HIV Decline Associated with Behavior Change in Eastern Zimbabwe
Gregson, S., Garnett, G. P., Nyamukapa, C. A., et al. Science (2006), 311(5761), pp. 664–666.
Researchers followed a cohort of nearly 10,000 adults in Manicaland over three years to assess the trajectory of the HIV epidemic. Overall HIV prevalence declined among men and women, with steepest declines taking place among men ages 17-29 (23 percent) and women ages 15-24 (49 percent). At baseline, nearly half of 17- to 19-year-old males reported being sexually active; three years later, only one-fourth of such males reported the same. Women ages 15-17 also reported declines in sexual debut (21 percent to 9 percent over three years). Furthermore, there was a significant decrease in the number of casual partners that men and women reported in the previous year. Similar declines in HIV prevalence took place in areas with and without partner reduction interventions. Because these findings mirror national HIV and local antenatal clinic HIV prevalence rates, the researchers concluded that there is a trend toward a declining prevalence of HIV in Zimbabwe. This decline may follow a pattern similar to Uganda’s—driven by delay of onset of sexual debut, partner reduction, with some contribution of consistent condom use with casual partners. Because prevalence estimates "reflect accumulation of infections over a period of more than 10 years," however, the researchers state that HIV prevalence is "insensitive to behavior change."