Sometimes, comparing two countries can tell you more about what you don’t know, than about what you do. Take one country, for example, where the average age of first sexual experience for young people is a little more than 16, fewer than 36 percent of young women used a condom during their last sex act, and young women between 18 and 24 years of age have had an average of 5.7 sex partners. Then look at a second country, where the average age of first sexual experience is higher, as is the rate of condom use, and the number of lifetime sexual partners is lower. The first country is the United States, the second country is South Africa. So what’s driving South Africa’s much higher HIV prevalence? This comparison, detailed in A tale of two countries: Rethinking sexual risk for HIV among young people in South Africa and the United States, concludes that the answer to that question lies “above and beyond sexual behavior.”
A reader sent the study, which was originally published in the Journal of Adolescent Health in September 2011, to Science Speaks following our report from CROI on research presented there debunking the influence of supposed proclivities for “sugar daddies,” and “multiple concurrent partnerships” on South Africa’s HIV rates. One of the studies showed that not only did no correlation exist in South Africa between a young woman having a relationship with a man five or more years older and a higher risk of getting HIV, but that women older than 30 in relationships with older men actually had lower risks. The other study showed that countries with higher rates of HIV did not have higher rates of overlapping sexual relationships with multiple partners. The authors of both studies suggest that billboards targeting these behaviors are missing the mark and providing a misleading impression where clarity is urgently needed. They suggest that research to more accurately identify epidemic drivers would be helpful.
This study, by Audrey E. Pettifor of the University of North Carolina and others, was the first to compare representative samples of young people from a high HIV prevalence country and a relatively low prevalence country. For this, researchers examined data collected in population based surveys from 7,548 South Africans between the ages of 18 and 24, and 13,451 Americans in that age range. Researchers did discover that young South African women have a slightly higher age difference between themselves and the people they have sex with. While their most recent partners were an average of four years older, American young women’s most recent partners averaged 2.6 years older. In other words, the difference in the average age difference was 1.4 years. More South African women than American women reported having had sex with only one person, ever, with an average of 2.4 partners as opposed to an American young woman’s 5.7 average partner number. Roughly 10 percent more young South Africans used condoms the last time they had sex than did young Americans.
“Overall,” the authors wrote, “the proportion of American youth reporting riskier sexual behavior (e.g. more sex partners, less condom use and earlier age of coital debut) is consistently higher than among their South African counterparts.” One conclusion, the authors write, is that prevention efforts would do well to allocate their resources to addressing other factors. They note that those factors include biological issues.
When HIV prevalence reaches the levels seen in sub-Saharan African countries, they point out, “‘common’ sexual behaviors lead to exceptionally high risk of HIV acquisition.” They conclude that successful prevention will require “extraordinary efforts,” that must include attention to structural issues as well as biomedical prevention strategies that can include pre-exposure preventive use of antiretroviral drugs, and the continued quest for topical anti-HIV microbicides.
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