Monday, May 16, 2011

Biological Factors that May Contribute to Huge Disparities in HIV Prevalence

The brief summary at the end of an excellent article on 'Biological Factors that May Contribute to Regional and Racial Disparities in HIV Prevalence' really gets to the point about how HIV prevention should be approached, but generally isn't:

"To develop better prevention tools, it is critical that communities, researchers and policy makers come together to discuss and investigate these tremendous [racial disparities in HIV prevalence, both between regions and within regions] in an open and non-judgmental fashion."

Instead, it is generally assumed that HIV transmission is driven by "stigmatizing socio-behavioural factors such as sexual concurrency or promiscuity, partner violence and so on." This article emphasizes that "biological factors such as endemic co-infections and immunology also play a key role."

The authors warn against blaming affected communities and individuals, something the HIV mainstream have been guilty of while at the same time, rather perversely, warning those in high prevalence communities that they should avoid stigmatizing attitudes. The highest prevalence figures are found in a handful of African countries and in specific regions in some countries.

Occasional mention is made about how inefficient heterosexual sex is when it comes to transmitting HIV, but without any logical conclusions being drwan from that fact. While the probability of transmission resulting from penile-vaginal sex appears to be higher in African countries, such transmission is still "the rare exception rather than the rule."

Co-infections with diseases common in African countries, such as TB, malaria (see also this abstract on malaria as a co-factor in HIV transmission) and various kinds of parasitic conditions may increase transmission by those infected with HIV and increase susceptibility in those uninfected. While it has been recognised that could treating these conditions would reduce transmission, no clinical trials have assessed the impact this might have.

Similar remarks apply to various sexually transmitted infections (STI). But while some trials have looked at reducing STIs as a means of reducing HIV transmission, factors such as non-sexual HIV transmission, perhaps through the STI treatment itself, may not have been taken into account. So not enough is yet known about this kind of intervention.

Male circumcision is discussed and the authors mention that HIV prevalence is higher in a non-circumcising population in Kenya's Nyanza's province. However, they don't mention that there are non-circumcising populations in other countries where HIV prevalence is lower than in circumcising populations.

Also, low HIV prevalence is often correlated with female genital mutilation (FGM), even in Nyanza province itself. The Luo tribe may not circumcise their men, but they don't circumcise their women either. Whereas in tribes that circumcise men and women, such as the Kisii, HIV prevalence is lower than national prevalence. Other tribes that practice FGM, such as the Somali, have even lower HIV prevalence than the Kisii.

Personally, I am opposed to FGM, but the arguments for male circumcision seem equally unconvincing. Some even claim that male circumcision reduces the number of Langerhans cells, which HIV targets. But there are Langerhans cells in the vagina as well and no one would argue that parts of it should be surgically removed to reduce susceptibility to HIV infection.

But if you are opposed to the view that Africans have extraordinary and probably animalistic sex lives, that they care little for their own health and welfare, or for that of their partners and their children, you need to read the above article.


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