Tuberculosis - Vaccination in Newborns


Vaccination against tuberculosis, known as Bacille Calmette-Guerin (BCG) discovered by two French scientists, Albert Calmette and Camille Guerin in 1922, has its own limitations, and its efficacy is highly variable. Still the vaccine is recommended for administration to all newborn to protect them against pulmonary and extrapulmonary tuberculosis.

The BCG vaccination works on the principle that if a newborn is vaccinated (or already infected in a natural way), the child will have a more fully developed immune system to fight exposure to the tuberculosis bacilli, and less likely to develop pulmonary tuberculosis. In the vaccination, the strains of Mycobacterium are weakened in their virulence (i.e. they become unable to produce the disease), and when the BCG vaccination is administered, it will only cause an appropriate immune response without the danger of developing the active disease.

In highly developed countries like the USA, this vaccine is only restricted to newborns who are more prone to tuberculosis, for example, when the baby is born of a mother suffering from the active disease, or the child is in close contact with a highly infectious drug-resistant patient of tuberculosis. In such countries, the BCG vaccination is not administered, in general, to all newborns, because of the fact that this vaccine makes the tuberculin test positive and it becomes difficult to track exposure to tb in communities. The BCG vaccination is recommended in newborns in less developed countries or communities where there is a high incidence of tuberculosis, or where it is known that the mother has an active tuberculosis infection.

 The BCG vaccination has little value in the case of adults, as reported in some studies. It has also been mentioned that the vaccination may prevent the reactivation of dormant or hidden tubercle bacilli which may be lying inside the body, but it may not prove helpful, when the infection is spread airborne from an patient with active pulmonary tuberculosis.

For  the BCG vaccination of the newborn, 0.1 ml of the vaccine is administered intradermally in the uppermost part of the upper arm (deltoid). A crust is formed within 4 days approximately, which heals in about 4-6 weeks, and the child thus develops hypersensitivity.