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Magill’s Medical Guide, 9th Edition

Tuberculosis (TB) vaccine

by Michael A. Buratovich, PhD

Category: Prevention

Also known as: Bacille Calmette-Guérin, BCG, Bacillus Calmette-Guérin vaccine

Anatomy or system affected: Immune system, lymphatic system, skin

Specialties and related fields: Bacteriology, immunology, microbiology, preventive medicine, public health

Definition: a vaccine primarily used against tuberculosis

Key terms:

attenuated strains: a strain of a microorganism whose pathogenicity has been reduced so that it will initiate the immune response without producing the specific disease

subunit vaccine: a vaccine that contains purified parts of the pathogen that are antigenic or necessary to elicit a protective immune response

whole-cell vaccines: vaccines that contain whole cells of the pathogen that have been genetically modified in the laboratory

DEFINITION

The tuberculosis (TB) vaccine is a weakened strain of live bacteria that infect cattle. Albert Calmette and Camille Guérin developed the vaccine to prevent TB, an infectious disease of humans and animals caused by various strains of bacteria of the genus Mycobacterium. The weakened strain (M. bovis) was obtained by repeatedly growing it in ox bile media until a strain was produced that would not kill experimental animals nor revert to an infectious state. The vaccine, also known as BCG (for its developers), was first used as a vaccine in 1921 after thirteen years of development.

VACCINE ADMINISTRATION

BCG is administered through the skin either by injection or by multiple punctures. Localized skin reactions can occur after vaccination. If drainage occurs, the wound must be covered to prevent transmission of the weakened live bacteria. Serious side effects may include bone infection and disseminated disease, especially in persons who have compromised immune systems.

VACCINE EFFICACY

Studies have shown that BCG protects against tuberculous meningitis and miliary (disseminated) TB in children but provides inadequate prevention against pulmonary TB in adults. Studies also conflict with the duration of protection, ranging from ten to fifteen years to fifty to sixty years. Study designs, geographical location, and statistical factors may have influenced these variable outcomes.

Several factors may influence vaccine efficacy, including the immune status of vaccinated persons. For example, although persons exposed to Mycobacterium that is endemic to their environment have some inherent protection against Mycobacterium infections, their immune response to BCG is not as pronounced as in persons who have not been exposed to Mycobacterium, such as newborns, infants, and those who live in nonendemic areas.

OFFICIAL RECOMMENDATIONS

BCG is not generally recommended in the United States because of the low prevalence of TB, variable vaccine efficacy, and interference of BCG with the tuberculin skin test (TST). Selective BCG use is recommended in some persons, such as children, with negative TST and continually exposed to adults with untreated TB or persons infected by strains resistant to isoniazid and rifampin. Healthcare workers should be considered for BCG vaccination in specific situations.

BCG vaccination should not be given to immunocompromised persons, such as those with cancer, those with viral infections such as human immunodeficiency virus (HIV), and those taking medications (such as steroids) that cause immune suppression. Pregnant women should not be vaccinated because of live bacteria in the vaccine.

FUTURE VACCINES

Several TB vaccines are under investigation because of drug-resistant strains, the threat of TB in immunocompromised persons, the easy spread of the disease through the air, and the increasing number of infections relative to population growth. These newer vaccines include genetically modified BCG strains, M. tuberculosis mutants, M. tuberculosis antigens introduced by viruses, and substances included in vaccine modifiers (adjuvants).

Subunit vaccines contain bits and pieces of the pathogen that the immune system recognizes and against which the immune system mounts a response. The most advanced subunit vaccine for TB, M72/AS01E, was developed by GlaxoSmithKline and was taken over by the Bill and Melinda Gates Medical Research Institute. In phase IIb clinical trials, this subunit vaccine protected half the subjects who received it from progressing to active tuberculosis over three years.

Whole-cell vaccines for tuberculosis include MTBVAC and VPM1002. MTBVAC is a genetically modified Mycobacterium tuberculosis strain that has a deletion of groups of genes required to produce infection. This vaccine reached phase II clinical trials. Currently, VPM1002 is the most advanced live vaccine in clinical trials, having successfully completed three phase III trials. This vaccine candidate is safer and more efficacious than BCG.

IMPACT

BCG is the most commonly used vaccine globally; more than three billion people have been immunized. Though with variable efficacy, the vaccine confers protection against different manifestations of tuberculosis. A more effective vaccine against TB is needed. It is a contagious disease that infects two billion people, approximately one-third of the world’s population.

For Further Information:

1 

Bacillus Calmette-Guerin (BCG) Vaccine. MedlinePlus, 25 Mar. 2022, medlineplus.gov/druginfo/meds/a682809.html. Accessed 31 Mar. 2022.

2 

Kaufmann, Stefan H. E. “Vaccine Development Against Tuberculosis Over the Last 140 Years: Failure as Part of Success.” Frontiers in Microbiology, vol. 12, 2021, p. 50124, doi:10.3389/fmicb.2021.750124.

3 

Savoy, Margot L. “Overview of Immunization.” Merck Manual Consumer Version. Mar. 2022, www.merckmanuals.com/home/infections/immunization/overview-of-immunization. Accessed 31 Mar. 2022.

4 

Tierney, Dylan, Nardell, Edward A. “Tuberculosis (TB).” Merck Manual Consumer Version, Jan. 2022, www.merckmanuals.com/home/infections/tuberculosis-and-related-infections/tuberculosis-tb?query=Tuberculosis. Accessed 31 Mar. 2022.

5 

Tait, Dereck R., et al. “Final Analysis of a Trial of M72/AS01E Vaccine to Prevent Tuberculosis.” New England Journal of Medicine, vol. 381, 2019, pp. 2429-39, doi:10.1056/NEJMoa1909953.

6 

Tuberculosis. Centers for Disease Control and Prevention, 17 Mar. 2022, www.cdc.gov/tb/. Accessed 31 Mar. 2022.

7 

Vaccines. Centers for Disease Control and Prevention, 15 Mar. 2016, www.cdc.gov/tb/topic/basics/vaccines.htm. Accessed 31 Mar. 2022.

Citation Types

Type
Format
MLA 9th
Buratovich, Michael A. "Tuberculosis (TB) Vaccine." Magill’s Medical Guide, 9th Edition, edited by Anubhav Agarwal,, Salem Press, 2022. Salem Online, online.salempress.com/articleDetails.do?articleName=MMG2022_1399.
APA 7th
Buratovich, M. A. (2022). Tuberculosis (TB) vaccine. In A. Agarwal, (Ed.), Magill’s Medical Guide, 9th Edition. Salem Press. online.salempress.com.
CMOS 17th
Buratovich, Michael A. "Tuberculosis (TB) Vaccine." Edited by Anubhav Agarwal,. Magill’s Medical Guide, 9th Edition. Hackensack: Salem Press, 2022. Accessed September 16, 2025. online.salempress.com.