Prevalence and clinical effects of delta agent. Infections in Norwegian population subgroups.

The distribution of antibodies against the delta agent was studied in different groups of hepatitis B patients in Norway. Such antibodies were detected only in drug addicts, predominantly among chronic HBsAg carriers. The results support the notion that the delta agent was introduced into Scandinavia in 1970-75. Although the proportion of anti-delta positive individuals among chronic HBsAg carriers increased, the annual increase of new anti-delta carriers was essentially stable. One death caused by hepatic failure was registered among 43 anti-delta negative and none among 21 anti-delta positive chronic HBsAg carrier addicts.