The Tuberculosis Vaccine
The tuberculosis vaccine is called BCG, which stands for Bacillus Calmette-Guérin. This vaccine is not used in the United States, but it is widely used in most other parts of the world. The reason this vaccine is not recommended for Americans is because tuberculosis is not common for people who are born in this country. Most cases of tuberculosis in this country occur among immigrants who may have received the BCG vaccine in their native country.
Why would these immigrants contract tuberculosis even after receiving the vaccine?
The BCG vaccine is not very effective in preventing lung infection caused by tuberculosis. However, it works very well in preventing brain infection caused by tuberculosis. Since brain infection is the most serious form of tuberculosis, this vaccine is still being used in most parts of the world.
The BCG vaccine was first introduced in 1921. However, an early vaccine accident greatly tainted the public image of this vaccine. In 1930, a batch of the BCG vaccine was contaminated with a virulent strain of the tuberculosis bacteria in Germany. Seventy-two babies died from tuberculosis as the result of this vaccine accident. It took more than a decade before this vaccine was gradually accepted by parents again.
Currently, the United States, Great Britain, and Netherlands are the only countries in the world that are not routinely vaccinating against tuberculosis. Great Britain used to have the BCG vaccine as part of its immunization program until 2006, when it decided that the risk of tuberculosis exposure in that country is low enough not to warrant vaccination.
The BCG vaccine contains a live but weakened strain of the tuberculosis bacteria. It is given as an injection. A relatively large scar may form in some people after the vaccination, and occasionally an abscess (a localized infection) may develop at the site of the injection.
Another reason why the BCG vaccine is not routinely recommended in the United States is that the vaccine can interfere with a screening tool used to test for tuberculosis exposure (the PPD, or purified protein derivative, skin test). The PPD test may turn falsely positive after a recent BCG vaccination.