Many countries in Asia are experiencing epidemics of human immunodeficiency virus (HIV) in injecting drug users and female sex workers. These epidemics are characterized by a marked contrast in patterns of HIV transmission both within and between countries. (1,2) The situation in the neighbouring countries of Cambodia, the Lao People's Democratic Republic and Viet Nam provides a particular illustration of sharply contrasting epidemic patterns. (3-6)
In Viet Nam significant HIV epidemics have been observed among both injecting drug users and female sex workers. (6) Among groups surveyed in the general population (antenatal clinic attendees, military recruits), HIV prevalence has been relatively low and below 1% in all places surveyed. In these groups, however, signs of a steady rise have been observed. (6-8) This evidence is based primarily on data from urban populations; little is known about the situation in rural areas, where at least 70% of the population resides. Another observation from Viet Nam is that female sex workers and injecting drug users are sexually linked, with female sex workers reporting injecting drug use at significant levels in some areas. (6-9)
As part of the intervention project Community Action for Preventing HIV/AIDS in Cambodia, Viet Nam and the Lao People's Democratic Republic, baseline surveys were. conducted in 2002 to provide a basis for short- and long-term evaluation. (10) These surveys were designed to inform the process of interventions. The aim of this paper is to examine the baseline data from Viet Nam in this regard. We examine HIV risk distribution and determinants in different population subgroups assumed to be at higher risk of HIV infection compared with the general population.
We selected four border provinces for particular intervention support under the Community Action for Prevention of HIV/AIDS Project for the period 2002-2004. (10) These included Lai Chau in the north and An Giang, Dong Thap and Kien Giang in the south. The surveys targeted four different population groups, i.e. female sex workers, injecting drug users, young unmarried men aged 15-24 years and groups assumed to be highly mobile, such as border traders and fishermen. We collected information about HIV status, demographic characteristics and risk behaviours. We administered a standard questionnaire during face-to-face interviews.
We used a two-stage cluster sampling strategy. Sites chosen for sampling were in the main cities and towns and districts in areas bordering another country. (10)
Street-based female sex workers: The total designated was 360 per province. In the first stage, we identified locations where street-based female sex workers were likely to be found. We randomly selected 36 locations using the probability proportional to size design method. From each location, we randomly selected 10 street-based female sex workers from all women present at the site at the time of the visit of the interviewing team.
Karaoke-based female sex workers: The total designated was 450 per province. We selected 150 sites using the probability proportional to size design method with a sampling frame that consisted of time-location clusters based on geographic sites, time of day and day of the week. We randomly selected three sex workers at each site.
Injecting drug users: We selected half of the designated sample (total 360) from the available list of those registered and the other half from mapped locations defined as locations where injecting drug users gather and could be accessed. From a sampling frame based on a list of district communes with registered injecting drug users, we randomly selected 15 injecting drug users. At each commune, we randomly selected 12 injecting drug users by choosing four primary respondents (index cases) from the list of registered injecting drug users. …