One of the most conspicuous risks of HIV transmission among drug injec
tors involves sharing injecting equipment which has been contaminated
by infected blood. The present study investigates the relationship bet
ween severity of dependence upon heroin and the sharing of previously
used injecting equipment (passive sharing). Four-hundred-and-eight her
oin users were contacted and interviewed. Two-hundred-and-eighty-one (
69% of the total heroin sample) had injected drugs on at least one occ
asion, and 204 of the 281 injectors (73%) had shared injecting equipme
nt on at least one occasion after it had been used by someone else. Th
e more severely dependent heroin injectors were more likely to have sh
ared injecting equipment. As users become more dependent upon heroin,
the types of factors which predispose them towards sharing may change.
Less dependent users were more likely to use in public and 'social' s
ettings, and they may be more likely to share injecting equipment with
people they do not know well. The more dependent users appear to use
heroin in private settings and to be at greater risk of sharing with d
ealers, perhaps because of the urgency of their need for drugs at time
s when they are in withdrawal. One of the most frequently cited reason
s for sharing was that sterile injecting equipment was difficult to ob
tain. It is a matter for some concern that many of the sharers in our
sample (24%) reported having shared used injecting equipment while in
custody. There was good overall awareness of the risks of health probl
ems associated with injecting among our subjects. However, awareness o
f risk was not associated with avoidance of sharing behaviour.