Hepatitis C-related chronic liver disease among asymptomatic blood donors in the north west of England

Should we treat HCV carriers with normal ALT levels? The '5Ws' dilemma

Approximately 30% of patients with chronic HCV infection have persistently normal ALT levels. Although formerly referred to as 'healthy' or 'asymptomatic' HCV carriers, and thus historically excluded from antiviral treatment, it has now become clear that the majority of these patients have some degree of histological liver damage that may be significant in up to 20% of cases and might progress towards a more severe degree of liver fibrosis. A significant proportion of patients experience periods of increased serum ALT associated with enhanced disease progression. However, controversies still exist in clinical practice regarding the definition of 'persistent' ALT normality, the virological and histological features of these subjects, the need for liver biopsy, the role of noninvasive tools for the assessment of liver fibrosis, the natural history and the usefulness of antiviral treatment. The advent of new therapeutic options (pegylated interferon plus ribavirin) has shifted treatment targets towards the eradication of underlying infection, with therapy decision based on age, severity of disease and likelihood of response rather than on aminotransferase levels. This review is aimed at approaching the main unresolved issues on this topic, trying to give evidence-based answers to the more frequently asked questions from patients and their physicians.

Seroepidemiologic study of hepatitis B virus, hepatitis C virus, human immunodeficiency virus and syphilis infections in Iranian blood donors

To determine the frequency of hepatitis B, hepatitis C, Human Immunodeficiency Virus (HIV) and syphilis infections in Iranian blood donors. The prevalence of serological markers of hepatitis B, hepatitis C, HIV and syphilis infections were evaluated in 318029 consecutive volunteer blood donors attending to Tehran blood transfusion service from March 2005 to March 2006. Those positive for hepatitis B surface antigen, anti-HCV, anti-HIV1/2 and VDRL (venereal disease research laboratory) reactivity were analyzed with a second independent HBsAg enzyme immunoassay (EIA) and neutralization assay; an additional independent anti-HCV EIA and HCV-RIBA assay; second independent anti-HIV1/2 test, HIV western blot and fluorescent Treponemal Antibody Absorbed (FTA-ABS), respectively. In 318029 participants, prevalence of positive HBsAg, HCV RNA, HIV western blot and FTA-ABS was 1684 (0.487%), 323 (0.093%), 11 (0.003%) and 19 (0.005%), respectively. In 1014 subjects randomly selected from these 318029 participants, besides standard interview, physical exam and routine serologic tests; anthropometric and biochemical were studies. In this selected group frequency of HBsAg was 3 (0.29, 95% CI: 0-0.64%); frequency of anti-HCV was 21 (2.07%), but it was (0.09%, 95% CI: 0-0.30%) by confirmatory HCV RNA test; frequency of HIV-Abl, 2 was 8 (0.78%), but it was 2 (0.19%, 95% CI: 0-0.48%) by confirmatory test; frequency of RPR was 0 (0%, 95% CI: 0-0.30%). Despite excluding subjects with high-risk behaviors by standard interview and physical examination, still a few asymptomatic hepatitis B, hepatitis C, HIV-infected subjects existed among volunteer blood donors with demographic and biochemical findings similar to non-infected ones.

Anti-HCV reactive blood donors: clinical and epidemiological factors associated with false-reactive results

BACKGROUND

In certain clinical settings, false-reactive anti-hepatitis C virus (HCV) results are rare because the majority of persons being tested have evidence of liver disease and the specificity of the screening assays is high. However, among healthy populations, such as blood donors, mainly in regions with a low prevalence of HCV infection, this situation does occur. In this study, we sought to assess clinical, epidemiological, and laboratory characteristics of blood donors with false-reactive anti-HCV screening tests.

METHODS

This retrospective cross-sectional study included 537 anti-HCV reactive blood donors referred to a tertiary care centre for liver diseases.

RESULTS

The mean age was 36.5+/-11.2 years and 71.8% were men. Blood donors of older age (P=0.010), history of alcohol abuse (P=0.039), past transfusion (P<0.001), intravenous drug use (P<0.001), and with antibody against core antigen of hepatitis B virus reactivity (P=0.003) were less likely to have a false-reactive anti-HCV result. By multivariate analysis, only the absence of parenteral risk factors (prior transfusion and intravenous drug use) was independently associated with false-reactive anti-HCV tests.

CONCLUSION

Blood donors with reactive anti-HCV screening tests with no risk factors for parenterally acquired HCV infection are more likely to present with false-reactive results.

Analysis of voluntary blood donors with biologic false reactivity on chemiluminescent immunoassays and implications for donor management

BACKGROUND

Biologic false-reactive (BFR) results in blood donors are problematic due to both component loss and donor-management issues. This report analyzes the results of a longitudinal study of BFR donors and the implications for donor management.

STUDY DESIGN AND METHODS

Donors who gave BFR results on HBsAg, HIV-1/HIV-2, HCV, or HTLV-I/HTLV/II chemiluminescent immunoassays (ChLIAs) (PRISM, Abbott) between May 1997 to March 1999 were analyzed. Donors were followed up for up to three donations after an index BFR episode. In addition, results of any negative donations before the index BFR result but within the study period were included in the analysis.

RESULTS

For donors who gave an index BFR result on the HBsAg ChLIA, 14.3 percent remained BFR at subsequent donations, whereas for the anti-HIV-1/HIV-2, anti-HCV, and anti-HTLV-I/HTLV-II ChLIAs, the figures were 66.0, 77.4, and 71.6 percent, respectively. For donors who gave a second BFR result, the percentage who remained BFR at subsequent donations was 75.0, 80.6, 84.6, and 74.5 percent for the four assays, respectively. The rate at which negative repeat donors became BFR during the study period was 0.02, 0.07, 0.12, and 0.02 percent for the HBsAg, anti-HIV-1/HIV-2, anti-HCV, and anti-HTLV-I/HTLV-II assays, respectively.

CONCLUSIONS

Our results indicate that donors who give an index BFR result on the ChLIAs (PRISM, Abbott) should be allowed to continue donating because most donors with a HBsAg BFR result were negative at subsequent donations, and between 22.6 and 34.0 percent of those with BFR results on the HIV-1/HIV-2, HCV, or HTLV-I/HTLV-II assays gave subsequent negative donations. However, donors who give a second BFR result should be counseled and deferred because they were very unlikely to give subsequent negative results.

Hepatitis C risk factors in Iranian volunteer blood donors: a case-control study

BACKGROUND

In order to evaluate some possible risk factors for the spread of hepatitis C infection a case-control study was undertaken.

METHODS

The study population consisted of first time blood donors referred to the Iranian Blood Transfusion Organization. Enzyme-linked immunosorbent assay and recombinant immunoblot assay anti-hepatitis C virus (HCV) tests were performed for all samples. Risk factors were evaluated using a questionnaire. A stepwise forward logistic regression analysis was used.

RESULTS

The case group consisted of 193 HCV-positive donors, and 196 HCV-negative donors comprised the control group. Transfusion, undergoing endoscopy, extramarital sexual activities, non-intravenous (i.v.) drug abuse, i.v. drug abuse, and receiving wounds at war were found to be independent risk factors of being HCV-positive (Odds ratio: 17, 4, 42.2, 34.4, 52.8 and 5.2, respectively). No apparent risk factors could be demonstrated in 24.5% of the positive cases.

CONCLUSION

This study could be of particular interest because of the low seroprevalence of hepatitis C and the religious culture of the study population. There are certain medical procedures, lifestyle patterns, and customs and cultural matters in Iran that predispose people to a number of HCV risk factors.

Anti-HCV confirmatory testing of voluntary blood donors: comparison of the sensitivity of two immunoblot assays

BACKGROUND

In this study, the sensitivity of two commercially available anti-HCV immunoblot assays (HCV Western blot (Wellcozyme] and RIBA 3.0 SIA [RIBA-3, Chiron]) was compared in a voluntary blood donor population.

STUDY DESIGN AND METHODS

Four groups of donor samples were retrospectively tested in this study. Groups 1 and 2 were donor samples that gave positive or indeterminate band patterns, respectively, when originally tested on the HCV Western blot between 1994 and 1998. These samples were tested on the RIBA 3.0. Donor samples in Groups 3 and 4 were originally tested on RIBA-3 during 1998 and 1999 and gave positive or indeterminate blot results, respectively. In this study these two groups were tested on the HCV Western blot. Samples with discrepant results on the two immunoblot assays were selected for genotyping or serotyping.

RESULTS

The two immunoblots showed similar sensitivity to the core and NS5 proteins. However, of 35 samples positive on Western blot or RIBA-3, the Western blot failed to detect NS4 in 14 samples compared with only 5 for RIBA-3. As well, the Western blot failed to detect NS3 in 6 samples compared to 2 for RIBA-3. Five (27.8%) of 18 samples that were Western blot indeterminate due to core reactivity showed an additional NS3 band on RIBA-3. Of the samples with additional NS3 and/or NS4 reactivity on RIBA-3 that were genotyped or serotyped, all were HCV type 3.

CONCLUSIONS

Western blot and RIBA-3 showed similar sensitivity to the HCV core and NS5 proteins. However, RIBA-3 showed greater sensitivity to both NS3 and NS4 compared to the Western blot. The reduced sensitivity of the Western blot to the NS3 and NS4 proteins was observed with HCV type 3 samples.

Presence and predictors of hepatitis C virus RNA in the semen of homeless men

Although the possibility of sexual transmission of the hepatitis C virus (HCV) remains controversial, little is known of the associations ofpositive semen specimens with potential demographic and behavioral risk factors. Knowledge of these predictors may suggest factors that increase risk of HCV RNA in the semen. Semen and bloodfrom 80 HCV-infected homeless men were evaluatedfor the presence of HCVRNA by means of branch DNA and transcription-mediated amplification analyses. Associations of selected demographic and behavioral characteristics of the participants with presence or absence of HCV in their semen were also assessed. HCV RNA was detected in the semen of 36% of the sample. Associations were found with HCV RNA in semen and older age, higher viral loads of HCV in blood, current alcohol and lifetime methamphetamine use, and having been vaccinated for the hepatitis B virus. Findings suggest that sexual transmission of HCV is plausible and shed light on the need to conduct more in-depth investigations.

Histological and virological features and follow-up of hepatitis C virus carriers with normal aminotransferase levels: the Italian prospective study of the asymptomatic C carriers (ISACC)

BACKGROUND/AIMS

To evaluate demographic characteristics, liver histology and virological features of hepatitis C virus (HCV) carriers with normal alanine transaminase (ALT) levels.

METHODS

A nationwide prospective study was started in 1997. Four Italian centres have participated in this study.

RESULTS

Eight hundred and eighty subjects entered the study. One hundred and eighty-nine (21.5%) were excluded during the follow-up because of ALT increase. Among the 691 patients with persistent ALT normality, 72% were females. An overall prevalence of genotype 2 was found (52%). Normal liver was found in 17% of the patients; 34% had minimal chronic hepatitis, 44% mild hepatitis, 4% moderate to severe hepatitis, and 1% had cirrhosis. Clinical and virological features did not differ between subjects with ALT flares and those with persistently normal ALT. Baseline ALT levels have no effects on liver histology and clinical outcome.

CONCLUSIONS

Many HCV carriers have significant chronic liver damage, although in the majority of them liver lesions are minimal or mild. Up to 60% of HCV carriers in Italy harbour non-1 HCV types. Current definition of HCV carriers with persistently normal ALT levels, based upon three normal ALT values over a 6-month period, is not adequate to discriminate between carriers with persistent ALT normality and those with transient biochemical remission. Longer follow-ups are needed.

Chronic hepatitis C with normal or abnormal aminotransferase levels: is it the same entity?

OBJECTIVE

The features of hepatitis C virus (HCV) infection with persistently normal serum alanine aminotransferase (ALT) activity levels are not well defined. This study evaluated the characteristics of HCV infection according to the presence or absence of elevated ALT.

METHODS

Demographic data, liver histology and HCV genotype were studied in a group of 80 HCV-RNA-positive subjects with persistently normal ALT (PNALT) (group 1), and compared with a second group of 455 HCV-RNA-positive patients with elevated ALT (group 2). The annual progression of liver fibrosis was also calculated.

RESULTS

A higher proportion of women was found in group 1:64% vs 42% in group 2 (P< 0.0002). The HCV genotype 1 was less frequent in group 1:49% vs 60% in group 2 and genotype 2 was more frequent: 16% in group 1 vs 4% in group 2 (P< 0.002). Cirrhosis was less frequent in group 1 (4% vs 13% in group 2 (P< 0.0001)). Normal liver was more frequent in group 1:9% vs 1% in group 2 (P< 0.0001). The Knodell score was significantly different between the two groups: 3.2 +/- 0.27 vs 7.15 +/- 0.22 (P< 0.0001). The progression of liver fibrosis was lower in group 1: 0.053 +/- 0.14 units/year vs 0.13 +/- 0.24 in group 2 (P < 0.007).

CONCLUSION

HCV infection with PNALT is associated with less severe histological liver disease and a lower fibrosis progression rate. This suggests that the natural history of HCV infection in these patients is different from that in patients with abnormal ALT.

Hepatitis C virus carriers with persistently normal aminotransferase levels: healthy people or true patients?

Since the discovery of hepatitis C virus, the availability of serological hepatitis C virus screening has led to the identification of many subjects with normal aminotransferase levels who are chronically infected by the hepatitis C virus. To date, the epidemiology and natural history of subjects with normal aminotransferase levels are far from being clarified. Further, whether subjects with persistently normal aminotransferase levels should routinely undergo liver biopsy is still extremely controversial, and benefit from interferon treatment in this group of patients is yet to be proven. On account of the consistent normality of aminotransferases, it is not easy to calculate the rate of persons with normal aminotransferase levels among chronic hepatitis C virus carriers, nor their prevalence in the general population. It has been estimated that up to 25% of patients with chronic hepatitis C virus infection have persistently normal aminotransferase levels (10% to 40%, according to different studies). Most studies showed a clear prevalence of females, ranging from 58% to 90%. Liver biopsy shows some degree of chronic liver disease in up to 80% of these subjects, although in the majority, histological damage is mild and probably does not progress to more severe liver disease, moreover, the progression to fibrosis is slower than in patients with elevated aminotransferase levels. Virological features of these subjects (hepatitis C virus genotype distribution, viral load, quasispecies diversity) do not differ with respect to patients with elevated aminotransferase levels although a higher frequency of non 1 hepatitis C virus types has been reported. To date, no biochemical or virological tools to assess the presence and severity of liver damage exist. Antiviral treatment with interferon may induce a long-term response in only a small proportion of hepatitis C virus carriers with persistently normal aminotransferase levels, and many patients develop aminotransferase-flare-up during or shortly after treatment. Thus, interferon or combination antiviral treatment of hepatitis C virus carriers with normal aminotransferase values should be avoided in clinical practice.

Results of HCV screening of volunteer blood donors with a chemiluminescent immunoassay and a second- or third-generation EIA: overlap of false-positive reactivity and its impact on donor management

BACKGROUND

This study reports the results of adopting a strategy of anti-HCV testing of volunteer blood donors that uses a primary screening assay, two secondary EIAs (Anti-HCV Version III, Murex; Monolisa Anti-HCV New Antigens, Sanofi Pasteur), and a confirmatory immunoblot (HCV WB, Murex).

STUDY DESIGN AND METHODS

A comparison was made of HCV test results from volunteer donors tested in two periods when different primary HCV screening assays were in use. The same two secondary screening assays and the same confirmatory test were used for the whole study. The two different primary assays were semi-automated second- or third-generation HCV EIA (Abbott Diagnostics) and an HCV chemiluminescent immunoassay (ChLIA), performed on a fully automated analyzer (PRISM, Abbott).

RESULTS

During the period of use of the EIAs as primary screening assays, there were 60 donors per year who were confirmed as anti-HCV-positive, 29 who were classed as having indeterminate HCV serologic results, and 236 who were assessed as having biologically false-positive anti-HCV results. These numbers compared with 57, 52, and 320 such donors, respectively, in the first year of routine use of the ChLIA. The significant increase (p<0.05) in the number of anti-HCV-indeterminate donors after the introduction of the ChLIA was primarily due to an increase in donors who reacted on Monolisa HCV, but not an HCV Murex (expected 18/year vs. the observed 31/year, p<0.01).

CONCLUSIONS

Compared to the second- or third-generation HCV EIA, the HCV ChLIA has a significantly greater overlap of false reactivity with the Monolisa HCV assay. This finding has implications for the selection of primary and secondary assays for anti-HCV screening of blood donors.

Serum HCV RNA titer does not predict the severity of liver damage in HCV carriers with normal aminotransferase levels

AIMS/BACKGROUND

Many HCV RNA positive subjects with normal aminotransferase levels have significant liver damage despite normal liver biochemistry. In these patients it is not possible to discriminate between "healthy" carriers and subjects with chronic liver damage, unless liver biopsy is performed. The aim of this study was to evaluate the usefulness of HCV RNA quantitation as a non invasive tool to predict the severity of liver injury in a group of HCV carriers with normal amino-transferase levels.

METHODS

59 HCV RNA positive subjects (20 males) with persistently normal ALT levels were studied. All patients underwent HCV RNA quantitation and percutaneous liver biopsy.

RESULTS

No correlation was found between serum HCV RNA titers and grading, while viraemia did correlate with staging. Patients were categorized into four subgroups, according to arbitrary serum HCV RNA cut-offs. Grading was not different between the four groups. Staging was significantly higher among subjects with viraemia > 1000 x 10(3) copies/mL than in patients with HCV RNA titers < 1000 x 10(3) copies/mL.

CONCLUSIONS

In HCV carriers with normal aminotransferase levels viraemia does not predict the grade of HCV-related chronic liver disease (CLD), although subjects with higher HCV RNA levels seem to have more severe fibrosis. Although these data suggest that patients with higher viraemia might have more intense architectural changes and more severe progression of liver disease than those with lower levels of HCV replication, the weak and imprecise correlation leads us to conclude that HCV RNA quantitation is not a useful indicator in clinical practice in the selection of patients for liver biopsy.

Risk of non-Hodgkin's lymphoma in patients with hepatitis C virus infection

Hepatitis C virus (HCV) has been suggested to play an etiological role in the development of B-cell non-Hodgkin's lymphoma (NHL) in Italy. However, another study in Scotland questioned increased risk of development of NHL in patients with chronic HCV infection. A total of 2,162 patients admitted to 3 hospitals in Osaka, where the incidence of HCV-related hepatitis is highest in Japan, during the period from 1957 to 1997 were followed up from the date of diagnosis of chronic HCV-related hepatitis until 30 October 1997. Overall, 12,404.5 person-years of observation were accrued with a follow-up period ranging from 0.25 to 40.4 (average 5.74) years. NHL of the B-cell type developed in 4 patients. The interval between onset of chronic HCV and NHL ranged from 6 to 36 (median 13) years. Expected number of cases of NHL in the sex-, age- and calendar year-matched general population was 1.90, which gave a relative risk (RR) of 2.10 (95% confidence interval 0.57-5.38; p = 0.247). Taking the much higher RR for hepatocellular carcinoma among patients with HCV infection into account, chronic HCV infection was considered to be moderately associated with increased risk of NHL.

Sexual transmission of hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) is the cause of almost all cases of parenterally transmitted non-A, non-B viral hepatitis (NANBH). HCV is an RNA virus, unrelated to the hepatitis viruses, A, B, D, or E; it was first identified in 1989. Although most infections become chronic, and it may lead to chronic liver disease, most patients with HCV infection are asymptomatic. The predominant modes of transmission are by blood, blood products, or other parenteral exposure, particularly injecting drug use. More contentious is the role of sexual transmission, although evidence for this was provided by studies of NANBH.

OBJECTIVE

This review considers the evidence for sexual transmission, and the types of studies used to estimate the rate of transmission and the factors that may influence it.

METHOD

A Medline search using the keywords hepatitis C, sex, transmission, and prevalence in MeSH and free text. References in papers were searched, and some unpublished data identified. References were further selected to illustrate different methodologies.

FINDINGS

Evidence for sexual transmission is provided by several types of study including prevalence studies in groups at risk of other STDs, investigation of cases identified from surveillance reports, and cross sectional and longitudinal partner studies. Many studies are limited by their small size, the sensitivity and specificity of early assays, lack of controls, or the difficulty of excluding other routes of transmission. One prospective cohort study reported an incidence of 12 per 1000 person years in the sexual partners of HCV infected patients. 1-3% of partners of HCV infected patients are found to be infected in cross sectional studies. Co-infection with HIV, duration of the relationship, or chronic liver disease may be independent cofactors increasing the risk of transmission. A meta-analysis of selected studies may be informative, and further larger prospective studies are required. There is a small but definite risk of sexual transmission of hepatitis C.

Hepatitis C virus infection: Review and implications for the dentist

OBJECTIVE

The purpose of this report was to review the current literature on hepatitis C virus infection, with particular attention to the aspects of interest for dental health care staff.

MATERIAL AND METHODS

The authors searched original research and review articles on specific aspects of hepatitis C virus infection, including articles on virology, epidemiology, transmission, diagnosis, natural history, extrahepatic manifestations, therapy and oral aspects of hepatitis C virus infection. The relevant material was evaluated and reviewed.

RESULTS

Hepatitis C virus is an RNA virus that is present throughout the world and has major geographic variations. The virus, transmitted mainly by means of blood contact, causes chronic hepatitis in up to 80% of cases and may give rise to hepatic cirrhosis and hepatocellular carcinoma in a significant proportion of patients. Although it is of limited efficacy, interferon alpha is currently the drug of choice in the treatment of the infection. Hepatitis C virus infection is associated with a number of extrahepatic manifestations that may include oral diseases such as lichen planus or sialadenitis. Although there are documented cases of nosocomial transmission to health care workers after percutaneous exposure, the prevalence of hepatitis C virus among dental staff members is probably similar to that in the general population.

CONCLUSION

Hepatitis C virus infection is a relatively common infection worldwide (1.4% in the US general population) that causes significant chronic hepatic disease. The dentist is thus likely to face a growing number of patients with a diagnosis of hepatitis C virus infection. For this reason it is essential for dental health care workers to be aware of the principal features of the disease and of its oral and dental implications.

HCV genotypes in Italian patients with HCV-related oral lichen planus

Hepatitis C virus (HCV) has high genomic variability and since its discovery, six different "types" and an increasing number of "subtypes" have been reported. HCV genotype may influence viral replication, natural history of disease and response to therapy. Recently, an association between lichen planus (LP) and HCV infection has been suggested, as there is an increased frequency of HCV infection among some groups of patients with LP, in particular from Italy and Japan. These results have not been confirmed by other reports from different geographical areas. Since HCV genotypes have a heterogeneous geographical distribution, we have determined by restriction fragment length polymorphism the genotypes of 39 HCV-seropositive Italian patients with oral LP in order to establish whether the association between LP and HCV infection is influenced by HCV subtype. Of the 33 (84.6%) viraemic patients, 17 (51%) were infected by HCV subtype 1b, 9 (27%) were infected by HCV subtype 2a, 2 by subtype 1a and 1 by subtype 2b. In four cases the gel patterns were uninterpretable. This distribution of HCV genotypes is similar to that reported in recent studies of Italian HCV-seropositive patients of unknown LP status. It is concluded from this small sample that the association of lichen planus with HCV infection and its differential geographic distribution is unlikely to be due to infection by a particular HCV genotype.

Hepatitis C in Prince Edward Island: a descriptive review of reported cases, 1990-1995

INTRODUCTION

The prevalence of hepatitis C in Canada is not known. There is limited information on most small area populations such as Prince Edward Island.

METHODS

A retrospective approach was used to obtain detailed information on all cases of hepatitis C identified in Prince Edward Island from December 1990 to September 1995. Cases were reviewed for demographic, clinical and risk factor information, including blood donation and transfusion histories.

RESULTS

There were 54 RIBA confirmed cases of hepatitis C infection included in the Prince Edward Island Hepatitis C Database, of which 38 (70%) were males. Age ranged from 18 to 76 years, with a mean age of 38 years. Twenty-eight (52%) of the cases had a history of injection drug use, and 24 (44%) had received blood or blood products in the past. There were five cases with neither of these risk factors identified.

DISCUSSION

The results suggest that, in this small, primarily rural population, injection drug use is the most common means of hepatitis C transmission, followed by receipt of blood or blood products.

High rate of hepatitis C virus infection in an isolated community: persistent hyperendemicity or period-related phenomena?

We investigated underlying risks for hyperendemic hepatitis C virus (HCV) infection among the 1853 inhabitants of a mountainous village in Eastern Taiwan with high prevalence of HCV and hepatitis B virus (HBV). Among the 80 selected adults, we found that having resided away from the village before 1985 was protective against HCV infection, while residing in the village after 1985 posed little risk for HCV infection to children and young adults < 30 years of age. Among the 559 school children 7 through 14 years of age, anti-HCV prevalence was 1.9%, and the HBV carrier rate was 29%. Following up 270 children 1 year later, we found that new HCV infection occurred in 0.74% and new or repeated HBV infection occurred in 6.5% of the children, indicating distinct transmission patterns between HBV and HCV. Children of anti-HCV-positive mothers were either anti-HCV-negative or were infected by distinct genotypes of HCV from those infecting their mothers; most married couples in whom both were infected, were infected by HCV of discordant genotypes, indicating negligible importance of sexual or vertical HCV transmission. A case-control study comparing 13 anti-HCV-positive and 53 anti-HCV-negative children showed that having received parenteral medication in local clinics was a significant risk for HCV infection. Our data indicate that, unlike the case of HBV, HCV transmission by vertical or sexual route, or through casual contact are extremely inefficient, and our data further suggest that HCV hyperendemicity is unlikely to persist as a result of the more stringent practice of parenteral precautions in nearly all aspects of daily life.