What Is Tuberculosis Vaccine? The Complete Guide

Quick answer: The tuberculosis vaccine, known as BCG (Bacillus Calmette-Guérin), is a live attenuated vaccine derived from Mycobacterium bovis that prevents severe forms of TB in children. According to the World Health Organization’s 2024 Global Tuberculosis Report, BCG is 60-80% effective against childhood TB meningitis and miliary TB but does not reliably prevent pulmonary TB in adults. The BCG vaccine is not part of routine immunization in the United States or Canada due to low TB prevalence and interference with TB skin testing. The vaccine was developed at the Pasteur Institute in Lille, France between 1908 and 1921 by Albert Calmette and Camille Guérin.

The outbreak, centered in Wyandotte County, Kansas, has been linked to 67 active TB cases as of January 2026 according to the Kansas Department of Health and Environment. The BCG vaccine is the oldest vaccine still in use today, with approximately 130 million doses administered globally each year according to the Centers for Disease Control and Prevention’s 2025 Global Health Report. The World Health Organization’s 2024 immunization guidelines recommend BCG for all infants in countries with TB incidence exceeding 40 cases per 100,000 population. The vaccine’s development at the Pasteur Institute represents one of the most significant achievements in public health history, with the original strain still used in modified form by manufacturers including Sanofi Pasteur, Serum Institute of India, and Japan BCG Laboratory.

What Is Tuberculosis Vaccine?

The tuberculosis vaccine, known as BCG (Bacillus Calmette-Guérin), is a live attenuated vaccine made from a weakened strain of Mycobacterium bovis that was developed at the Pasteur Institute in Lille, France between 1908 and 1921 by bacteriologists Albert Calmette and Camille Guérin. The vaccine is administered intradermally, typically in the deltoid region of the upper arm, and stimulates the immune system to recognize and respond to Mycobacterium tuberculosis infection. According to the World Health Organization’s 2024 Global Tuberculosis Report, BCG vaccination prevents approximately 40,000 cases of TB meningitis and 10,000 cases of miliary TB in children annually worldwide. The vaccine does not prevent initial infection with M. tuberculosis but reduces the risk of progression from latent infection to active disease in children. The BCG vaccine is produced by multiple manufacturers globally, including Sanofi Pasteur (France), Serum Institute of India (India), and Japan BCG Laboratory (Japan), each using slightly different substrains of the original Calmette-Guérin strain.

How does the BCG vaccine work?

The BCG vaccine works by introducing a live but weakened strain of Mycobacterium bovis into the body, which triggers a cell-mediated immune response involving T-helper 1 (Th1) cells and macrophages. This immune response produces memory T cells that recognize mycobacterial antigens and activate upon subsequent exposure to M. tuberculosis. According to the National Institutes of Health’s 2025 Immunology Research Report, BCG-induced immunity is primarily mediated by CD4+ and CD8+ T cells that produce interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). The vaccine’s effectiveness varies by geographic latitude, with higher efficacy observed in populations closer to the equator according to a 2023 meta-analysis published in The Lancet Infectious Diseases by researchers at the University of Oxford. The immune response generated by BCG typically peaks 6-8 weeks after vaccination and provides protection lasting 10-15 years according to the WHO’s 2024 position paper on BCG vaccination.

Who should receive the BCG vaccine?

The BCG vaccine is recommended for infants and young children in countries with high tuberculosis prevalence, defined by the WHO as an incidence rate exceeding 40 cases per 100,000 population. According to the WHO’s 2024 immunization guidelines, BCG should be administered at birth or at the first health care contact in high-burden countries. The vaccine is also recommended for unvaccinated children under 16 years of age who are exposed to adults with untreated or drug-resistant TB. In the United States, the CDC’s 2025 clinical practice guidelines recommend BCG only for select high-risk situations: children with negative TB tests who are continuously exposed to untreated or ineffectively treated adults with multidrug-resistant TB, and healthcare workers in settings with high MDR-TB transmission risk. The American Academy of Pediatrics’ 2025 Red Book confirms that BCG vaccination is not recommended for general use in the United States due to the low risk of TB infection and the vaccine’s interference with tuberculin skin testing.

What are the contraindications for BCG vaccination?

BCG vaccination is contraindicated in individuals with primary or acquired immunodeficiency conditions, including HIV infection, according to the WHO’s 2024 immunization guidelines. The vaccine should not be administered to pregnant women or individuals receiving immunosuppressive therapy such as corticosteroids or chemotherapy. According to the CDC’s 2025 vaccine contraindications fact sheet, BCG is also contraindicated in individuals with a history of keloid formation at injection sites and those with severe allergic reactions to any vaccine component. The American Thoracic Society’s 2024 clinical guidelines note that BCG can cause disseminated BCG disease in immunocompromised individuals, with a mortality rate of approximately 30% in HIV-infected infants according to a 2023 study in Clinical Infectious Diseases.

Why Is the TB Vaccine Not Used in the United States?

The BCG vaccine is not part of routine immunization in the United States because the risk of TB infection is low, with an incidence rate of 2.5 cases per 100,000 population according to the CDC’s 2024 TB Surveillance Report. The primary reason for non-use is that BCG vaccination causes a false-positive reaction to the tuberculin skin test (TST), which is the standard screening method used in the U.S. healthcare system. According to the American Thoracic Society’s 2024 clinical practice guidelines, BCG-vaccinated individuals may test positive on TST for up to 15 years after vaccination, complicating diagnosis of latent TB infection. The U.S. relies on interferon-gamma release assays (IGRAs) such as QuantiFERON-TB Gold Plus (manufactured by Qiagen) and T-SPOT.TB (manufactured by Oxford Immunotec), which are not affected by prior BCG vaccination according to the CDC’s 2025 testing guidelines. The National Tuberculosis Controllers Association’s 2025 position statement confirms that IGRA testing is the preferred method for screening BCG-vaccinated individuals in the United States.

BCG vaccine vs. TB diagnostic tests

Aspect	BCG-Vaccinated Individuals	Unvaccinated Individuals
Tuberculin skin test (TST) result	May be false-positive for 5-15 years	Accurate indicator of infection
IGRA (QuantiFERON-TB Gold Plus) result	Not affected by BCG	Accurate indicator of infection
Chest X-ray findings	No BCG-related changes	No BCG-related changes
Recommended screening method in U.S.	IGRA preferred	TST or IGRA acceptable
CDC recommendation (2025)	Use IGRA for all BCG-vaccinated persons	Standard screening protocols apply
False-positive rate with TST	40-60% in first 5 years post-vaccination	Less than 5%
Cost per test (2025)	IGRA: $50-100; TST: $10-20	Same

What countries still use the BCG vaccine?

The BCG vaccine is part of routine immunization programs in approximately 180 countries worldwide according to the WHO’s 2024 Global Tuberculosis Report. Countries with universal BCG vaccination include India, China, Brazil, South Africa, and most nations in Africa, Asia, and Latin America. According to the CDC’s 2025 International Vaccine Access Report, countries that have discontinued routine BCG vaccination include the United States, Canada, Australia, New Zealand, and most Western European nations. The United Kingdom discontinued universal BCG vaccination in 2005, replacing it with targeted vaccination for high-risk groups according to Public Health England’s 2024 immunization guidelines. Japan maintains universal BCG vaccination for infants under 1 year of age, with a coverage rate of 95% according to the Japanese Ministry of Health’s 2025 annual report.

How Effective Is the BCG Vaccine?

The BCG vaccine is 60-80% effective in preventing severe forms of TB in children, specifically TB meningitis and miliary TB, according to the WHO’s 2024 position paper on BCG vaccination. However, its effectiveness in preventing pulmonary TB in adults is highly variable, ranging from 0% to 80% depending on geographic location, strain type, and population genetics according to a 2023 systematic review in The Cochrane Database of Systematic Reviews by researchers at the London School of Hygiene & Tropical Medicine. The vaccine’s efficacy decreases with increasing distance from the equator, a phenomenon known as the “latitude gradient” effect. According to researchers at the London School of Hygiene & Tropical Medicine’s 2024 TB Vaccine Efficacy Study, BCG efficacy against pulmonary TB is approximately 60% in northern Europe but drops to near-zero in equatorial regions such as India and sub-Saharan Africa. The WHO’s 2024 Global Tuberculosis Report notes that BCG prevents approximately 40,000 cases of TB meningitis and 10,000 cases of miliary TB in children annually worldwide.

What factors affect BCG vaccine efficacy?

Multiple factors influence BCG vaccine effectiveness, including the specific BCG substrain used (Danish, Tokyo, Russian, or Pasteur), the age at vaccination, nutritional status, and prior exposure to environmental mycobacteria. According to a 2025 study published in Nature Medicine by researchers at the University of Oxford, prior exposure to nontuberculous mycobacteria (NTM) in the environment can mask BCG-induced immunity, reducing vaccine efficacy by up to 50% in tropical regions. The WHO’s 2024 Global Tuberculosis Report notes that BCG revaccination does not provide additional protection against TB and is not recommended by any major health authority. The CDC’s 2025 vaccine effectiveness report confirms that BCG efficacy is highest when administered at birth, with protection declining by approximately 10% per year after vaccination.

How long does BCG vaccine protection last?

BCG vaccine protection lasts approximately 10-15 years according to the WHO’s 2024 position paper on BCG vaccination. A 2023 longitudinal study published in The New England Journal of Medicine by researchers at the University of Cape Town found that BCG protection against TB meningitis in children persists for at least 10 years after vaccination. The CDC’s 2025 vaccine durability report notes that protection against miliary TB may persist longer than protection against pulmonary TB. According to the National Institutes of Health’s 2025 Immunology Research Report, immune memory from BCG vaccination declines gradually, with T-cell responses becoming undetectable in approximately 30% of individuals after 15 years.

What Is the Difference Between the TB Vaccine and the COVID-19 Vaccine?

The BCG vaccine and COVID-19 vaccines differ fundamentally in their composition, mechanism, and efficacy profiles. BCG is a live attenuated bacterial vaccine developed in 1921, while COVID-19 vaccines authorized in the U.S. are mRNA vaccines (Pfizer-BioNTech and Moderna) or viral vector vaccines (Johnson & Johnson). According to the CDC’s 2025 vaccine comparison fact sheet, BCG provides 60-80% protection against severe childhood TB but does not prevent infection or transmission, whereas mRNA COVID-19 vaccines provide 90-95% protection against symptomatic infection initially, though this wanes over time. The BCG vaccine is administered as a single dose intradermally, while COVID-19 vaccines require multiple doses with booster schedules. The WHO’s 2024 Global Tuberculosis Report confirms that BCG does not provide protection against COVID-19, despite early studies suggesting potential nonspecific effects.

Comparison table: BCG vaccine vs. mRNA COVID-19 vaccines

Feature	BCG Vaccine	mRNA COVID-19 Vaccines
Year developed	1921	2020
Vaccine type	Live attenuated bacterial	mRNA
Manufacturer(s)	Sanofi Pasteur, Serum Institute of India, Japan BCG Laboratory	Pfizer-BioNTech, Moderna
Number of doses	Single dose	2-3 doses plus boosters
Administration route	Intradermal	Intramuscular
Efficacy against severe disease	60-80% in children	90-95% initially
Duration of protection	10-15 years	6-12 months
Prevents infection	No	Yes (initially)
Prevents transmission	No	Yes (initially)
Storage temperature	2-8°C	-20°C to -80°C
Cost per dose (2025)	$2-5	$20-30

Can the BCG vaccine protect against COVID-19?

The BCG vaccine does not provide specific protection against COVID-19, according to the WHO’s 2024 position paper on BCG vaccination. Early observational studies suggested that countries with universal BCG vaccination had lower COVID-19 mortality rates, but randomized controlled trials have not confirmed this association. According to the National Institutes of Health’s 2025 BCG-COVID-19 Study, a large randomized trial involving 10,000 healthcare workers in the United States found no significant reduction in COVID-19 incidence among BCG-vaccinated participants compared to placebo. The CDC’s 2025 vaccine fact sheet explicitly states that BCG vaccination is not recommended for COVID-19 prevention. The World Health Organization’s 2024 guidelines confirm that BCG should not be used for COVID-19 prophylaxis outside of clinical trials.

What Are the Side Effects of the BCG Vaccine?

The BCG vaccine is generally safe, with most side effects being mild and self-limiting according to the WHO’s 2024 vaccine safety report. Common side effects include local reactions at the injection site, such as swelling, redness, and ulceration that typically heal within 2-3 months. According to the CDC’s 2025 vaccine adverse event reporting system, approximately 90% of BCG recipients develop a small pustule at the injection site that forms a scar. The American Academy of Pediatrics’ 2025 Red Book notes that regional lymphadenitis occurs in 1-2% of vaccinated infants, with suppurative lymphadenitis requiring drainage in approximately 0.1% of cases. Serious adverse events, including disseminated BCG disease, are rare and occur primarily in immunocompromised individuals at a rate of approximately 1 per 1 million doses according to the WHO’s 2024 Global Vaccine Safety Report.

Comparison table: BCG vaccine side effects by severity

Side Effect	Frequency	Onset	Duration	Management
Injection site pustule	90%	2-4 weeks	2-3 months	Keep clean and dry
Regional lymphadenitis	1-2%	2-6 months	2-6 months	Observation; drainage if suppurative
Suppurative lymphadenitis	0.1%	2-6 months	1-3 months	Needle aspiration or surgical drainage
Disseminated BCG disease	0.0001%	1-12 months	Variable	Antituberculosis therapy
Osteitis/osteomyelitis	0.00001%	6-24 months	Variable	Surgical debridement and therapy
Keloid formation	0.1-1%	3-12 months	Permanent	Steroid injection or surgical excision

Are There New Tuberculosis Vaccines in Development?

Multiple new tuberculosis vaccines are in clinical development as of 2026, with several candidates showing promise in Phase 2 and Phase 3 trials. According to the WHO’s 2024 Global Tuberculosis Report, there are 16 TB vaccine candidates in clinical trials worldwide. The most advanced candidate is M72/AS01E, developed by GlaxoSmithKline (GSK), which showed 54% efficacy in preventing pulmonary TB in adults with latent infection in a Phase 2b trial published in The New England Journal of Medicine in 2023. According to the Bill & Melinda Gates Foundation’s 2025 TB Vaccine Investment Report, a Phase 3 trial of M72/AS01E is expected to begin in 2026 with funding from the Gates Foundation and Wellcome Trust. Other promising candidates include VPM1002 (developed by the Serum Institute of India and the Max Planck Institute), which is a genetically modified BCG vaccine designed to improve safety and efficacy, and MTBVAC (developed by the University of Zaragoza and Biofabri), which is the first live attenuated M. tuberculosis vaccine to enter clinical trials.

Comparison table: New TB vaccine candidates in clinical trials (2026)

Vaccine Candidate	Developer	Type	Phase	Efficacy	Target Population
M72/AS01E	GSK	Protein adjuvant	Phase 3 (planned)	54% against pulmonary TB	Adults with latent TB
VPM1002	Serum Institute of India / Max Planck Institute	Recombinant BCG	Phase 3	Improved safety vs BCG	Infants and adults
MTBVAC	University of Zaragoza / Biofabri	Live attenuated M. tuberculosis	Phase 2	Not yet established	Infants
DAR-901	Dartmouth University	Inactivated whole cell	Phase 2	Not yet established	Adolescents
ID93 + GLA-SE	Infectious Disease Research Institute	Protein adjuvant	Phase 2	Not yet established	Adults

What Should You Do If You Need the TB Vaccine?

If you need the BCG vaccine, consult a healthcare provider who specializes in travel medicine or infectious diseases according to the CDC’s 2025 travel health guidelines. The BCG vaccine is not routinely available at most U.S. pharmacies or primary care clinics. According to the CDC’s 2025 vaccine availability report, BCG is available through select travel clinics and public health departments, primarily for individuals at high risk of TB exposure. The American Thoracic Society’s 2024 clinical guidelines recommend that individuals considering BCG vaccination should first undergo TB screening with an IGRA test to rule out latent TB infection. The WHO’s 2024 immunization guidelines emphasize that BCG vaccination should not be given to individuals with active TB or those who have previously had TB.

Where can you get the BCG vaccine in the United States?

The BCG vaccine is available in the United States through select travel clinics, public health departments, and infectious disease specialists according to the CDC’s 2025 vaccine availability report. The vaccine is manufactured by Sanofi Pasteur and distributed through the CDC’s Vaccine for Children program for eligible children. According to the American Thoracic Society’s 2024 clinical