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 most frequently used because the local complication rate is smallest when that site is used. Nonetheless, the buttock is an alternative site of administration because it provides better cosmetic outcomes. BCG vaccine should be given intradermally. If given subcutaneously, it may induce local infection and spread to the regional lymph nodes, causing either suppurative and nonsuppurative lymphadenitis. Conservative management is usually adequate for nonsuppurative lymphadenitis. If suppuration occurs, it may need needle aspiration. For nonresolving suppuration, surgical excision may be required. Evidence for the treatment of these complications is scarce. Uncommonly, breast and gluteal abscesses can occur due to haematogenous