Sunday, January 15, 2012

Pepin's Spectacular 'Origins of Aids'; Looking Forward to Part II

I have been reading Jacques Pepin's recently published book 'The Origins of Aids'. He has produced a huge amount of research and thinking on the issue of where HIV came from and how it spread all over Africa and beyond in a relatively short space of time. He also considers some competing theories and proto-hypotheses and effectively shows why they do not provide an adequate or comprehensive explanation, either because they are not borne out by evidence or because they don't show what they purport to show.

Few would disagree with Pepin's conclusions that unsafe medical practices 'kick started' what became the current HIV pandemic, a process that was required for a virus that was difficult to transmit sexually to eventually infect people who were not sexually active, or not particularly so. Also very clear is one of Pepin's lessons learned: that profound social changes resulting from colonization, urbanization and the like, were highly significant.

But this is where I start to feel less convinced by Pepin's further remarks on what 'profound social changes' is usually taken to mean for HIV: sexual behavior. Pepin speculates about how 'unsafe' sexual behavior could have reached levels that explain later explosions in HIV transmission, but he never shows that enough people actually engaged in the requisite quantities and types of this behavior to account for some of the very high, or even medium prevalence epidemics.

In fact, since detailed figures have been collected, the connection between sexual behavior, unsafe or otherwise, has never been very strong. This is not to say that sexual transmission of HIV has never occurred, just that it has never been shown how it could reach a creshendo and then, as if spontantously, reduce and drop to a very low and steady rate, at least in some countries. But the drop in incidence (and/or the drop in 'unsafe' sexual behavior) does 'appear' to have been spontaneous in some countries, occurring long before any serious HIV reduction programs took place.

Vulnerable groups, such as sex workers, are small. If they face very high risks, their clients face higher risks than they would if they stuck with a single regular partner; but they face lower risks than the sex worker. And partners of sex workers' clients face lower risks still. Prevalence in the general population in some countries, people who did not belong to any high risk group, has often been higher than prevalence in extremely high risk groups in non-African countries; how do extreme levels of transmission among those who face the highest risks also arise in those who don't face the highest risks? I've never been convinced by talk of 'bridging populations', people who have sex with high risk groups and spread the virus among low risk populations.

For example, HIV prevalence among sex workers in India is less than 10%, often a lot less. But HIV prevalence in one whole region in Tanzania and among one large tribe in Kenya is two or three times higher. In some countries, such as South Africa, Swaziland, Lesotho, Botswana, Zambia, Zimbabwe and others, prevalence in the general population is many times higher. In some African countries, ordinary people doing ordinary things are infected with a virus that is difficult to transmit sexually and it is assumed that most of them were infected sexually. Is this not illogical? Even UNAIDS produce figures showing that the majority of HIV transmissions in many African countries result among people who have no obvious sexual or other risks.

Pepin seems to go beyond his own evidence in concluding that although unsafe healthcare played the major part in the spread of HIV at one time, that it no longer plays a particularly significant role. He may be right, but I don't see how this conclusion is borne out by evidence. In fact, just as there is still a serious lack of convincing research into sexual behavior in African countries, there is an even more glaring lack of investigation into instances where HIV has clearly been transmitted in healthcare facilities and in contexts where sexual behavior is unlikely to have played a part.

Over thirty years, it has become quite evident that sexual behavior doesn't miraculously change because of some perceived threat, such as HIV. For several decades before HIV was identified, the bulk of health development spending was thrown at persuading African women, and the donor community, that birth control would solve all their development problems, poor health, poverty, malnutrition, drought, famine, flooding, etc; if only people would just have fewer children. Many still believe it, Bill Gates being no exception in that respect.

What can change very quickly is practices in health facilities, if the right training and other resources are available. The spontaneous event that resulted in a sharp reduction in HIV incidence early on in various African country epidemics (and elsewhere) is unlikely to have been related to sexual behavior; but changes in healthcare practices took place very early on, especially in countries where such changes were affordable. Even in Western countries, some of the largest groups infected were haemophilics and others who regularly needed various forms of skin-piercing healthcare.

I wonder why Pepin didn't answer the often asked question: 'What happened in Uganda'. He had the answer at his fingertips. Uganda reacted to advice that was still given to developing countries in the 1980s, but is considered unmentionable now: HIV can be transmitted most efficiently through contaminated blood. Pepin shows us how amazingly common non-sexual transmission was in the past but he doesn't appear to have looked into how common this mode of transmission might have continued to be for the last twenty years or so, or how common it is now.

[I have also written about Pepin on the Don't Get Stuck With HIV website and blog, where we are trying to collect together cases of nosocomial (hospital acquired) HIV outbreaks, unexpected HIV infections and investigations that have taken place around the world.]


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