Concurrent sexual partnerships help to explain Africa's high HIV prevalence: implications for prevention

As Kiat Ruxrungtham and colleagues describe in today’s Lancet HIV transmission in most Asian countries remains strongly associated with particularly high-risk activities—ie injection-drug use male-male sex prostitution and in China paid donation of plasma. Although there is understandable concern that the virus could soon spread widely through the general population. HIV has been present in Asia for nearly two decades and such extensive spread has yet to occur. For example analysis of trends in India suggests that HIV prevalence both in high-risk groups and in the generally low-risk antenatal clinic population has probably stabilised in recent years. It is possible that large-scale heterosexual epidemics will never emerge in most of Asia except perhaps on the island of Papua. Furthermore in some of the world’s most populated countries—Pakistan Bangladesh Indonesia and the Philippines home to some one billion people-nearly all men are circumcised further restricting the potential for extensive heterosexual spread. In chilling contrast as Emil Asamoah-Odei and colleagues report also in today’s Lancet HIV rates remain very high in much of east and especially southern Africa. The overwhelming burden of HIV/AIDS is still concentrated in this region which accounts for only 3% of the global population yet some 50% of global HIV cases. For example infection rates in adults in South Africa Botswana Zimbabwe and western Kenya range from 20 to 40% roughly an order of magnitude higher than anywhere else in the world. (excerpt)