BCG vaccine fine powder. Sometimes the powder is sealed with vacuum in a glass ampoule. Such a glass ampoule has to be opened slowly to prevent the airflow from blowing out the powder. Then the powder has to be diluted with saline water before injecting. The history of BCG is tied to that of smallpox. Jean Antoine Villemin first recognized bovine tuberculosis in 1854 and transmitted it, and Robert Koch first distinguished "Mycobacterium bovis" from "Mycobacterium tuberculosis". Following the success of vaccination in preventing smallpox, established during the 18th century, scientists thought to find a corollary in tuberculosis by drawing a parallel
BCG vaccine 71%. The studies included in this review were limited to those that used interferon gamma release assay. The duration of protection of BCG is not clearly known. In those studies showing a protective effect, the data are inconsistent. The MRC study showed protection waned to 59% after 15 years and to zero after 20 years; however, a study looking at Native Americans immunized in the 1930s found evidence of protection even 60 years after immunization, with only a slight waning in efficacy. BCG seems to have its greatest effect in preventing miliary TB or TB meningitis, so it is still