"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. 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 2013, 1,318 cases of hepatitis C (both acute and chronic cases) were reported. In 47 per cent of the reported cases, no information was provided about the presumed mode of transmission, but in the cases where the mode of transmission is known, 91 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 the number of cases of newly acquired hepatitis C infection has declined or increased among drug users in recent years.
"Among OST patients, the status survey for 2013 (see Chapter 5.2.2) shows that 63 per cent of the clients were hepatitis C antibody positive, roughly the same proportion as in 2012. This is lower than expected, and the explanation is probably that the percentage with unknown status was as high as 18 per cent.
Since 2002, small-scale prevalence surveys have been carried out in connection with needle distribution and the drug injection room in Oslo in order to register the prevalence of several infectious diseases among injecting drug users. These surveys are the only prevalence surveys that are carried out regularly among a sample of drug users in Norway. The 2012 survey showed that 62 per cent of the injecting drug users tested had had a hepatitis A infection or had been vaccinated against the disease, while 35 per cent had had a hepatitis B infection and 64 per cent had had a hepatitis C infection. Forty-one per cent had hepatitis B markers, indicating that they had been vaccinated against hepatitis B. No survey was carried out in 2013."