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
BCG disease outbreak in Finland in the 2000s been crimes committed relating to use of the BCG vaccine. BCG disease outbreak in Finland in the 2000s BCG disease is an adverse effect of the Bacillus Calmette-Guérin vaccine. The vaccine contains living "Mycobacterium bovis" BCG, and in BCG disease, the bacterium causes a disease in persons vaccinated. Between 2000 and 2006, several hundred children in Finland had serious adverse events from the vaccine, including osteitis and osteomyelitis, disseminated (usually fatal) BCG infection, arthritis, and lymph node abscesses. Four deaths were registered in the official adverse event register, and while in only two cases a clear causal link was considered