Is HIV spread through promiscuity?

Francois Venter questions whether the popular wisdom is right

Helen Zille's recent very public foray in to HIV prevention and treatment -  ‘why should we be pay for irresponsible sexual behaviours?'- is only a more recent example of this popular wisdom; the formation a decade ago of the Moral Regeneration Movement, ironically lead by Jacob Zuma, Thabo Mbeki's reflections on black male sexuality in an address at Fort Hare University, the various politicians that have lectured the nation on ABCs (often hilariously getting caught subsequently with their pants down in the wrong bedroom) have all pandered to popular wisdom. Sex moral panic periodically infects politics in South Africa, like it does everywhere else in the world.

I sit in my HIV clinic with my frightened, bewildered patients who have to endure the headlines screaming for their punishment. These people look pretty normal to me. When I ask about their sex histories, it doesn't feature the rampant sexuality conjured up in the fevered brains of politicians, letter writers and corridor conversationalists I have to endure. Their sexual history is of a couple of boyfriends or girlfriends, a marriage, children, pretty mundane-sounding sex lives, and shocking and unexpected positive test.

The weirdness of HIV in South Africa started during the Mbeki regime, where a counter-science movement, with a cast of supporting international crazies, distracted us from the single biggest question: Why is HIV so bad in such a small area of the globe?  Southern Africa, from Zambia down, accounts for over half the global HIV numbers. South Africa alone houses 1 in 5 of the world's HIV infected population.

The underlying common-sense premise is that ‘different' sexual behaviours power the epidemic. Southern Africans shag more, shag too many people, or shag differently, in a way not seen anywhere else in the world.  HIV prevention billboards implore us to be ‘responsible', to cut down on our number of partners, and to consider abstinence. In the background is a moral disapproval of sex for fun, which conveniently allows conservative messages to be dressed up as public health.

HIV is actually not terribly transmissible when looking at risks per sex act measured in developed countries, when compared to other viruses like herpes. Despite this, a young woman in KwaZuluNatal has an almost 1 in 3 chance of being HIV positive by the age of 21 years. Her counterpart in Toronto, Rio or Paris has a lifetime chance of well below 0.5%. 

If it is something about sexual behaviour only, it must be something seriously different. The alternative explanation, which seems to me so much more plausible, even when you haven't reviewed the data, would be that there is something biological that makes sexual transmission far more efficient. The data is starting to emerge.

There is accumulating evidence that people in our region are more vulnerable to HIV per sex act than our European, Asian or American counterparts. No one disputes that people can modify their HIV risk, but the devil seems to be in the geography, rather than sex behaviour. Studies suggest that in places like Thailand and the US, men with 3 times more sex partners have one-tenth of the risk of acquiring HIV compared with Uganda. 

It would appear it matters far more where you live than who you sleep with.  It is extremely plausible that something about the HIV species wondering our South African bedrooms may be more virulent, or the genes in our populations more susceptible, or some environmental factor we haven't discovered, makes sex many-fold more risky.

There is now data to support this - a recent study by researchers in our Institute demonstrated far higher rates of HIV per sex acts among young women in South Africa when compared to their US counterparts; there is some evidence that the HIV subtype in our region may be more infectious longer, and that our genetic makeup may make us more prone to contracting HIV.

Theories advanced recently included the possibility that local genital co-infections may play a role, and perhaps even a nutritional co-factor.  Its sex, sure, but high risk sex largely independent of how or who with you have it.

The data to support the theory that some sexual behaviour is peculiar to our region is very sparse. Convenient labels  (‘sugar daddies', ‘multiple partners', concurrency', ‘dry sex', ‘prostitutes') give us easy targets to moralise about, but may not explain much. HIV is a sexually transmitted disease; of course sexual behaviour matters and of course these behaviours happen, and contribute to individual risk. It seems unlikely that this could explain the different in HIV infection rates here versus Europe or the US, and we do not have evidence to show that it does.

The sexual behaviour transmission model is popular, as it plays into convenient moral, racial and gender stereotypes, according to which world you come from. South African men are often portrayed as rampantly promiscuous with ‘many partners' (conveniently ignoring the mathematical improbability of this) and women as hapless victims (reducing them to pitied vectors of disease). A distressing number of statements made in public and private communications I deal with, suggest a common racial stereotype of black men, as hypersexual and lacking impulse control.

The so-called collapse of the family, the mysterious and sudden deterioration in moral fibre, promiscuity,  ‘sugar daddies' are also conveniently invoked to support a comprehensive moral theory with precious little to back it up.  The reality is that sex is hard to study. It relies on self-reported behaviour, with people respond to questioning depending on their culture, often lying to researchers. Studies that look at ‘hard biological' outcomes, like pregnancy, new incidence of sexually transmitted infections and HIV, or evidence of recent sex, are few and far between.

Frustrated campaigners for sexual behaviour change often throw at me "How can you NOT suggest decreasing your number of partners will decrease HIV risk?"  Well, I give behaviour change messages often, and the message is relatively simple: Use condoms, be honest in your sexual relationships, anticipate that your partner may not be faithful for your entire relationship, and regularly check your HIV status. These are all sensible as individual advice.  "Bonk less" hasn't worked particularly well at any time in history, so I tend to avoid that.

We need better sex behaviour science and more money (behavioural studies are notoriously difficult to get funding for) for this kind of research.  I suspect our sex lives are not that different from anyone else's, and in a while, we'll have a proper scientific explanation for our extraordinary epidemic.  Till then, those of us in the HIV world will have to put up with politicians not understanding the admittedly complex world of HIV acquisition.

* Professor Francois Venter is a doctor working in HIV, deputy executive director of the Wits Reproductive Health and HIV Institute (WRHI), and outgoing president of the Southern African HIV Clinicians Society. This article - which first appeared on the Health-e website - is based on a talk given at the Wits AJ Orenstein 2011 Memorial Lecture.

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