Molecular epidemiologic analysis of hepatitis C virus infection in injecting drug users with acute hepatitis C in Japan

BACKGROUND AND AIM: The aim of this study was to examine whether particular hepatitis C virus (HCV) subtypes are spreading among injecting drug users (IDUs) in Yamaguchi prefecture, on the south-western tip of the island of Honshu in Japan, as found in European countries. METHODS: We prospectively enrolled acute hepatitis C patients from January 2001 to March 2003. E2 gene sequences of HCV isolates from IDUs with acute hepatitis C were phylogenetically compared to those from 30 chronic hepatitis C patients with the same HCV subtypes who had or did not have a history of intravenous drug use. RESULTS: Nine of 11 patients (82%) with acute hepatitis C were IDUs. The HCV subtypes were 2a in four and 2b in five, which contrasted with the high prevalence of subtype 1b in patients with chronic liver diseases in Japan. IDUs with acute hepatitis C (22.0 +/- 2.4 years old) were significantly younger than those with chronic hepatitis C (49.5 +/- 9.5 years old) for subtype 2a (P = 0.0005), but not for subtype 2b (25.6 +/- 5.4 vs 28.1 +/- 2.4 years old). Some HCV isolates of subtype 2b from IDUs with acute hepatitis C were phylogenetically related to those from IDUs with chronic hepatitis C. By contrast, there was no phylogenetic segregation of HCV in IDUs with subtype 2a. HCV isolates from non-IDUs were genetically divergent from each other and those from IDUs, irrespective of the HCV subtype. CONCLUSION: Hepatitis C virus of the non-1b subtype, particularly subtype 2b, seemed to be transmitted between IDUs very recently in Yamaguchi prefecture, Japan.     

Spread of hepatitis C virus among European injection drug users infected with HIV: a phylogenetic analysis

To describe the spread of hepatitis C virus (HCV) among HCV/human immunodeficiency virus (HIV)-coinfected injection drug users (IDUs), the molecular epidemiology of HCV was studied among 108 IDUs from 7 European countries. Phylogenetic analysis based on the NS5B region showed great sequence variation of HCV within each country and no clear phylogenetic clustering by geographic region. The most prevalent subtypes were 1a and 3a, but the percentage of genotype 4 was also relatively high, ranging from 7% in northern Europe to 24% in southern Europe. Genotype 4 consisted mainly of subtype 4d and has entered the majority of the IDU populations studied. The significantly lower evolutionary distances within subtype 4d suggest that this subtype may have entered the European IDU population relatively recently. In conclusion, HCV exchange between European IDU populations has occurred on a large scale, and, overall, country-specific clustering for HCV was less than that shown for HIV.     

HCV RNA levels in a multiethnic cohort of injection drug users: human genetic, viral and demographic associations

In patients with chronic hepatitis C, the hepatitis C virus (HCV) RNA level is an important predictor of treatment response. To explore the relationship of HCV RNA with viral and demographic factors, as well as IL28B genotype, we examined viral levels in an ethnically diverse group of injection drug users (IDUs). Between 1998 and 2000, the Urban Health Study (UHS) recruited IDUs from street settings in San Francisco Bay area neighborhoods. Participants who were positive by HCV enzyme immunoassay were tested for HCV viremia by a branched-chain DNA assay. HCV genotype was determined by sequencing the HCV nonstructural 5B protein region. For a subset of participants, IL28B rs12979860 genotype was determined by Taqman. Among 1,701 participants with HCV viremia, median age was 46 years and median duration of injection drug use was 26 years; 56.0% were African American and 34.0% were of European ancestry (non-Hispanic). Human immunodeficiency virus type 1 (HIV-1) prevalence was 13.9%. The overall median HCV RNA level was 6.45 log(10) copies/mL. In unadjusted analyses, higher levels were found with older age, male gender, African-American ancestry, hepatitis B virus infection, HIV-1 infection, and IL28B rs12979860-CC genotype; compared to participants infected with HCV genotype 1, HCV RNA was lower in participants with genotypes 3 or 4. In an adjusted analysis, age, gender, racial ancestry, HIV-1 infection, HCV genotype, and IL28B rs12979860 genotype were all independently associated with HCV RNA. CONCLUSION: The level of HCV viremia is influenced by a large number of demographic, viral, and human genetic factors.     

Changing serological status and low vaccination-induced protection rates against hepatitis B characterize chronic hepatitis C virus-infected injecting drug users in Greece: need for immunization policy

OBJECTIVE: To evaluate the serological status of hepatitis B virus infection among Greek injecting drug users with chronic hepatitis C virus infection; to correlate hepatitis B virus infection status with the possible time of infection and the principal genotype of hepatitis C virus infection. METHODS: Two hundred and thirty consecutive injecting drug users with chronic hepatitis C virus infection were evaluated for serological markers of hepatitis B virus infection. One hundred and three of them (44.8%) reported intravenous drug use beginning before 1992 (group A) and 127/230 (55.2%) after 1992 (group B). Statistical analysis of data was based on Student's t-test and chi analyses. RESULTS: Eighty-five of 103 patients from group A (82.5%) and 28/127 (22%) from group B had serological markers of previous hepatitis B virus infection (P<0.001). Eleven patients from group A (10.6%) and 78 (61.4%) from group B were seronegative for all hepatitis B virus markers (P<0.001). Only 3.8% (4/103) of group A patients and 16.5% (21/127) of group B had vaccination-induced protective antibody levels (anti-HBs) against hepatitis B (P=0.02). The majority of patients were infected with hepatitis C virus genotype-3 (64.7% from group A vs 56.7% from group B, P=0.42). The percentages of patients infected with genotype-1 were also comparable in both groups (15.5% from group A vs 30.8% from group B, P=0.09). A significantly higher percentage of group A patients were infected with genotype-4 (19.7%) than those in group B (4.9%, P=0.02). CONCLUSION: The serological profile of hepatitis B virus infection among Greek hepatitis C virus-infected injecting drug users is changing. The proportion of successfully vaccinated hepatitis B virus injecting drug users, although significantly higher than the previous decades, is still relatively low. Vaccination policy in this high-risk group for viral hepatitis is urgently needed.     

Evidence for a substantial role of sharing of injecting paraphernalia other than syringes/needles to the spread of hepatitis C among injecting drug users

In industrialized countries, transmission of hepatitis C occurs primarily through injecting drug use. Transmission of hepatitis C in injecting drug users is mainly associated with the sharing of contaminated syringes/needles, although evidence for risk of hepatitis C infection through sharing of other injecting paraphernalia is increasing. In this paper, the independent effects of sharing paraphernalia other than syringes/needles have been estimated. The prevalence and force of infection were modelled using three serological data sets from drug users in three centres in Belgium as a function of the sharing behaviour. It was found that sharing of materials other than syringes/needles indeed seemed to contribute substantially to the spread of hepatitis C among injecting drug users.     

Evaluation of a reverse hybridization assay for genotyping of hepatitis C virus

Background/Aims: Several strains of the hepatitis C virus exist; distinct genotypes and subtypes can be identified by sequence comparison of the viral genomes. Recent evidence that the genotype/subtype of hepatitis C virus may infuence the clinical course of chronic hepatitis C and the response to interferon-a therapy for this disease suggests that methods to identify the genotype may become clinically useful. In the present study we evaluated a recently introduced reverse hybridization assay.Methods: HCV-RNA was isolated from serum samples from 61 consecutive patients attending our out-patient clinic and subsequently sequenced in the 5′-noncoding and the nonstructural-5 region by the dideoxynucleotide chain termination method. HCV-genotyping was performed by phylogenetic analysis of nonstructural-5 sequences. The amplification product for the reverse hybridization assay was obtained by “nested” polymerase chain reaction using biotinylated primers corresponding to the 5′-noncoding region. The assay is based on hybridization of the resulting polymerase chain reaction product with oligonucleotide probes immobilized as paralleled lines on membrane strips.Results: According to the phylogenetic analysis of the nonstructural-5 region the prevalence of hepatitis C virus subtypes was as follows: 1a 18%. 1b 51%, 2a 3%, 2b 3%, 2c 7% and 3a 18%. The reverse hybridization assay correctly identified each hepatitis C virus genotype (1, 2, and 3). However, differentiation of hepatitis C virus subtypes was insufficient. HCV-1a isolates was incorrectly classified by the reverse hybridization assay as HCV-1b and vice versa HCV-1b isolates as HCV-1a. Classification of hepatitis C virus subtypes 2a, 2b and 3a was correct, but HCV-2c isolates were misinterpreted by the assay a HCV-2a.Conclusions: The reverse hybridization assay can differentiate between hepatitis C virus genotypes 1, 2, and 3, but is not completely reliable for hepatitis C virus subtyping.     

Acute Hepatitis B in Western Sweden – Genotypes and Transmission Routes

A retrospective study of acute hepatitis B (AHB) during 1995-1996 in G?teborg, Sweden, was carried out to investigate whether the increasing number of hepatitis B virus (HBV) carriers due to immigration in northwestern Europe has influenced the incidence or genotype heterogenicity. 24 cases of AHB were identified, the probable transmission route of which was intravenous drug use (IVDU) in 11 (46%), heterosexual in six (25%), homosexual in one, hemodialysis in two and unknown in four cases. In no case was the source an immigrant with chronic HBV infection. Genotype D was seen in 12 patients, seven being anti-HCV-positive IVD users, two probably infected heterosexually and three with an unknown source. Genotype A was found in six patients: three IVD users, a sexual partner of an IVD user and two dialysis patients. Genotype B was found in one patient infected during travel to Vietnam, and genotype C in one patient, probably infected sexually from a previously identified chronic carrier. In conclusion, genotype D is the main genotype and IVDU still the major risk factor for AHB in Goteborg, while transmission from immigrants appears to be of minor importance despite the fact that this group comprises over 90% of the young, highly infectious carriers.     

Hepatitis C virus infection in Italian intravenous drug users: epidemiological and clinical aspects

Abstract: The epidemological and clinical features of hepatitis C virus infection have been evaluated in a cohort of 227 intravenous drug users enrolled at a drug dependence treatment center in the Veneto area in 1992–1993 and followed periodically. Hepatitis C virus infection was detected using second-generation anti-HCV ELISA in 171 (75%) subjects at enrollment. Anti-HCV seropositivity correlated with: a) the duration of drug abuse: 91% of intravenous drug users injecting for more than 8 years were seropositive as compared to 40% of those with a history of abuse lasting 4 years or less, p<0.001; b) sharing of injection equipment: 85% anti-HCV positive intravenous drug users had shared at some time as compared to 64% seronegative subjects, p<0.001; c) seropositivity for immunodeficiency virus infection: 25% anti-HCV positive intravenous drug users were coinfected as compared to 3.5% anti-HCV negative, p<0.001; d) markers of ongoing (two cases) or previous hepatitis B virus infection were detected in 62% of anti-HCV positive but in 21% of anti-HCV negative cases, p<0.01. Two initially anti-HCV negative intravenous drug users seroconverted during follow up giving an incidence rate of hepatitis C virus infection of 6.2 per 100 person-years. During the survey abnormal alanine aminotransferase levels were detected in 75% anti-HCV positive but in 24% anti-HCV negative cases (p<0.001), with significantly higher levels in the former. These findings suggest that the circulation of hepatitis C virus among intravenous drug users has been decreasing in recent years, although new infections still occur. In agreement with the high rate of chronicization of parenterally transmitted hepatitis C, the majority of anti-HCV positive subjects had biochemical features of associated liver disease.     

Genetic diversity of hepatitis D virus genotype‐1 in Europe allows classification into subtypes

Hepatitis delta virus (HDV) is an RNA virus which leads to both acute and chronic forms of hepatitis. At present, HDV isolates have been classified into eight major genotypes distributed over different geographical regions. Recent increase in HDV sequences in Europe and worldwide has enabled us to revisit the taxonomic classification of HDV. A total of 116 large hepatitis delta antigen (L‐HDAg) nucleotide sequences and 13 full‐length HDV genome sequences belonging to genotype‐1 from our European cohort, as well as 621 L‐HDAg nucleotide sequences belonging to genotype‐1 to genotype‐8 retrieved from the GenBank NCBI were included in this study. All 116 isolates of our cohort and 341 of 621 isolates (60%) account for genotype‐1, while the remaining 40% of isolates were unevenly distributed across genotype‐2 to genotype‐8. Phylogenetic analysis of 98 L‐HDAg sequences selected after elimination of redundant sequences of all 737 isolates was performed to identify plausible subtypes within HDV genotype‐1. Pairwise genetic distances for L‐HDAg sequences were calculated to estimate the inter‐genotype and inter‐subtype differences. The HDV genotype‐1 isolates phylogenetically formed five distinct clusters (genotype 1a‐1e), each of them corresponding to a distinct geographic region. Two distinct subtypes for HDV genotype‐2 and ‐4 (ie ‐2a and ‐2b; ‐4a and ‐4b, respectively) could be identified based on isolate sequences from GenBank. The previously defined genotype‐1 to genotype‐8 have an inter‐genotypic difference of ≥10%, while the newly defined subtypes of genotype‐1, ‐2 and ‐4 show an inter‐subtype difference of ≥3% to <10% from the average diversity. In addition, we identified unique amino acid residues, known as specificity‐determining positions, amongst the proposed subtypes.     

Age trend in hepatitis C virus genotype distribution as seen in a Brussels teaching hospital

The hepatitis C virus genotype distribution was studied among age groups in 501 referred patients with chronic hepatitis C by INNO-LiPA HCV II (Innogenetics, Belgium). Ten patients had coinfection with several genotypes. Two hundred seventy of 491 singly infected individuals (57%) had 1b, 66 (13.4%) 3a, 57 (11.6%) 1a. HCV subtype 1b was predominant but its prevalence increased with age (76.5% of patients born in the '20s, 39.3% in the '70s) (P < 0.0001). Three possibilities could explain the shift towards a wider variety of genotypes in younger age. (1) 1b could be the original subtypes in this population, (2) the non-1b subtypes could give less chronic carriers, (3) the non-1b subtypes could have a higher mortality, which seems improbable. The 1b genotype seems the oldest subtype in our country while others were imported later through increased population movements and changing habits.     

Serotyping and Genotyping of Hepatitis C Virus in Belgium

Background: Given that both pathogenicity and the response to treatment are possibly associated with hepatitis C virus (HCV) serotype, it appeared sensible to establish the prevalence of the different HCV types in Belgium. Materials and Methods: The HCV serotypes were determined in 68 HCV-RNA and anti-HCV-positive samples taken from Belgian patients and compared with the results of the genotyping assay. Possible associations with age and sex were investigated. Results: Antibodies were identified in 55 (80.9%) of the 68 samples, with serotype 1 (58.8%) and serotype 3 (19.1%) showing the highest prevalence. 17 samples contained several serotypes with serotype 1 being detected in 82.4% of cases. Nine of the 11 samples undetermined by serotyping could be determined by genotyping. There was no significant difference in the distribution of HCV types with respect to gender. Compared with genotype 3 (p < 0.01) and genotypes 2 and 4 (p = 0.05), genotype 1 was detected among older patients. Conclusion: Our data showed a 96.0% correlation between the serotyping and genotyping assays. Genotypes 1 and 3 are the most prevalent types among Belgian patients. The data suggest that genotype 1 spread earlier than genotypes 2, 3 and 4. This corroborates previous European studies. Received: January 3, 2002 · Revision accepted: December 2, 2002 Liesbet De Cock (corresponding author)     

Effectiveness of a multi-disciplinary standardized management model in the treatment of chronic hepatitis C in drug addicts engaged in detoxification programmes

AIM: To evaluate the effect of a multi-disciplinary standardized management model on the efficacy of pegylated (Peg)-interferon alpha-2b plus ribavirin treatment of chronic hepatitis C in drug addicts undergoing substitutive or antagonist therapy. DESIGN: Observational prospective multi-centre study. SETTING: Six clinical infectious disease centres in collaboration with 11 drug dependency units (DDU) in five Italian regions. PARTICIPANTS: Intravenous drug users affected by chronic hepatitis C engaged in detoxification programmes. METHODS: Application of a multi-disciplinary standardized management model for HCV treatment involving DDU operators, psychologists or psychiatrists and infectious disease specialists. MEASUREMENTS: Very early, early, end-of-treatment and sustained virological response to Peg-interferon alpha-2b plus ribavirin. FINDINGS: Fifty-three subjects were studied [43.4% with hepatitis C virus (HCV) genotypes 1 or 4]. Intent-to-treat analysis showed an end-of-treatment virological response in 58.5% of patients (39.1% genotypes 1 or 4; 73.4% genotype 3) and a sustained virological response in 54.7% (34.8% genotypes 1 or 4; 70.0% genotype 3). There were 19 (35.8%) dropouts and three (5.7%) non-responders: one genotype 1 and two genotype 4. Two (3.8%) patients relapsed: genotypes 1 and 3. On-treatment analysis showed negative HCV-RNA in 40 (93.1%) of 43 subjects who completed the first 12 treatment weeks and in 35 who completed the first 24 treatment weeks. All subjects with an end-of-treatment response, except one with genotype 3 infection, had a sustained response. CONCLUSIONS: Our data show that antiviral treatment in the context of a multi-disciplinary standardized management model helps many HCV-positive drug addicts achieve a good virological response.     

Hepatitis C Virus Genotype 5 in Southern Belgium: Epidemiological Characteristics and Response to Therapy

Data are scarce on patients infected with hepatitis C virus of genotype 5, due to the low prevalence of this genotype around the world. To better define the characteristics of these patients, we reviewed the files of 16 genotype 5 patients. Mean age was 38 +/- 14. All patients were of European origin. Most of them (75%) had been contaminated by transfusion within a short time period (between 1980 and 1991). There were no intravenous drug addicts. Seven patients received treatment. One patient did not respond to interferon (IFN) monotherapy. Of four patients treated with IFN and ribavirin, three became sustained viral responders. Two patients treated with pegylated IFN and ribavirin became sustained viral responders. In our region, genotype 5 patients seem to have been contaminated within a relatively short time period. Treatment with IFN or pegylated IFN and ribavirin gave a high rate (83%) of sustained viral responses.     

Molecular epidemiology of hepatitis C virus infection among intravenous drug users

Background/Aims: The clinico-pathologic features of hepatitis C virus infection intravenous drug users are different from those found in other hepatitis C virus-infected patients. Our airm was to test whether specific viral variants circulate within this particular patient population.Methods: We studied the distribution of hepatitis C virus genotypes in 90 drug addicts and 484 controls, according to the method described by Okamoto.Results: Hepatitis C virus type 1a and 3a infections were more frequent among intravenous drug users than in 125 age-matched controls (48.8% and 21.1% vs 17.6% and 11.2%), accounting for the majority of infections in intravenous drug users. Analysis of hepatitis C virus genotypes according to age showed that, in the general population, hepatitis C virus types 1a and 3a were more prevalent among patients younger than 40 years of age than in older individual (17.6% and 11.2% vs. 1.4% and 0.6%).Conclusions: These findings suggest that hepatitis C virus types 1a and 3a were recently introduced in Italy, presumably via needle-sharing among intravenous drug users, and from this reservoir they are extending to the general population, particularly among younger subjects.     

Similar compliance and effect of treatment in chronic hepatitis C resulting from intravenous drug use in comparison with other infection causes

OBJECTIVES: There is some reluctance to treat intravenous drug users (IVDUs) with chronic hepatitis C (CHC) because of presumed lower compliance and response to antiviral therapy. We intended to evaluate the compliance and response to antiviral treatment for CHC in IVDUs compared with non-IVDUs. METHODS: A retrospective cohort study--secondary analysis of the results of a treatment trial--was performed in Belgium and The Netherlands. A total of 406 previously untreated CHC patients, including 98 (24%) IVDUs, were studied for compliance (presentation at the end of treatment), complete response (alanine aminotransferase within normal limits and serum hepatitis C virus polymerase chain reaction negative) at the end of therapy and sustained virological response (SVR). RESULTS: Non-compliance (8.2%) in IVDUs was not different from non-IVDUs (6.8%) (relative risk=1.20; 95% confidence interval=0.55-2.62). Complete response after controlling for hepatitis C virus was similar (relative risk=1.19; 95% confidence interval=0.89-1.60). Controlling for treatment arm, age, sex, presence of cirrhosis or hepatitis C virus viral load before treatment did not change these results. There was a marginally significant difference in the sustained virological response between IVDUs (46.6%) and non-IVDUs (34.6%) (relative risk=1.35; 95% confidence interval=1.00-1.81), also disappearing after adjusting for genotype. No difference in compliance or sustained virological response was found between active and non-active IVDUs or between IVDU patients in or without a methadone maintenance program. CONCLUSIONS: In this group of Benelux patients, IVDUs showed similar compliance and response to treatment with interferon and ribavirin compared with other patients with CHC infection. Therefore, it is no longer justifiable to withhold treatment to chronic hepatitis C patients who use intravenous drugs.     

Methods of transmission of hepatitis C

Summary. The route of transmission of hepatitis C virus is still controversial. Parenteral exposure via blood or blood products leads to infection in the majority of cases, and the majority of intravenous drug users become infected by repetitive exposure to contaminated injection equipment. The risk of infection from a single need lipstick injury is 5–15% and may depend on the size of the innoculum. Other parenteral routes of transmission may include traditional healing practices and the use of contaminated medical equipment.
Transmission is less common within a family but the prevalence of hepatitis C viral antibodies is higher in family members and sexual partners of carriers than in the general population. There are some well-documented instances of acute hepatitis C occurring after a defined sexual exposure. Vertical transmission is rare unless the mother has high levels of circulating HCV RNA as may occur in those also infected with HIV. The detection of hepatitis C in saliva and the higher than expected prevalence of infection in dentists may point to the possibility of transmission by salivary contamination. There remain large numbers of hepatitis C carriers in whom no route of infection can be identified.     

TT virus infection in Italy: prevalence and genotypes in healthy subjects, viral liver diseases and asymptomatic infections by parenterally transmitted viruses

This study was aimed to evaluate TT virus prevalence in subjects with hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections in patients affected by hepatitis of unknown origin (non-A–non-E hepatitis) and in healthy subjects who had not been exposed to HBV, HCV and HIV. A total of 317 subjects were tested; 40 were HBsAg asymptomatic carriers, 57 subjects were anti-HCV positive (45 without chronic hepatitis and 12 with HCV-related chronic hepatitis), and 27 had chronic non-A–non-E hepatitis. Fifty-seven subjects were intravenous drug users (IVDUs) (52 with HCV or/and HIV infections), seven patients underwent a liver transplant for fulminant hepatitis and 137 were healthy subjects from the general population. Overall, TTV-DNA was detected in 62 subjects (19.6%): in 17.9% of the HBsAg carriers, in 14% of the anti-HCV-positive patients (in 8.3% and in 15.5% of patients with and without chronic hepatitis, respectively), in 22.2% of non-A–non-E hepatitis patients, in 22.8% of IVDUs, in 57.1% of fulminant hepatitis patients. TTV-DNA was also found in 20.4% healthy subjects. The prevalence in the different subgroups was not statistically different. The genotypes were identified in 40 of the 62 (64.5%) TTV-DNA positive samples: genotype 1a in 17.5%, 1b in 27.5%, genotype 2 in 27.5%, genotype 3 in 15.0%, genotype 4 in 5.0% and genotype 5 in 7.5%; the genotype distribution in the subsets of patients was not significantly different. In conclusion, this study showed that TTV infection is common in Italy; it is widespread throughout the entire population and five genotypes are present in Sardinia. Our results further dismiss the role of TTV as cofactor in influencing the clinical course of infections with other hepatitis viruses as well as the role of HIV in enhancing TTV transmission and replication.     

Recent Ⅳ-drug users with chronic hepatitis C can be efficiently treated with daily high dose induction therapy using consensus interferon： An open-label pilot study

AIM： To investigate the use of high dose consensusinterferon in combination with ribavirin in former iv drug users infected with hepatitis C.
METHODS： We started, before pegylated （PEG）interferons were available, an open-label study to investigate the efficacy and tolerability of high dose induction therapy with consensus interferon （CIFN） and ribavirin in treatment of naiive patients with chronic hepatitis C. Fifty-eight patients who were former iv drug users, were enrolled receiving 18 μg of CIFN daily for 8 wk, followed by 9 μg daily for up to wk 24 or 48 and 800 mg of ribavirin daily. End point of the study was tolerability and eradication of the virus at wk 48 and sustained virological response at wk 72.
RESULTS： More than 62% of patients responded to the treatment with CIFN at wk 24 or 48, respectively, showing a negative qualitative PCR [genotype 1 fourteen patients （56%）, genotype 2 five （50%）, genotype 3 thirteen （87%）, genotype 4 four （50%）]. Forty-eight percent of genotype 1 patients showed sustained virological response （SVR） six months after the treatment. CONCLUSION： CIFN on a daily basis is well tolerated and side effects like leuko- and thrombocytopenia are moderate. End of therapy （EOT） rates are slightly lower than the newer standard therapy with pegylated interferons. CIFN on a daily basis might be a favourable therapy regimen for patients with GTI and high viral load or for non-responders after failure of standard therapy.     

The epidemiology of hepatitis C among injecting drug users in Belgium

In industrialised countries, injecting drug use is currently the most important risk factor for infection with hepatitis C, resulting in high prevalence rates of hepatitis C among injecting drug users. To contain the hepatitis C epidemic major efforts should be done to prevent new infection among injecting drug users. Monitoring infection rates are crucial as it may provide feedback on the effectiveness of interventions. In this article the epidemiology of hepatitis C among injecting drug users in Belgium is briefly reviewed. More specifically the prevalence of anti-HCV antibodies, the prevalence of co-infections, the proportion of chronic HCV carriers, the distribution of genotypes and preventive measures among injecting drug users in Belgium are discussed and compared to the situation elsewhere in Western Europe.