BCG vaccine immunity against human tuberculosis. The BCG vaccine can be anywhere from 0 to 80% effective in preventing tuberculosis for a duration of 15 years; however, its protective effect appears to vary according to geography and the lab in which the vaccine strain was grown. A number of different companies make BCG, sometimes using different genetic strains of the bacterium. This may result in different product characteristics. OncoTICE, used for bladder instillation for bladder cancer, was developed by Organon Laboratories (since acquired by Schering-Plough, and in turn acquired by Merck & Co.). Pacis BCG, made from the Montréal (Institut Armand-Frappier) strain,
Inoculation Needham states that this information comes from the "Zhongdou xinfa" (種痘心法) written in 1808 by Zhu Yiliang, centuries after the alleged events. The first clear and credible reference to smallpox inoculation in China comes from Wan Quan's (1499–1582) "Douzhen xinfa" (痘疹心法) of 1549, which states that some women unexpectedly menstruate during the procedure, yet his text did not give details on techniques of inoculation. Inoculation was first vividly described by Yu Chang in his book "Yuyi cao" (寓意草), or "Notes on My Judgment", published in 1643. Inoculation was reportedly not widely practised in China until the reign of the Longqing