The BCG vaccine can prevent tuberculosis (TB) bacteria from spreading within the body, thus preventing the disease from developing. The vaccine is administered to infants in parts of the world where tuberculosis is much more common. In the United States, it is typically not recommended because of factors such as the vaccine's variable effectiveness against adult pulmonary TB and potential interference with TB skin test reactivity.
What Is the BCG Vaccine?
In the parts of the world where tuberculosis is common, infants may receive a vaccine called BCG (Bacille Calmette Guerin) for prevention of the disease. This BCG vaccine is made from a live weakened bacterium related to tuberculosis (TB) bacteria (Mycobacterium tuberculosis). The BCG vaccine prevents the bacteria from spreading within the body, thus preventing TB from developing.
The BCG vaccine is not generally recommended for use in the United States because of the low risk of infection with tuberculosis bacteria, the variable effectiveness of the vaccine against adult pulmonary tuberculosis, and the vaccine's potential interference with TB skin test reactivity. The vaccine should be considered only for certain people who meet specific criteria, and only in consultation with a TB expert.
Recommendations for the BCG Vaccine
In the United States, the BCG vaccine may be recommended in certain cases involving children or healthcare workers.
The BCG vaccine should only be considered for children who have a negative tuberculin skin test (PPD test) and who are continually exposed and cannot be separated from adults who:
- Are untreated or ineffectively treated for TB disease (if the child cannot be given long-term treatment for infection)
- Have TB caused by strains resistant to isoniazid and rifampin.
In healthcare workers, the BCG vaccine should be considered on an individual basis in settings in which:
- A high percentage of TB patients are infected with tuberculosis strains resistant to both isoniazid and rifampin
- There is ongoing transmission of such drug-resistant TB to healthcare workers and subsequent infection is likely
- Comprehensive TB infection-control precautions have been implemented but have not been successful.
Healthcare workers considered for the vaccine should be counseled regarding the risks and benefits associated with both BCG vaccination and treatment of latent tuberculosis.