Lead with B
Recent articles in the Washington Post and New York Times based on presentation of data from Rakai in Uganda from 1994 to 2003 challenge the position that primary sexual risk reduction - partner reduction/fidelity (the "B" of the abstain, be faithful, or use a condom [ABC] formula) and abstinence - was the main driver of decline in HIV in Uganda in the 1990's. Rather, mortality was cited as the major cause of declining prevalence. What is your view?
B was clearly the predominant factor in the decline in HIV incidence that occurred in Uganda from the late 1980s to about 1994. Unfortunately, the articles confuse incidence with prevalence. Moreover, by 1994, the starting point for the reported data from Rakai, the decline in incidence, nationally, was essentially over. So those data "miss the boat".
Bear in mind, these are very highly respected researchers, and the Rakai study is the premier of such studies on HIV in Africa. While Rakai has been a site of intensive effort, it is probably somewhat reflective of Uganda overall. However:
1. To assess prevention efforts, we are really interested in incidence, not prevalence. Prevention efforts can only affect new infections (that is, incidence.) In a generalized epidemic, the large reservoir of people who are already infected dominate prevalence.
2. Death is essentially the only way prevalence can decrease with a lifelong infection. (Setting aside subtle effects of demographic change.) So when death is described as the major contributor to decline in prevalence, it is no surprise. (However, for this to happen, incidence has to be lower than mortality.)
3. Most importantly, 1994-2003 is too late to explain the earlier large decline in incidence nationally in Uganda. While incidence estimates have to be inferred from other data, in all likelihood incidence peaked in Uganda about 1989, declined dramatically and stabilized around 1994 (though there may have been subtle changes thereafter). But prevalence continued to decline through 2000 as people died who were infected years earlier. (See Stoneburner RL and Low-Beer D. Science 2004:714-718.) So data from Rakai beginning in 1994 miss the prior major decline in incidence.
What the Rakai data can describe quite well is the dynamic of B and C from 1994 onward. But it is actually worrisome re: prevention and the condom. The Rakai study is powerful in that it includes ongoing HIV incidence and also sexual behavior. Over the 1994-2003 time period, HIV incidence varied, but was fairly stable. So the previous downward momentum on HIV incidence was largely lost. But during that period, there appears to have been some substitution of condoms for B, or, in other words, "compensating" behavior of more C and less B. This is worrisome. It may reflect so-called "disinhibition" of risky sex practice as has occurred among gay men in the US.
This argues for promoting B, C, and A in a mutually supportive way to maximize overall risk reduction. But B is the most powerful in a generalized epidemic, especially reduction of concurrent partners. So, in my view, we should - LEAD WITH B.
The "Pearls" offer answers to commonly asked questions about family planning. These "Pearls" are prepared by Dr. James D. Shelton, Senior Medical Scientist, Office of Population, United States Agency for International Development (USAID)
