President Thabo Mbeki dismisses the frightening appraisals by international organisations of the prevalence of HIV in South Africa as "hysterical estimates", a characterisation which extends logically to that contained in the latest UN-Aids report.
The report's "hysterical estimate" is that nearly one in five adult South Africans is infected with Aids and that, "With a total of 4.2 million infected people, South Africa has the largest number of people living with HIV-Aids in the world."
But, confusingly, an official publication of the Department of Health endorses the UN-Aids reckoning. It states: "The HIV epidemic is severely affecting the young, black and economically poor populations of South Africa. Currently there are approximately 4.2 million South Africans living with HIV."
The statement is made without caveat or qualification.
Juxtaposition of Mr Mbeki's statement with that in the Department of Health publication on its strategy to contain the epidemic means Mr Mbeki is rejecting his own department's appraisal of the extent of the challenge facing it.
The situation is further compounded by a dearth of comprehensive statistical data on Aids in South Africa.
As Alan Whiteside and Clem Sunter note in their newly-published study, Aids, The Challenge for South Africa, the collection and publication of AIDS case data ceased in 1995 and AIDS is no longer a notifiable disease.
The most reliable available data on the epidemic is that obtained by ante-natal clinics across the country. It points to a steady increase in HIV prevalence among pregnant women attending government ante-natal clinics, rising from 0.8 per cent in 1990 to 22.4 per cent in 1999.
These figures, which reflect a slight decrease from 1998 to 1999, when the prevalence fell from 22.8 to 22.4 per cent, have been used by epidemiologists to project the overall prevalence of HIV-AIDS in the South African population.
Four potentially-distorting factors are taken into account in the exercise: that HIV-infected women tend to become infertile; that men have a lower HIV prevalence rate than women; that HIV-prevalence in children between the ages of four and 14 is negligible; and that HIV is similarly low in people over 65.
According to Mr Whiteside (director of HIV-Aids research at the University of Natal) and Mr Sunter (Oxford graduate and author of several books on socio-economic issues in contemporary South Africa), the arithmetical conclusion is that between 3.4 million and 3.6 million South Africans are HIV positive.
Commenting on Mr Mbeki's rejection of the UNAids figure of 4.2 million, Mr Sunter observes that the president is correct in describing it as an estimate. But he does not concur that it is "hysterical".
Of the extrapolated figure cited in the book which he co-authored with Mr Whiteside, MrSunter is confident that it is statistically accurate. The sample is large enough, the methodology sound, and testing technique at the clinics accurate, he states.
But the dissident scientists serving on the international panel established by Mr Mbeki are preparing an assault on the testing technique. If they succeed in persuading him that it is inaccurate, the HIV total is likely to be revised downward, amid more condemnation of "hysterical estimates".
