| For        the comprehension of interventions for tuberculosis control and        elimination, the same model as proposed for the epidemiology of        tuberculosis is utilized.  Interventions for tuberculosis control are        interventions that reduce the incidence of infection with M.        tuberculosis.  Interventions for tuberculosis elimination are interventions that reduce the prevalence of infection with M.        tuberculosis. Chemotherapy of tuberculosis has two        effects.  Individually, it reduces the risk of death from        tuberculosis and restores health.  Epidemiologically, it interferes        with transmission, reducing exposure time in the community and thus the        incidence of infection with M. tuberculosis. Prophylactic treatment is defined as the        provision of treatment for a person exposed but not yet infected with M.        tuberculosis with the aim to reduce the risk of acquisition of        infection.  Prophylactic treatment reduces thus the incidence of        infection. Preventive therapy is defined as the        provision of treatment to a person already infected with M.        tuberculosis with the aim to reduce the risk of progression from        subclinical, latent infection to overt clinical tuberculosis.         Preventive therapy reduces thus the incidence of infection. BCG vaccination must be given before        infection with M. tuberculosis has been acquired.  Its aim is        to reduce the risk of progression from latent infection to tuberculosis in        case such infection is acquired subsequent to vaccination.  Its        expected effect is thus similar to one that reduces the prevalence of        infection. |