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 vaccine was first marketed by Urocor in about 2002. Urocor was since acquired by Dianon Systems. Evans Vaccines (a subsidiary of PowderJect Pharmaceuticals). Statens Serum Institut in Denmark markets BCG vaccine prepared using Danish strain 1331. Japan BCG Laboratory markets its vaccine, based on the Tokyo 172 substrain of Pasteur BCG, in 50 countries worldwide. According to a UNICEF report published in December 2015 on BCG vaccine supply security, global demand increased in 2015 from 123 to 152.2 million doses. In order to improve security and to [diversify] sources of affordable and flexible supply," UNICEF awarded seven new manufacturers contracts to