Bacillus Calmette-Guerin, commonly known as BCG, is a vaccine used against tuberculosis, particularly against tuberculosis meningitis. It is given to newborns immediately after birth or within 72 hours after birth in countries where immunity level is very low. Adults also take this vaccine when they are exposed to places or people where there is high prevalence of tuberculosis. BCG vaccine has been found to be effective against Buruli ulcer, occurrence of infectious painless open wounds and some of the other mycobacteria infections.
WHO and BCG vaccine:
The World Health Organization has formulated international requirements for the manufacture, control and administration of the BCG vaccine. Tuberculosis is found to be the leading cause of human disease and death in many of the developing countries.
BCG against tuberculosis:
BCG vaccine is administered immediately after birth of the baby and is found to be effective in protecting against tuberculosis almost 80% of the time. Further, factors such as region, genetic differences of community or population, exposure to other bacterial infections and genetic differences in the strain of vaccine being used, can influence the efficacy of the BCG vaccine.
It has also been found to be effective against some of the non-tuberculosis mycobacteria that cause leprosy and Buruli ulcer. BCG vaccine is also used against cancer as a part of immunotherapy, providing an initial stimulation of the immune system of the person.
Who can be given the vaccine:
Apart from newborn children, older children, who were not given the vaccine during birth are recommended to go for the vaccine if they are exposed to adults with tuberculosis.
Health care workers must be considered to go for a BCG vaccine if they are exposed to populations with tuberculosis, especially those resistant to isoniazid and rifampin.
Contraindications of BCG:
BCG vaccine must not be given under some circumstances.
- People who are infected with HIV
- Person who has been immunocompromised, for example, a person who is about to receive an organ transplant
- Pregnant or lactating women
Latent TB Infection or LTBI:
Some people are infected with Mycobacterium Tuberculosis but they do not show any symptoms of the disease. Such people are not infectious and can neither spread the infection to others. Such people can be diagnosed only based on a positive tuberculin skin test or TB blood test. However, treatment is recommended for people with LTBI when they come in contact with the disease, show signs on chest radiograph, if they are injection drug users, if they are mycobacteriology laboratory person and other such reasons.