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 the sprouts", an idea of transplanting the disease which fit their conception of beansprouts in germination. Needham quotes an account from Zhang Yan's "Zhongdou xinshu" (種痘新書), or "New book on smallpox inoculation", written in 1741 during the Qing dynasty (1644–1912), which shows how the Chinese process had become refined up until that point: Two reports on the Chinese practice were received by the Royal Society in London in 1700; one by Dr. Martin Lister who received a report by an employee of the East India Company stationed in China and another by Clopton Havers. But no action was taken. According