For many years, UNAIDS and the rest of the HIV industry have been sending out the message that everyone is at risk of being infected with HIV. However, it has never been true that everyone is at risk and there was never any reason for claiming this. The fact that HIV tended to cluster in urban areas, among wealthier, more mobile and better educated populations has been clear for a long time.
One of the latest papers to include detailed spacial data which demonstrates this clustering effect is entitled 'Localized spatial clustering of HIV infections in a widely disseminated rural South African epidemic', by Frank Tanser and colleagues. The data they produce is very interesting, but the same can certainly not be said of the conclusions they draw.
Unsurprisingly, they assume throughout that HIV is almost always transmitted through heterosexual sex in African countries, the so called 'behavioral paradigm'. And the study is in South Africa, the country with the largest number of people living with HIV in the world. As usual, the assumption is unexamined and unsupported in any way.
The study finds that high HIV prevalence clusters close to the National Road and that it is far lower in inaccessible rural areas. 40% of infected people live within 1km of the National Road. Also the "estimated density of HIV-infected individuals (total HIV cases per square kilometre) living within 1km of the road is 15.7 times higher than the mean density of infected individuals across the remainder of the study area."
Those infected are also better educated, wealthier and far more likely to be employed. No surprises there. And they are also less likely to be migrants. Migrants, especially internal migrants, are one of the groups often said to be at high risk of being infected and of infecting others. But the HIV industry has always been bad at identifying risk groups or, I should say, good at ignoring any evidence that may help identify them.
Whatever theories the paper's authors may have, indeed, whatever prejudices, all this data supports the view that HIV is not entirely spread sexually. The populations in this and other studies also have something else in common: they all live close to or have easy access to health facilities. Wealthy, well educated, mobile people with jobs tend to go to health facilities.
On the other hand, rural people tend to go to health facilities far less often, for various reasons, including poverty, lack of mobility, lack of health related education and the sheer lack of decent, affordable, accessible health facilities. Do these features of serious underdevelopment give people protection from HIV infection? Well, that's a hard question to answer if researchers like Tanser and colleagues don't even raise it.
The authors speculate about why the factors that may have been significant in HIV transmission during an early phase of the epidemic appear to be significant still and why this apparently heterosexually transmitted virus has not been more evenly spread among the population. Just how many warning signs do they need that their overall hypothesis about the virus being spread almost entirely through heterosexual sex is wrong and is little more than an anti-African prejudice?
As if things are not bad enough, this sort of idle speculation and pig-headed refusal to consider some fairly obvious alternatives to the behavioral paradigm is going to encourage those baying for 'treatment as prevention' and pre-exposure prophylaxis (essentially, means of substantially increasing the tonnage of drugs being thrown at the epidemic) to be rolled out in high prevalence countries.
Showing posts with label multiple partners TB. Show all posts
Showing posts with label multiple partners TB. Show all posts
Sunday, July 24, 2011
Monday, July 18, 2011
The Sound of a One Legged Argument Kicking Itself
As I mentioned in yesterday's blog, a recent article finds evidence for the concurrency hypothesis 'compelling', despite liberal use of words that suggests a lot of doubt. The hypothesis is that lots of unsafe sex alone, involving numerous partners, low condom use, etc, does not account for high HIV prevalence; but if sexual relationships overlap with each other, HIV transmission will be very high.
A lot of work has been done to show that the concurrency hypothesis is entirely unsupported by evidence, particularly work by Eileen Stillwaggon and Larry Sawers. But in the article mentioned yesterday, Mah and Shelton dismiss anything challenging the hypothesis rather than addressing the failure of all the arguments that claim to support it.
Well, an article just published by Frank Tanser and colleagues finds that there is "no evidence to suggest that concurrent partnerships are an important driver of HIV incidence in [a] typical high-prevalence rural African population." But instead they argue that multiple partnerships are an important driver of incidence.
While Mah and Shelton denied that non-sexually transmitted HIV plays an important role in hyperendemic scenarios, without arguing the case, Tanser and colleagues don't even mention the possibility of non-sexual transmission. While obligingly neutralizing an argument that should never have been given much credence, and one that has been convincingly refuted by others, they seem to be taking a step backwards.
We have been hearing the oversexed African hypothesis for several decades now, it even predates the identification of HIV. So all Tanser has done is revived that tired old reflex as an explanation of massive rates of HIV transmission. But what is it about Africans that results in a virus that is difficult to transmit sexually spreading so fast in a population in which sexual behavior is little different from that found in many other low HIV prevalence populations?
Rates of new infections per year for both males and females in the study population are shockingly high But the researchers don't appear to have established how HIV was being transmitted. They have just assumed that transmission is all through heterosexual sex and then attempted to work out how risky heterosexual sex is among participants. But why is heterosexual sex so risky there? We are not told.
The authors find that "More than 24% of the adult population are infected with HIV and infection peaks at more than 50% in women aged 25–29 years and 44% in men aged 30–34 years." Given the fairly low probability of sexual transmission of HIV, 80 or 90% of women must be exposed to HIV if such high percentages end up infected.
The fact that male prevalence peaks in an older age group than female prevalence is sometimes explained by the 'fact' that older men have younger partners. But only some men have younger partners. Some have partners the same age as themselves. Like a lot of HIV related data, you could be forgiven for thinking that HIV in males is a different virus from HIV in females.
Despite flogging the dead horse of concurrency, which is worthwhile when you consider how much credence it still seems to have in the HIV industry, the authors remark that concurrency may have played a big part in earlier stages in high prevalence epidemics. But earlier treatment of the concurrency hypothesis suggest otherwise, so this concession doesn't exactly strengthen their argument for a return to the promiscuity theory of HIV.
And when it comes to their recommendations for HIV prevention strategy they really seem to weaken. They argue that 'messages' shouldn't be 'diluted'. Pumping out a fairly undiluted though highly stigmatizing message about HIV for many years has not resulted in UNAIDS having much success in reducing transmission, despite spending billions. In fact, the pharmaceutical lobby trying to increase drug use in the pretence that it will reduce transmission even refers to the institution's prevention work as a failure.
Telling people the truth about HIV transmission is not 'diluting' anything. If people are at risk they need to know about the risks and how to avoid them. UNAIDS have used the issue of 'dilution' as a reason for denying non-sexual risks, with the result that most people don't know that such risks exist, and therefore cannot avoid them. HIV prevention is not just an advertising campaign, even if it's never looked much different from one.
A lot of work has been done to show that the concurrency hypothesis is entirely unsupported by evidence, particularly work by Eileen Stillwaggon and Larry Sawers. But in the article mentioned yesterday, Mah and Shelton dismiss anything challenging the hypothesis rather than addressing the failure of all the arguments that claim to support it.
Well, an article just published by Frank Tanser and colleagues finds that there is "no evidence to suggest that concurrent partnerships are an important driver of HIV incidence in [a] typical high-prevalence rural African population." But instead they argue that multiple partnerships are an important driver of incidence.
While Mah and Shelton denied that non-sexually transmitted HIV plays an important role in hyperendemic scenarios, without arguing the case, Tanser and colleagues don't even mention the possibility of non-sexual transmission. While obligingly neutralizing an argument that should never have been given much credence, and one that has been convincingly refuted by others, they seem to be taking a step backwards.
We have been hearing the oversexed African hypothesis for several decades now, it even predates the identification of HIV. So all Tanser has done is revived that tired old reflex as an explanation of massive rates of HIV transmission. But what is it about Africans that results in a virus that is difficult to transmit sexually spreading so fast in a population in which sexual behavior is little different from that found in many other low HIV prevalence populations?
Rates of new infections per year for both males and females in the study population are shockingly high But the researchers don't appear to have established how HIV was being transmitted. They have just assumed that transmission is all through heterosexual sex and then attempted to work out how risky heterosexual sex is among participants. But why is heterosexual sex so risky there? We are not told.
The authors find that "More than 24% of the adult population are infected with HIV and infection peaks at more than 50% in women aged 25–29 years and 44% in men aged 30–34 years." Given the fairly low probability of sexual transmission of HIV, 80 or 90% of women must be exposed to HIV if such high percentages end up infected.
The fact that male prevalence peaks in an older age group than female prevalence is sometimes explained by the 'fact' that older men have younger partners. But only some men have younger partners. Some have partners the same age as themselves. Like a lot of HIV related data, you could be forgiven for thinking that HIV in males is a different virus from HIV in females.
Despite flogging the dead horse of concurrency, which is worthwhile when you consider how much credence it still seems to have in the HIV industry, the authors remark that concurrency may have played a big part in earlier stages in high prevalence epidemics. But earlier treatment of the concurrency hypothesis suggest otherwise, so this concession doesn't exactly strengthen their argument for a return to the promiscuity theory of HIV.
And when it comes to their recommendations for HIV prevention strategy they really seem to weaken. They argue that 'messages' shouldn't be 'diluted'. Pumping out a fairly undiluted though highly stigmatizing message about HIV for many years has not resulted in UNAIDS having much success in reducing transmission, despite spending billions. In fact, the pharmaceutical lobby trying to increase drug use in the pretence that it will reduce transmission even refers to the institution's prevention work as a failure.
Telling people the truth about HIV transmission is not 'diluting' anything. If people are at risk they need to know about the risks and how to avoid them. UNAIDS have used the issue of 'dilution' as a reason for denying non-sexual risks, with the result that most people don't know that such risks exist, and therefore cannot avoid them. HIV prevention is not just an advertising campaign, even if it's never looked much different from one.
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