When HIV was first identified as the virus that causes the syndrome now known as Aids, it was quickly established that it could be transmitted through exchange of bodily fluids, blood, semen, breast milk and through other routes. This means that it can be transmitted through sexual contact, through blood contact (during medical and cosmetic procedures, also by intravenous drug users) and from mother to child (also called vertical transmission).
Nearly thirty years later, sexual transmission is still the mode of transmission that gets the most attention. The received view, supported by organisations such as UNAIDS, the WHO and others, is that the vast majority of HIV positive people in African countries were infected through some form of sexual contact. Of course, many probably were. But heterosexual transmission is not the most efficient mode of transmission. In fact, it is a relatively inefficient mode of transmission.
Mother to child transmission is an efficient mode of transmission without medical intervention. But with medical intervention, transmission is low, even in developing countries. Now, in countries like Kenya, an increasing number of pregnant women are being tested for HIV as soon as they start attending ante-natal clinics. They are usually monitored and treated if they are found to be HIV positive in order to prevent transmission of HIV from mother to child.
However, exchange of contaminated blood is a very efficient mode of transmission, whether it occurs through intravenous drug use, a visit to the doctor or even a visit to the beautician. One hopes that all the public information and education there have been about the risk of contracting or transmitting HIV through exchange of blood would make people aware of these risks, whether they are drug users, health care workers, patients or clients of hairdressers.
But as I have said, sexual transmission is the mode that has received the most attention. It has and continues to dominate HIV prevention programmes with any other modes of transmission receiving far less attention, if any.
So what is the meaning of the received view of HIV, that 80-85% of it is transmitted sexually? In particular, why would HIV prevalence in Greece be .008% when prevalence in Kenya is 8% and prevalence in Lesotho is 28%? Does this mean that Greeks have orders of magnitude less sex than people in Kenya and Lesotho?
Well, for a start, UNAIDS distinguishes between generalised and concentrated epidemics. Countries with generalised epidemics usually, but not always, have high HIV prevalence, above 1%, and affecting people who are not in groups thought to be at especially high risk. Those at high risk include men who have sex with men, intravenous drug users and commercial sex workers. Greece has a low level, concentrated epidemic. Those infected in Greece are almost all in one of those high risk groups.
In contrast, Lesotho and Kenya have generalized epidemics. According to UNAIDS, the WHO and others, sexual behaviour explains high prevalence of HIV in these two countries, but not in Greece. They say that risky sexual behaviour such as unprotected sex, high numbers of lifetime partners, high levels of concurrency (having sexual relationships with several different people where those relationships overlap to a significant extent) and others are responsible for the terrible HIV epidemics of the sort found almost exclusively in Sub-Saharan African countries.
The claim, then, is that people in these countries indulge in more risky sexual behaviour, but how much more? It would need to be a great deal more but there is little or no evidence to show that this is the case. Rather, when people are diagnosed as HIV positive in African countries, it is assumed that they were infected sexually, either by their main partner or by some other sexual contact. If their partner turns out to be HIV negative it is assumed that they had sexual contact with someone else.
Many people have been diagnosed as HIV positive and it has turned out that their partner is HIV negative. It is then assumed that the HIV positive partner, often the woman, had an affair with someone else. If she denies this, it is assumed that she is lying. Although that’s the case in Kenya and Lesotho, it’s unlikely to be the case in Greece or any other Western country. The assumption that people are just lying partly stems from the received view: that 80-85% of HIV is transmitted sexually in countries with generalized epidemics. Some may lie, but some may lie in Greece too. So how many instances like this have been investigated? In African countries, precisely zero.
Consider another phenomenon: infants and children who have been found to be HIV positive when their mother is not. It’s harder to claim that so many infants and children have been, one, sexually assaulted, two, sexually assaulted by someone who is HIV positive and three, that they were infected as a result of this sexual assault. South Africa recently found quite a worrying number of HIV infections among children who were not sexually active and whose mothers were not HIV positive. Further research was called for, into the possibility of sexual assault and the possibility of medical transmission. Neither, as far as I know, has yet been carried out.
Accepting that HIV is mostly transmitted by heterosexual intercourse means accepting that a lot of people are having a lot of unsafe sex with a lot of other people over a long period of time. It involves accepting that this happens in Sub-Saharan African countries to an extent not found in most other countries, indeed, to an extent that is just not credible.
If unbelievably high rates of risky sex are a figment of the imagination of those who work for or who follow the pronouncements of UNAIDS and WHO, what could account for all the generalized epidemics in Africa?
A number of suggestions have been made (by those who dare to diverge from the received view). Some have suggested that low levels of health care and education and high rates of poverty in many African countries make people more susceptible to HIV infection. But, while it is true that these circumstances are found in many African countries, they are also found in countries where HIV prevalence is far lower. And even in African countries, HIV prevalence has often been higher among the rich and well educated.
A better suggestion is that high rates of disease and low levels of nutrition make people more susceptible. Many preventable and treatable conditions, such as TB, malaria, human parasites and certain sexually transmitted infections have been shown to significantly increase the risk of HIV transmission, especially sexually, though also through blood contact and through vertical transmission.
But then this doesn’t really explain why well off and well educated people were infected in greater numbers than poor and badly educated people, especially in the early stages of the epidemic. Well off and well educated people would be less likely to suffer from these conditions and would have had better access to healthcare.
It’s time for people to question the idea that inordinately high levels of unsafe sex in certain African countries can fully explain the high prevalence of HIV found there. We need to re-examine all other modes of transmission, especially where blood exposure could be involved. Barbers’ and beauticians’ shops don’t always look too sterile. But nor do hospitals and clinics. Putting it a different way, it must be wondered how the sort of badly equipped, understaffed, overcrowded facilities found in African countries can avoid transmitting HIV and other diseases, at least sometimes. Questions about the safety of health and other facilities urgently need to be raised.
The received view, that 80-85% of HIV transmission in Sub-Saharan African countries has been through sexual contact, can not be correct. How much can truly be put down to sexual transmission is unclear because a lot of the research has just not been carried out. What research has been done has been ignored because it contradicts the received view. But we owe it to people who are HIV positive, despite never having engaged in unsafe or illicit sex, to do this research. We owe it to everyone who is HIV positive because we don’t know how they became infected. They may not even know themselves. The stigma comes from an assumption that we are not entitled to make.
If, as some people would argue, a substantial amount of HIV was transmitted by non-sexual means, perhaps a lot by medical transmission, this could explain why HIV reached levels where even sexual transmission started to become far more significant than in other countries, where prevalence remained low. Most children and pregnant women, especially, receive a lot of injections and other medical treatment and a very common form of contraception is given by injection. And many other people in African countries also receive a lot of injections, for example, commercial sex workers and men who have sex with men. The highly efficient transmission of HIV that would occur through blood exposure could quickly spread an infection to many people. There is no evidence that the same rates of transmission could occur through sexual transmission alone, even if risky sex was as common as claimed by the received view.
Reducing stigma is always going to be a difficult task, whatever its target. But it should be easier to reduce stigma once it is clearer how HIV really reached such high levels of prevalence in some countries and not others. Sexually transmitted HIV could only have infected large numbers of people once a high prevalence of HIV had already been reached through some other mode. Research to establish how HIV reached present levels is urgently needed, starting with medical and cosmetic transmission.
HIV is stigmatized because of the received view that it is mostly transmitted by heterosexual sex in Sub-Saharan Africa. However, rates of unsafe sex would need to reach incredible levels for this received view to be correct. Though stigmatizing sick people should always be avoided, there must be other reasons than sexual behaviour to explain why HIV prevalence is so high in some African countries, reasons which would show that this stigma is misplaced. Those who are infected through non-sexual routes, of course, can also go on to transmit HIV sexually. Therefore, a large amount of sexual transmission, which can occur once HIV infects a critical percentage of the population, can also be partly attributed to non-sexual transmission. Some, perhaps most, of this non-sexual transmission may come from unsafe medical and cosmetic practices.
Sunday, April 25, 2010
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6 comments:
It's great to see a discussion of the different ways of transmission, and it's good to draw attention to medical transmission, as it is wholly preventable and could contribute to a significant number of infections. However, even if sexual transmission accounted for all new infections, a conceivable difference in sexual behaviour between regions could account for differences For example, taking SSA as a whole and comparing with the west, the whole difference could be explained by a 2-fold higher unsafe sex rate in SSA than in the west, taking into account the 50-year history of the epidemic. This is due to the infectious nature of HIV, where small differences are amplified by onging transmission. This is also what i wrote to New Internationalist many years ago! ("rubber up", http://www.thefreelibrary.com/Letters-a092912728)
Thank you Claire, the argument about whether Africans do or don't have more sex or more unsafe sex is on unsteady ground due to the lack of decent research.
However, there is no evidence that high HIV prevalence African countries do have double the amount of unsafe sex or that differences in levels of unsafe sex in any way correspond to high levels of HIV.
There are places where unsafe sex has been shown to be high and HIV rates are low, also, places where unsafe sex has been low and HIV rates high.
But the biggest problem with medical transmission is not just that the shady issue of sexual transmission is used as an excuse for not bothering to research it.
Even if those in Lesotho have twice as much unsafe sex as those in Greece and this results in a prevalence 3,500 times higher, this doesn't excuse the lack of research in to health conditions that could easily transmit HIV and other blood borne diseases at significant rates.
On the contrary, in countries where unsafe sexual behaviour is (or is considered to be) high and HIV prevalence is high, neglecting medical transmission is even more stupid as any of those who become infected medically can go on to infect others sexually.
Even if, as UNAIDS claim on the basis of little or no evidence, medical transmission only accounts for 0.6-2.0% in Kenya, sexual transmission among them could account for a lot more.
Consider the people most likely to be infected through medical transmission. They include sex workers and men who have sex with men being treated for sexually transmitted infections. A clinic dealing almost exclusively with these clients would have ample opportunity to transmit all sorts of things if their practices were not safe.
Women who are attending ante natal clinics because they are pregnant or reproductive health clinics because they need contraceptives (injectable contraceptives are very popular here) are all sexually active and therefore at risk of spreading medically transmitted HIV further.
Vaccinations are often given en masse to children (and sometimes adults) where rates of HIV testing are low. Reuse of needles may be lower because of greater awareness but reuse of syringes may still be common and reuse of vials is widespread because they are often multidose to cut costs.
Unsafe sexual behaviour is very high in some groups in developed countries, such as men who have sex with men and commercial sex workers. HIV is high among men who have sex with men but far lower than in many Sub-Saharan African countries, despite the fact that anal sex, homosexual or heterosexual, carries a much higher risk than vaginal sex.
Also, in rich countries, HIV rates among sex workers are low unless the sex workers are also intravenous drug users. In other words, the drug use is more likely to be the higher risk factor, given the levels of unsafe sex often found among commercial sex workers.
Of course, it is still important to address the stigma issue, especially when much of the stigma arises from adherence to the behavioural paradigm. That sort of stigma emanates from the preachings of UNAIDS, the very institution that is tasked with addressing stigma, as well as HIV transmission, by whatever mode.
S
Claire, thinking about your argument in your Rubber Up letter, it seems to depend on HIV being around for a long time. While it probably originated a lot longer than 50 years ago, it stayed at a very low level for a long time and probably only spread to other areas much later.
HIV prevalence is relatively low in areas where it is thought to have originated, Western Equatorial countries. It's higher in Eastern African countries, where it is thought to have spread first. And it's highest in Southern African countries, where it is thought to have spread more recently.
In addition, evidence from stored blood samples suggest that HIV prevalence was very low or zero in the seventies and even early eighties. Evidence suggests that HIV remained at very low levels at its point of origin until probably the seventies. And in areas where it subsequently reached highest prevalence, it probably reached those countries even later.
I wonder how that affects the figure of 'slightly less than twice' the levels of unsafe sex found in rich countries?
If HIV arrived in high prevalence countries relatively late in the pandemic, where levels had previously been low or zero, doesn't this still require that inordinately high levels of unsafe sex must have played a part if the behavioural paradigm is to work as UNAIDS would like it to?
S
A really strong piece -
Stigma is one of the hardest things to deal with - I mean HIV is treatable these days, the one thing that holds people living with HIV back from leading a normal life.
This is something we constantly try to tackle over on our MTV www.staying-alive.org blog, and if you would be interested in writing a similar article for our site get in contact - anderson.ben@mtvne.com
Thanks
>However, there is no evidence that high HIV prevalence African countries do have double the amount of unsafe sex or that differences in levels of unsafe sex in any way correspond to high levels of HIV.
I was arguing that *even* if there were no other differences between the populations, that would be the level of difference that would explain it, and i'm not saying that is the only difference, just that double doesn't seem that great a difference to me, it doesnt have to be twice as much sex, just twice as much unsafe sex, on average.
>There are places where unsafe sex has been shown to be high and HIV rates are low, also, places where unsafe sex has been low and HIV rates high.
these anomalies can occur in some places and unsafe sex still be a large influence on prevalence overall.
Agree that concentrating exclusively on sex can lead to ignoring other, highly preventable routes of transmission!
> it stayed at a very low level for a long time
a low level (e.g 0.1%) can still mean very large and increasing numbers of people infected, which is an integral part of the establishment of an epidemic. the campaigns in the UK and US started before prevalence had even reached these levels, thus they were able to nip it in the bud, as crude as they were back then.
> I wonder how that affects the figure of 'slightly less than twice' the levels of unsafe sex found in rich countries?
Thanks for this question, th every low prevalence found in blood samples is still consistent with the sexual epidemic model; many years are required for this slowly- tranmitting pathogen to build up before it reached noticeable levels. Sex plus medical transmission is also consitent with the data,
Thanks Claire. I don't think there is evidence that unsafe sex is significantly higher in African countries, nor is it higher in areas with high HIV prevalence.
By low level I mean a lot less than 0.1%. Many HIV subtypes went nowhere, but only in countries in and around the epicentre, Cameroon, I think. But in other countries, one clade, clade C, for example, moved to the highest prevalence countries in Southern Africa. Clade C is one of the most recent, so the epidemic didn't have that long to develop. Older clades often didn't come to much at all.
Western epidemics such as the one in the UK are quite different, there was never any threat that it would become a generalized epidemic. So I'm not sure how much 'nipping in the bud' there could have been. And I'm not sure if the US would have claimed to have nipped anything in the bud, considering they have the highest heterosexual prevalence in the developed world. Some areas in the US, such as Washington DC, have prevalence levels higher than a lot of African countries.
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