An epidemic of hepatitis B virus infection among intravenous drug users in Iceland

This study describes an outbreak of hepatitis B primarily among intravenous drug users in Iceland which has a population with a very low incidence of hepatitis B virus infection. The incidence of acute hepatitis B is generally low in the Nordic Countries, in the order of one to five cases per 100,000 people per year. Between 1989 and 1992 there was an outbreak of hepatitis B virus infection primarily among the intravenous drug user (IVDU) population in Iceland. At the Department of Medical Virology, University of Iceland there were 44 cases of acute hepatitis B identified during the peak year 1990, an incidence of 16.9 cases of acute hepatitis B per 100,000 people. 63.6% of these were known to be IVDUs. The seroprevalence of the hepatitis B core antibody (anti-HBc) marker was assessed among 1100 randomly selected individuals. The average prevalence of this marker was 2.9% and rose from zero at the age of 15 and younger to 6.5% at the age of 65 and older. Among IVDUs attending a detoxification clinic in 1990 the prevalence of the anti-HBc was 32%. In contrast, those attending the same clinic, due to alcoholism only, did not have a significantly higher prevalence of anti-HBc than the group used for comparison.