Who should receive the BCG (Bacillus Calmette-Guérin) vaccine for tuberculosis prevention?

BCG Vaccine Recipients for Tuberculosis Prevention

BCG vaccination is NOT recommended for routine use in the United States and should only be considered in very specific high-risk situations where children cannot be separated from infectious TB sources or where healthcare workers face ongoing exposure to multidrug-resistant TB despite comprehensive infection control measures. 1

Primary TB Control Strategy in the United States

The cornerstone of TB prevention in the U.S. is early identification and treatment of active infectious TB cases, not vaccination. 2 The second-line strategy involves identifying persons with latent M. tuberculosis infection and providing preventive therapy with isoniazid or rifampin. 2, 1

BCG has limited utility in the U.S. because:

• Its effectiveness in preventing infectious pulmonary TB in adolescents and adults is variable and uncertain 1, 3
• Post-vaccination tuberculin reactivity interferes with diagnosing new M. tuberculosis infections 2, 1
• The overall risk of M. tuberculosis infection in the U.S. population is low 2

Specific Indications for BCG Vaccination

Children (Infants and Children <5 Years)

BCG should be considered ONLY when ALL of the following criteria are met: 2, 1

1. The child has a negative tuberculin skin test (<5mm induration) 4

2. AND one of these exposure scenarios exists:

   • Continuous exposure to an untreated or ineffectively treated adult with infectious pulmonary TB, where the child cannot be separated from the infectious source and cannot receive long-term preventive therapy 2, 1
   • Continuous exposure to a patient with infectious pulmonary TB caused by M. tuberculosis strains resistant to both isoniazid AND rifampin, where separation is impossible 2, 1

Critical pediatric considerations:

• BCG provides >80% protection against severe childhood TB forms (tuberculous meningitis and disseminated TB) 1, 3
• Children <5 years are at highest risk for severe TB disease, warranting special protection efforts 2
• BCG is absolutely contraindicated in HIV-infected children due to risk of fatal disseminated BCG disease 2, 1, 5
• If maternal HIV status is unknown or positive, confirm infant HIV testing before vaccination 5
• Infants exposed to maternal anti-TNF biologics (infliximab, adalimumab, golimumab) during the second half of pregnancy must delay BCG until at least 6 months of age 5

Healthcare Workers

BCG vaccination of healthcare workers should be considered on an individual basis ONLY when ALL three conditions are present: 2

1. A high percentage of TB patients are infected with M. tuberculosis strains resistant to both isoniazid AND rifampin 2

2. Transmission of such drug-resistant strains to healthcare workers and subsequent infection is likely 2

3. Comprehensive TB infection-control precautions have been implemented and have NOT been successful 2

Important healthcare worker caveats:

• BCG should never be required for employment or work assignments 2
• BCG is not recommended as a primary prevention strategy because protective efficacy in healthcare workers is uncertain 2, 1
• Even if BCG protects an individual worker, it does not protect other persons in the facility (patients, visitors, other staff) 2
• BCG is absolutely contraindicated in HIV-infected or immunocompromised healthcare workers 2, 1, 5
• In low-risk settings (most U.S. healthcare facilities), BCG is not recommended 2

Counseling requirements before vaccination: Healthcare workers must be informed about: 2

• Variable data on BCG efficacy
• Interference with diagnosing newly acquired M. tuberculosis infection
• Possible serious complications in immunocompromised persons, especially HIV-infected individuals
• Lack of efficacy data for preventive therapy against isoniazid and rifampin-resistant strains
• Drug toxicity risks with multidrug preventive therapy regimens

HIV-Infected Persons

BCG vaccination is NOT recommended for HIV-infected persons of any age. 2, 1, 5 This is based on:

• Unknown protective efficacy in HIV-infected individuals 2
• Risk of disseminated BCG disease, which can be fatal 2, 5
• Case reports of disseminated BCG infection in HIV-infected children and adults 2

Instead, TB preventive therapy with isoniazid should be administered (unless contraindicated) to HIV-infected persons who might be coinfected with M. tuberculosis, with demonstrated 61-83% reduction in active TB disease risk. 2

Absolute Contraindications

Never administer BCG to: 2, 1, 5, 4

• HIV-infected individuals (any age)
• Immunocompromised persons
• Pregnant women 4
• Symptomatic HIV infection or AIDS patients 3
• Persons with tuberculin skin test ≥5mm induration (indicating possible prior TB infection) 4

Pre-Vaccination Requirements

Before BCG administration: 4

• Tuberculin skin testing with 5 tuberculin units of PPD must show <5mm induration 4
• Confirm HIV-negative status if any risk factors present 5, 4
• Verify no immunocompromising conditions 5, 4
• Check for maternal anti-TNF biologic exposure in infants 5

Post-Vaccination Management

Expected normal reaction: 4

• Bluish-red pustule forms within 2-3 weeks
• Eventually ulcerates and forms a lesion
• Heals within 3 months, leaving a permanent scar
• Perform tuberculin skin test 3 months post-vaccination to document reactivity 4

Warning signs requiring evaluation: 5

• Persistent reactions beyond 4 months warrant evaluation for BCG osteitis or disseminated infection
• If disseminated BCG disease suspected, initiate anti-TB therapy immediately but NEVER use pyrazinamide (all BCG strains are universally resistant) 2, 5

Critical Practice Point

Physicians considering BCG vaccination must consult with local TB control programs before proceeding. 1, 4 BCG is rarely indicated in the United States, and expert guidance is essential for appropriate patient selection. 1, 4