Human immunodeficiency virus (HIV) infection patterns and risk behaviours in different population groups and provinces in Viet Nam.

Objective: To study patterns and determinants of HIV prevalence and risk-behaviour characteristics in different population groups in four border provinces of Viet Nam.
Methods: We surveyed four population groups during April-June 2002. We used stratified random-cluster sampling and collected data concomitantly on HIV status and risk behaviours. The groups included were female sex workers (n = 2023), injecting drug users (n = 1391), unmarried males aged 15-24 years (n = 1885) and different categories of mobile groups (n = 1923).
Findings: We found marked geographical contrasts in HIV prevalence, particularly among female sex workers (range 0-24%). The HIV prevalence among injecting drug users varied at high levels in all provinces (range 4-36%), whereas lower prevalences were found among both unmarried young men (range 0-1.3%) and mobile groups (range 0-2.5%). All groups reported sex with female sex workers. Less than 40% of the female sex workers had used condoms consistently. The strongest determinants of HIV infection among female sex workers were inconsistent condom use (adjusted odds ratio [OR], 5.3; 95% confidence interval [CI], 2.4-11.8), history of injecting drug use and mobility, and, among injecting drug users, sharing of injection equipment (adjusted OR, 7.3; 95% CI, 2.3-24.0) and sex with non-regular partners (adjusted OR 3.4; 95% CI 1.4-8.5).
Conclusion: The finding of marked geographical variation in HIV prevalence underscores the value of understanding local contexts in the prevention of HIV infection. Although lacking support from data from all provinces, there would appear to be a potential for sex work to drive a self-sustaining heterosexual epidemic. That the close links to serious injecting drug use epidemics can have an accelerating effect in increasing the spread of HIV merits further study.