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Bacillus of Calmette and Guérin (BCG) is a vaccine against tuberculosis that is prepared from a strain of the attenuated (weakened) live bovine tuberculosis bacillus, Mycobacterium bovis that has lost its virulence in humans by specially culturing in artificial medium for years. The bacilli have retained enough strong antigenicity to become an effective vaccine for the prevention of human tuberculosis.
Albert Calmette, a French bacteriologist, and his assistant and later colleague, Camille Guérin, a veterinarian, were working at the Pasteur Institute in Lille in 1908. Their work included the subculturing of virulent strains of the tuberculosis bacillus and the testing of different culture media. They noted that a glycerin-bile-potato mixture grew bacilli that seemed less virulent. They changed the course of their research to see if repeated subculturing would produce a strain that was attenuated to be considered for use as a vaccine. Throughout World War I, the research continued until 1919 when the now non-virulent bacilli was unable to cause tuberculosis disease in research animals. They transferred to the Paris Pasteur Institute in 1919. In 1921, the BCG vaccine was developed for human use.
In 1928 it was adopted by the Health Committee of the League of Nations. However, because of opponents of vaccination, it was not widely used until after World War II. From 1945 to 1948. relief organizations (International Tuberculosis Campaign or Joint Enterprises) vaccinated over 8 million babies in eastern Europe and prevented the predicted increase of TB after a major war.
The vaccine proved to be the safest and the most widely used vaccine. It has an efficacy of between 50 and 80 percent, depending on the natural occurrence of other forms of mycobacteria other than mycobacterium tuberculosis in the environment in which a person lives.
It is not currently recommended in developed countries as routine childhood vaccination because the incidence of tuberculosis tends to be much lower there, with the exception of the UK, where it is routinely given to children aged 14 to 15.
Having had a previous BCG vaccination will affect a Mantoux test result: it is generally positive, although a very high-grade reading is usually due to active disease.
The BCG vaccination should be given intradermally by a nurse skilled in the technique.
References
- Thomas Dormandy (1999). The White Death: A History of Tuberculosis. Chapter 30 Vaccines. ISBN 0814719279 HB - ISBN 1852853328 PB
- Comstock GW. The International Tuberculosis Campaign: a pioneering venture in mass vaccination and research. Clin Infect Dis 1994;19(3):528-40. PMID 95110996.