The BCG vaccine helps prevent severe forms of tuberculosis, such as miliary tuberculosis and tuberculous meningitis. It works by stimulating the immune system to develop protection against Mycobacterium tuberculosis, the bacterium that causes tuberculosis
The vaccine contains a live, weakened form of Mycobacterium bovis known as Bacillus Calmette-Guérin. Because the bacteria are weakened, the vaccine does not cause tuberculosis and is generally considered safe
In the United States, the BCG vaccine is not routinely given because tuberculosis is relatively uncommon. It may be considered in specific situations when a person has a high and ongoing risk of exposure to tuberculosis
What it’s for
The BCG vaccine helps prevent severe forms of tuberculosis, including miliary tuberculosis and tuberculous meningitis
The vaccine contains live, weakened bacilli of Mycobacterium bovis. When these weakened bacteria enter the body, they stimulate the immune system to develop an immune response against Mycobacterium tuberculosis, the bacterium that causes tuberculosis
The BCG vaccine may also provide partial protection against leprosy, an infectious disease that can cause pale or reddish skin patches, loss of sensation in the skin, and muscle weakness
BCG vaccine in newborns
The BCG vaccine is not routinely given to newborns in the United States. It may be considered for certain children who have a high and ongoing risk of exposure to tuberculosis
Because a baby’s immune system is still developing, vaccination may help protect high-risk children against severe forms of tuberculosis when BCG vaccination is considered appropriate
When to get it
In the United States, the BCG vaccine is not part of the routine childhood vaccination schedule
It may be considered for certain children who:
Have a negative tuberculosis test;
Are continually exposed to an adult with untreated or ineffectively treated infectious tuberculosis;
Cannot be separated from that person or given appropriate preventive treatment
BCG vaccination should be considered in consultation with a tuberculosis expert
How long does protection last?
There is no single established duration of protection from the BCG vaccine. However, the vaccine is especially effective at protecting babies and children against severe forms of tuberculosis
Protection can decrease over time because the immune response produced by the vaccine may not remain strong enough to provide long-lasting protection into adulthood
For this reason, BCG has variable effectiveness against pulmonary tuberculosis in adults and is not routinely recommended for adults in the United States
How it’s administered
The way the BCG vaccine is administered depends on the vaccine product. It should always be given by a doctor, nurse, or other properly trained health care professional
The FDA-approved BCG vaccine used for tuberculosis prevention in the United States is administered through the skin using a multiple-puncture device
A local skin reaction normally develops after BCG vaccination. A small raised red area may appear and later develop into a small sore before gradually healing and leaving a scar
Care after the vaccine
After BCG vaccination, the vaccination site should generally be left uncovered and allowed to heal naturally. Bandages or adhesive dressings should not be routinely placed over the area unless recommended by a health care professional
Ointments, medications, or other substances should not be applied to the site unless specifically recommended by a health care professional. The area should be kept clean while it heals
Possible adverse reactions
Common reactions to the BCG vaccine include redness, tenderness, and swelling at the vaccination site. A small bump may develop and later become a small ulcer before gradually healing and leaving a scar
Although uncommon, some children may develop swollen lymph nodes, skin lesions, swelling in the armpit, or a larger ulcer that takes longer than expected to heal. If these reactions occur, a pediatrician or other health care professional should be consulted
BCG vaccine scar
A scar after BCG vaccination is a normal local reaction and shows that the body responded to the vaccine
The size of the scar and the time it takes to develop can vary. The local reaction may take several weeks or months to heal and can leave a small scar
However, not developing a scar does not necessarily mean that the vaccine did not work. Revaccination solely because a scar did not form is generally not recommended
Who should not get it
The BCG vaccine should not be given to people for whom the vaccine is contraindicated. A health care professional should determine whether vaccination is appropriate
Because BCG is a live vaccine, it should not be given to people with significantly weakened immune systems
BCG vaccination should not be given to people with HIV or other significant immunodeficiencies, people receiving immunosuppressive treatment, or anyone with a serious allergy to a component of the vaccine. BCG vaccination is also not recommended during pregnancy
Update History
We regularly update our content with the latest scientific information to maintain an exceptional level of quality.
- 12 August, 2026 (Current version)
Updated by
Daisy Oliveira – Registered Nurse
Updated by
Daisy Oliveira – Registered Nurse
Updated by
Daisy Oliveira – Registered Nurse - 11 August, 2026
- Created on
August, 2026
by
Daisy Oliveira
– Registered Nurse
References
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- Badurdeen S, Marshall A, Daish H, Hatherill M, Berkley JA. Safety and Immunogenicity of Early Bacillus Calmette-Guérin Vaccination in Infants Who Are Preterm and/or Have Low Birth Weights: A Systematic Review and Meta-analysis. JAMA Pediatrics. 2019;173(1):75-85.
- Bannister S, Sudbury E, Villanueva P, Perrett K, Curtis N. The safety of BCG revaccination: A systematic review. Vaccine. 2021;39(20):2736-2745.
- Kuan R, Muskat K, Peters B, Lindestam Arlehamn CS. Is mapping the BCG vaccine-induced immune responses the key to improving the efficacy against tuberculosis?. Journal of Internal Medicine. 2020;288(6):651-660.
- Bisetto LHL, Ciosak SI. Analysis of adverse events following immunization caused by immunization errors. Revista Brasileira de Enfermagem. 2017;70(1):87-95.
- Okuno H, Satoh H, Morino S, Arai S, Ochiai M, Fujita K, Naito S, Kato A, Ishii K, Oishi K, Suzuki M, Tanaka-Taya K. Characteristics and incidence of vaccine adverse events after Bacille Calmette-Guérin vaccination: A national surveillance study in Japan from 2013 to 2017. Vaccine. 2022;40(33):4922-4928.
- World Health Organization. Summary of the WHO Position Paper on BCG vaccines: WHO position paper – February 2018. World Health Organization. 2018. Accessed 11 Aug 2026 https://www.who.int/docs/default-source/immunization/position_paper_documents/tuberculosis-(bcg)/pp-bcg-summary-2018.pdf
- World Health Organization. Table 1 BCG efficacy and effectiveness. World Health Organization. 2018. Accessed 11 Aug 2026 https://cdn.who.int/media/docs/default-source/immunization/position_paper_documents/tuberculosis-(bcg)/bcg-efficacy-tb.pdf?sfvrsn=371c45ae_2
- World Health Organization. Table 5 Need for revaccination. World Health Organization. 2018. Accessed 11 Aug 2026 https://cdn.who.int/media/docs/default-source/immunization/position_paper_documents/tuberculosis-(bcg)/bcg-evidence-recommendation-table-revaccination.pdf?sfvrsn=7eb27cf3_2
- U.S. Food and Drug Administration. Package Insert: BCG Vaccine, for Percutaneous Use. U.S. Food and Drug Administration. Accessed 11 Aug 2026 https://www.fda.gov/files/vaccines%2C%20blood%20%26%20biologics/published/Package-Insert—BCG-Vaccine.pdf
- Centers for Disease Control and Prevention. Bacille Calmette-Guérin (BCG) Vaccine for Tuberculosis. Centers for Disease Control and Prevention. Updated 31 Jan 2025. Accessed 11 Aug 2026 https://www.cdc.gov/tb/hcp/vaccines/index.html
- Centers for Disease Control and Prevention. Vaccines By Disease. Centers for Disease Control and Prevention. Updated 14 Aug 2024. Accessed 11 Aug 2026 https://www.cdc.gov/vaccines/hcp/by-disease/
- U.S. Food and Drug Administration. BCG Vaccine. U.S. Food and Drug Administration. Accessed 11 Aug 2026 https://www.fda.gov/vaccines-blood-biologics/vaccines/bcg-vaccine
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