Incidence of Hepatitis C Among Injection Drug Users
"The monitoring of hepatitis C in Norway was intensified from 1 January 2008. The notification criteria were changed so that all laboratory-confirmed cases of hepatitis C must now be reported to MSIS [Norwegian Surveillance System for Communicable Diseases]. Previously, only acute illness had to be reported, and this resulted in a very inadequate overview of the real incidence of the disease in the country. In 2011, 1,676 cases of hepatitis C (both acute and chronic cases) were reported. No information was provided about the presumed mode of transmission in about half of the reported cases, but in the cases where the mode of transmission is known, 83 per cent were infected through the use of needles. For the time being, data from MSIS cannot distinguish between cases involving new infection with hepatitis C and cases where the infection occurred many years ago. It is therefore not known whether newly acquired hepatitis C infection has declined or increased among drug users in recent years.
"Among OST patients, the status survey for 2011 (see Chapter 5.2.2) shows that, for the country as a whole, 65 per cent of the clients were hepatitis C antibody positive, roughly the same proportion as in 2010. This is lower than expected, and the explanation is probably that the percentage with unknown status was as high as 20 per cent."
Norwegian Institute for Alcohol and Drug Research, "The Drug Situation in Norway 2012: annual report to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA)," (Oslo, Norway: December 2012), p. 33.