The World Health Organization is aware that MMR vaccines (a combination vaccine against measles, mumps, and rubella) are infected with avian leukosis virus, which is associated with the onset of leukemia. One of the latest scandalous vaccines is Rotarix, which was found to be among those infected with animal DNA - in this case, from pigs.
RE: How the Measles Vaccination Program has Destroyed Herd Immunity