After baseline screening, patients are randomized to one of two treatment arms and are evaluated by means of clinic visits monthly for the first three months, then every three months for the first year (there are additional clinic visits for INH patients). Patients are then evaluated every six months. One group of patients takes INH plus vitamin B6 for 12 months. The other group of patients takes 1 of 2 doses of rifampin (depending on patient's weight) plus pyrazinamide in 3-4 divided doses for 60 days.