Multiple concurrent partners and inter-generational sex – the two main drivers of the HIV epidemic?

In much of Africa the cultural norm is to be in relationships with more than one partner at a time (concurrent partners) in what has been termed a ‘net’ of sexual partners. This  could be a polygamous marriage in which a man has several wives; a marriage in which one or both of the married partners has additional sexual partners; or a sexual relationship in which either or both partners have other concurrent sexual partners. The last two scenarios may also involve stable long-term arrangements which means that condoms are less likely to be used. In the West the more common pattern is to have sex in ‘strings’ or one after the other. So a man or woman could have many more sexual partners over the same period of time but the more traditional pattern is to have sex with one partner at a time, or serially rather than concurrently.

 

HIV replicates faster through nets than strings. This is because the risk of transmission is dependent on the stage of HIV infection. The acute phase is when you have just been infected with HIV but do not yet test positive (the so-called window phase). During this stage, before your immune system learns how to fight the virus, the level of HIV in your blood and sexual fluids is at its highest - higher even than during the final phase of AIDS. This stage, which usually lasts  about three months, is therefore associated with the highest risk of passing the infection onto your partner. A person in this stage who has several concurrent sexual partners will put them all at risk during unprotected sex. As many of these partners may also have multiple concurrent partners, these will all be drawn into the HIV net. HIV is therefore able to spread very quickly throughout this ever-increasing, never-ending net of connected people. On the other hand, people who traditionally have sex in strings will usually only put one person at risk during the period that they are most infectious. This reduces the potential for HIV to spread.

 

A survey by the HSRC suggests that multiple partners and inter-generational sex (typically younger women having sex with older men, often referred to as sugar daddies as they have the means to give the younger girls a good time and expensive presents) are common behaviours in South Africa and important epidemic drivers. The survey showed that 30.8% of males and 6.0% of females in the 15-24 age group have multiple partners.  This percentage drops by approximately half in both 25-49 age groups but remains significant.

 

Inter-generational sex is a common pattern with 27.6% of 15-19 year old females having sex with someone who is at least 5 years older compared with 1.5% of males in the same age group. Worryingly, the percentage in females has increased quite dramatically from 18.5% in 2005. Inter-generational sex ensures that the HIV net ensnares the newly sexually active youth.  If people only had sex within their own age group (intra-generational sex), the epidemic would eventually die out as the members of that generation all died. Inter-generational sex therefore guarantees the continuation of the epidemic. This behaviour pattern needs to be aggressively addressed through appropriate interventions if South Africa is to have any hope of limiting the recruitment of the younger generation into the HIV net.

 

The age prevalence figures (total numbers of HIV-infected in each group) tell this story quite graphically with young females having much higher prevalence rates than their contemporary males (4x in the 20-24 age group). By 30-34 years, the prevalence rates start to converge and then in the 40-44 age group the male rates peak and exceed the female rates. One can therefore see clear evidence of the HIV loop between older men and younger women, and how a new generation of youth become exposed to HIV.