Using daily isoniazid (300 mg, four-times daily) for tuberculosis (TB) preventive therapy programme (TB PTP) in HIV-infected subjects. Depending on the site and the time horizon of the study, six scenarios were considered:
(1) the preventive program is implemented in a voluntary testing and counselling site (VTC) and the course of therapy is for six months,
(2) referral is made to a TB clinic implementing TB PTP from a VTC (separation of VTC and TB clinics),
(3) referral is made to a TB clinic implementing TB PTP from an STD clinic(separation of STD and TB clinics),
(4) implementing TB PTP in an occupational or residential site involving a large number of people,
(5) separation of occupational site and TB PTP clinics,
(6) implementing TB PTP in the form of a lifelong therapy assuming a life expectancy of 5 years.