Where do the virus and or microbes used within vaccines come from?
Answer:
The viruses are cultured contained by cells. Usually cell from chick embryos are used. Once the virus is cultured in adequate quantity, it is attenuated or deactivated, usually near heat, so that it is not infectious. The factory that make vaccines are held to the unmatched quality control standards.
In 1963, a researcher name Dr. Maurice Hilleman cultured the mumps virus from his daughter Jeryl Lynn. The Jeryl Lynn strain of the mumps virus is the strain that has be developed to manufacture the mumps vaccine used today.
Alas, most origins of viral vaccines remain rarefied. For an early history of bacterial vaccines read "Microbe Hunters" by Paul deKruif. There are interesting stories roughly Cotton Mather, the religious leader, and his role surrounded by smallpox immunization.