Potential impact of HIV among IDUs on heterosexual transmission in Asian settings: Scenarios from the Asian Epidemic Model

Tobi J. Saidel, Don Des Jarlais, Wiwat Peerapatanapokin, Jimmy Dorabjee, Siddharth Singh, Tim Brown

Research output: Contribution to journalArticlepeer-review


Introduction: An important public health question is the degree to which HIV epidemics among injecting drug users (IDUs) can contribute to more generalised spread of the virus heterosexually among non-IDUs. Mathematical models can be of use in understanding the complexities of such epidemiological problems. Methods: In this paper, the Asian Epidemic Model (AEM) is used to explore different scenarios for potential HIV transmission by IDUs to non-injecting sexual partners and beyond. The model is applied to a 'general Asian' setting, in which (1) there is the potential for sex work to drive a self-sustaining heterosexual epidemic, and (2) the vast majority of IDUs are male and do not engage in sex work themselves, but a substantial minority of the IDUs do purchase sexual services from sex workers. Within such a setting, three different scenarios are modeled, and within each scenario, the level of HIV prevalence among IDUs is varied, to see the impact of preventing HIV among IDUs at different stages. Results: The number of HIV infections attributable to IDUs over a 15-year period was greatest when the epidemic among IDUs started in advance of a generalised heterosexual epidemic, with a 171% increase in infections if the IDU prevalence was not kept under control. Once a heterosexual epidemic was underway, controlling HIV prevalence among IDUs still resulted in a meaningful reduction in infections (23%), including among non-IDUs. Once the heterosexual epidemic started to decline, the relative proportion of infections attributable to IDUs increased, creating a situation for IDUs to feed into new epidemics. Discussion: In the early stages of a heterosexual epidemic, maintaining HIV prevalence at low levels among IDUs can buy critical time to address the potential for rapid heterosexual transmission. In more advanced heterosexual epidemics, preventing HIV among IDUs can still avert a substantial number of infections.

Original languageEnglish (US)
Pages (from-to)63-74
Number of pages12
JournalInternational Journal of Drug Policy
Issue number1
StatePublished - Feb 2003


  • AIDS
  • Epidemiology
  • HIV
  • HIV transmission
  • Injection drug users
  • Modeling

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Health Policy


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