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 opinion. These contexts include: politics (e.g., Pfau et al., 1990; see Compton & Ivanov, 2013, for a review), health campaigns (e.g., Pfau & VanBockern, 1994; see Compton, Jackson, & Dimmock, 2016, for a review), marketing (e.g., Compton & Pfau, 2004) and education (Compton, 2011), among others. (See Banas & Rains, 2010, for a meta-analysis, and Compton, 2013, for a narrative overview.) The inoculation process is analogous to the medical inoculation process from which it draws its name; the analogy served as the inaugural exemplar for how inoculation confers resistance. As McGuire (1961) initially explained, medical inoculation works by exposing the