New clues on the historical origin of the vaccine used to eradicate smallpox

(Publicase Comunica ç ã o Cient í fica) For centuries, researchers assumed that the active ingredient in the vaccine providing immunity against smallpox was the cowpox virus but a study just published in the New England Journal of Medicine indicates otherwise.
Source: EurekAlert! - Cancer - Category: Cancer & Oncology Source Type: news