What do we know about AIDS in South Africa? About 5.3 million people of an adult population of around 33 million in South Africa has HIV according to the UN. Adult Mortality in SA in 2003 was around 450 thousand a year, of which somewhere between half to two thirds has been attributed to AIDS. (source)
Lets make an assumption that the vast majority of infected people are going to die in the next 5 years. This is likely given that (a) anti-retrovirals are being rolled out very slowly, (b) there should be serious doubts as to the effectiveness of wide spread anti-retroviral treatment, especially if compared to the treatment of other difficult to treat diseases such as TB, (c) untreated and undernourished people living in unsanitary conditions such as squatter camps can expect to live less than 2 years with HIV/AIDS and (d) even with the correct anti-retroviral treatment life expectancy for most people living with the disease is going to be much lower than compared with first world countries.
Assuming deaths attributed to AIDS in 2003 was 250 thousand, some simple calculations should show that if mortality rates increase in a linear fashion, we can expect an increase of up to 50% to our mortality rate each year due t0 AIDS for the next 5 years, culminating in the death of 2 million people in 2008, two years before the 2010 Soccer world cup. For South Africa this is an almost existential crisis.
On the other hand, Adult mortality rates have been recorded since 1998. Taking them at face value, as the UN report does, the increases in mortality was only 16% in 1999 and has been increasing consistently at only 10% for the last 5 years despite the fact that half of all deaths have been attributed to AIDS since 2000.
If this trend were to continue, that would mean that only 400 thousand people are going to die of AIDS in 2008, and that only 1.7 million people are going to die of AIDS over the next 5 years.
If our assumption that most people with HIV is going to die in the next 5 years is correct however then the infection rate in SA is much lower than believed. (Only 5%,rather than the 16.5% that the UN believes).
I have assumed the increase in mortality is linear. That might be incorrect but is backed up by the behaviour or Adult mortality rates for the last 5 years. I have also assumed that the majority of people living with HIV today will be dead in 5 years. If this number is lower, that is people die sooner, then that means that the actual infection rate is even lower than 5%. If people live longer, how much longer?
Taking our current mortality rate increase of 10%, and the belief by the UN that there are 5.3 million people with AIDS in South Africa, how long will it take these people to die? Answer? 11 years.
These numbers are very suspicious. They are suspicious because that is about the minimum number of years that people can be expected to live with modern anti-retroviral drug therapies in western countries.
If a UN researcher went and did a quick back of the envelope calculation where people with HIV have a maximum life expectancy of 11 years (which is about the minimim in Zurich, plus a year) along with the mortality rate increase of South Africa (which is one of the few almost reliable statistics available to anyone), then the answer he would come up with is 5 million people in South Africa are infected with HIV. If people with HIV die sooner however, then the number of people infected decreases dramatically.
Are UN statistics on the number of people infected with HIV in South Africa being inflated? And for what purpose? If the current trend in the Adult mortality rate for South Africa continues, then one of two things could be possible. One, the UN statistics could be criminally wrong or two, most people with HIV in africa with no access to modern medicine living for the most part in squatter camps can live up to 11 years.
If you think the answer is the latter, then you have to meet one of my friends called Occum.
(Full disclaimer: I’m neither a statistician (I’ve a passing knowledge) , a doctor (I’ve done a first aid course), an AIDS activist (I’ve given to AIDS charities) or a prophet (I predict death and taxes). All predictions, assumptions or facts come with no warranty included.)