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 existed for all hypotheses. The results of their experimentation yielded the understanding that inoculation coupled with reactance-enhanced messages leads to "stronger resistance effects" (p. 148). Consistent with the medical analogy of inoculation theory, Miller, et al. (2013) liken reactance-enhanced messages to a "booster shot," increasing the success of the inoculation. Another unique feature of the study is examining low-controlling language versus high-controlling language and its impact on affect and source credibility. Similarly, Miller, et al. (2007) utilizes psychological reactance theory (Brehm, 1966, 1972; Brehm & Brehm, 1981) to avoid or eliminate source derogation and message rejection. In this study, their