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 to re-infection. In 1798, the English surgeon/scientist Edward Jenner published the results of his experiments and thus introduced the far superior and safer method of inoculation with cowpox virus, a mild infection that also induced immunity to smallpox. Jenner was not the first person to inoculate with cowpox nor the first to realize that infection with cowpox gave immunity to smallpox. However, he was the first to publish evidence that it was effective and to provide advice on its production. His efforts led to smallpox inoculation falling into disuse and eventually being banned in England in 1840. Inoculation The terms