SA and Botswana are possible exceptions, but "only to a limited extent", says the study's author, Markus Haacker of the IMF's research department, in an analysis that highlights the quandary faced by SA policy makers.

By 2010, Haaker estimates, the cost of providing highly antiretroviral treatment to 30%, or less than a third, of South Africans who need it would represent about 1,4% of gross domestic product (GDP).

With just 10% of those needing the treatment receiving it, the cost of all HIV-related health services for SA would be close to 1% of GDP in 2010, equivalent to nearly a third of public health expenditure in 1997. For SA's poorer neighbours, the forecast is much gloomier. Providing one in ten HIV-infected Mozambicans with antiretrovirals right now would raise Mozambique's total HIV-related health expenditure to 3% of GDP, rising to 5,9% in 2010.

This assumes an annual cost of $1500 a patient to administer the complex therapy, possible only if the combination of drugs involved can be obtained at about $500. This is well below current cost estimates for treating HIV-positive patients in the region. A recent World Bank study put the annual per patient cost of the treatment in higher- income southern African countries at $1400 for the drugs and 1000 for supporting services.

This compared with $698 for the clinical treatment of opportunistic infections associated with HIV, $79 for the prevention of infections and $28,50 for palliative care.

Haacker also assumes in his calculations that antiretroviral treatment will not work as effectively in the region as it does in developed countries. His figures are based on patients receiving the treatment for only four years before they die, their lives on average prolonged by two years beyond the point they would be expected to succumb untreated.

This might be unduly pessimistic for countries like SA and Botswana with their relatively advanced health infrastructures. But that means their costs of providing treatment would be higher as longer-living patients consumed more drugs.

SA health officials, seeking to explain President Thabo Mbeki's opposition to giving patients antiretrovirals dependent on stateprovided care, have argued SA cannot afford to administer the therapy on a sustainable basis.

Haacker concludes that even getting antiretrovirals to 10% of patients will be difficult. "Given the serious shortages in personnel and infrastructure the health sector is facing, the scope for alleviating the (effect) of HIV/AIDS on the health sector through financial aid is limited."