Epidemiology of hepatitis C virus infections in Finland between the years 1995 and 2011

In Finland all clinically diagnosed hepatitis C virus infections have been reported to National Infectious Disease Register (NIDR) starting at 1995. Between the years 1995 and 2011 approximately 24,000 HCV infections have been reported. Because of the changed policies in HCV reporting, same individuals may have been reported to NIDR several times at early stages of NIDR existence. Therefore we have characterized the epidemiology of HCV infection in individuals who were reported to NIDR with their social security number. This group contains nearly 20,000 individuals of whom almost 2000 were of foreign origin. Two-thirds of HCV cases are males. At the time of HCV diagnosis most people were young adults, between 20 and 30 years of age. There has been some fluctuation in the age group-specific trends. The incidence has been the highest among 20–24 years females and in 25–29 males during the last years. Regionally the highest HCV incidence (33/100,000) was found in the hospital district of Helsinki metropolitan area and lowest (6–10/100,000) in the hospital districts of Eastern Savo, Åland, Kainuu, Central and Southern Ostrobothnia. Almost half of the cases were found within Helsinki university hospital district. 17% of HCV cases have died by the end of the year 2011. The most common causes of death were either related to liver diseases: viral hepatitis, cirrhosis and cancer, caused by alcohol abuse and intoxications or by accidents or suicides. HCV-infected individuals appear to die younger than the average Finnish people. The most common way to contract HCV infection in Finland is intravenous drug use. HCV-antibody prevalence among intravenous drug users in Finland was over 60% in 2009 and over 40% among studied inmates in 2006. HCV prevalence among pregnant women has increased from 0.19% to 0.64% during 1985–2010. However, among blood donors HCV prevalence has been clearly decreasing being 0.006% in 2011. According to HCV-genotyping studies the main HCV-genotypes circulating in Finland belong to 3a, 1a, 1b and 2b subtypes.