Tuberculosis FACT SHEETS

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BCG

What is BCG?

Photo courtesy of the National Library of Medicine,
used by permission of the World Health Organization

Bacille Calmette-Guérin or BCG is a TB vaccine developed by scientists Albert Calmette and Camille Guérin in the 1920s. It helps protect babies and young children against the most severe forms of active TB disease such as TB meningitis or miliary TB. Today, only infants in some First Nations and Inuit communities with high rates of TB are routinely vaccinated.

BCG and TB skin tests

People vaccinated with BCG may have a false positive result to a TB skin test. In other words, the skin test may show that the person has TB but the person does not really have TB. If the person was born in Canada, was vaccinated after 12 months of age and has not spent time in a foreign country or in Canadian Aboriginal community with a high rate of TB disease, then the result may be due to a latent TB infection. New blood tests for latent TB infection can help determine if BCG caused the positive TB skin test. As a precaution, anyone with a positive TB skin test should have further testing to rule out active TB disease.

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