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 spreading inoculation through talk with others on issues that involve negative cognitions and affect. In previous research, the assumption that talk was subvocal (existing only intrapersonally) was prevalent, without concern for the impact of vocal talk with other individuals. Ivanov, et al. (2012) deems vocal talk important to the incubation process. Their study concluded that individuals who receive an inoculation message that contains threat will talk to others about the message and talk more frequently than individuals who do not receive an inoculation message. Additionally, the act of postinoculation talk bolsters their attitudes and increases resistance to the message as