Dear Dr. Roach: Can you please speak about the BCG vaccine? My daughter was born in Bolivia and received it as an infant. Now she always tests positive for tuberculosis, and people in the medical field never seem to know or understand when we explain about the vaccine. Its such a hassle to get straightened out. M.P.A.
Answer: Bacille Calmette-Guerin is a common cause of false positive tuberculosis tests. BCG is a vaccine strain of bacteria similar to tuberculosis that many countries use to reduce the risk of developing this very infectious disease. It is not used in the United States because public health officials feel it is not very effective, and because it can make the tuberculin skin test more difficult to interpret.