Controversies in BCG immunization.

Despite controversies BCG vaccination has stood the test of time. World Health Organization continues to recommend its use in infant immunization programme in countries with heavy endemicity and where threatening HIV epidemic in an emerging problem > 85% efficacy have been established in recent years against hematogenous spread of the disease and > or = 50% efficacy even against pulmonary tuberculosis. Host related factors, agent related factors, vaccine related factors and inadequacy of evaluation tests determine the BCG vaccine efficacy. Identification of complete BCG genome in 1998 has opened new vistas in newer BCG vaccine development. Adoption of a '5C' concept viz. Case detection, Chemotherapy short course, Contact elimination, Chemoprophylaxis and lastly control in BCG vaccine will be a desirable national approach in combating adult and childhood TB.