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 inoculation's efficacy can be boosted with other persuasion processes, like reactance (Miller et al., 2013). Inoculation theory states that to prevent persuasion it is necessary to strengthen preexisting attitudes, beliefs, or opinions. First, the receiver must be made aware of the potential vulnerability of an existing position (e.g., attitude, belief). This establishes threat and initiates defenses to future attacks. The idea is that when a weak argument is presented in the inoculation message, processes of refutation or other means of protection will prepare for stronger arguments later. It is critical that the attack is strong enough to keep the receiver