Tuberculosis The main use of<unk>  is for vaccination against tuberculosis.<unk>  can be administered after birth intradermally.<unk> tion can cause a false positive Mantoux test, although a very high-grade reading is usually due to active disease. The most controversial aspect of<unk>  is the variable efficacy found in different clinical trials, which appears to depend on geography. Trials conducted in the UK have consistently shown a protective effect of 60 to 80%, but those conducted elsewhere have shown no protective effect, and efficacy appears to fall the closer one gets to the equator. A 1994 systematic review found that<unk>  reduces the risk of getting tuberculosis by about 50%. Differences in effectiveness depend on region, due to factors such as genetic differences in the populations, changes in environment, exposure to other bacterial infections, and conditions in the laboratory where the vaccine is grown, including genetic differences between the strains being cultured and the choice of growth medium. A systematic review and meta-analysis conducted in 2014 demonstrated that the<unk>  reduced infections by 19–27% and reduced progression to active tuberculosis by 71%. The studies included in this review were limited to those that used interferon gamma release assay. The duration of protection of<unk>  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.<unk>  seems to have its greatest effect in preventing miliary tuberculosis or tuberculosis meningitis, so it is still extensively used even in countries where efficacy against pulmonary tuberculosis is negligible. The 100th anniversary of<unk>  was in 2021. It remains the only vaccine licensed against tuberculosis, which is an ongoing pandemic. Tuberculosis elimination is a goal of the World Health Organization (WHO), although the development of new vaccines with greater efficacy against adult pulmonary tuberculosis may be needed to make substantial progress. Efficacy A number of possible reasons for the variable efficacy of<unk>  in different countries have been proposed. None has been proven, some have been disproved, and none can explain the lack of efficacy in both low tuberculosis-burden countries (US) and high tuberculosis-burden countries (India). The reasons for variable efficacy have been discussed at length in a WHO document on<unk> . # Genetic variation in<unk>  strains: Genetic variation in the<unk>  strains used may explain the variable efficacy reported in different trials. # Genetic variation in populations: Differences in genetic make-up of different populations may explain the difference in efficacy. The Birmingham<unk>  trial was published in 1988. The trial, based in Birmingham, United Kingdom, examined children born to families who originated from the Indian subcontinent (where vaccine efficacy had previously been shown to be zero). The trial showed a 64% protective effect, which is very similar to the figure derived from other UK trials, thus arguing against the genetic variation hypothesis. # Interference by nontuberculous mycobacteria: Exposure to environmental mycobacteria (especially Mycobacterium avium, Mycobacterium marinum and Mycobacterium intracellulare) results in a nonspecific immune response against mycobacteria. Administering<unk>  to someone who already has a nonspecific immune response against mycobacteria does not augment the response already there.<unk>  will, therefore, appear not to be efficacious because that person already has a level of immunity and<unk>  is not adding to that immunity. This effect is called masking because the effect of<unk>  is masked by environmental mycobacteria. Clinical evidence for this effect was found in a series of studies performed in parallel in adolescent school children in the UK and Malawi. In this study, the UK school children had a low baseline cellular immunity to mycobacteria which was increased by<unk> ; in contrast, the Malawi school children had a high baseline cellular immunity to mycobacteria and this was not significantly increased by<unk> . Whether this natural immune response is protective is not known. An alternative explanation is suggested by mouse studies; immunity against mycobacteria stops<unk>  from replicating and so stops it from producing an immune response. This is called the block hypothesis. # Interference by concurrent parasitic infection: In another hypothesis, simultaneous infection with parasites changes the immune response to<unk> , making it less effective. As Th1 response is required for an effective immune response to tuberculous infection, concurrent infection with various parasites produces a simultaneous Th2 response, which blunts the effect of<unk> . Mycobacteria<unk>  has protective effects against some nontuberculosis mycobacteria. * Leprosy:<unk>  has a protective effect against leprosy in the range of 20 to 80%. * Buruli ulcer:<unk>  may protect against or delay the onset of Buruli ulcer. Cancer Micrograph showing granulomatous inflammation of bladder neck tissue due to Bacillus Calmette–Guérin used to treat bladder cancer, H&E stain<unk>  has been one of the most successful immunotherapies.<unk>  has been the "standard of care for patients with bladder cancer (NMIBC)" since 1977. By 2014 there were more than eight different considered biosimilar agents or strains used for the treatment of nonmuscle-invasive bladder cancer. * A number of cancer vaccines use<unk>  as an additive to provide an initial stimulation of the person's immune systems. *<unk>  is used in the treatment of superficial forms of bladder cancer. Since the late 1970s, evidence has become available that instillation of<unk>  into the bladder is an effective form of immunotherapy in this disease. While the mechanism is unclear, it appears a local immune reaction is mounted against the tumor. Immunotherapy with<unk>  prevents recurrence in up to 67% of cases of superficial bladder cancer. *<unk>  has been evaluated in a number of studies as a therapy for colorectal cancer. The US biotech company Vaccinogen is evaluating<unk>  as an adjuvant to autologous tumour cells used as a cancer vaccine in stage II colon cancer.
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Typhus vaccine
DTaP-IPV vaccine
Measles vaccine