A retrospective study of notified hepatitis B virus (HBV) infection
in Edinburgh during
1975–92 identified 525 acute cases. For 343 where a probable
transmission route could be
determined, 215 were due to shared equipment by injection drug users (IDUs),
29 to
homosexual intercourse, 25 to heterosexual or household contact with IDUs,
21 to
heterosexual contact with infected non-IDU partners and 53 to various other
or multiple routes. Cases were unevenly distributed geographically, particularly
those among IDUs. The
highest incidence within a post code district was approximately 2·5
times that for all Edinburgh. Annual cases peaked in 1984 then declined
to low
levels in the early 1990s. This
reduction was most marked among IDUs, and may be ascribed both to changed
injecting
behaviour and decreased susceptibility within this group. The latter
factor implies that HBV
infections may be an unreliable guide to human immunodeficiency virus
(HIV) infection in populations where HBV is highly prevalent.