CDC issues recommendations on the role of BCG vaccine in the prevention and control of tuberculosis – Centers for Disease Control and Prevention, bacille Calmette-Guerin – Special Medical Reports
The Centers for Disease Control and Prevention has updated previous recommendations regarding the use of bacille Calmette-Guerin (BCG) vaccine to treat populations at high risk of developing tuberculosis. The report was issued to summarize current considerations and recommendations regarding the use of BCG vaccine in the United States. Since the previous recommendations were published in 1988, cases of tuberculosis have increased among adults and children, and outbreaks of multidrugresistant tuberculosis have occurred in institutions. In addition, new information about the protective efficacy of BCG has become available.
The joint recommendations of the CDC’s Advisory Committee on Immunization Practices and the Advisory Committee on Elimination of Tuberculosis were published in the April 15,1996, issue of the recommendations and reports series of Morbidity and Mortality Weekly Report (MMWR 1996;45[no. RR-4]:1-18). Electronic copy is available from CDC’s World Wide Web server at http://www.cdc. gov/ or from CDC’s file transfer protocol server at ftp.cdc.gov.
The statement contains information on the background of tuberculosis control and prevention in the United States, BCG vaccine efficacy and safety, recommendations and contraindications for use, implementation of the vaccination and surveillance. The following information has been excerpted from the report.
The risk of Mycobacterium tuberculosis infection in the overall U.S. population is low. The most important strategy for controlling tuberculosis is to minimize the risk for transmission by early identification and treatment of patients who have active infectious tuberculosis. Another strategy is the identification of persons who have latent M. tuberculosis infection and, if indicated, the use of preventive therapy with isoniazid to prevent the latent infection from progressing to active tuberculosis disease. Rifampin is used for preventive therapy in persons who are infected with isoniazidresistant strains of M. tuberculosis. An additional preventive strategy is to implement effective tuberculosis infection-control programs in health care facilities and other institutional settings.
The BCG vaccine is a live vaccine derived from a strain of Mycobacterium bovis that was attenuated by Calmette and Guerin at the Pasteur Institute in France. Many different BCG vaccines are available worldwide. The vaccine currently available for immunization in the United States, the Tice strain, was developed from a strain that originated at the Pasteur Institute. The U.S. Food and Drug Administration is considering another vaccine for licensure in the United States. BCG vaccination is not recommended as a routine strategy for tuberculosis prevention in the United States. It should be reserved for selected persons who meet specific criteria.
Recommendations for Children
Unless specifically contraindicated, preventive therapy should be administered to all tuberculinpositive children, even if it is not known when or how infection with M. tuberculosis occurred. BCG vaccination should be considered for an infant or child who has a negative tuberculin skin test result only if the following circumstances are present:
* The child is exposed continually to an untreated or ineffectively treated person who has infectious pulmonary tuberculosis, and the child cannot be separated from the presence of the infectious person or given long-term primary preventive therapy.
* The child is exposed continually to a person who has infectious tuberculosis caused by M. tuberculosis strains resistant to isoniazid and rifampin, and the child cannot be separated from the presence of the infectious person.
BCG vaccination is not recommended for children infected with human immunodeficiency virus (HIV).
Recommendations for Health Care Workers
In some areas of the country, the likelihood for transmission of M. tuberculosis in health care facilities is high because of a high incidence of tuberculosis in the patient population. Even in these areas, more than 90 percent of patients with tuberculosis are infected with M. tuberculosis strains that are susceptible to isoniazid or rifampin. Untreated or partially treated patients who have active tuberculosis disease can potentially transmit M. tuberculosis to health care workers, patients, volunteers and visitors in the health care facilities.
BCG vaccination of health care workers should not be used as the primary strategy for two reasons. The protective efficacy of the vaccine in health care workers is uncertain, and even if BCG vaccination is effective in an individual health care worker, other persons in the facility are not protected against possible exposure to and infection with drug-resistant strains of M. tuberculosis. The recommendations for considering the use of BCG vaccine in health care workers are as follows:
* BCG vaccination of health care workers should be considered on an individual basis in the following settings: (1) a high percentage of patients with tuberculosis are infected with M. tuberculosis strains resistant to both isoniazid and rifampin; (2) transmission of such drug-resistant M. tuberculosis strains to health care workers and subsequent infection are likely, and (3) comprehensive tuberculosis infection-control precautions have been implemented and have not been successful.
* Health care workers considered for BCG vaccination should ule counseled regarding the risks and benefits associated with both BCG vaccination and tuberculosis preventive therapy. They should be informed about the variable data regarding the efficacy of BCG vaccination, the interference with diagnosing a newly acquired M. tuberculosis infection in a BCG-vaccinated person, and the possible serious complications of the BCG vaccine in immunocompromised persons, especially those with HIV. They should also be told about the lack of data regarding the efficacy of preventive therapy for M. tuberculosis infections caused by strains resistant to isoniazid and rifampin and the risks for drug toxicity associated with multidrug preventive therapy.
BCG is not recommended for health care workers who are infected with HIV or are otherwise immunocompromised. In settings in which the risk for transmission of M. tuberculosis strains resistant to both isoniazid and rifampin is high, 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 tuberculosis disease. At the request of health care workers, employers should offer a work assignment in which the health care worker would have the lowest possible risk for infection with M. tuberculosis.
* In most areas of the United States, the risk for M. tuberculosis transmission in health care facilities is low. BCG vaccination is not recommended for health care workers in these low-risk settings.
* BCG vaccination is not recommended for HIV-infected children or adults in the United States.
Skin Testing After Vaccination
Postvaccination BCG-induced tuberculin reactivity ranges from no induration to an induration of 19 mm at the skin-test site. Tuberculin reactivity caused by BCG vaccination wanes with the passage of time and is unlikely to last for more than 10 years after vaccination in the absence of M. tuberculosis exposure and infection. BCG-induced reactivity that has weakened might be boosted by administering a tuberculin skin test one week to one year after the initial postvaccination skin test; ongoing periodic skin testing also might prolong reactivity to tuberculin in vaccinated persons.
The presence or size of a post-vaccination tuberculin skin-test reaction does not predict whether BCG will provide any protection against tuberculosis disease. In addition, the size of a tuberculin skin-test reaction in a BCG-vaccinated person is not a factor in determining whether the reaction is caused by M. tuberculosis infection or the prior BCG vaccination. The results of one community-based survey indicated that the prevalence of tuberculin reactions of 10 mm or more induration in adolescents and young adults was similar in those persons vaccinated during infancy and those never vaccinated. Although the prevalence of skin-test results of 10 mm or more induration was significantly higher in those persons vaccinated after infancy than in those never vaccinated, the size of the reaction did not distinguish between reactions possibly caused by BCG vaccination and those possibly caused by M. tuberculosis infection. The results of a different study indicated that if a BCG-vaccinated person has a tuberculin skin test after exposure to M. tuberculosis and this test produces a reaction of more than 15 mm larger than that of a skin test conducted before the exposure, the increase in size between the two tests is probably associated with newly acquired M. tuberculosis infection.
Tuberculin skin testing is not contraindicated for persons who have been vaccinated with BCG, and the skin-test results of such persons are used to support or exclude the diagnosis of M. tuberculosis infection. A diagnosis of M. tuberculosis infection and the use of preventive therapy should be considered for any BCG-vaccinated person who has a tuberculin skintest reaction of 10 mm or more of induration, especially if any of the following circumstances are present: (1) the vaccinated persons is a contact of another person who has infectious tuberculosis, particularly if the infectious person has transmitted M. tuberculosis to others; (2) the vaccinated person was born or has resided in a country in which the prevalence of tuberculosis is high, or (3) the vaccinated person is exposed continually to populations in which the prevalence of tuberculosis is high.
Tuberculosis preventive therapy should be considered for BCG-vaccinated persons who are infected with HIV and who are at risk for M. tuberculosis infection if they have a tuberculin skin-test reaction of 5 mm or more of induration or if they are nonreactive to tuberculin. Responsiveness to tuberculin or other delayed-typed hypersensitivity antigens may be decreased in persons infected with HIV. A diagnosis of active tuberculosis disease should be considered for BCG-infected persons–regardless of their tuberculin skin-test results or HIV serostatus–if they have symptoms suggestive of tuberculosis, especially if they have been exposed recently to infectious tuberculosis.
Although BCG vaccination often results in local adverse effects, serious or long-term complications are rare (see table). BCG vaccination is usually administered by the intradermal method, and reactions that can be expected include moderate axillary or cervical lymphadenopathy, and induration and subsequent pustule formation at the injection site. More severe local reactions include ulceration at the vaccination site, regional suppurative lymphadenitis with draining sinuses, and caseous lesions or purulent drainage at the puncture site; these manifestations might occur within the five months after vaccination and could persist for several weeks. Higher rates of local reactions may result from subcutaneous injection in comparison with intradermal injection.
The most serious complication of BCG vaccination is disseminated BCG infection. BCG osteitis can occur from four months to two years after vaccination. The risk of developing BCG osteitis varies by country; in one review, the risk ranged from 0.01 cases per million vaccinees in Japan to 32.5 and 43.4 cases per million vaccinees in Sweden and Finland, respectively. Regional increases in the incidence of BCG osteitis have been noted following changes in either the vaccine strain or the method of production.
The safety of BCG vaccination in HIV-infected adults has not been determined by controlled or large studies. Persons who are infected with HIV are possibly at greater risk for lymphadenitis and other complications than are persons who are not infected with HIV. Case reports have indicated that BCG-related lymphadenitis, local ulceration and disseminated BCG disease may be more frequent among persons who have symptomatic HIV infection than among persons who are not infected with the virus or who have asymptomatic HIV infection.
All suspected adverse reactions (see table) to BCG vaccination should be reported to the Vaccine Adverse Event Reporting System; telephone: 800-822-7967.
Age-Specific Estimated Risks for Complications
After Administration of Bacille Calmette-Guerin (BCG) Vaccine
Complication Age<1 Year(*) Age 1 to
Local subcutaneous abscess, regional 387 25
Musculoskeletal lesions 0.39 to 0.89 0.06
Multiple lymphadenitis, nonfatal 0.31 to 0.39 0.36
Fatal disseminated lesions 0.19 to 1.56 0.06 to 0.72
(*)–Incidence per 1 million vaccinations.
From 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 of the Advisory Council for the Elimination of Tuberculosis and the
Advisory Committee on Immunization Practices. MMWR 1996;45(No. RR4):1-18.
COPYRIGHT 1996 American Academy of Family Physicians
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