South Africa has been hailed as a world leader in rolling out a preventive antibiotic therapy to stop people developing tuberculosis.
Isoniazid preventive therapy - taking an isoniazid tablet each day for six months - is proven to dramatically reduce the risk of HIV-positive people contracting TB.
A recent study by University of Cape Town researchers showed HIV-positive patients on IPT and anti-retrovirals combined were 37% less likely to contract TB.
On Tuesday, the UNAIDS global report on HIV and Aids said South Africa had expanded its roll-out of IPT to 373000 South Africans, a threefold increase since 2010, when the therapy was introduced at government clinics.
The World Health Organisation and the UN recommend that all HIV-positive people take IPT.
Dr Thabile Vezi from the Right to Care organisation said the drug was highly effective, but some patients had difficulty staying on it for six months, especially if they developed side effects.
Dr Avron Urison, from AllLife, a life insurance provider for HIV-positive people, said: "One of the difficulties when rolling out the therapy is that you have to be 100% sure the patient is TB-free before you administer IPT."
The medical director of Médecins Sans Frontières, Dr Gilles van Cutsem, said more HIV-positive people needed to ask for the therapy as a means to ward off TB.