No single factor, biological or behavioural, determines the spread of HIV infection. Most HIV transmission in sub-Saharan Africa occurs through sexual intercourse, with unsafe blood transfusions and unsafe injections accounting for a small fraction.
While sexual behaviour is the most important factor influencing the spread of HIV in Africa, that behaviour varies greatly across cultures, age groups, socioeconomic class, and gender. Sexual behaviour is itself influenced by a host of factors, ranging from the daily and pragmatic (such as economic and social circumstance), to the complex and abstract (such as culture).
For example, higher numbers of sexual partners has consistently been found to be associated with greater likelihood of HIV infection, but the chances of individuals engaging with commercial sex workers, and thus having more partners, is clearly enhanced when large numbers of single, migrant men live together. These communities of single, male migrants (such as those in the mining communities of southern Africa, for example) have been established as a result of a complex interplay of economics and history. And this is only one example. Forced migration due to war, long-term travel along transit routes for commercial reasons, and the lack of secure livelihoods are other factors.
The interplay of multiple factors obscures causal linkages and prevents categorical conclusions. A study in four African cities (Cotonou, Kisumu, Ndola and Yaoundé) revealed that the most common behavioural and biological factors in those cities with the highest HIV prevalence were: young age at women’s first sexual intercourse; young age at first marriage; age difference between spouses; the presence of HSV-2 infection and trichomoniasis (a sexually transmitted infection); and lack of male circumcision. There is substantial evidence that sexually transmitted infections enhance the risk of sexual transmission of HIV, while other analyses suggest that male circumcision may be associated with reduced risk of transmission.
Young women have consistently been found to have higher prevalence rates of HIV infection than men of the same age group. The assumption that this results from women having sex with older men suggests a possible inter-generational driver of the infection from men to women.
Young women are also physiologically more susceptible to sexually transmitted infections than young men. For instance, in Kisumu, Kenya, in 1998, the prevalence of HIV infection among women aged 15–19 was 23%; among young men the same age, it was 3.5%. Sociocultural systems in many cases also limit women’s control over their sexual lives.
In addition, a large share of sub-Saharan Africa’s population is young and, therefore, more likely to be sexually active. This helps explain the higher incidence of HIV and other sexually transmitted infections.
Where these facilitating factors are absent, HIV infection can remain ‘hidden’ for many years. In the presence of social, socioeconomic and biological factors that facilitate spread, however, the epidemic may grow at a rapid rate. While the complex interplay of factors makes it difficult to estimate the likely growth of the epidemic, evidence from the past decade shows that HIV can spread rapidly and widely from very low general seroprevalence levels. All countries with risk factors must employ the range of policies and programmes available (detailed throughout this report) so as to avoid a high-prevalence epidemic.
Originally Posted by NooNoo
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