The relative importance of factors which influence order of injecting witha shared needle and syringe

Injecting drug users (IDUs) in Adelaide, South Australia, rated the likelih ood of first use of a shared needle and syringe by persons who have charact eristics which have previously been suggested as influencing order of injec ting. This enabled the relative importance of these factors to be assessed. It was found that those who supply their own drug and injecting equipment have the greatest likelihood of using first, bur it is also somewhat advant ageous if one is able to promote one's needs, has recently been tested for HIV or is at home when the opportunity to inject a,ises. Older IDUs and reg ular users may be slightly advantaged, as may those who inject others and t hose who were denied first use the last time sharing occurred. A model for predicting order of use is proposed.