(Needle use is defined as the injection of cocaine, opiates, or psychotherapeutics for nonmedical reasons at least once in the previous 12 months.) This difference is too small to change prevalence estimates noticeably, but it would result in a one-third increase in the population estimates often used by providers for estimating the number of people in need of treatment and, for that matter, HIV prevention services.

One noteworthy point is that most of the injection drug users were found in the household population (about two-thirds). It is of course the case that some unknown portion of injection drug users either denied such