BCG vaccine bacilli that seemed less virulent, and changed the course of their research to see if repeated subculturing would produce a strain that was attenuated enough to be considered for use as a vaccine. The BCG strain was isolated after subculturing 239 times during 13 years from virulent strain on glycerine potato medium. The research continued throughout World War I until 1919, when the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919. The BCG vaccine was first used in humans in 1921. Public acceptance was slow,
Inoculation theory counterarguments, the inoculation receiver will then seek out supporting information to further strengthen their threatened position. Finally, the held attitude or belief becomes resistant to a stronger attack, hence the medical analogy of a vaccine. Inoculation is a theory developed to strengthen existing attitudes and beliefs while building resistance to future counterarguments. For inoculation to be successful it is crucial that a threat (motivation for resistance) is imposed upon these existing ideas and refutational preemption (ability to build defenses against potential counterarguments) takes place after the inoculation. The argument that is presented through inoculation must be strong enough to initiate