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 prisoners due to be hanged, an experiment which was witnessed by a number of notable doctors. All survived, and in 1722 the Prince of Wales' daughters received inoculations. The practice of inoculation slowly spread amongst the royal families of Europe, usually followed by more general adoption amongst the people. The practice is documented in America as early as 1721, when Zabdiel Boylston, at the urging of Cotton Mather, successfully inoculated two slaves and his own son. Mather, a prominent Boston minister, had heard a description of the African practice of inoculation from his Sudanese slave, Onesimus, in 1706, and later