Jenner found that the cowpox virus did make the little girl immune to smallpox.
From the abcnews.go.com
He reported that variolation induced no reaction in persons who had had cowpox.
From the en.wikipedia.org
In fact, what Jenner used was not cowpox but vaccinia, a close viral relation.
From the economist.com
When Jenner infected James with cowpox, the boy's immune system responded.
From the scienceblogs.com
As Jenner noted in the 18th century, the cowpox virus is also readily transmitted to man.
From the sciencedaily.com
For example, the discovery that cowpox vaccines can prevent smallpox dates back to 1798.
From the sciencedaily.com
Jenner inoculated Phipps with cowpox pus in both arms on the same day.
From the en.wikipedia.org
Vaccinia, cowpox, and monkeypox viruses can infect both humans and other animals in nature.
From the en.wikipedia.org
Vaccinia is in the same family as cowpox and variola but is genetically distinct from both.
From the en.wikipedia.org
More examples
A viral disease of cattle causing a mild skin disease affecting the udder; formerly used to inoculate humans against smallpox
Cowpox is a skin disease caused by a virus known as the Cowpox virus. The pox is related to the vaccinia virus, and got its name from the distribution of the disease when dairymaids touched the udders of infected cows. ...
A relatively minor viral disease of cattle, often transmitted to humans that milk them. It causes pox (pustules) on the hands and arms but generally is not fatal. Because the cowpox virus is very similar to the smallpox virus, people who had cowpox are immune to smallpox. See immunity.