afrol News / SciDev.Net, 29 November - A South African tuberculosis expert has called for a cheap and readily available drug for tuberculosis prevention to be given to all HIV-positive children not receiving antiretroviral treatment.

Tuberculosis (TB) is a widespread infection in developing countries and can exist in two forms: latent and active. People with HIV/AIDS are particularly susceptible to developing the active form of TB.

But the antibiotic isoniazid, or INH, can prevent this from happening for people living with HIV but who are not taking antiretroviral drugs (ARVs).

The World Health Organization currently recommends that isoniazid be given to HIV-positive children exposed to a household contact with TB.

However recent research indicates that INH can halve the number of deaths due to AIDS related illnesses for HIV-positive children, regardless of household situation.

Heather Zar, a paediatrician at the University of Cape Town in South Africa, and colleagues administered isoniazid to 263 HIV-positive children either daily or three times a week.

The team observed a 50 per cent reduction in the number of deaths and a 70 per cent reduction in the number of TB cases among the children, said Zar.

Their results were published in the British Medical Journal on 3 November.

"I think this is a very important study," Zar told SciDev.Net. "The treatment was found to reduce mortality and TB incidence greatly — which is very novel and very different to the way in which INH has been used before."

She said the study has potentially large public health implications, adding that a strong case could be made for using INH in HIV-infected children who are not on ARVs and live in high TB prevalence areas.

Most children they studied were not on AIDS treatment, says Zar, explaining that the team are still waiting for results of an ongoing study in children on ARVs.

Earlier this year American researchers warned that INH would lose its effectiveness in the future as its widespread use may speed the emergence of drug-resistant forms of TB (see 'Warning over drug for patients with TB and HIV').

But Zar said that so far, resistance had only been found in people already infected with TB and who were given INH by mistake, instead of receiving TB treatment.

"Before putting any child or adult on [preventive treatment] it is important to screen for and exclude TB, which requires treatment with three or four drugs," she said.

The rise of TB in developing countries, especially in Africa, is in part related to the prevalence of HIV/AIDS.

In Uganda, where TB surged by 150 per cent between 2003 and 2004, 20 per cent of TB patients are also HIV-positive.


By Gideon Munaabi

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