August 19, 2003
The researchers examined current levels and trends in prevalence patterns in Cambodia, Indonesia, Honduras, Russia, and Kenya. Even countries considered to have the same type of epidemic -- i.e., low-level, concentrated, or generalized -- showed wide variation of incidence by category of exposure. "Failure to examine current patterns of incidence can lead to inappropriate prevention efforts," they wrote.
Although drug injection and sex work accounted for approximately the same proportion of infections in Indonesia in 2002, according to the study, an escalating epidemic of injection drug use is likely to account for more than 75 percent of new HIV infections in 2003.
In Cambodia, an active sex industry accounted for much HIV infection. Efforts to decrease unprotected sex-work transactions have been successful. Total new infections dropped from an estimated 40,000 in 1994 to 6,500 in 2002. However, the authors noted, "Because HIV infection resulting from sex work has fallen so radically the proportion of new infections transmitted within marriage has grown from 11 percent to 46 percent. Clearly, more attention should now be given to prevention strategies aimed at reducing transmission between spouses who may previously have been exposed to HIV through buying or selling sex, while sustaining existing prevention efforts focused on sex work."
Cambodia is classified as having a generalized epidemic, meaning that the nexus of infection has shifted beyond identifiable high-risk groups. But most people becoming infected have partners who exhibited high-risk behavior in the past. The scientists suggested that if Cambodia continues its success in reducing risky sex-work transactions and succeeds in reducing transmission between spouses, HIV prevalence could fall to the low endemic levels of many industrialized nations.
Kenya is also classified as having a generalized epidemic. By 1989, national HIV prevalence in adults reached nearly 4 percent. HIV prevalence among Nairobi sex workers then was 60-70 percent. Despite prevention efforts and an increase in condom use with non-marital partners, sex work remains a key factor in the spread of HIV.
Although recent emphasis has been on altering structural factors such as poverty and sexual inequality that prevent people from protecting themselves from HIV, the study stated, "an understanding of the dynamics of a country's HIV epidemic, how it changes over time, and who is currently at greatest risk is essential to guiding decisions about effective prevention." The authors pointed out that structural change takes time. They urged public health officials to focus on new infections and let political and religious leaders take the lead on initiating changes in the social and cultural factors that influence sexual and drug-taking habits.