Bcg Vaccine

BCG Vaccine is one of the most widely used vaccines in the world. Its efficacy against TB meningitis in the pediatric age-group is established; but its efficacy against pulmonary TB is appears to be variable. Many countries use BCG for prevention of TB. But a few countries like U.S, they do not use BCG for routine vaccination. This is probably because they believe in detecting the active disease by a reliable Mantoux test, instead of practicing the routine vaccination against a relatively rare condition i.e, the incidence of TB is very low.-The most controversial aspect of BCG is its variable efficacy when used in various clinical trials. This appears to depend on the geography. The efficacy of 14% to 84% upto 5 years after immunization. However a clinical trials conducted in South India showed no protective effect.But BCG vaccine seems to be very effective in preventing miliary TB & TB meningitis. Hence it is still extensively used in countries where efficacy against pulmonacy TB is negligible.