BCG vaccine nesting birds and rusted electrical conduits. The resulting closure of the plant for over two years resulting in shortages of bladder cancer and tuberculosis vaccines. On October 29, 2014 Health Canada gave the permission for Sanofi to resume production of BCG. The global supply situation was analyzed in 2017 and concluded that the global supply is sufficient to meet forecasted BCG vaccine demand but risks for shortages remain mainly due to supply concentration. A weakened strain of bovine tuberculosis bacillus, "Mycobacterium bovis" is specially subcultured in a culture medium, usually Middlebrook 7H9. Some BCG vaccines are freeze dried and become
Inoculation theory and others had found previously, inoculation was able to confer resistance to arguments that were not specifically mentioned in the inoculation message. Compton and Ivanov (2013) offer a comprehensive review of political inoculation scholarship and outline new directions for future work. Sample studies include: Pfau and some of his colleagues examined inoculation through the use of direct mail during the 1988 presidential campaign. The researchers were specifically interested in comparing inoculation and post hoc refutation. Post hoc refutation is another form of building resistance to arguments, however, instead of building resistance prior to future arguments, like inoculation, it attempts to