Infection with TB bacilli is very common, and it is estimated that almost 50% of South Africans have been infected. Most infections take place during childhood. However, only about 10% of all people with TB infection progress to tuberculosis (TB disease) during their lifetime. Therefore, TB infection is far more common than tuberculosis.

Tuberculosis is uncommon in most developed countries. However, tuberculosis is common in developing countries such as South Africa where the incidence has increased rapidly in the last few years. Tuberculosis is particularly common in the Western Cape and KwaZulu-Natal.