BCG vaccine screened for active tuberculosis. BCG is also contraindicated in certain people who have IL-12 receptor pathway defects. BCG is given as a single intradermal injection at the insertion of the deltoid. If BCG is accidentally given subcutaneously, then a local abscess may form (a "BCG-oma") that can sometimes ulcerate, and may require treatment with antibiotics immediately, otherwise without treatment it could spread the infection causing severe damage to vital organs. However, it is important to note an abscess is not always associated with incorrect administration, and it is one of the more common complications that can occur with the vaccination.
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