[Chemoprophylaxis of tuberculosis]

Chemoprophylaxis of tuberculosis may be primary or secondary. Primary chemoprophylaxis is intended for infants and children with negative tuberculin tests and exposed to contagion, in order to avoid primary tuberculosis. It lasts for three months and consists of oral isoniazide in one single daily dose of 5 to 10 mg/kg. Secondary chemoprophylaxis applies to all subjects, but principally to children, with a tuberculin test that has recently become positive in the absence of BCG vaccination. Its purpose is to protect against clinical tuberculosis. It lasts for six months and consists of isoniazid combined with rifampicin.