Yes, there is a tuberculosis vaccine, but it works differently than most vaccines you know

The BCG vaccine (Bacille Calmette-Guérin) is the main tuberculosis vaccine used worldwide. It protects against the most severe forms of TB, especially in young children, but it does not prevent all TB infections. In the United States, the BCG vaccine is rarely given to the general population because TB rates are low here and the vaccine can interfere with a skin test doctors use to detect TB infection.

Most people in the U.S. who are at high risk for TB are instead given preventive medications rather than the vaccine. If you have been exposed to TB or have a positive TB skin test, your doctor will likely recommend medicine to stop the infection from becoming active disease.

Key Takeaways

  • The BCG vaccine protects against severe TB in children but does not prevent all TB infections in adults.
  • The BCG vaccine is not routinely given in the United States because TB rates are low and the vaccine interferes with TB screening tests.
  • People at high risk for TB in the U.S. typically receive preventive medications instead of the vaccine.
  • The BCG vaccine is standard in countries where TB is common, and protection tends to fade over time.
  • Newer TB vaccines are being developed and tested to improve protection in adults.

How the BCG vaccine works and what it protects against

The BCG vaccine contains a weakened form of the bacterium that causes TB. When you receive the vaccine, your immune system learns to recognize and fight that bacterium. The vaccine is most effective at preventing severe TB in infants and young children—it reduces the risk of TB meningitis (infection of the membranes around the brain and spinal cord) and disseminated TB (TB that spreads throughout the body).

In adults, the BCG vaccine is less effective at preventing TB infection altogether. Studies show it prevents active TB disease in adults about 60 to 80 percent of the time, and this protection decreases over the years after vaccination. The vaccine does not prevent you from being infected with the TB bacterium, but it can reduce your chances of developing active disease if you are exposed.

Why the BCG vaccine is not used in the United States

The U.S. does not include the BCG vaccine in its routine childhood vaccination schedule for several reasons. First, TB rates in the U.S. are much lower than in countries where BCG is standard. Second, the BCG vaccine can cause a positive result on the tuberculin skin test (also called the Mantoux test), which doctors use to detect TB infection. This makes it harder for doctors to tell whether a positive skin test means someone has TB infection or simply received the vaccine.

Because of this interference with TB testing, people who received the BCG vaccine may need different tests—such as TB blood tests—to check for infection. The CDC recommends BCG vaccination only for specific groups in the U.S., such as healthcare workers or people living with someone who has drug-resistant TB, and only after careful discussion with a doctor.

Who receives the BCG vaccine and where it is used

The BCG vaccine is part of the standard childhood vaccination schedule in more than 180 countries, particularly in regions where TB is common. It is given to newborns or infants in most of Africa, Asia, Latin America, and Eastern Europe. In these countries, the benefit of preventing severe TB in children outweighs the drawback of interfering with TB testing.

If you were born outside the U.S. or in certain U.S. communities with high TB rates, you may have received the BCG vaccine as a child. You can ask your parents or check your vaccination records to find out. Having received the BCG vaccine does not mean you are immune to TB for life—protection fades over time, and you can still develop TB if exposed to the bacterium.

Preventive medications as an alternative to vaccination

In the U.S., people who have been exposed to TB or who have a positive TB test are usually given preventive medications rather than the vaccine. These medications stop TB infection from progressing to active disease. The most common preventive regimen is isoniazid, taken daily for 6 to 9 months, though shorter courses with different drug combinations are also used.

Preventive medications are highly effective—they reduce the risk of developing active TB by about 90 percent in people with TB infection. This approach is preferred in the U.S. because it targets people who actually need protection and does not interfere with TB testing. Your doctor will recommend preventive medications if you have a positive TB test, have been in close contact with someone who has active TB, or have certain medical conditions that increase your TB risk.

New TB vaccines in development

Scientists are working on new TB vaccines designed to improve protection in adults and to work better alongside existing TB tests. These vaccines are being tested in clinical trials in several countries. Some are designed to boost immunity in people who received the BCG vaccine as children, while others are entirely new approaches.

One vaccine candidate, called M72/AS01E, has shown promise in clinical trials and may become available in the coming years. These newer vaccines aim to provide better protection against TB in adults and to avoid the testing interference problem that limits BCG use in the U.S. However, they are not yet approved for routine use, and it will take time before they become widely available.

What happens if you have been exposed to TB

If you have been in close contact with someone who has active TB, your doctor will likely order a TB test to see if you have been infected. This test can be a skin test or a blood test. If the test is positive, it means you have TB infection, but not necessarily active disease.

Your doctor will then examine you for signs of active TB and may order a chest X-ray. If you have TB infection but no active disease, you will be offered preventive medications to reduce your risk of developing active TB later. Taking these medications as prescribed is the most effective way to protect yourself. The BCG vaccine would not be given at this point because you have already been exposed to the bacterium.

Frequently Asked Questions

If I received the BCG vaccine as a child, am I protected from TB for life?

No. BCG protection fades over time, typically within 10 to 20 years. If you received the vaccine as a child and are now an adult, your protection has likely decreased significantly. If you are exposed to TB, you should still be tested and may need preventive medications.

Can I get the BCG vaccine in the U.S. if I want it?

The BCG vaccine is not routinely given in the U.S., but it may be offered to certain high-risk groups after discussion with a doctor. Talk to your healthcare provider about whether the vaccine is appropriate for your situation. They can explain the benefits and drawbacks specific to you.

What is the difference between a TB vaccine and TB preventive medications?

A vaccine trains your immune system to fight TB before exposure. Preventive medications are taken after exposure or after a positive TB test to stop infection from becoming active disease. In the U.S., preventive medications are the standard approach for people at risk.

If I have a positive TB skin test, does that mean I have active TB?

No. A positive skin test means you have TB infection, but your body may be controlling it without symptoms. Your doctor will do additional tests, such as a chest X-ray and sputum test, to determine whether you have active TB disease. If you have infection only, preventive medications can stop it from progressing.

Are the new TB vaccines better than BCG?

The new vaccines being tested aim to provide better protection in adults and to avoid interfering with TB testing. However, they are still in development and not yet approved for routine use. When available, they may offer an additional tool for TB prevention, especially in high-risk populations.