HCV genotypes and age distribution in patients of Vienna and surrounding areas

Efficacy and safety of pegylated interferon α and ribavirin in patients monoinfected with HCV genotype 4

INTRODUCTION

Dual therapy (PegIFN and ribavirin) (DT) was the standard of care in patients infected with HCV genotype 4 (HCV-4) until 2014. Nowadays, new treatment options are available including interferon (IFN)-based and other IFN-free regimens.

AIM

To assess the efficacy (SVR24) and safety of DT and the selected predictor factors of SVR in HCV-4 infected patients.

MATERIAL AND METHODS

One hundred and twelve patients (62 men) of median age 23 years were treated with DT for 48/72 weeks (107/5) in the years 2006-2014. Most of them were treatment naïve (80.4%) and with fibrosis F ≤ 2 (83.1%). To select a subset of independent predictors of SVR Logistic Regression Analysis was applied.

RESULTS

SVR24 was achieved in 46/112 (41.1%) patients. The mean viral load was 5.55 log10 IU/ml. Lack of therapy experience increases the odds of achieving SVR (OR = 4.17; 1.04-16.67), whereas more advanced fibrosis and higher baseline viral load tend to decrease the probability of SVR (OR = 0.05; 0.01-0.52 and OR = 0.44; 0.17-1.13, respectively). In contrast, the weight loss is associated with higher probability of virological response (OR = 4.31; 1.37-13.60). Two hundred and seventy-nine adverse events (AEs) were reported in 96 individuals. The rates and types of AEs were similar in patients treated with PegIFN-α2a/RBV and PegIFN-α2b/RBV. Overall, 3 (2.7%) patients discontinued therapy prematurely because of serious AEs.

CONCLUSIONS

SVR24 was low. Loss of weight was a new positive predictive factor of SVR found in our study. Most of the AEs were typical of those previously reported for DT.

Hepatitis C virus infection epidemiology among people who inject drugs in Europe: a systematic review of data for scaling up treatment and prevention

BACKGROUND

People who inject drugs (PWID) are a key population affected by hepatitis C virus (HCV). Treatment options are improving and may enhance prevention; however access for PWID may be poor. The availability in the literature of information on seven main topic areas (incidence, chronicity, genotypes, HIV co-infection, diagnosis and treatment uptake, and burden of disease) to guide HCV treatment and prevention scale-up for PWID in the 27 countries of the European Union is systematically reviewed.

METHODS AND FINDINGS

We searched MEDLINE, EMBASE and Cochrane Library for publications between 1 January 2000 and 31 December 2012, with a search strategy of general keywords regarding viral hepatitis, substance abuse and geographic scope, as well as topic-specific keywords. Additional articles were found through structured email consultations with a large European expert network. Data availability was highly variable and important limitations existed in comparability and representativeness. Nine of 27 countries had data on HCV incidence among PWID, which was often high (2.7-66/100 person-years, median 13, Interquartile range (IQR) 8.7-28). Most common HCV genotypes were G1 and G3; however, G4 may be increasing, while the proportion of traditionally 'difficult to treat' genotypes (G1+G4) showed large variation (median 53, IQR 43-62). Twelve countries reported on HCV chronicity (median 72, IQR 64-81) and 22 on HIV prevalence in HCV-infected PWID (median 3.9%, IQR 0.2-28). Undiagnosed infection, assessed in five countries, was high (median 49%, IQR 38-64), while of those diagnosed, the proportion entering treatment was low (median 9.5%, IQR 3.5-15). Burden of disease, where assessed, was high and will rise in the next decade.

CONCLUSION

Key data on HCV epidemiology, care and disease burden among PWID in Europe are sparse but suggest many undiagnosed infections and poor treatment uptake. Stronger efforts are needed to improve data availability to guide an increase in HCV treatment among PWID.

Distribution of hepatitis C virus genotypes in Chinese patients with chronic hepatitis C: correlation with patients' characteristics and clinical parameters

OBJECTIVE

This study aimed to explore the most up-to-date distribution of hepatitis C virus (HCV) genotypes in China, especially the association between HCV genotypes and patients' characteristics and clinical parameters.

METHODS

Sera from 483 HCV antibody-positive patients were genotyped using a HCV genotyping chip assay. The distribution of HCV genotypes, clinical parameters, modes of transmission and duration of infection were determined and the relationships among these parameters were analyzed.

RESULTS

A total of 424 patients were successfully genotyped. HCV genotypes 1, 2, 3 and 6 were found with a constituent ratio of 72.1%, 12.3%, 10.6% and 5.0%, respectively, in which subtypes 1b (69.1%), 2a (11.6%) and 3a (7.5%) were prevalent. The mean age of patients with genotype 1 and 2 was significantly elder than those with genotype 3 and 6 (P < 0.05). The distribution of HCV genotypes in relation to the mode of HCV transmission was remarkable (P < 0.001). Transfusion of blood and blood products was the main mode of transmission. Most genotype 1 infection (53.1%) was found in the group with a duration of HCV infection of 10-20 years. Genotype 1b was independently associated with age (P = 0.001) and mode of HCV transmission (P = 0.007).

CONCLUSIONS

The main HCV subtype was genotype 1b in Chinese patients. The prevalence of HCV genotypes was correlated with age and the mode of HCV transmission. Genotype 3a and 6 may become an increasing threat in the future.

Dynamic coinfection with multiple viral subtypes in acute hepatitis C

INTRODUCTION

Acute hepatitis C virus (HCV) infection is rarely studied, but virus sequence evolution and host-virus dynamics during this early stage may influence the outcome of infection. Hypervariable region 1 (HVR1) is genetically diverse and under selective pressure from the host immune response. We analyzed HVR1 evolution by frequent sampling of an acutely infected HCV cohort.

METHODS

Three or more pretreatment samples were obtained from each of 10 acutely infected subjects. Polymerase chain reaction amplification was performed with multiple primer combinations to identify the full range of sequences present. Positive samples were cloned and sequenced. Phylogenetic analyses were used to assess viral diversity.

RESULTS

Eight of the 10 subjects were coinfected with at least 2 HCV subtypes. Multiple subtypes were detected in individual samples, and their relative proportions changed through acute infection. The subjects with the most complex subtype structure also had a dynamic viral load; however, changes in viral load were not directly linked to changes in subtype.

CONCLUSIONS

This well-sampled cohort with acute HCV infection was characterized by dynamic coinfection with multiple viral subtypes, representing a highly complex virologic landscape extremely early in infection.

The neglected hepatitis C virus genotypes 4, 5 and 6: an international consensus report

Abstract Hepatitis C virus (HCV) genotypes 4, 5 and 6 represent >20% of all HCV cases worldwide. HCV-4 is mainly seen in Egypt, where it represents 90% of all HCV cases. Antischistosomal therapy was the main cause of contamination there, followed by procedures performed by informal providers and traditional healers such as dental care, wound treatment, circumcision, deliveries, excision and scarification. It is also highly prevalent in sub-Saharan Africa and in the Middle East. In Europe, its prevalence has recently increased particularly among intravenous drug users and in immigrants. HCV-5 is mainly found in South Africa, where it represents 40% of all HCV genotypes, but four pockets of HCV-5 were found in France, Spain, Syria and Belgium and sporadic cases were found elsewhere. The mode of transmission is mainly iatrogenic and transfusion. HCV-6 is found in Hong Kong, Vietnam, Thailand and Myanmar and also in American and Australian from Asian origin. The response to treatment in HCV-4 is intermediate between HCV-1 and HCV-2 and HCV-3. A sustained viral response is achieved in 43-70% with pegylated interferon and ribavirin. It is higher in Egyptians than Europeans and Africans and is negatively related to insulin resistance and to the severity of fibrosis. It increases to >80% with 24 weeks of therapy only if a rapid virological response is achieved. In HCV-5, a sustained virological response is achieved in >60% with 48 weeks of therapy. HCV-6 is also considered an easy-to-treat genotype, leading to a response in 60-85% of cases.

Hepatitis C virus genotypes in 1,504 patients in Slovenia, 1993-2007

In order to identify the main routes of hepatitis C (HCV) transmission and to determine the HCV genotype distribution and its dynamics during a 15-year period in Slovenia, HCV genotypes were detected using the INNO-LiPA HCV II (Innogenetics) test for serum samples obtained from 1,504 patients representing 72.6% of all patients with chronic hepatitis C diagnosed from 1993 to 2007. HCV genotype 1 was predominant (56%), followed by genotypes 3, 2, and 4, with a prevalence of 37.8%, 5%, and 1.2%, respectively. HCV genotypes 5 and 6 were not detected in any patient. Patients infected with HCV genotype 3 were significantly younger (mean age 28.9 +/- 8.5 years) than those infected with genotype 1 (mean age 38.9 +/- 14.8 years; P < 0.0001) and those infected with HCV genotype 2 (mean age 50.3 +/- 18.2 years; P < 0.0001). Intravenous drug use was identified as the most frequent possible HCV transmission route (34.3%), followed by medical-related transmission such as transfusion of HCV-contaminated blood or blood products, and hemodialysis (12.5%). Being an intravenous drug user was found to be strongly associated with HCV genotype 3 (OR, 3.71 [95% CI, 2.97-4.65]; P < 0.0001) and reporting infection by transfusion of blood or blood products was found to be strongly associated with HCV genotype 1 (OR, 3.28 [95% CI, 2.18-4.95]; P < 0.0001). During the 15-year period, the proportion of genotype 3 increased substantially, reflecting the fact that the HCV epidemic in Slovenia is driven mostly by intravenous drug use.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.

Critical issues in the treatment of hepatitis C virus infection in methadone maintenance patients

AIMS

Hepatitis C virus (HCV) infection is a common chronic complication of injection drug use. Methadone maintenance programs contain large numbers of patients infected with HCV. This paper reviews HCV infection with emphasis on the medical care of HCV-infected, or HCV and human immunodeficiency virus co-infected, patients on methadone or buprenorphine maintenance.

METHODS

Literature searches using PubMed, PsycINFO and SocINDEX were used to identify papers from 1990-present on antiviral therapy for HCV in methadone maintenance patients and on liver transplantation in methadone maintenance patients.

RESULTS

Injection drug use is the most significant risk factor for HCV infection in most western countries. The prevalence of HCV antibody is high in injection drug users (53-96%) and in patients enrolled in methadone maintenance programs (67-96%). Studies of antiviral therapy for HCV in methadone maintenance patients show rates of sustained virological response (SVR), defined as negative HCV-RNA 24 weeks after the end of treatment, of 28-94%. In studies with contrast groups, no significant differences in SVR between methadone and contrast groups were found. Excellent completion rates of antiviral therapy (72-100%) were found in five of six studies. There are many barriers to methadone maintenance patients' receiving antiviral therapy, and research on overcoming barriers is discussed. Liver transplantation has been successful in methadone maintenance patients but has not been utilized widely.

CONCLUSION

High quality medical care for all aspects of HCV infection can be provided to methadone maintenance patients. The literature supports the effectiveness of such services, but the reality is that most patients do not receive them.

The changing epidemiology of hepatitis C virus infection in Europe

The epidemic of hepatitis C virus (HCV) infection in Europe is continuously evolving and epidemiological parameters (prevalence, incidence, disease transmission patterns and genotype distribution) have changed substantially during the last 15 years. Four main factors contribute to such changes: increased blood transfusion safety, improvement of healthcare conditions, continuous expansion of intravenous drug use and immigration to Europe from endemic areas. As a result, intravenous drug use has become the main risk factor for HCV transmission, prevalent infections have increased and genotype distribution has changed and diversified. Hence, prevalence data from studies conducted a decade ago may not be useful to estimate the current and future burden of HCV infection and additional epidemiological studies should be conducted, as well as new preventive strategies implemented to control the silent epidemic. This review summarizes recently published data on the epidemiology of HCV infection in Europe focusing on the factors currently shaping the epidemic.

Distribution of hepatitis C virus genotypes in patients with chronic hepatitis C infection in Western Turkey

OBJECTIVE

The primary aim of this study was to determine the recent distribution of various genotypes of hepatitis C virus (HCV) in patients with chronic HCV infection in Western Turkey. Additional objectives were to determine whether there are any associations of genotype with gender and age, and to determine the nucleotide similarities and risk factors of non-1 HCV genotypes.

METHODS

Serum samples from 345 patients (176 male, 169 female; mean age 53.3+/-12.7 years, range 10-81 years) with chronic HCV infection were analyzed in this study. Viral genotypes were determined by a restriction fragment length polymorphism (RFLP)-based in-house assay. To confirm genotypes for the samples with band patterns other than genotype 1, the 5' UTR was amplified and sequenced.

RESULTS

Genotype 1 was observed in 335 of the 345 patients (97.1%). Of these, 34 patients showed infection with subtype 1a (9.9%) and 301 with subtype 1b (87.2%). Genotypes 2, 3, and 4 were determined in 0.9%, 1.4%, and 0.6% of the patients, respectively. Patients infected with type 1 were significantly older than patients infected with non-1 genotypes; however no significant differences were recorded in gender distribution.

CONCLUSIONS

Genotypes other than genotype 1 are quite rare; these are possibly acquired in other countries. Turkish patients with chronic hepatitis C still represent a rather homogenous group with genotypic diversity encountered rarely.

Epidemiological characteristics and response to peginterferon plus ribavirin treatment of hepatitis C virus genotype 4 infection

Hepatitis C virus genotype 4 (HCV-4) infection is progressing in Europe, where epidemiology and sustained virological response (SVR) seem to be different than in the Middle East. We analysed epidemiological features and SVR rates in a retrospective study of 1532 HCV-4-infected patients, including 1056 patients infected in France, 227 immigrants infected in Egypt and 249 in sub-Saharan Africa. SVR rates were assessed in 242 naive patients of the 1532, who received peginterferon plus ribavirin for 48 weeks. HCV subtype 4a or 4d was the most common among patients infected in France, where the predominant route of transmission was intravenous drug abuse. The 4a subtype was largely predominant (93%) among patients infected in Egypt, where transmission was mostly because of parenteral treatment for schistosomiasis. More than seven different subtypes and no predominant route of infection were found in patients infected in sub-Saharan Africa. Liver fibrosis was significantly less severe in patients infected in France and Africa than in patients infected in Egypt. SVR rates were higher in patients infected in Egypt, compared with those infected in France or Africa (54.9%, 40.3% and 32.4%, respectively, P < 0.05). An overall better response was observed in patients infected with the 4a subtype. In multivariate analysis, two factors were associated independently with SVR: the Egyptian origin of transmission and the absence of severe fibrosis. In conclusion, the distribution of HCV-4 subtypes varies with the geographical origin of transmission and affects the SVR following antiviral treatment.

Genetic characterization of hepatitis C virus strains in Estonia: fluctuations in the predominating subtype with time

During the last decade, there has been a dramatic increase in intravenous drug use in young adults in Estonia with an increased incidence of both hepatitis B and C as a consequence. Since genetic data are limited regarding hepatitis C virus (HCV) strains in Estonia, the aim of the study was to characterize HCV strains in different risk groups to determine their relatedness to strains from other geographical regions. Three hundred fifty-three anti-HCV positive sera collected during 1994-2004 from hospitalized patients, blood donors and health care workers were used as source of HCV RNA. Two hundred nine (59%) of the sera were positive for HCV RNA by PCR directed to the 5'-UTR region. For 174 strains the HCV subtype was determined by analyses of the NS5B and/or the 5'UTR-core regions. 1b (71%) was the most common subtype followed by 3a (24%), 2c (2%), 1a (1%), and 2a (1%). The 1b and 3a strains were similar to strains from other regions of the former USSR. Within genotype 1b there were several HCV lineages. However, for 3a there seemed to be two separate introductions into Estonia. There was a relative shift from subtype 1b to 3a in 1999-2000 with a further replacement of 3a with 1b in intravenous drug users in 2001 and onwards (P < 0.05). However, both subtypes were found to co-circulate in the community independent of risk factors. One patient was infected with the 2k/1b recombinant presumed to originate from St. Petersburg being the first isolate of this recombinant recovered outside Russia.

Changes in the distribution of hepatitis C virus (HCV) genotypes over time in Spain according to HIV serostatus: implications for HCV therapy in HCV/HIV-coinfected patients

BACKGROUND

Changes in the prevalence of distinct hepatitis C virus (HCV) genotypes and subtypes over time have not been explored in detail.

METHODS

A retrospective analysis was carried out in all specimens from subjects with chronic hepatitis C sent for testing to a reference laboratory in Spain since 1998-2004.

RESULTS

A total of 1226 distinct subjects were analyzed. The most frequent HCV genotype was 1 (64.1%), followed by 3 (20.9%) and 4 (11.7%). The most frequent HCV subtype was 1b (32.4%). A total of 797 patients (65%) were HIV-positive. Although genotype 1 was the most frequent, it represented 74.6% of HIV-negative and 58.5% of HIV-positive patients (p<0.01). While HCV subtype 1a was the most frequent among HIV-positive subjects (32.1%), 1b was the most common in HIV-negative patients (53.8%). There was a significant increase in the prevalence of genotype 4 and conversely a decline in genotype 3 among HIV-positive patients over time.

CONCLUSION

Genotype 1 is the most frequent HCV variant circulating in Spain. Genotypes 3 and 4 are significantly more prevalent in HIV/HCV-coinfected than in HCV-monoinfected patients. However, HCV-3 has declined and HCV-4 is increasing in the former group. These findings are relevant given their different susceptibility to interferon-based therapies.

Follow-up of the prevalence of hepatitis C virus genotypes in Spain during a nine-year period (1996-2004)

BACKGROUND

Recent data suggest that the prevalence of genotype 4 HCV strains among Spanish carriers is increasing.

OBJECTIVE

To assess changes in the prevalence of HCV genotypes in Spain during the last nine years.

METHODS

HCV RNA was amplified by the polymerase chain reaction from 3161 serum samples from unselected, anti-HCV-positive individuals, and the HCV genotype was identified by a reverse hybridisation assay (line probe assay, LiPA). Samples came from 17 different regions of Spain and were obtained between January, 1996 and December, 2004.

RESULTS

The overall prevalence of HCV genotypes was: 1b, 41.3%; 1a, 24.1%; 3, 19.6%; 4, 11.6%; 2, 3.1%; and 5, 0.3%. The prevalence of genotypes 1a, 3 and 4 increased significantly among patients born after 1950, and that of genotype 1b decreased among them. These significant differences in regard to age were also observed among patients lacking notified high-risk factors. A main switch-up in prevalence of genotypes 1a and 3 was found when patients born in 1941-1950 were compared with those born in 1951-1960, but the same finding in genotype 4 was delayed to patients born in 1961-1970.

CONCLUSIONS

Two separate epidemics of HCV seem to have occurred in Spain during the last 30 years. The former one involved the spread of HCV genotypes 1a and 3. The second was more recent, and involved the spread of genotype 4.

The hepatitis C virus genotype and subtype frequency in hepatitis C virus RNA-positive, hepatitis C virus antibody-negative blood donors identified in the nucleic acid test screening program in Poland

BACKGROUND

Since 2002, blood donors in Poland have been tested not only for hepatitis C virus antibodies (anti-HCV) but also for HCV RNA or HCV core antigen. This screening program identifies asymptomatic, recently infected individuals with no anti-HCV (in the "window period"). The aim of this study was to compare HCV genotype and subtype distribution in window-period (wp) donors, anti-HCV-positive donors, and chronic hepatitis C (CHC) patients.

STUDY DESIGN AND METHODS

A total of 2.37 million donors were investigated for HCV RNA, and 340,000 for HCV core antigen. HCV genotypes and subtypes were investigated in 50 HCV RNA-positive, anti-HCV-negative donors; in 70 anti-HCV-positive donors; and in 170 CHC patients. Re-questioning of wp donors for probable risk factors was introduced.

RESULTS

HCV RNA was detected in 50 donors of 2.71 million (1:54,200) anti-HCV-negative blood donations. Of these 50 donors, 36 percent exhibited Subtype 1b, whereas Subtypes 3a and 4c/d were identified in 40 and 14 percent, respectively. In anti-HCV-positive donors and CHC patients, the frequency of Subtype 1b was significantly higher (75.7 and 85.3%, respectively); in both groups the lower frequency of Subtypes 3a (14.3 and 10.6%, respectively) and 4c/d (4.3 and 1.2%, respectively) was found. The probable source of infection was identified in 9 wp donors.

CONCLUSIONS

The frequency of wp donors is 18.5 per 1 million. The unexpected high frequency of Genotype 4 and Subtype 3a and the low frequency of Subtype 1b was observed in wp donors compared to anti-HCV-positive individuals. Additional epidemiologic questioning introduced after HCV RNA detection may help to identify infection source.

Correlation between histologic staging, hepatitis C virus genotypes and clinical features in HCV chronic hepatitis: evidence of a new pattern

Genome heterogeneity may be related to the wide variability of clinical and pathological features in hepatitis C virus (HCV)-related chronic liver disease. This paper addresses the possible association between HCV subtypes and clinical and histological features of chronically infected patients. Sixty-eight consecutive liver biopsies of chronic hepatitis constituted the basis of the study. HCV genotyping was performed on frozen tissue. Grading of necroinflammatory activity and staging of fibrosis were histologically assessed. Serologic HCV-RNA and liver function were assessed at the same time. All information was compared with clinical data including age, sex, HCV serology, and probable data and route of infection. Two cases were excluded as inadequate tissue was available. Five cases were negative to HCV-RNA in both serum and tissue. In 61 cases HCV RNA was present at the same time in serum and liver tissue. Forty-four patients were men (72%) and 17 (28%) were women. Two peaks of age were observed: 1 in the 4th decade of life, the 2nd in the 7th. The 2 groups had different HCV genotypes. Patients with genotypes 1b (mean age 50.7 years), 2c (mean age 61.3 years), and a subgroup of coinfections (mean age 60 years) were older than patients with genotypes 1a (mean age 35.5 years), 3 (mean age 36 years), and a subgroup of coinfections (mean age 33 years). Patients with genotypes 1b, 2, or 2c and a subgroup of coinfections more frequently had a history of blood transfusion and or surgical intervention dating up to 49 years previously. Patients with HCV 1a, 3, and a subgroup of coinfections frequently admitted a period of intravenous drug abuse. Patients with advanced liver disease, i.e., severe fibrosis and cirrhosis, showed the same 2 peaks of incidence: in the 4th and 7th decades of life, the first group mainly comprising patients with HCV types 1a and 3, the second, patients with HCV types 1b and 2c. Both these groups shared a clinical history of a long-standing infection. Two profiles of patients emerged. The largest group was composed of elderly patients, infected by HCV genotypes 1b or 2c, with a history of blood transfusion and/or surgery, presenting an advanced stage of liver disease (namely, severe fibrosis or cirrhosis). The second group was composed of younger patients, mainly in the 4th decade of life, infected by HCV types 3 or 1a, often presenting with chronic hepatitis in the stage of severe fibrosis or cirrhosis. The latter could be the profile of HCV infection in the near future.

Hepatitis C virus genotypes in Hungarian and Austrian patients with chronic hepatitis C

Hepatitis C virus (HCV) genotypes are relevant to epidemiological questions, vaccine development, and clinical management of chronic HCV infection. The aim of this study was to determine HCV genotypes of South Hungarian and Southeast Austrian patients with chronic hepatitis C. Results were obtained by the largely automated TruGene HCV 5'NC Genotyping Kit (Visible Genetics, Toronto, Ontario) and by phylogenetic analysis. All of the 20 Hungarian patients and 15 out of 20 Austrian patients were infected with genotype 1. The remaining Austrian patients were infected with genotypes 3 or 2. With the commercially available assay, it was not possible to determine the HCV subtype in a total of three patients. The TruGene HCV 5'NC Genotyping assay for the determination of HCV genotypes proved to be useful for a high-throughput routine diagnostic laboratory.

Determination of HCV genotype by direct sequence analysis of quantitative PCR products

Hepatitis C virus (HCV) genotyping, combined with quantitative evaluation of HCV RNA, may be beneficial for the management of chronic hepatitis C and in the selection of candidates for interferon treatment. In this study, the COBAS AMPLICOR HCV MONITOR test, a commercially available quantitative assay for HCV RNA, was used. Amplification products obtained from HCV-positive cases were subjected to direct sequencing and genotyping based on seven phylogenetically informative regions within the 5'UTR. Results were compared with those obtained by INNO-LiPA assay. Typing results yielded by both methods were in complete accordance for type and subtype assignment. Twenty-nine of 500 specimens (5.8%) were unclassifiable and belonged to samples with a titer of <70.000 IU, as determined by quantitative assay. Despite this limitation, the overall gain in efficiency, the low rate of test failure and a better resolution of mixed genotypes all constitute a considerable advantage of this system over the commercial hybridization technique for routine clinical laboratory use.