Tuesday, August 29, 2006

ARE SOME PEOPLE HIV RESISTANT?

Kenyan prostitutes are apparantly at the top of this list! Based on a study presented last week at the 16th Int'l Aids Conference in Toronto, it appears that a large percentage of sex workers in Kenya did not contract HIV despite having had unprotected sex with more than 500 men each!

Let's do some rough math based on the numbers in the article:
- The study followed 850 sex workers in Nairobi, Kenya over 3 years
- 130 did not contract HIV, while 720 did

This means that for our limited Kenyan sample, the average of those sex workers who appear to be immune from HIV is 0.15 or 15%.

If we then apply some basic statistics, we can say that, at 95% confidence, between 13% and 18% of women in Nairobi, Kenya are immune to HIV infection, even after being exposed dozens, if not hundreds of times.

The article indicates that these women may posess a gene which protects them from infection known as human leukocyte. This gene enables the immune system to recognize HIV and other similar viruses.

The real question now becomes: Is this study applicable outside of women prostitutes in Nairobi, Kenya? Does this gene exist elsewhere in the world, and how frequent is its occurance.

All that being said, this is some of the best news to come out about this virus in a long time.


UPDATE #1: Did some more digging on this issue and found out some interesting facts. If you can believe it, the New York Times actually reported on this issue back in 1998! Check out these quotes from that article:
"...an unprecedented number of people have the H.I.V. resistance gene. Dr. O'Brien and others have found that nearly 14 percent of some populations have a copy of the gene, which slows the progress of H.I.V. infections by several years, and 1 percent have two copies, which provides nearly complete immunity to H.I.V."

"The H.I.V. resistance gene, for example, is present in almost 14 percent of Swedes but appears in only about 5 percent of Italians and is absent in Saudi Arabia. It is absent in Africans, American Indians and Asians."

So this article, from 1998 mind you, seems to confirm some of the results of the Nairobi study. It is amazing that the 14 percent number quoted is consistant with the results of the sample from Kenya. However, the article also seems to suggest that this gene is "absent in Africans" which is completely inconsistant with the study's findings. Perhaps there just wasn't enough research and study done in 1998 to confirm that maybe this gene is expressed in approximately 15% of people worldwide?



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