infectious diseases
Tuberculosis (TB)
Prevention of TB
 Treatment (eg, staying at home, avoiding visitors, covering coughs with a tissue or hand) are followed. 80% of the world’s children, primarily in high-burden countries. Overall average efficacy is probably only 50%, but BCG clearly reduces the rate of extrathoracic TB in children, especially TB meningitis, and may prevent TB infection. Thus, it is considered worthwhile in high-burden regions. Immunization with BCG has few indications in the US, except unavoidable exposure of a child to an infectious TB case that cannot be effectively treated (ie, Drug resistance or Although BCG vaccination often converts the TST, the reaction is usually smaller than the response to natural TB infection, and it usually wanes more quickly. The TST reaction due to BCG is rarely>15 mm, and 15 years after BCG administration, it is rarely>10 mm. The CDC recommends that all TST reactions in children who have had BCG be attributed to TB infection (and treated accordingly) because untreated latent infection can have serious complications. IGRAs are not influenced by BCG vaccination and should ideally be used in patients who have received BCG to be sure that the TST response is due to infection withM. tuberculosis. 