The BCG-vaccinated are a special group of individuals who may require further testing for TB infection.
The Bacille Calmette-Guerin (BCG) vaccine is used in many parts of the world where TB disease is common. The World Health Organization (WHO) recommends the administration of the BCG vaccine during infancy in TB endemic countries. BCG protects young children from serious TB meningitis and miliary TB. (Miliary TB is a serious situation where a large number of the bacteria disseminate throughout the bloodstream and body.)
BCG is not recommended for use in the United States because of the low risk of infection with M. tuberculosis.
In the next section, TB infection test methods will be discussed. Note that vaccination with BCG may cause a false-positive tuberculin skin test (TST) reaction. A positive TST result will, therefore, prompt further testing to rule out actual infection with Mycobacterium tuberculosis bacteria.
