Tuesday, November 14, 2017

The Story is Father to the Author

The story of 'How HIV found its way to a remote corner of the Himalayas', is related in an article in the English Guardian. It was male economic migrants who went to India and "returned home with a very different legacy to the one [they] anticipated", infecting their partners, who then had children born with the virus. (But things are now improving because of the actions of the female victims.)

Here's a comment on an 'interview' with one of the males who went to India to work: "Like many other men interviewed in Achham, Sarpa has a well-rehearsed story that explains how he believes he contracted HIV, but it does not involve any sex workers, whom researchers believe are the primary source of migrants’ HIV infections."

Journalist Kate Hodal doesn't bother telling us how Sarpa says he was infected, preferring instead to believe the testimony of 'researchers'. How these researchers know that Sarpa is a liar, along with all the other people they have interviewed (and disbelieved), is anyone's guess. Perhaps they have some independent explanation or account of the HIV risks that people face in India?

While Sarpa speaks "coolly", his wife Sita "has had to accept the likelihood [Sarpa] visited Indian brothels", indicating all this with a shake of her head.

Hodal is clearly something of a psychic, who can know that while Sarpa lies, Sita tells the truth, but without uttering it. Hodal also knows that the opinion of researchers about HIV risks is of more value than the self-reported accounts of people who are infected, or who may become infected.

Meanwhile in Canada, journalist Ashifa Kassam writes about a pop-up restaurant run by HIV positive people. Far from pointing the finger at people with HIV, the article is about ‘challenging stigma’. The words of those interviewed are quoted, and their honesty is not in question.

Population figures, numbers of people living with HIV, prevalence, even the breakdown by gender of those infected, are not vastly different in Canada and Nepal. Although Nepal’s epidemic is usually described as ‘concentrated’, in contrast to Canada’s ‘low-level’ epidemic, the two are remarkably similar in some ways.

In contrast, in Canada, the vast majority of people are infected with HIV through unprotected, receptive anal sex and injecting drug use. But neither of those routes are thought to be so common in Nepal.

However, there is a huge difference in the way HIV in Nepal and Canada are viewed by the media. In Canada, those with HIV are wholeheartedly encouraged to continue their fight against stigma. But in Nepal, the journalist writes something she may have believed before she left her desk: HIV is ‘spread’ by promiscuous men, to unwitting women and children.

HIV positive Canadians can speak for themselves, and are not required to explain or justify their status. But Nepalese men need journalists and researchers to call them out on their lies about how they were infected; and Nepalese women need the same intermediaries to identify them as victims, unable to name the aggressors, or to speculate about how their partners became infected.


Sunday, October 29, 2017

HIV and Sex: Fallacy of the Single Cause

The four Kenyan counties of Kisumu, Homa Bay, Siaya and Migori that I mentioned in my last blog post have been in the news following the rerun of the presidential elections on Thursday 26 October. Voting in these four counties was suspended at an early stage and scheduled to resume on Saturday 28, but they did not go ahead.

The result of the presidential elections held in August was disputed in court, hence the rerun. But the opposition leader, Raila Odinga, later called for the elections to be boycotted, and turnout has been very low. The four counties in question are home to the majority of Odinga’s own Luo tribe, and a large proportion of people who might vote for him as president.

Astoundingly, one third of all of Kenya’s 1.6m HIV positive people live in these four counties, even though only about one tenth of Kenyans live there. These counties make up the bulk of the former Nyanza Province, in the southeast. In the blog post before that I wrote about a contrasting area, where 0.2% of HIV positive people live: Mandera, Garissa and Wajir, the former northwestern province, with a population of about 1.6m (3.5% of Kenya’s population).

In the earlier of these two posts I speculated that HIV prevalence in the northeastern counties may have remained low because of the geographical isolation of the area. Few roads go there, infrastructure is underdeveloped, health services are few and far between, and usage of health services tends to be low. Quality of health services is also likely to be low, but less harm can result if most people stay away from facilities.

In the southwest, where infrastructure is a bit better, usage of health services is higher. This means that a lot more people are being exposed to potentially unsafe healthcare. Over 4m people live in 10,200 km2, compared to the 1.6m people in the northeast, an area of 127,300 km2. Population density can be lower than 10/km2 in the northeast and as high as 460/km2 in the southwest.

Variations in sexual behavior don’t correlate very well with variations in HIV prevalence or distribution, so it can’t be the single or simple cause of HIV transmission. UNAIDS and other establishments involved in HIV programming claim that 80-90% of HIV transmission in high prevalence African countries is due to ‘unsafe’ sexual behavior, but they have never been able to demonstrate how such a claim could be true, or even plausible.

However, it could be argued that variation in exposure to potentially unsafe healthcare practices correlates much better with HIV transmission. Both areas are isolated politically, and have been for many decades. Low usage of health facilities and social services (and low availability) seems to be a consequence of the political isolation experienced by the northwest. It is home to many of Kenya’s ethnic Somalis, a piece of land that was formerly part of Somalia.

Down in the southwest, the politically isolated Luo population experienced a certain amount of growth and prosperity after independence, especially during the explosion in the population of Nile Perch in Lake Victoria. People with a bit more money are likely to spend some of that money on healthcare. But if that healthcare is not of high quality, is not safe, this might explain why wealthier people in high prevalence African countries tend to be more likely to be infected with HIV than poorer people.

These two geographical areas have certain things in common: they are overwhelmingly populated by one ethnic group, and have both sought to distance themselves from the rest of Kenya; there has even been talk of complete political separation. But there must also be something very different about the two areas that explains why the HIV burden is over 160 times higher in the southwest than it is in the northeast.

Search for ‘sexual reductionism’ on Google and you’ll come across a discussion about a Vermeer exhibition at the New York Metropolitan Museum of Art. This will give you some idea of how current HIV epidemiology seems to proceed. Apparently the texts accompanying the paintings treat every detail of the art works as being about sex.

For UNAIDS, variation in HIV prevalence is all about sex: poor people sell sex, rich people buy sex, as do employed people, women are more vulnerable to sexual exposure than men, men are more promiscuous, sexual mores are different in Muslim communities, etc. But an alternative explanation is that variation in access to potentially unsafe healthcare facilities can better account for variation in HIV prevalence within and between geographical areas.

The history of the isolation of the southwest and northeast counties of Kenya from much of the rest of the country, political, geographical, ethnic and other forms of separation, is a long and complex one. But so too is the history of the HIV epidemic, from its origins in equatorial Africa to its global spread, and the multiple causal factors that resulted in hyperendemic levels in some countries (and within some countries), but low levels in others.


Saturday, October 21, 2017

Via Negativa and ‘First do no Harm’

I am in favor of routine vaccination, for my children and for children in my care. I always take children to a doctor when there is something that won’t go away on its own, or that I don’t recognize, and I would do the same for myself. So I am certainly not advocating ‘doing nothing’ as a response to medical problems. I write as a layperson, with an interest in healthcare and development.

But all healthcare must also be safe healthcare; people should be granted their right to know everything they need to know in order to make the best choices for themselves and their dependents, in accordance with the Lisbon Declaration on the Rights of the Patient, along with other instruments relating to patient safety. I feel that people, especially in developing countries, are frequently denied these rights, and that the results of this can be fatal.

In his guest post for this blog, Helmut Jager discusses the example of the infection of millions of Egyptians with hepatitis C (HCV) through unsafe healthcare, resulting in the highest prevalence of the virus in the world. Jager states that the “causes of the infections [globally] mostly are: bad medicine or intravenous drug addiction”.

The ‘bad’ medicine Jager refers to is a program intended to reduce infection with schistosomiasis (bilharzia), caused by a waterborne parasite. This program involved the use of syringes, needles and perhaps other equipment that were not always sterile. Under such conditions bloodborne pathogens, in this case, HCV, can be transmitted from patient to patient.

The medicine Jager describes is ‘bad’ because conditions in healthcare facilities are unsafe, instruments are being reused without adequate sterilization, etc. Rising numbers of people with HCV in the population eventually visiting health facilities meant increasing numbers of healthcare associated transmissions, also called ‘iatrogenic’; a vicious cycle.

Jager is not suggesting that healthcare facilities should do nothing about schistosomiasis (or any other condition) in order to avoid the risk of iatrogenic transmission of HCV or other bloodborne pathogens. He is recommending that unsafe practices be eradicated, practices such as the reuse of injecting and other equipment and processes that involve piercing the skin, or even come in contact with bodily fluids, such as speculums, gloves, etc.

Reducing unnecessary medicine is another of Jager's recommendations. The WHO estimates that 16 billion injections are administered globally every year. In some countries up to 70% are probably unnecessary. About 37% were said to involve reused injecting equipment. Therefore, reuse of other skin-piercing equipment may also add substantially to the problem.

Jager’s blog is about the high cost of Gilead’s ‘sofosbuvir’ and the damage this does to programs aimed at eradicating the virus. Sofosbuvir has been recommended by the WHO for the treatment of HCV: it is unaffordable for people in poor countries, who make up the bulk of those living with the virus, at risk of suffering serious illness from it, and of dying from it. Jager cites a source reporting that “treatment costs in the US are US$84,000 and in the Netherlands €46,000. The production cost of the drug is estimated not to exceed US$140.”

There are two man-made disasters here: first, there’s the raising of the Aswan Dam in the 1960s. The dam was intended to control the flow of the Nile in order to improve irrigation provision and generate hydroelectricity; this damaged ecosystems and led to an increase in schistosoma infestations. The second was the massive outbreak of HCV caused by unsafe healthcare procedures, employed to address the schistosomiasis endemicity, that affected millions of people.

Apparently environmental impact assessments evolved in the 1960s, but it is likely there was something similar before the specific phrase was adopted. After all, it was known that introducing invasive species of fish to Lake Victoria would cause huge and irreversible problems early in the last century; the invasive species were introduced anyway, because certain parties wanted them to be (the colonials wanted to introduce sport fishing to the lake for their enjoyment). The fragility of ecologies has been recognized for a long time.

Whether either or both these disasters could have been avoided 50 or more years ago, strategies to eradicate schistosomiasis sometimes seem to concentrate on a quick technical fix (there’s even a vaccine in development now), such as mass administration of Praziquantel. Praziquantel works, up to a point. It cures patients, and reduces the infected population, which promotes herd immunity and helps interrupt the life cycle of the parasite. But it is less effective in eradicating the parasite when used on its own.

Research in Lake Victoria finds that the population affected by schistosomiasis also needs access to safe drinking and domestic water supplies, reduced contact with contaminated water, adequate waste disposal (which can interrupt the life cycle of the parasite), etc. In other words, the first disaster Jager alludes to, schistosoma infestation in the waterways, affects a much larger population than those who live close to and depend on the waters of the Nile.

This is a larger and more general problem, because all massive infrastructure projects risk destroying ecosystems and environments. And the medical treatment people need once their water supply is infested can be too little; but possibly not too late. It’s too little because those affected will still need access to safe water and sanitation, but some of these issues can be addressed, bearing in mind the counsel of ‘first, do no harm’.

Water and sanitation provision is vital, as is promotion of good health related information. Gilead are unlikely to scale back their profits much unless they are compelled to do so; yet, intervention would not be unprecedented. Unsafe healthcare can be eradicated, much more cheaply and efficiently than mopping up the victims of unsafe healthcare. And unnecessary healthcare can also be reduced, substantially, which will also reduce unsafe healthcare.

In my previous post I speculated that counties in Kenya with very low HIV prevalence, such as Wajir, Garissa and Mandera, may have escaped high levels of transmission through unsafe healthcare by having very low levels of healthcare provision of any kind. I also speculated that high HIV prevalence in counties such as Homa Bay, Kisumu, Siaya and Mogori may be a result of greater access to healthcare facilities and health programs whose practices are not particularly safe.

So those four counties on the shores of Lake Victoria, with fishing as one of the most important activities, must have very high rates of intestinal parasites (and other conditions). If use of health facilities is high, the chances of a pathogen such as HIV contaminating medical equipment, which is then reused without adequate sterilization, must also be high.

Where healthcare is unsafe, carrying the risk of exposure to bloodborne pathogens, such as HCV, HIV and others through reuse of skin-piercing instruments, it’s best avoided; via negativa is the best counsel, even if most avoidance is a result of poverty now. There is still the option of ‘doing no harm’, but only if the contribution of unsafe healthcare to HIV epidemics so far is thoroughly investigated. If that's not done, people would be better off to stay away from healthcare facilities.


Thursday, October 19, 2017

Via Negativa: the way to low HIV prevalence?

Wajir is a city and county in Kenya’s former North Eastern Province. From a HIV perspective, the county stands out for having the lowest prevalence of all Kenya’s 47 counties, currently estimated at 0.4%. The next highest counties are Mandera (0.8%) and Garissa (0.9%). Wajir, Mandera and Garissa make up what was the province, formerly a part of Jubaland, in Southern Somalia.

Homa Bay is a town and county in the south west, formerly part of Nyanza Province, and the number one county for HIV prevalence, 26%. Indeed, the only counties with prevalence above 10% are Siaya, Kisumu (19.9%), Migori (14.3%) and Homa Bay, which (along with Kisii and Nyamira) made up Nyanza. That accounts for one third of all HIV positive people in Kenya.

The question of why HIV prevalence is so high in certain parts of Kenya is usually answered, implicitly or explicitly, with half baked notions about ‘African’ sexual behavior, ‘African’ mores, ‘traditions’, sexual practices, ‘unsafe’ sex, promiscuity. In a word: sex. It’s all about sex, and in the worst hit counties experts have persuaded the US to part with hundreds of millions of dollars for mass male circumcision programs.

A lot less seems to be written about the extremely low HIV prevalence found in the north east. Look up Mandera, Garissa or Wajir on PubMed and you will only come across just over 300 papers altogether, compared to thousands for other locations (and almost 50,000 for Kenya as a whole). But it would be interesting to know how HIV prevalence has remained as low as in many western countries in the north west of Kenya, yet it has risen as high as the worst hit countries in southern Africa in the south west of Kenya.

Sex happens in north eastern counties too. In fact, condom use is generally lower in these counties. Polygamy is more common, as are intergenerational sex and marriage, phenomena the HIV industry sometimes insists are risks for HIV transmission. Knowledge about HIV transmission and how to avoid it tends to be lower in these counties, too. Birth rates are higher than in other parts of the country.

Circumcision is said to be widespread in a number of counties, not just in Wajir (and Mandera and Garissa) but also, for example, in Kilifi. But HIV prevalence in Kilifi is a lot higher, at 4.5%. The populations are predominantly Muslim in both counties, so circumcision is not likely to be the full explanation, nor is religion. There are commercial sex workers and men who have sex with men in every county, with no evidence that these practices are less common in low prevalence counties.

The north eastern counties are, in fact, very different from the rest of Kenya. Kenya was divided up on ethnic lines by the British, which is why the territory once called the ‘Northern Frontier District’ became one province: it was, and still is, populated by ethnic Somalis. They are geographically isolated, in the sense that there are few major roads. Much of the north of Kenya is arid and sparsely populated. Even the Somalis who live elsewhere in Kenya, such as in Nairobi, tend to live in predominantly Somali suburbs.

A similar kind of isolation, albeit on a much larger scale, can be found in northern Africa. The Sahara is sparsely populated and there are few major roads traversing it. HIV prevalence is low in all North African countries. In fact, HIV arrived relatively late in North Africa, and analysis of the common subtypes there suggest that the epidemic spread to a large extent from southern Europe, and to a lesser extent from West and central Africa.

The most common HIV subtype in Kenya is type A, followed by D, with a small proportion of type C. But the most common subtype in the north east of Kenya is type C, this being the most common subtype in southern Africa, Ethiopia and a number of other countries. So the former province really does seem to have a different epidemic or ‘subepidemic’. Type C is known to have evolved later than A and D, so the former North Eastern Province’s subepidemic is newer, like those in North African countries.

But it is still unclear how the above features of certain epidemics and subepidemics are associated with very low prevalence. Instead of looking for phenomena behind very high prevalence in some south western counties, are there certain phenomena that are absent in the north west (and in North Africa)? Isolation doesn’t mean less sex, nor even less ‘unsafe’ sex, and sexual behavior is very poorly correlated with HIV transmission.

We don’t know much about Wajir, Mandera and Garissa because not much research has been carried out there, and it’s not surprising that little HIV research has been carried out where there's little HIV transmission. But what about other healthcare research? I notice almost all the articles on PubMed are about HIV, and were published in the last 20-30 years. So the area has been isolated from research for a long time.

Now, if there are few roads and limited infrastructures, is healthcare infrastructure similarly limited? It could be expected that access to healthcare facilities is poor and that many people rarely or never go to a hospital, or see any kind of health professional. The majority of women probably give birth at home, coverage of mass drug administration programs, including routine immunizations, is probably lower for these and other more isolated counties.

Borrowing Nicholas Nassim Taleb’s ‘via negativa’ in his book ‘Antifragile’, perhaps HIV prevalence in the north east of Kenya (and in North Africa) has remained low because of infrequent contact with healthcare facilities. This is not to say that healthcare facilities are unsafe in the north east, although it does suggest that they are unsafe in high prevalence counties. Also, it is suggested that HIV is circulating in health facilities, more in some than in others.

Many (including Taleb) like to repeat that ‘absence of evidence is not evidence of absence’. There is a possibility that HIV has been, and is still circulating in health facilities in Kenya, and may account for a significant proportion of infections, perhaps the majority of infections. Little research has been carried out to estimate the relative contribution of healthcare associated HIV transmission. We will never know until the evidence is sought: does limited contact with healthcare keep HIV prevalence low in the north east of Kenya?


Wednesday, October 11, 2017

UNAIDS: Still Spanking the Chimp

How are we to make sense of a HIV epidemic such as the one in Uganda? We are told that it is mostly a result of ‘unsafe’ sex. But data about sexual behavior in Uganda is unremarkable; most people don’t engage in high levels of unsafe sex, and types of sexual behavior considered unsafe appear not to be so unsafe after all.

In 2007, it was estimated that there were almost one million people living with HIV, 135,000 newly infected with HIV in that year, and 77,000 deaths from Aids. The Demographic and Health Survey for Uganda in 2011 concluded that “Differences in HIV infection according to higher risk sexual activity are minor”.

In fact, the vast majority of the 18,000 people surveyed did not engage in sexual behavior considered to be risky. Most people had a maximum of one partner in the last 12 months, most who had more than one partner did not have concurrent (overlapping) partnerships, most did not report large numbers of lifetime partners, most didn’t pay for sex and most didn’t engage in ‘higher risk’ sex in the past 12 months.

So it’s hard to believe that the table appearing on page 15 of the Modes of Transmission Survey (MoT) for Uganda, for 2009, can be anything but fiction. It claims that almost 90% of HIV incidence is a result of multiple partnerships, partners of multiple partnerships and people engaged in mutually monogamous heterosexual relationships.

Even incidence attributed to sex workers doesn’t reach 1%, nor does that attributed to men who have sex with men, plus their female partners. Injecting drug use doesn’t play a big part in most of the epidemics in sub-Saharan Africa either.

The DHS figures for Uganda clearly do not support the MoT figures. They do not support the contention that high HIV prevalence indicates high rates of ‘unsafe’ sexual activity; HIV prevalence is high in Uganda, but sexual activity is not exceptional, nor is it closely associated with HIV transmission.

DHS continues: “HIV prevalence by the number of sexual partners in the 12 months before the survey does not show the expected patterns”. It is noted that “HIV prevalence shows the expected relationship with the number of lifetime sexual partners” but the author doesn’t mention that the numbers of people involved is very small. So they conclude that “it is important to remember that responses about sexual risk behaviours may be subject to reporting bias”.

Uganda was one of the first countries to expose itself to the scrutiny of the rapidly developing HIV industry, from the 1980s. As a result, a lot more studies took place there, a lot more papers were published about Uganda and tens of millions more dollars were spent there than in any other African country, even countries that later turned out to have far worse epidemics.

It takes more than a bit of fluffing to get from the Demographic and Health Survey’s flaccid data on sexual behavior to the conclusion that almost 90% of HIV transmission is a result of unsafe heterosexual sex. But if the industry doesn’t come clean about where the bulk of new infections are coming from, resources targeted at those thought to or claimed to engage in ‘unsafe’ sex will continue to be wasted.


Thursday, September 28, 2017

HIV: A Rich Seam in a Long Abandoned Mine?

Here's a stomach-churning quote from The Eugenics Review, 1932: "East Africa [has] a heavily syphilized native population", where tests suggest that "not less than 60 per cent. to 70 per cent. of the general native population" have some kind of sexually transmitted disease.

At that time, several conditions were mistaken for syphilis (or other STIs). For example, yaws and endemic syphilis, neither of which are sexually transmitted. Prejudices about 'African' sexual behavior were used to prop up beliefs about prevalence of STIs (and prejudices about STIs proped up beliefs about sexual behavior).

You might think that things would have moved on a bit, what with eugenics no longer having the cache it had in the thirties, right? But the received view of HIV in high prevalence countries is that 80-90% of transmission is a result of sexual behavior, mostly heterosexual behavior.

From this 'expert’ opinion about ‘Africa’, it is assumed that high HIV prevalence indicates high rates of 'unsafe' sexual behavior, and that high rates of 'unsafe' sexual behavior (or rates that are assumed to be high) indicates high HIV prevalence, or that prevalence will reach high levels in the foreseeable. It’s pretty easy to spot the pig-headed circularity in the argument.

So, how far have we moved on 80 years after the Eugenics Review quote, above? Here’s Catherine Hankins, from the Amsterdam Institute for Global Health and Development (formerly a senior officer in UNAIDS):
As Hankins surmises, in some cultures what you do with your sexual partners over time is different. In the West we tend to be serially monogamous.
In Africa, if you've had sex with someone at some point, the door isn't considered closed on picking up on that relationship again.
"Take a middle-class African businessman. He has had five women - nothing excessive. But the pattern we find is that he has a wife. He also has an on-off affair with an office colleague. He also has what the French call a 'deuxième bureau' - a mistress who might have a child. And once a year he goes back to his home village and has sex with his original village sweetheart. Then he gets HIV from a bar girl on a business trip.
"Within a year he may have infected four other women. Now, if I've had five sexual partners and catch HIV from the fifth, as a western woman I'm unlikely to return to the other four and infect them!"
You might object that it is unfair to criticize what is clearly just an opinion, however ‘expert’. But policy is based on such opinions, HIV programs are guided by them, enormous amounts of money are spent (entirely in vain) on them. Worse still, the scientific data so assiduously collected shows that Hankins is as wrong as the eugenicists. Ostensibly, at least, Hankins was responding to scientific findings, published in a scientific journal, not to someone's opinion.

You can look through any Demographic and Health Survey you like, where you will find numerous tables about sexual behavior, family life, people’s ability to recall selective tidbits about HIV, etc, but you will not find a country where a large number of people have lots of sexual partners, or engage in sexual activities considered to be unsafe.

In addition, the circularity mentioned above comes across very clearly in Hankins’ invective: HIV prevalence is high because rates of ‘unsafe’ sexual behavior are high, and we know about sexual behavior because HIV prevalence is high. Hankins clearly believes all these prejudices that she expresses about sexual behavior among ‘Africans’!

Three countries account for about one third of all HIV positive people, globally; South Africa (6.8m), Nigeria (3.2m) and India (2m). The same three countries also accounted for more than half of all aids-related deaths in the past few years. It is notable that prevalence is low in India, at less than 0.3%. This compares to about 3% prevalence in Nigeria, and about 19% in South Africa, more than 60 times higher than in India (and it can rise to well over 100 times higher in certain demographics).

Whatever is behind the huge rates of HIV transmission in these countries, which tend to be concentrated in certain geographical areas and populations, it is likely to be something that is amenable to scrutiny, whether it involves the copious quantities of sex that UNAIDS would claim, or something else, for example, dangerously low standards of hygiene and infection control in some health facilities.

Hankins seems intent on mimicking the media approach to HIV, concentrating on relatively rare and infrequent phenomena (deliberate transmission, ‘virgin cures’, fake healers, ‘traditional’ practices, etc), but failing to notice the appalling conditions in healthcare in some of the areas worst hit by HIV. What is it that is deflecting attention from everyday phenomena, allowing such extreme views to prevail, but failing to reduce infections in the worst hit areas?


Friday, September 15, 2017

Pre-Exposure Prophylaxis: Risks in the Pipeline?

An estimated 1 million Kenyans are receiving antiretroviral drugs, about 64% of all HIV positive people. Partly as a result of this, death rates, along with the rate of new infections, have continued a decline that started in the early 2000s, and the early to mid 90s, respectively. Now pre-exposure prophylaxis (PrEP) is being added to the country’s HIV strategy, a course of antiretroviral drugs taken by HIV negative people, which should significantly reduce the risk of their being infected.

So this should be a good time to look at how HIV treatment in its various forms should be targeted. ARVs are relatively straightforward, people testing positive can be put on treatment. But PrEP, if it is expected to reduce infections, needs to be prescribed for those most at risk. This is not as simple as it sounds, because HIV resources have so far been flung far and wide in Kenya, as if those who most need them will magically benefit.

The ruling assumption for high prevalence countries has been that 80-90% of all HIV transmission is a result of ‘unsafe’ sexual behavior. HIV prevalence is seen as a reliable indicator of ‘unsafe’ sexual behavior, and ‘unsafe’ sexual behavior, or perceived behavior, is seen as a reliable indicator of prevalence.

This is completely circular, of course. But if these prejudices are carried over from addressing the HIV positive population, and applied equally to the HIV negative population, the bulk of the drugs may as effectively be flushed down the toilet. The majority of Kenyans are, were, or will be sexually active. But the majority are not at risk of being infected with HIV.

Kenya’s HIV epidemic, in common with the epidemics in several other East African countries, is quite old. The virus has been circulating since the 50s and 60s, so the epidemic is about half a century old, give or take a few years. In other countries, such as the DRC, the virus has probably been around for about 100 years, although it must have affected only small numbers of people for many decades.

Don’t be fooled by figures suggesting that HIV has only been around since it was first recognized by doctors in the early 1980s (or just a little bit earlier), and later described by scientists. UNAIDS estimate that prevalence was already about 3% in Kenya by 1990, rising to over 10% later in the decade, to peak at almost 11%. From 2000, prevalence declined for a few years, rose again from 2005, then dropped to 6%.

This suggests that the rate of new infections (incidence) peaked and started to decline in the early to mid 90s, prevalence peaked and started to decline by the late 90s, and death rates would have peaked in the early 2000s. By 2007 prevalence was 8% and it is now 6%, so it has hovered between 6 and 8% for more than 10 years. Declines are slow, irrespective of major interventions.

Although the widespread use of ARVs, which began in the late 2000s, has contributed to a decline in new infections, prevalence and death rates, it is not possible to attribute these improvements to drugs alone. Making PrEP available to all those assumed to be ‘at risk’ of being infected, purely on the basis of the circular argument mentioned above means that this is going to be an expensive, but very ineffective intervention.

This sounds like bad news, but it doesn’t have to be seen that way. If the HIV risks people face could be identified, whether they are sexual or non-sexual, this will reduce the number of people who need PrEP. Most non-sexual risks, for example, exposure to blood and other bodily fluids through unsafe healthcare, cosmetic and traditional practices, are easily and cheaply avoided. No need to give PrEP to all the patients at a clinic when you could just clean up the clinic, right?

But also, things have changed, PrEP allows us to target those most at risk much more accurately than before. If people know they can protect themselves, they will. Clinics can now safely return to the practice of ‘contact tracing’, identifying how each person testing positive may have been infected, and then addressing that source of infection, whether it was a sexual partner, a clinic, a tattoo artist, or whatever.

The decision to discontinue tracing contacts, which was made in a very different context (a rich country, where the bulk of HIV transmissions were occurring among a relatively small population, and resulting from an easily identified set of behaviors) is inappropriate for a country with a massive HIV epidemic, where the risks have not been clearly demonstrated, and averted. In Kenya, for example, the majority of people who become infected with HIV do not face the high risks identified in rich countries, receptive anal sex and injecting drug use.

If identifying how people become infected can allow HIV negative people to avoid being infected, and allow HIV positive people to avoid infecting others, then contact tracing is vital in high prevalence countries. It is also vital if interventions such as PrEP are to be effective, or even affordable. Already, researchers have found that not being able to identify where the risks are coming from will significantly increase the quantity of drugs each person needs, in addition to vastly increasing the number of people deemed to be in need of PrEP.

Despite ample evidence that non-sexual risks are as important as sexual risks, evidence that has been available since the virus was first identified as causing Aids, most research concentrates on reporting sexual risk only, collecting data about sexual risks, recommending strategies to reduce sexual risks only, while ignoring, denying or failing to collect data on non sexual risks.

Mass ARV rollout complements pre-existing trends in HIV epidemics, though not as much as it could have, had the contribution of non-sexual transmission been acknowledged. However, PrEP will be a slow and inefficient solution unless targeted at those truly at risk, as opposed to the tens or hundreds of millions who are sexually active. People can only protect themselves if they know what the risks are, whether they do it by avoiding exposure, or by taking prophylactic drugs.