AIDS in Africa wildly overestimated - Is epidemiological science really this poor?

[astro]

Looks like a lot of not too reliable modeling assumptions were made re the epidemiological spread of AIDS in Africa. Are epidemiologists really his clueless or were the overstatements politically driven? Does it really take a mental giant to project that rural and urban AIDS rates in 3rd world environments are likely to have wildly different profiles.
How AIDS in Africa was overstated
Reliance on data from urban prenatal clinics skewed early projections

KIGALI, Rwanda - Researchers said nearly two decades ago that this tiny country was part of an AIDS Belt stretching across the midsection of Africa, a place so infected with a new, incurable disease that, in the hardest-hit places, one in three working-age adults were already doomed to die of it.

But AIDS deaths on the predicted scale never arrived here, government health officials say. A new national study illustrates why: The rate of HIV infection among Rwandans ages 15 to 49 is 3 percent, according to the study, enough to qualify as a major health problem but not nearly the national catastrophe once predicted.

Years of HIV overestimates, researchers say, flowed from the long-held assumption that the extent of infection among pregnant women who attended prenatal clinics provided a rough proxy for the rate among all working-age adults in a country. Working age was usually defined as 15 to 49. These rates also were among the only nationwide data available for many years, especially in Africa, where health tracking was generally rudimentary.

The new studies show, however, that these earlier estimates were skewed in favor of young, sexually active women in the urban areas that had prenatal clinics. Researchers now know that the HIV rate among these women tends to be higher than among the general population.

The new studies rely on random testing conducted across entire countries, rather than just among pregnant women, and they generally require two forms of blood testing to guard against the numerous false positive results that inflated early estimates of the disease. These studies also are far more effective at measuring the often dramatic variations in infection rates between rural and urban people and between men and women.

[Nava]

Any science is more rudimentary in the African backcountry (which is quite abundant) than elsewhere.

Overestimated or not, it’s still very bad.

[Apos]

It’s interesting: this will be just more grist for the mill of AIDS denialists. Interesting though, that the REASONS for the overstatement are different from what the denialists were up in arms about, and the better measurements show something that denialists, well, deny: that the disease affects more females than those dirty homosexual men.

Expect Dean Esmay to go wild about this soon:
http://www.deanesmay.com/

[Sal_Ammoniac]

It would be a mistake to downplay the effect of AIDS on Africa. From the cite: “Yet the disease is devastating southern Africa, according to the data. It is in that region alone – in countries including South Africa, Botswana, Swaziland and Zimbabwe – that an AIDS Belt exists, the researchers say. 'What we know now more than ever is southern Africa is the absolute epicenter,” said David Wilson, a senior AIDS analyst for the World Bank, speaking from Washington. In the West African country of Ghana, for example, the overall infection rate for people ages 15 to 49 is 2.2 percent. But in Botswana, the national infection rate among the same age group is 34.9 percent. ’

Just because epidemiologists got in wrong in Rwanda does not mean AIDS is not still a serious crisis in Africa. Just think of some things that happened in Rwanda that may have made getting accurate data there difficult.

[Ludovic]

Also, a surprisingly low death rate from AIDS could point to a newer, less virulent strain, which wouldn’t be much better if you don’t have access to drugs, but would delay death long enough to make death rates seem lower compared to the previous, more virulent strain (and incidentally give infected people more time to infect others.)

[Colibri]

Here’s information on two different surveys from South Africa, which provides some comparison between rates from pre-natal clinics versus those from more general population surveys. The site provides much more detail on methodological problems with the various surveys.

HIV prevalence according to the Department of Health Study 2004:

* 28.5-30.5% amongst antenatal clinic attendees (29.5% is the best estimate)
* 22.6-26.5% amongst all people aged 15-49 years old (24.6% is the best estimate).

HIV prevalence according to the National HIV Survey 2005:

* 9.9-11.6% in the whole population (10.8% is the best estimate)
* 14.9-17.7% amongst all people aged 15-49 years old (16.2% is the best estimate).

Clearly, the esimates differ, but they still lead to the conclusion that AIDs is a very serious problem in the country.

With access to the results of the previous household survey of 2002, the Department of Health Study of 2003, and the results of many smaller surveys, UNAIDS/WHO made their own estimate of 21.5% prevalence in those aged 15-49 years old, at the end of 2003. Their high and low estimates are 18.5% and 24.9% respectively. According to their own estimate of total population size (which is another contentious issue), this implies that around 5.3 million South Africans were living with HIV at the end of 2003, including 230,000 children under 15 years old.

Conclusion

What is clear from every study is that there is an exceptionally severe epidemic of HIV/AIDS in South Africa. This epidemic affects all parts of the population, though women are more likely to be infected than men. Many tens of thousands of people are dying.