Noun
A pustular eruptive disease of the cow, which, when communicated to the human system, as by vaccination, protects from the smallpox; vaccinia; -- called also kinepox, cowpock, and kinepock.
Source: Webster's dictionaryI hope that some day the practice of producing cowpox in human beings will spread over the world - when that day comes, there will be no more smallpox. Edward Jenner
After infection by the cowpox virus, the body (usually) gains the ability to recognize the similar smallpox virus from its antigens and is able to fight the smallpox disease much more efficiently. Source: Internet
After inoculation, vaccination using the cowpox virus became the primary defense against smallpox. Source: Internet
Edward Jenner had also discovered vaccination using cowpox ( Vaccinia ) to give cross-immunity to smallpox in 1796, and by Pasteur's time this had generally replaced the use of actual smallpox ( Variola ) material in inoculation. Source: Internet
At some point, the virus in use was no longer cowpox, but vaccinia. Source: Internet
By 1768, English physician John Fewster had realized that prior infection with cowpox rendered a person immune to smallpox. Source: Internet