as early as 1801 he predicted eradication of smallpox. 'It was his relentless promotion and devoted research of vaccination that changed the way medicine was practiced' and ...
"The limping truth is that Edward Jenner was a political opportunist who obtained priority in the discovery of vaccination (1796) through his reputation (he was elected a fellow of the Royal Society in 1779 on the strength of his research on cuckoos) and aristocratic social standing (he received financial support from the Duke of Bedford and the lord mayor of London)."
In science credit goes to the man who convinces the world, not the man to whom the idea first occurs. — Francis Galton