Comparison of Four Survey Methods Designed to Estimate the Prevalence of HIV among Female Prostitutes Who Inject Drugs

In Glasgow, during the period January 1990 to December 1992, 4 different methods were used to determine HIV prevalence among female prostitutes who inject drugs: the surveillance of prostitutes undergoing voluntary named tests, an unlinked anonymous survey of prostitutes attending a health care drop-in centre, a community-wide voluntary anonymous survey of injecting drug users including female prostitutes, and a voluntary anonymous survey of female prostitutes recruited in Glasgow's red-light area. HIV prevalence varied from 1.2 to 4.7% though overlapping confidence intervals indicated no significant differences. A comparison of each approach leads the authors to suggest that the former 2 methods which are relatively inexpensive should be conducted, if possible, on high risk groups such as prostitutes and injecting drug users on a continuous basis. If these indicate HIV rates which are stable and less than 5%, implementation of more sophisticated voluntary anonymous approaches need only be done every 3 to 4 years. However, if rates are unstable and/or greater than 5% then such surveys should be initiated more frequently, perhaps biannually.