Eurosurveillance - Volume 13, Issue 21, 22 May 2008

Hepatitis C virus (HCV) infection is a serious public health problem in Europe, and it is estimated that a large number of people are unaware of their infection [1-3]. HCV infection may lead to symptomatic chronic liver disease after many years of asymptomatic infection. Effective treatment is available for HCV infection; however, the efficacy for many genotypes remains low and therapy is prolonged, involving both weekly injections and daily oral medication, and can be associated with significant adverse effects [4,5]. Where documented, injecting drug use is a major transmission route for HCV infections [1,6,7]. In many European countries, national surveillance of HCV infections has been established relatively recently.

In 2004, the Scottish Government recognised that 'Hepatitis C is one of the most serious and significant public health risks of our generation' [1] . By December 2006, Health Protection Scotland (HPS) estimated that 50,000 people in Scotland had been infected with the hepatitis C virus (HCV) and that 38,000 were chronic carriers (Figure 1) [2]. Following an extensive consultation in 2005, the Health Minister and Chief Medical Officer launched Scotland's 'Action Plan for Hepatitis C' in September 2006 [3]. .

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are frequent causes of acute and chronic hepatitis worldwide and leading causes for hepatic cirrhosis and cancer. There is a distinct geographical variation in HBV and HCV incidence and prevalence in the European Union (EU) and European Economic Area/European Free Trade Association (EEA/EFTA) member states and neighbouring countries. The HBV carrier prevalence ranges from 0.1 to 8.0% and that of HCV from 0.1 to 6.0%. Within the last few years, the HBV incidence has decreased while the HCV incidence has increased. Both diseases are concentrated in certain subpopulations, such as injecting drug users, with tens of times higher prevalence than in the general population. Most EU and EEA/EFTA countries have a surveillance system for HBV and HCV infections, but due to differences in system structures, reporting practices, data collection methods and case definitions used, the surveillance data are difficult to compare across countries. The harmonisation and strengthening of HBV and HCV surveillance at the European level is of utmost importance to obtain more robust data on these diseases.

In Sweden, infection with hepatitis C virus (HCV) has been a notifiable disease since 1990, when diagnostic methods became available. Blood donor screening indicated that about 0.5% of the Swedish population (9 millions) had been HCV infected. Here we present the Swedish hepatitis C epidemic based on data from all the HCV notifications 1990-2006. During this time about 42,000 individuals (70% men) were diagnosed and reported as HCV infected. The majority (80%) were born in 1950 or later, with a high percentage (60%) born in the 1950s and 1960s. Younger people, 15-24 years old at notification, were reported on the same level each year. The main reported routes of HCV transmission were intravenous drug use in 65%, blood transfusions/products in 6%, and sexual in 2%, though unknown or not stated in 26%. Approximately 6,000 of all notified individuals have died during the study period. To conclude, the Swedish HCV epidemic is highly related to the increase of intravenous drug use in the late 1960s and 1970s, with a high proportion of people now chronically infected for more than 25 years, resulting in an increase of severe liver complications in form of cirrhosis and hepatocellular carcinoma. Furthermore the unchanged number of notifications of newly infected younger people indicates an ongoing HCV epidemic.

Infection by the Hepatitis B virus (HBV), which is often asymptomatic at the acute phase, can progress to chronic liver disease, particularly when infection occurs early in life. Hepatitis B is mainly transmitted sexually or through blood or body fluids. Episodes of healthcare-associated transmission of HBV have been previously described [1-3]. Transmission of HBV results either from patient to patient through invasive healthcare procedures with improper disinfection of devices used between patient care or from a patient to a healthcare worker (HCW). Transmission can also take place from a chronically infected HCW to a patient. In those episodes, breaches in healthcare practices and standard precaution play a major role. Prevention of HBV transmission in healthcare settings also relies on the immunisation of HCW, which has been mandatory in France since 1991. HCW are considered immune if they have documented proof that they were vaccinated before 13 years of age, or if a positive anti-HBs antibody test is provided [4].

As a part of the HIV behavioural surveillance system in Switzerland, repeated cross-sectional surveys were conducted in 1993, 1994, 1996, 2000 and 2006 among attenders of all low threshold facilities (LTFs) with needle exchange programmes and/or supervised drug consumption rooms for injection or inhalation in Switzerland. Data were collected in each LTF over five consecutive days, using a questionnaire that was partly completed by an interviewer and partly self administered. The questionnaire was structured around three topics: socio-demographic characteristics, drug consumption, health and risk/preventive behaviour. Analysis was restricted to attenders who had injected drugs during their lifetime (IDUs). Between 1993 and 2006, the median age of IDUs rose by 10 years. IDUs are severely marginalised and their social situation has improved little. The borrowing of used injection equipment (syringe or needle already used by other person) in the last six months decreased (16.5% in 1993, 8.9% in 2006) but stayed stable at around 10% over the past three surveys. Other risk behaviour, such as sharing spoons, cotton or water, was reported more frequently, although also showed a decreasing trend. The reported prevalence of HIV remained fairly stable at around 10% between 1993 and 2006; reported levels of hepatitis C virus (HCV) prevalence were high (56.4% in 2006). In conclusion, the overall decrease in the practice of injection has reduced the potential for transmission of infections. However as HCV prevalence is high this is of particular concern, as the current behaviour of IDUs indicates a potential for further spreading of the infection. Another noteworthy trend is the significant decrease in condom use in the case of paid sex.

Around 25% of people infected with hepatitis C virus (HCV) are able to clear the infection spontaneously, while the majority become chronically infected, with a subsequent risk for the individual patient of progressive inflammatory liver disease, cirrhosis, hepatocellular carcinoma and liver-related death (Figure 1). Much is known about the epidemiology, pathogenesis, diagnosis and management of chronic HCV infection. In comparison, knowledge about acute HCV infection is patchy. In this article, we will highlight concerns relating to acute HCV infection and suggest that public health bodies responsible for managing the HCV epidemic should redirect at least some of their resources to dealing with these issues.