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 to Voltaire (1742), the Turks derived their use of inoculation to neighbouring Circassia. Voltaire does not speculate on where the Circassians derived their technique from, though he reports that the Chinese have practiced it "these hundred years". The Turkish practice was presented to the Royal Society in 1714 and 1716, when the physicians Emanuel Timoni and Giacomo Pylarini independently sent letters from Constantinople. Variolation is documented in India from the eighteenth century, thanks to the 1767 account by J. Z. Holwell. Holwell's extensive 1767 description included the following, that points to the connection between disease and "multitudes of imperceptible animalculae