BCG vaccine an option in high-risk TB settings

Not for HIV infected, low risk settings

Immunocompetent health care workers in facilities at high risk of transmission of multidrug-resistant tuberculosis should be considered "on an individual basis" for vaccination with bacillus of Calmette and Guerin (BCG) if other infection control measures are not working, the Centers for Disease Control and Prevention recommends.1

BCG vaccination of health care workers should be considered if a high percentage of TB patients are infected with strains resistant to both isoniazid and rifampin, transmission of such strains to workers subsequent infection are likely, and comprehensive TB infection control precautions have been implemented and have not been successful. Vaccination with BCG should not be required for employment or for assignment of workers in specific work areas, the agency advised.

In making the qualified recommendation, the CDC reiterated the possible serious complications of administering BCG vaccine to the immunocompromised, particularly those infected with HIV.

"BCG vaccination is not recommended for health care workers who are infected with HIV or are otherwise immunocompromised," the CDC emphasized.

Offer, but don't compel work assignment

In high-risk settings for transmission of TB strains resistant to both isoniazid and rifampin, employees and volunteers who are infected with HIV or are otherwise immunocompromised should be fully informed about this risk and about the even greater risk associated with immunosuppression and the development of active TB disease. At the request of an immunocompromised worker, employers should offer, but not compel, a work assignment in which the worker would have the lowest possible risk for infection with TB, the CDC stated.

The preferred strategies for the prevention and control of TB in health care facilities are a comprehensive infection control program that includes prompt identification, isolation, and treatment of patients. TB skin testing programs should also be in place for workers. Even in high-risk health care facilities, comprehensive application of TB infection control practices should be the primary strategy used to protect health care workers.

BCG vaccination should not be used as a primary strategy for two reasons, the CDC stated. First, the protective efficacy of the vaccine in is uncertain. Second, even if BCG vaccination is effective in an individual health care worker, other persons in the health care facility (e.g., patients, visitors, and other workers) are not protected against possible infection with drug- resistant TB strains.

Those workers considered for BCG vaccination should be counseled regarding the risks and benefits associated with both BCG vaccination and TB preventive therapy. Counseling information should include:

* the variable data regarding the efficacy of BCG vaccination;

* the difficulty in diagnosing a newly acquired TB infection in a BCG-vaccinated person;

* the possible serious complications of BCG vaccine in immunocompromised persons, especially those infected with HIV;

* the lack of data regarding the efficacy of preventive therapy for M. tuberculosis infections caused by strains resistant to isoniazid and rifampin;

* the risks for drug toxicity associated with multidrug preventive therapy regimens.

Reference

1. Centers for Disease Control and Prevention. The role of BCG vaccine in the prevention and control of tuberculosis in the United States: A joint statement by the Advisory Council on Tuberculosis and the Advisory Committee on Immunization Practices. MMWR 1996; 45:1-18. *