Those of you who've spoken to me about it will know that Africa's AIDS pandemic depresses the crap...

Those of you who've spoken to me about it will know that Africa's AIDS pandemic depresses the crap out of me, because the population of an entire continent is rapidly infecting itself, producing mind-boggling statistics like 38% of the population infected (Swaziland and Botswana) and life expectancy of 40 years (Zambia), and not nearly enough is being done about it. And the story is beginning to repeat itself in India and China. But today I found some surprisingly positive news.

Until recently I was under the impression that infection rates in Africa were still rising, but apparently there are signs of stabilising infection rates for the continent as a whole, as decreases in some countries balance continuing increases in others (mainly in the south). This isn't massively cheerful, of course -- the stabilisation is partially because those currently infected are beginning to die at a rate equal to new people becoming infected.

The other thing I didn't know, which in retrospect should have been obvious, is that some people are turning out to be immune to HIV. These people first started turning up in populations where infection rates have been traditionally high, such as prostitutes in Thailand, Kenya and Côte d'Ivoire and gay men in San Francisco. They all appear to have some form of immunity -- as in, an effective response to HIV from their immune system that kills HIV -- although no-one yet seems to have isolated the particular magic substance that lets their immune systems do what nobody else's can. There is also another kind of immunity: about 1% of caucasians appear to have a genetic mutation that prevents HIV from infecting their cells. The mutation appears to be otherwise harmless. I don't know about you, but that sounds like a good case for human genetic engineering to me. Fiddle with my kid's genes so he can't get catch an incurable disease? No problem, bring on the needles.

I suppose I shouldn't be surprised that I hadn't heard either of these facts before: it's in nobody's interest to give idiots the news that there's a 1 in 100 chance that they'll be immune: these are the same people who buy lottery tickets every week at odds of millions to one. And stabilising an infection rate when the rate is 38% isn't good news, no matter what way you try to spin it.