Yes, there is a tuberculosis vaccine called BCG, but it is not routinely given in the United States

The BCG vaccine (Bacillus Calmette-Guérin) has existed since the 1920s and is used in many countries around the world. It protects against severe forms of tuberculosis, particularly in infants and young children. In the U.S., however, the CDC does not recommend BCG for the general population because TB rates are low and the vaccine's protection decreases over time.

BCG is given to certain groups in the U.S.: healthcare workers with ongoing TB exposure, people with confirmed TB infection who cannot take preventive medications, and people who will live in countries where TB is common. Outside the U.S., BCG is part of routine childhood vaccination schedules in most countries where TB remains a significant public health problem.

Key Takeaways

  • BCG is a live vaccine that protects against tuberculosis, especially severe disease in young children, but protection wanes over time.
  • The U.S. does not routinely vaccinate children with BCG because TB rates are low and preventive medications are available for people with TB infection.
  • BCG is offered in the U.S. to healthcare workers with TB exposure, people who cannot take TB preventive drugs, and those relocating to high-TB countries.
  • Most other countries give BCG as part of standard childhood vaccines because TB remains a common threat in their populations.
  • If you have been exposed to TB or have a positive TB test, preventive medications are the standard approach in the U.S., not vaccination.

How BCG protects against tuberculosis

BCG is a weakened form of the bacterium that causes TB. When injected, it trains your immune system to recognize and fight TB bacteria. The vaccine is most effective at preventing severe TB disease in infants and young children—it reduces the risk of TB meningitis and disseminated TB (TB that spreads throughout the body) by roughly 60 to 80 percent in vaccinated children.

Protection from BCG decreases over time, typically becoming less effective after 10 to 15 years. This is one reason the U.S. does not rely on it for TB control. Instead, the U.S. strategy focuses on finding people with TB infection early and treating them with preventive medications before they develop active disease.

Why the U.S. approach differs from other countries

The United States has a low rate of TB compared to most of the world. Because TB is uncommon here, the CDC determined that the benefits of routine BCG vaccination do not outweigh the drawbacks. BCG can cause a false-positive result on a TB skin test (the tuberculin skin test or TST), which complicates TB screening and diagnosis. In a country with low TB rates, this false-positive problem creates more confusion than benefit.

Countries with higher TB rates—including most of Africa, Asia, and parts of Latin America—include BCG in their routine childhood vaccination schedules. The vaccine's protection against severe disease in young children justifies the trade-off of false-positive skin tests in those settings.

Who receives BCG in the United States

BCG is offered to specific groups in the U.S., though it remains uncommon. Healthcare workers who have ongoing exposure to TB patients and have tested negative for TB infection may receive BCG. People with a positive TB test who cannot take or tolerate preventive medications (usually isoniazid or rifampin) may also be offered the vaccine, though this is rare.

People planning to live, work, or study in countries where TB is common may receive BCG before departure. Your doctor or travel medicine clinic can advise whether BCG makes sense for your situation based on your destination and how long you will be there.

What happens if you have been exposed to TB

If you have been exposed to TB or have tested positive for TB infection, the standard U.S. treatment is preventive medication, not vaccination. Medications such as isoniazid, rifampin, or newer regimens like isoniazid-rifapentine can reduce your risk of developing active TB disease by up to 90 percent. These medications work whether or not you have been vaccinated.

Your doctor will order a TB test (skin test or blood test) to determine whether you have TB infection. If the test is positive, you will be offered preventive treatment. BCG vaccination does not replace this treatment and is not used as a response to TB exposure in the U.S.

BCG and TB skin testing

One practical consequence of BCG vaccination is that it can cause a positive TB skin test result even if you do not have TB infection. This happens because the vaccine contains a weakened TB bacterium, and your immune system reacts to it the same way it would react to the real bacterium. Blood tests for TB infection (such as interferon-gamma release assays) are not affected by BCG and can help clarify whether a positive skin test means actual infection or just prior vaccination.

If you have received BCG and later have a positive TB skin test, tell your doctor about the vaccination. Your doctor may order a blood test or chest X-ray to determine whether you have actual TB infection or whether the positive skin test is from the vaccine.

Traveling to countries where TB is common

If you plan to live or work in a country with high TB rates, ask your doctor or travel medicine clinic whether BCG is recommended for you. The decision depends on how long you will be there, what kind of work you will do, and your personal risk of TB exposure. Healthcare workers, teachers, and others in close contact with many people may benefit more from BCG than tourists or short-term visitors.

Some countries require proof of BCG vaccination for entry or employment. Check the requirements for your destination before you travel. If you need BCG, your doctor can refer you to a travel medicine clinic or infectious disease specialist who administers the vaccine.

Frequently Asked Questions

Can I get BCG if I have already tested positive for TB?

No. BCG is only given to people who have tested negative for TB infection. If you have TB infection, you need preventive medication instead. The vaccine would not provide additional protection because your immune system has already encountered TB bacteria.

If I received BCG as a child in another country, do I need it again in the U.S.?

No. One dose of BCG provides protection for many years. You do not need a repeat dose. If you have a positive TB skin test after receiving BCG, ask your doctor for a blood test to determine whether you have actual TB infection or whether the positive result is from the vaccine.

Does BCG prevent all forms of tuberculosis?

No. BCG is most effective at preventing severe TB disease in young children, such as TB meningitis. It is less effective at preventing pulmonary TB (TB of the lungs) in adults. This is one reason preventive medications are preferred in the U.S.—they work against all forms of TB in all age groups.

What side effects does BCG cause?

BCG typically causes mild redness and swelling at the injection site. Some people develop a small scar. Serious side effects are rare. Because BCG is a live vaccine, it is not given to people with weakened immune systems, including those with HIV or those taking certain medications that suppress immunity.

If I work in healthcare, should I get BCG?

Only if you have ongoing exposure to TB patients and have tested negative for TB infection. Most healthcare workers in the U.S. are protected through TB screening programs and preventive treatment if needed. Talk to your occupational health department or doctor about whether BCG is appropriate for your specific role.