HIV prevalence in Zimbabwe declined by nearly half over the course of a decade (from 29 percent estimated adult prevalence in 1997 to 16 percent in 2007). HSPH’s Daniel Halperin and colleagues explored the causes of this remarkable success story in a paper published online in PLoS Medicine on Feb. 8. The researchers found that a reduction in sexual partners played a key role in reducing HIV prevalence in Zimbabwe. They trace this behavior change to a greater awareness of AIDS deaths, in addition to the country’s economic deterioration, which left many men with less disposable income to pay for sex or maintain multiple relationships. Prevention programs that provided educational messages through the mass media and interpersonal communication likely also played a role, according to the researchers.

Drawing on the lessons of Zimbabwe’s success, the researchers believe that a focus on partner reduction, in addition to promoting consistent condom use in casual sex, and other effective approaches such as male circumcision, is crucial for developing prevention programs in other countries where the disease is endemic.