vaccinia

noun

1. (countable, uncountable)An infection of cowpox.

   “On the other hand, Professor Heim inquired minutely into all the circumstances of the case, and says he is convinced of the variolation of the cow, and of the transmission from her of a disease similar to vaccinia.”

2. (broadly, countable, uncountable)A virus which causes this infection (Orthpoxvirus vaccinia).

   “Since then, a handful of vaccinia cases have been reported to the Centers for Disease Control and Prevention, including one, described in the May 4 Morbidity and Mortality Weekly Report, of vulvar infection in an Alaskan woman whose sex partner was a serviceman.”

3. (countable, uncountable)A closely related poxvirus, used as a smallpox vaccine.