Monday, January 21, 2008

Statistics, AIDS, Africa, and the Bobblehead

From the Economist: ON THE face of things, a fall in the number of people infected with HIV (the virus that causes AIDS) from 39.5m to 33.2m over the course of a single year should be cause for rejoicing. That is the news from this year’s AIDS epidemic update from the World Health Organisation (WHO) and UNAIDS published on Tuesday November 20th. Indeed, it is good news, for it means there are fewer people to treat, and fewer to pass the infection on, than was previously thought. But the fall is not a real fall. Rather, it is due to a change in the way the size of the epidemic is estimated.

Factor that change in and the number of infected individuals has actually risen since last year, by 500,000. And even that is not necessarily bad news in the paradoxical world of AIDS. As treatment programmes are installed around the world, death rates are falling. According to the revised figures, the peak, of 2.2m a year, was in 2005. Now the figure is 2.1m. Since the only way for an infected person to drop out of the statistics in reality (as opposed to by sleight of statistical hand) is for him to die, such increased survivorship inevitably pushes up the total size of the epidemic.

The best news of all, however, is that the new figures confirm what had previously been suspected—that the epidemic has peaked. The highest annual number of new infections around the world was 3.4m in 1998. That figure has now fallen to 2.5m.

I mentioned this about 2 years back when the Atomic City was a health and fitness only blog. I had comments open to all and boy did I get slammed. I did acknowledge that the AIDS epidemic in Africa was real but that I had a hard time accepting the statistics. I felt the number was too high. There is precedent for that. A number of years back statistics in Canada showed an epidemic amongst straight women. However the numbers were misleading. In reality, the numbers were showing a small population of straight women having AIDS (or HIV) as opposed to an huge increase.

Boy did the Bobblehead get slammed in the comments. It was as if I were attacking the entire AIDS situation. No, I pointed out in vain, I was concerned that the statistics were misleading the proper course of actions for treatments and prevention. Oh well. The AIDS climb in Africa appears to have peaked in 1998. Also survival rate is up. AIDS is a terrible disease and Africa is ripe for a spread like this. While the Bobblehead is happy he was right (Told you so! Told you so!) he is still disturbed that decades later HIV is a nastier, adapting critter than we had expected. I expect to get slammed here as well...