BCG vaccine extensively used even in countries where efficacy against pulmonary tuberculosis is negligible. A number of possible reasons for the variable efficacy of BCG in different countries have been proposed. None have been proven, some have been disproved, and none can explain the lack of efficacy in both low-TB burden countries (US) and high-TB burden countries (India). The reasons for variable efficacy have been discussed at length in a WHO document on BCG. BCG has protective effects against some non-tuberculosis mycobacteria. BCG has been one of the most successful immunotherapies. BCG vaccine has been the "standard of care for patients with
Inoculation theory in South Dakota and had the students watch a video warning them of future pressures to smoke. In the first year, resistance was highest among those with low self-esteem (Pfau et al., 1992). At the end of the second year, students in the group showed more attitudinal resistance to smoking than they did previously (Pfau & Van Bockern 1994). Importantly, the study and its follow-up demonstrate the long-lasting effects of inoculation treatments. Other recent areas of study include vaccination safety. Wong and Harrison (2014) studied 212 female students and their attitudes about the HPV vaccine. They found that inoculation messages