Hepatitis C virus in a hemodialysis unit: molecular evidence for nosocomial transmission

Development of an investigation form for hemodialysis infection outbreak: Identifying sources in the early stage

BACKGROUND

There are many infectious factors causing the outbreak of hemodialysis infection, which may easily lead to the delay of investigation and treatment. This study aimed to develop an investigation form for hemodialysis infection outbreak (HIO), and to identify sources of outbreak in early stage.

METHODS

After an exhaustive literature review, we used the Delphi method to determine the indicators and relative risk scores of the assessment tools through 2 rounds of specialist consultation and overall consideration of the opinions and suggestions of 18 specialists.

RESULTS

A total of 87 studies of HIOs were eligible for inclusion. The mean authority coefficient (Cr) was 0.89. Kendall's W coefficient of the specialist consultation was 0.359 after 2 rounds of consultation (P < .005), suggesting that the specialists had similar opinions. Based on 4 primary items and 13 secondary items of the source of HIO, and tripartite distribution characteristics of infected patients, we constructed the investigation form.

CONCLUSIONS

The investigation form may be implemented during the initial phase of an outbreak investigation, it is a prerequisite for taking effective control measures, avoiding HIO occurrence. However, the efficacy of the investigation form needs to be further evaluated.

Eliminating viral hepatitis C in Belgium: the micro-elimination approach

BACKGROUND

Hepatitis C virus is one of the leading causes of chronic liver disease and liver-related deaths worldwide. The estimated prevalence of chronic hepatitis C viral infection among the general Belgian population was 0.57% (n = 64,000) in 2015. Although Belgium has had a 'Hepatitis C Plan' since 2014, elimination efforts are unclear. This study employs the best available data and modelling estimates to define the burden of hepatitis C viral infection among key subgroups in Belgium, identify information gaps and propose potential approaches to screening, linkage to care and treatment, and cure.

METHODS

We examined the peer-reviewed and grey literature since 2012 for data on the prevalence of hepatitis C viral infection in Belgium in key subgroups identified by national experts and in the literature. Ultimately, this research is primarily based on data provided by the key stakeholders themselves due to a lack of reliable data in the literature. Based on this, we modelled the treatment rates required to reach elimination of hepatitis C in several subgroups.

RESULTS

Eleven potential subgroups were identified. There were no data available for two subgroups: generational cohorts and men who have sex with men. In six subgroups, fewer than 3000 people were reported or estimated to have hepatitis C infection. Migrants and people who inject drugs were the most affected subgroups, and children were the least affected subgroup. Only two subgroups are on target to achieve elimination by 2030: patients living with haemophilia and transplant recipients.

CONCLUSIONS

Removing Belgian treatment reimbursement restrictions in January 2019 was a big step towards eliminating HCV. In addition, increasing surveillance, including with a national registry, treatment prescription by other health-care providers and availability of treatment in local pharmacies are central to improving the current situation and getting on track to reach the 2030 WHO hepatitis C elimination targets in Belgium.

Prevention of Nosocomial Transmission of Hepatitis C Infection in a Hemodialysis Unit. A Prospective Study

Hepatitis C virus (HCV) infection in hemodialysis patients can be transmitted by transfusions and nosocomially. A high prevalence of HCV infection, over 50%, was demonstrated in our hemodialysis (HD) unit. In order to prevent the nosocomial spread of HCV infection in the HD unit a prospective study was begun separating anti-HCV positive patients from the negative ones. A total of 170 patients (83 anti-HCV positive) started this study in September 1994 and were followed for 4 years. A separate room and dedicated equipment were assigned to anti-HCV positive and anti-HCV negative patients. Of those 170 patients there were 15 hepatitis B virus (HBV) positive patients, 5 of whom were anti-HCV positive, who were treated in a separate room on dialysis equipment for anti-HCV positive or negative patients. Application of general precautions, as recommended by the Center for Disease Control and Prevention (CDC), was reinforced. During the first 12 weeks after implementing the precautions seven more anti-HCV positive patients were detected, and by December 1995 another two HCV infected patients were found. The follow-up included all changes in HD population treated until the end of 1998. The incidence of seroconversion to HCV was 12.9% in 1995, 7.1% in 1996, 5.0% in 1997, and 6.6% in 1998. The higher incidence of seroconversion in September to November 1994 was probably due to the nosocomial infection being in the incubation period at the time of isolation.

This prospective study in a large HD unit with a high prevalence of HCV infection demonstrates a relatively successful prevention of HCV spread. Procedure-related transmission of HCV in hemodialysis could be prevented by rigorous application of universal precautions as recommended by the CDC. As a second line of prevention, in highly burdened dialysis centers, segregation of HCV positive patients can help control nosocomial transmission.

Transmission of hepatitis C virus infection in hemodialysis: Current concepts

A variety of epidemiological data provides evidence for the occurrence of nosocomial transmission of hepatitis C virus (HCV) infection to hemodialysis (HD) patients. The most important factor implicated in HCV transmission between patients treated in the same dialysis unit is cross-contamination from supplies and surfaces as a result of failure of staff to follow infection control procedures. Parts of the HCV genome are highly variable and lend themselves to fingerprinting of each isolate using nucleic acid testing (NAT) and sequencing. This approach has permitted investigation of possible transmission routes within HD units. A systematic review of molecular virology papers revealed transmission of HCV via internal fluid pathways of the dialysis machines in a minority of reports only. Dialyzer reuse was not identified as a risk factor for HCV acquisition in multicenter databases. No randomized controlled trials exist on the impact of isolation on the risk of transmission of HCV to hemodialysis patients. A Belgian prospective multicenter study showed a reduction from 1.4% to 0% in the annual incidence of seroconversion for HCV without any isolation measures, by implementation of strict infection control procedures designed to prevent transmission of blood-borne pathogens, including HCV. However, an isolation policy for HCV-infected dialysis patients should be considered in dialysis units where nosocomial transmission of HCV persists despite reinforcement and audit of hygienic precautions for hemodialysis. Routine audit precautions (general and for dialysis machines) are recommended on a regular basis within HD units.

Outbreak of Hepatitis C Virus Infection in a Hemodialysis Unit: Potential Transmission by the Hemodialysis Machine?

Objective:

To identify the routes of transmission during an outbreak of infection with hepatitis C virus (HCV) genotype 2a/2c in a hemodialysis unit.

Design:

A matched case-control study was conducted to identify risk factors for HCV seroconversion. Direct observation and staff interviews were conducted to assess infection control practices. Molecular methods were used in a comparison of HCV infecting isolates from the case-patients and from patients infected with the 2a/2c genotype before admission to the unit.

Setting:

A hemodialysis unit treating an average of 90 patients.

Patients:

A case-patient was defined as a patient receiving hemodialysis with a seroconversion for HCV genotype 2a/2c between January 1994 and July 1997 who had received dialysis in the unit during the 3 months before the onset of disease. For each case-patient, 3 control-patients were randomly selected among all susceptible patients treated in the unit during the presumed contamination period of the case-patient.

Results:

HCV seroconversion was associated with the number of hemodialysis sessions undergone on a machine shared with (odds ratio [OR] per additional session, 1.3; 95% confidence interval [CI95], 0.9 to 1.8) or in the same room as (OR per additional session, 1.1; CI95, 1.0 to 1.2) a patient who was anti-HCV (genotype 2a/2c) positive. We observed several breaches in infection control procedures. Wetting of transducer protectors in the external pressure tubing sets with patient blood reflux was observed, leading to a potential contamination by blood of the pressure-sensing port of the machine, which is not accessible to routine disinfection. The molecular analysis of HCV infecting isolates identified among the case-patients revealed two groups of identical isolates similar to those of two patients infected before admission to the unit.

Conclusions:

The results suggest patient-to-patient transmission of HCV by breaches in infection control practices and possible contamination of the machine. No additional cases have occurred since the reinforcement of infection control procedures and the use of a second transducer protector.

Hepatitis C virus screening and management of seroconversions in hemodialysis facilities

Over the past two decades, healthcare-associated exposure has increasingly been proved to be a means of hepatitis C virus (HCV) transmission, especially in hemodialysis facilities. The prevalence of HCV among hemodialysis patients is known to be several times greater than that of the general population of the United States, and chronic HCV infection is associated with significant morbidity and mortality among these patients. During 2008-2011, HCV infection outbreaks were identified in multiple US hemodialysis facilities, resulting in at least 46 new HCV infections among hemodialysis patients. These outbreaks, linked to infection control breaches, also highlight the failure of some facilities to follow established guidelines for routine HCV antibody (anti-HCV) screening and response to new HCV infection among hemodialysis patients. Current national guidelines recommend screening of hemodialysis patients for anti-HCV on facility admission and, for susceptible patients, on a semiannual basis. Here, we seek to underscore the importance of compliance with national recommendations for anti-HCV screening of hemodialysis patients and actions to be taken in the event of possible HCV transmission within a hemodialysis facility. These include general steps to ensure that: hemodialysis patients are routinely screened for anti-HCV to facilitate early detection of new infections; newly infected patients are informed of the change in their HCV status and undergo clinical evaluation; and public health officials are notified of new HCV infections in a timely manner. We then focus on the need to assess infection control practices at the facility, with particular attention given to safe handling of injectable medications, hand hygiene and disinfection practices. In the absence of a vaccine, routine screening and adherence to standard infection control practices will remain the key strategies for preventing HCV transmission in hemodialysis units.

The role the type of vascular access plays in the transmission of hepatitis C virus in a high prevalence hemodialysis unit

BACKGROUND

The necessity of having a vascular access site as well as extracorporeal blood circulation, may add to the risk for patients being dialyzed in units with high HCV prevalence of acquiring hepatitis C virus (HCV) infection. This study endeavors to determine the role the type of vascular access plays in the transmission of HCV infection in the hemodialysis (HD) unit of a Middle Eastern country.

METHODS

The records of 198 patients with end-stage renal disease (ESRD) enrolled on maintenance HD from November 1995 to November 2000 at this tertiary care center, were retrospectively reviewed to match the HCV prevalence and seroconversion rates among patients groups being dialyzed through various types of vascular accesses. Factors such as, number of units of blood transfused and dialytic age (time-span since the initiation of the HD treatment), implicated in transmission of HCV infection in HD units, were also recorded, and compared among these cohorts.

RESULTS

The overall, high HCV seroprevalence of 43.4% (86/198) and annual seroconversion rate of 8.6% per year were recorded. Patients with arteriovenous fistula (AVF) documented peak anti-HCV prevalence [61.7% (63/102)] and annual seroconversion rates (12.3%) as compared to lowest prevalence of 12.9% (4/34) and seroconversion rate of 2.5%, observed among patients with permanent Catheters (PC). Patients dialyzed through polytetrafluoroethylene (PTFE) grafts recorded the next highest HCV prevalence of 47.8% (11/23) with seroconversion rate of 9.5% but temporary catheter (TC) group had HCV prevalence of 19% (8/42) and seroconversion rate of 3.8% [Odd Ratio (OR)-1.58, 95% Confidence Interval (CI) (0.37-7.12), p-NS].

CONCLUSIONS

Considerably higher annual seroconversion rates in AVF [OR-10.90, 95% CI (3.2-40.0), p<0.0001] and PTFE [OR-5.71, 95% CI (1.31-26.79), p<0.016)] groups, appear to suggest that the patients being dialyzed through AVF and PTFE, carried significantly higher risk of acquisition of HCV infection compared to those dialyzed through TC and PC (reference group). This could possibly be attributed to likely accessibility of HCV to blood circulation due to possible breakdown of standard infection control precautions during repeated punctures and cannulations of AVF and PTFE to perform a HD, in a unit with high baseline HCV prevalence.

Hepatitis C infection and related factors in hemodialysis patients in china: systematic review and meta-analysis

BACKGROUND AND AIMS

To provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for hepatitis C virus (HCV) infection in maintenance hemodialysis (HD) patients in China, and to help inform prevention programs and guide future research.

METHODS

A systematic review was constructed based on the computerized literature database by two reviewers independently. Ninety-five percent confidence intervals (CI) of infection rates were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models.

RESULTS

Forty-three studies met our inclusion criteria. The pooled prevalence of HCV infection among HD patients in China was 41.1% (95% CI 39.5-42.6%). No significant difference was found in HCV infection rates between male and female HD patients (OR = 0.75, 95% CI 0.52-1.07, p = 0.11). HD patients with blood transfusion were 5.65 times more likely to be infected with HCV than HD patients without blood transfusion. A longer duration of HD was associated with increased HCV prevalence. Co-infection with hepatitis B virus did not increase the probability of HCV infection among HD patients (OR = 1.19, 95% CI 0.34-3.20, p = 0.73).

CONCLUSIONS

Viral hepatitis is still one of the main complications in HD patients, with hepatitis C being the most common one. The key to reducing the incidence of viral hepatitis in HD patients is to control contagion and reduce the frequency of blood transfusion and cross-infection.

Prevalence and associations of hepatitis C viremia in hemodialysis patients at a tertiary care hospital

Hepatitis C virus (HCV) infection in hemodialysis (HD) is a significant problem. We evaluated the prevalence and associations of HCV viremia in our HD patients. All patients undergoing maintenance HD at our center were tested for HCV RNA by PCR after written informed consent. Detailed history regarding age, sex, and duration of dialysis, frequency of dialysis, blood transfusions in one year, number of dialysis centers, dialyzer reuse/fresh use, and recent laboratory data was recorded. A total of 119 patients (77 males and 42 females) were tested for HCV RNA. Thirty three (27.7%) tested positive. Duration of dialysis was significantly longer in HCV RNA positive group (P = 0.001). 45.2% of patients with duration of dialysis more than 16 months were HCV RNA positive while only 7.4% of patients with dialysis duration Collapse

Key Words

• Duration of dialysis
• hemodialysis
• hepatitis C
• polymerase chain reaction

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MESH Headings Collapse

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Affiliation(s)

S. Jasuja Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
A. K. Gupta Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
R. Choudhry AHERF, Fortis Hospitals, Delhi, India
V. Kher Department of Nephrology, Fortis Hospitals, Delhi, India
D. K. Aggarwal Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
A. Mishra Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
M. Agarwal Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
A. Sarin Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
M. K. Mishra Department of Nephrology, Indraprastha Apollo Hospital, Delhi, India
V. Raina Department of Immunology and Molecular Biology, Indraprastha Apollo Hospital, Delhi, India

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Hepatitis C virus infection in haemodialysis: the 'no-isolation' policy should not be generalized

Hepatitis C virus (HCV) infection is the most common blood-borne viral infection in haemodialysis. It causes significant morbidity and long-term mortality. Practice of universal precautions has been reported to be sufficient to prevent HCV seroconversion in dialysis units. However, the seroconversion rate remains very high in many dialysis units. A previous study from 1995 to 1998 at our own hospital without isolation showed that nosocomial transmission is the major cause of HCV seroconversion. The present study was therefore conducted with the aim to study the impact of isolation on HCV seroconversion. In this prospective cohort study, with non-probability consecutive sampling, patients with HCV infection were dialysed in an isolated room. In addition, standard universal precautions were practiced. HCV seroconversion rate was compared with the previous study. All patients with end-stage kidney disease (ESKD) admitted to our hospital for renal replacement therapy were included in the present study. At the time of admission, HCV screening was done. All anti-HCV-positive patients were dialysed in an isolated room. While on maintenance haemodialysis, all patients were monthly tested for anti-HCV, aspartate aminotransferase and alanine aminotransferase. Any patient who had HCV seroconversion was transferred to an isolated room for maintenance haemodialysis. Patients with HCV infection were managed by further testing for HCV-RNA and liver biopsy. Every patient who ultimately received renal transplantation at our hospital was also tested for HCV just prior to renal transplantation as well as 3 months after renal transplantation. HCV infection was diagnosed by detecting anti-HCV antibodies using an ELISA-based third-generation diagnostic test kit. Serum bilirubin, aspartate aminotransferase and alanine aminotransferase were assayed using standard laboratory techniques. From March 2003 to February 2006, 1,417 patients were admitted for haemodialysis in our unit. Of these 1,077 (76%) had ESKD. Mean age of patients was 42.47 +/- 16.2 (14-94) and 70.39% were males. Patients with ESKD had had more dialysis sessions (10.9 +/- 39.5 vs. 4.4 +/- 5.95, p = 0.009), more blood transfusions and more pre-existing HCV infections (4.72 vs. 1.5%, p = 0.009) than patients with acute renal failure. Of the ESKD patients, 65.7% were discharged, 9.47% died, 1.85% were shifted to chronic ambulatory peritoneal dialysis and 22.46% patients received renal transplantation. Of the patients who received renal transplantation, HCV seroconversion was detected in 2.75%. In the previous study without isolation practices, the HCV seroconversion rate in transplanted patients was 36.2%. The hazard of HCV seroconversion was 0.97 (95% CI 0.93-1.02, p = 0.2) for each additional dialysis and 1.09 (95% CI 0.88-1.36, p = 0.37) for each additional blood transfusion. The study concludes that isolation of HCV-infected patients during haemodialysis significantly decreases the HCV seroconversion rate.

Molecular analysis and patterns of ALT and hepatitis C virus seroconversion in haemodialysis patients with acute hepatitis

BACKGROUND

Haemodialysis (HD) continues to carry the risk of hepatitis C virus (HCV) transmission, with delayed seroconversion and often normal alanine aminotransferase (ALT) values increasing the likelihood of undetected infection and thus uninterrupted spread of HCV. The aim of this study was to identify the characteristic patterns of ALT changes and seroconversion during an outbreak of HCV in a HD unit. We also wanted to establish the relationship between infecting viruses using molecular analysis.

METHODS

All patients (n = 72) and staff (n = 23) of the HD unit were prospectively followed for 14 months. Serial measurements for ALT, HCV antibody and HCV-RNA were performed besides HCV sequence analysis.

RESULTS

The initial screening for anti-HCV and HCV-RNA confirmed chronic infection in 16/72 (22%) subjects and identified three subjects with recent seroconversion. In addition, five cases were reverse transcription-polymerase chain reaction positive alone for a total of eight recent cases. The interval between the initial observation of ALT changes and seroconversion varied from 1 to 8 months, and in several individuals ALT fluctuations only below the upper limit of normal were detected. However, relating each subject's ALT values to ALT at baseline, ALT levels increased between 1.6- and 4.7-fold. Molecular analysis provided evidence for transmission from two chronically infected source patients, probably because of inappropriate infection control measures.

CONCLUSION

Our data highlight the importance of well-implemented safety precautions and regular HCV-RNA testing to prevent the further spread of HCV in this population, and suggest the use of ALT baseline values to identify infections that may remain unnoticed otherwise.

A cost-identification analysis of screening and surveillance of hepatitis C infection in a prospective cohort of dialysis patients

The Center for Disease Control and Prevention (CDC) recommends screening and surveillance of dialysis patients for hepatitis C virus (HCV), but there are limited data on the real life performance of confirmatory tests. We performed a cost-identification analysis of CDC recommendations using a large database of dialysis subjects. Screening and surveillance were performed according to CDC guidelines: enzyme immunoassay (EIA) testing upon entry then biannual surveillance. All positive EIA tests were confirmed by either polymerase chain reaction (PCR) or radioimmunoblot assay (RIBA). A total of 12,563 patients were tested from 1997 to 2004. By EIA, the prevalence of HCV was 8.4% and annual incidence was 0.96%. The prevalence after confirmation by RIBA and PCR was 5.8% and 4.8%, respectively. The annual incidence of hepatitis C confirmed by RIBA and PCR was 0.13% and 0.084%, respectively. Using Medicare reimbursement, the cost to screen and confirm one case of hepatitis C by RIBA was $372 versus $503 by PCR. However, the cost to identify an incident infection increased to $30,594 by RIBA and $48,622 by PCR. In the sensitivity analysis, the cost of identifying incident HCV infection dropped by 50% when the surveillance interval was extended to 1 year or when seroconversion rates for EIA occurred at 2%. Due to high surveillance cost, further studies are necessary to determine optimal intervals and settings.

Nosocomial transmission of hepatitis C virus during contrast-enhanced computed tomography scanning

We have investigated two cases of acute hepatitis C that occurred in patients who underwent digestive endoscopy and contrast-enhanced computed tomography (CT) scanning at two different centers. Investigations to identify the sources of infection included an on-site review of diagnostic procedures, interview of the involved healthcare staff, serological testing of the patients who underwent the procedures before and after the index cases and a molecular analysis of viral isolates from the patients and from potential viremic sources. In both cases, the epidemiological investigation identified a chronic hepatitis C virus (HCV) carrier who had been subjected to CT-scanning immediately before the index patient. Genetic distance and molecular phylogenetic analyzes of HCV sequences showed a close relationship between the isolates from these carriers and those from the acute-hepatitis patients, strongly suggesting that patient-to-patient transmission had occurred during CT. This is the first report describing two well documented cases of HCV nosocomial patient-to-patient transmission during contrast-enhanced CT scanning.

[Development of a Web-based Program to Calculate Sample Size for Evaluating the Performance of In Vitro Diagnostic Kits.]

BACKGROUND

Many studies evaluating the performance of in vitro diagnostic kits have been criticized for the lack of reliability. To attain reliability those evaluation studies should be preceded by sample size calculation ensuring statistical power. This study was intended to develop a web-based system to estimate the sample size, which was often neglected because it would require expert knowledge in statistics.

METHODS

For sample size calculation, we extracted essential parameters from the performance studies on the 3rd generation anti-hepatitis C virus (HCV) kits reported in the literature. We developed a system with PHP web-script language and MySQL. The statistical models used in this system were as follows; one sample without power consideration (model 1), one sample with power consideration (model 2), and two samples with power consideration (model 3).

RESULTS

Among the articles published between 1989 and 2005, 13 articles that evaluated the performance of anti-HCV kits were identified by searching with Medical Subject Headings (MeSH). The diagnostic sensitivity was 83-100% with a median of 145 samples (range; 12-1,091) and the specificity was 97-100% with a median of 1,025 samples (range; 33-4,381). The estimated sample size would be 280 in the model 1, 817 in the model 2, and 1,510 in the model 3, when we set 2% prevalence of HCV infection, 95% sensitivity of a conventional kit, 97% sensitivity of a new kit , 95% significance level (two-sided test), 2% allowable error, and 80% power.

CONCLUSIONS

Our study indicates that an insufficient sample size is still a problem in performance evaluation. Our system should be helpful in increasing the reliability of performance evaluation by providing an appropriate sample size.

Impact of hepatitis C virus infection and other comorbidities on survival in patients on dialysis

The impact of hepatitis C virus (HCV) and other comorbid conditions upon survival is not well quantified in patients on dialysis. We identified HCV-infected and uninfected persons in the USRDS using claims data in 1997-1998 and followed until September 22, 2002 or death. We used Gray's time-varying coefficients model to examine factors associated with survival. Subjects with a renal transplant were excluded. A total of 5737 HCV-infected and 11 228 HCV-uninfected persons were identified. HCV-infected subjects were younger (mean age 57.8 vs 65.3 years), more likely to be male (57.6%vs 49.6%) and black (54.0%vs 36.4%). They were more likely to have a diagnosis of drug (16.5%vs 4.6%) and alcohol use (14.0%vs 3.1%), and to be human immunodeficiency virus (HIV) co-infected (7.4%vs 1.8%) (all comparisons, P < 0.0005). In an adjusted Gray's time-varying coefficient model, HCV was associated with an increased risk of mortality (P < 0.0005). The hazards were highest at the time of HCV diagnosis and decreased to a stable level 2 years after diagnosis. Other factors associated with increased risk of mortality were (P < 0.0005 unless stated) HIV coinfection; diagnosis of drug use (P = 0.001); coronary artery disease (P = 0.006); stroke; diabetes as the primary cause for renal failure; peripheral vascular disease; depression and presence of anaemia. HCV was associated with higher risk of death in patients on dialysis, even after adjusting for concurrent comorbidities. The risk was highest at the time of HCV diagnosis and stabilized over time. Clinical trials of HCV screening and treatment to reduce mortality in this population are warranted.

Hepatitis C infection in risk groups

Hepatitis C infection is important global health problem with wide spectrum of health, social and economic consequences. The goal of this research was to estimate prevalence of hepatitis C virus infection in risk groups, and to determine association hepatitis C virus (HCV) infection and risk factors. Research included 4627 subjects divided in two groups. Test group included 2627 subjects divided in 4 subgroups with risk for HCV infection: those who received blood transfusion without screening on HCV (it was introduced in 1995) (700); intravenous drug users (60); patients on hemodialysis (168) and health care workers (1699). Control group included 2000 healthy volunteer blood donors. In all subjects anti-HCV antibodies were tested with third generation ELISA test. Positive serum samples were tested for presence of HCVRNA, using reaction of reverse transcription and polymerase chain reaction. In all anti-HCV positive subjects further epidemiological and clinical workup was performed. Prevalence of HCV infection in risk groups was: 4.6% in subjects who have received blood transfusions without HCV blood screening, 35% in intravenous drug users, 58.9% in patients on chronic dialysis, and 0.4% in health care workers. In control group prevalence was low (0.2%). In the group of 158 anti-HCV positive subjects, 73.4% had HCVRNA. The largest number of subjects with HCV infection was in the age group of 30-49 years (45.8%). This study showed that multiple blood transfusions before introducing the blood screening for HCV, longer duration of intravenous drug abuse, longer duration of hemodialysis treatment, larger number of accidental injuries in health care workers are independent and statistically significant risk factors for those groups examined. Results of this study confirm that general screening for HCV infection is recommended in risk groups for HCV infection in order to identify to prevent and to treat it.

Determining the source of nosocomial transmission in hemodialysis units in Tunisia by sequencing NS5B and E2 sequences of HCV

Hepatitis C virus infection is a significant problem in hemodialysis units. HCV is very variable genetically with six genotypes. Clinical and epidemiological investigation of a new infection requires the determination of both the genotype and the strain of the HCV involved. A prospective, epidemiologic study of 395 dialysis patients in Tunisia was conducted from November 2001 to November 2003 to identify the source of nosocomial transmission using phylogenetic analysis of NS5b and E2 sequences. Hepatitis C infection was diagnosed by screening for anti-HCV antibodies and HCV RNA in sera using third generation ELISA and a qualitative RT-PCR assay. HCV strains were genotyped by sequencing the NS5b region. The genetic relatedness of the HCV strains was studied by sequencing the NS5b and the HVR-1 regions of the HCV genome. Two de novo cases of HCV infection were detected during the follow-up. One of them has been described previously. The case described in this study occurred in a center in which 12 patients were already infected with HCV strains belonging to genotypes 1b (n = 8) and 1a (n = 4). Phylogenetic analysis of the NS5b region from the HCV strains circulating in this center disclosed four clusters, confirmed by analysis of the HVR-1 region, providing strong evidence for nosocomial infection. Epidemiological data showed that these patients were dialyzed during the same shift and in the same area. Phylogenetic analysis of NS5b sequences is useful for determining the HCV genotype and providing evidence of nosocomial transmission.

Hepatitis C: a review for primary care physicians

Primary care physicians see many of the estimated 250 000 Canadians chronically infected with the hepatitis C virus (HCV). Of this number, about one-third are unaware they are infected, which constitutes a large hidden epidemic. They continue to spread HCV unknowingly and cannot benefit from advances in antiviral therapy that may clear them of the virus. Many HCV-infected people remain asymptomatic, which means it is important to assess for risk factors and test patients accordingly. The third-generation enzyme immunoassay for HCV antibodies is a sensitive and specific test, although the presence of the virus can be confirmed by polymerase chain reaction testing for HCV RNA in some circumstances. Pegylated interferon-alpha and ribavirin combination therapy clears the virus in about 45%-80% of patients, depending on viral genotype. Preventive strategies and counselling recommendations are also reviewed.

A cluster of hepatitis C virus infections associated with ozone-enriched transfusion of autologous blood in Rome, Italy

OBJECTIVE

To describe an outbreak of hepatitis C virus (HCV).

DESIGN

Retrospective cohort study.

SETTING

Outpatient department of a hospital in Rome, Italy.

PATIENTS

All 42 patients exposed to ozone therapy by autohemotherapy or intramuscular injection from January to June 2001.

METHODS

Epidemiologic investigation, serologic analysis, and virus genotyping.

RESULTS

Thirty-one (74%) of the patients agreed to participate in the study. Three (9.7%) had symptoms of HCV infection. This incidence rate was higher than the rate of 1.4 per 100,000 per year in the regional population. Six patients were positive for HCV antibodies and HCV RNA for a prevalence rate of 19.4%, which was much higher than the estimate of 0.9% in the population. Virus genotype 1b was found in two case-patients (one symptomatic) and 2c in four case-patients (two symptomatic), one of whom was known to have an HCV infection since 1986 and could have been the source of infection. The infected patients were all being exposed to ozone-enriched transfusions of autologous blood. Although the specific mode of transmission between patients was not detected, transmission probably occurred during one of the three busiest therapeutic sessions in the 6-month period.

CONCLUSIONS

Transmission of HCV infection may occur during medical procedures with limited bleeding. Standard precautions must be applied in any healthcare setting; restricting the number of individuals treated during each therapeutic session could be an effective way of avoiding accidental transmission of infection.

Molecular epidemiology of hepatitis C virus (HCV) in Greece: temporal trends in HCV genotype-specific incidence and molecular characterization of genotype 4 isolates

This study aimed to estimate the overall HCV genotype distribution and to reconstruct the HCV genotype-specific incidence in Greece during the recent decades. It also focused at the identification of genotype 4 subtype variability in Greek isolates. A total of 1686 chronically infected HCV patients with detectable serum HCV RNA by RT-PCR, belonging to different risk groups were studied. Amplified products from the 5'-noncoding region were typed using a commercially available assay based on the reverse hybridization principle. The HCV genotype-specific incidence was estimated using a previously described back calculation method. HCV genotype 1 was the most prevalent (46.9%) followed by genotype 3 (28.1%), 4 (13.2%), 2 (6.9%) and 5 (0.4%). A high prevalence of genotype 1 (66.3%) in haemophilia patients was recorded whereas HCV genotype 3 was found mainly among patients infected by I.V. drug use (58.2%). Data on the temporal patterns of HCV genotype-specific incidence in Greece revealed a moderate increase (1.3-1.6 times) for genotypes 1 and 4, and a decrease (1.5 times) for genotype 2 from 1970 to 1990, whereas there was a sharp (13-fold) increase for genotype 3. The molecular characterization of 41 genotype 4 HCV isolates belonging to various risk groups revealed that, subtype 4a was the most frequently detected (78%). Phylogenetic comparison of the Greek 4a isolates with all HCV-4a isolates reported worldwide so far revealed a topology which does not discriminate Greek isolates from the others. HCV-4 does not represent a recent introduction in Greece.

Incidence of HCV infection in French hemodialysis units: a prospective study

A large prospective study was carried out from 1997 to 2000 in 25 French hemodialysis units including 1,323 patients to determine the incidence of hepatitis C virus (HCV) infection. Monthly testing of alanine aminotransferase (ALT) activity, and assessment of HCV RNA and anti-HCV antibodies if the ALT activity was elevated, identified 14 new infections in 7 different units, giving an incidence of 0.4% new HCV infections per year. Molecular analyses and epidemiological data indicated that five patients became infected with HCV outside the unit where they were dialyzed, while the nine remaining patients acquired HCV from infected patients on dialysis during the same shift at the same unit. HCV was cleared in six of the seven (85.7%) patients with acute hepatitis C who were given standard doses of alpha-interferon (alpha-IFN). The persistence of nosocomial transmission of HCV in hemodialysis units emphasizes the need to implement infection control practices. Identifying new infections is crucial because alpha-IFN treatment results in long term clearance of HCV RNA in a large proportion of patients.

Hepatitis C virus infection in 2,744 hemodialysis patients followed regularly at nine centers in Hiroshima during November 1999 through February 2003

Patients on maintenance hemodialysis (HD) are at increased risk of infection with hepatitis C virus (HCV). A prospective follow-up study on HCV infection from November 1999 to February 2003 was conducted in nine hemodialysis (HD) units in Hiroshima. A total of 2,744 HD patients were surveyed regularly for HCV RNA in serum. The prevalence of HCV RNA decreased from 15.7% (262/1,664) on the first survey to 12.9% (242/1,882) in the last one (P<0.05). This decrease may be attributed to the inclusion of patients with a lower prevalence of HCV RNA compared to patients leaving dialysis centers (111/1,080 [10.3%] vs. 132/862 [15.3%], P<0.01). During the 40 months of this study, 16 de novo HCV infections were documented in the nine HD units corresponding to an incidence of 0.33% per year. These cases included eight new HCV infections, three re-infections, and five infections that presumably occured in the window period when tested during the first survey. Our study shows that the annual incidence of de novo HCV infection during HD was 0.33%, and emphasizes the need for frequent serum HCV RNA testing and for stringent disinfection procedures in order to prevent the transmission of HCV in these settings.

Prolonged time until seroconversion among hemodialysis patients: the need for HCV PCR

OBJECTIVE

Patients on maintenance hemodialysis are known to have an elevated risk of acquiring hepatitis C virus (HCV) infection. Therefore, a reliable diagnosis of HCV infection is essential in order to prevent the spread of the disease in dialysis units. However, whether PCR examination is dispensable in hemodialysis patients has been debated.

METHODS

From 1995 to 2002, serum samples from all hemodialysis patients at our hospital (n = 1,774) were screened by serological assays and by polymerase chain reaction (PCR).

RESULTS

In 25 of these patients acute HCV infection was observed and in 11 patients HCV seroconversion was delayed for 3-16 months. During this time the infection was exclusively detectable by PCR.

CONCLUSION

Despite the growing demand for cost-effectiveness in the health system, HCV PCR examination must remain an essential part of the routine screening in hemodialysis patients.

Brote de 18 casos de hepatitis C en una unidad de hemodiálisis

OBJECTIVES

On September 30, 2001 we had notice of a probable outbreak of hepatitis C virus (HCV) infection in a hemodialysis unit in Ciudad Real (Spain). We conducted an investigation of the outbreak to determine its cause and implement control measures.

METHODS

We performed a descriptive study and another analytic study (retrospective cohort study). In the descriptive study, the incidence of HCV infection in the unit between 01/01/98 and 09/30/01 was studied. In the cohort study, 86 subjects were included, of which 18 were infected with HCV during the outbreak. Virologic study was performed, including serology of anti-HCV antibodies, specific IgG avidity study, polymerase chain reaction and phylogenetic analysis of the viral subtypes found.

RESULTS

In the study period, there were 86 patients under treatment in the hemodialysis unit, of which 27 (31.4%) were HCV-positive before 03/01/01. The epidemic curve suggested a common source with secondary cases. Since 1998 only one seroconversion had been documented (in 1999). Statistically significant differences were found only for the variable of dialysis shift. None of the patients who underwent dialysis on the Tuesday-Saturday-Thursday shift exclusively was infected. All cases were genosubtype 4d, which is uncommon in Spain (accounting for 3%), suggesting a common initial source for all cases. Most of the previous cases of HCV in the hemodialysis unit were 1b; three were 4c/4d and one was 1a. The IgG avidity study suggested that not all the cases were infected at the same time, supporting the hypothesis of a common source with secondary spread.

CONCLUSIONS

The outbreak of HCV was confirmed, with 18 cases among dialyzed patients in the central unit. The outbreak was caused by the same viral strain, probably due to a common source with secondary person-to-person transmission among the patients.

Nosocomial transmission of HCV in the liver unit of a tertiary care center

Despite its medical and legal implications, there are no prospective studies analyzing the incidence and mechanisms involved in the nosocomial transmission of hepatitis C virus (HCV) in liver units. This study prospectively investigates the nosocomial transmission of HCV in the liver unit of a tertiary care center from August 2000 to October 2002. The median prevalence of HCV infection among hospitalized patients was 50%. Anti-HCV-negative patients admitted to the liver unit during the study period were prospectively followed, and serum markers of HCV infection were repeated 6 months after discharge. All known risk factors for HCV transmission (including the physical allocation of HCV-infected and noninfected patients during hospitalization) were recorded. Complete follow-up data were available in 1301 (84.5%) of 1540 patients. Six patients (0.46%) acquired HCV infection (annual incidence: 0.27/100 admissions). Phylogenetic analyses of recovered HCV sequences identified the source of infection as an HCV-infected roommate (3 cases) and a patient receiving care by the same nurse team (1 case). The most relevant risk factors associated with HCV acquisition were duration of hospitalization (>10 days; OR, 35; 95% CI, 1.96-622) and hospitalization with an HCV-infected roommate (>5 days; OR, 12; 95% CI, 1.39-103). In fact, HCV infection occurred in 1.7% of the 357 patients hospitalized longer than 10 days. In conclusion, HCV nosocomial infection appears to occur via patient-to-patient transmission in liver units, particularly in individuals who require long hospitalizations. Continuous reinforcement of universal prevention measures and, when possible, isolation of patients at higher risk might further reduce nosocomial HCV transmission.

Contamination by hepatitis B and C viruses in the dialysis setting

BACKGROUND

Hepatitis virus infections continue to be a major concern in the dialysis setting. We studied levels of hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) RNA contamination in dialysis units to better define the role of the dialysis environment and machines in the nosocomial transmission of hepatitis viruses.

METHODS

Possible contamination by hepatitis B virus (HBV) and HCV was studied by collecting environmental samples in 3 dialysis units located in Rome, Italy. Samples and controls were tested for HBsAg by a microparticle enzyme immunoassay, and for HCV RNA, by qualitative transcription-mediated amplification assay.

RESULTS

HCV RNA and HBsAg were detected in 1 of 64 (1.6%) and 1 of 64 samples (1.6%), respectively. The only HCV RNA-positive sample was found in 1 dialysis unit on the external surface of the dialysate (inlet-outlet) connector of a dialysis machine used for HCV-negative patients. The only HBsAg-positive sample was found in another dialysis unit on the internal surface of the blood pressure monitor cuff of a dialysis bed dedicated for HBsAg-positive patients.

CONCLUSION

A segregation policy for HBsAg-positive patients is a necessary measure despite its high cost-effectiveness; we found HBsAg contamination in the segregated HBV-infected room. Conversely, the finding of HCV RNA contamination on a dialysis machine not dedicated to HCV-positive patients suggests that isolation of HCV-infected dialysis patients and use of dedicated machines are unjustified. Major attention should be given to strict adherence to infection control measures in the dialysis setting.

A novel DNA virus (SEN) among patients on maintenance hemodialysis: prevalence and clinical importance

BACKGROUND

A recently discovered DNA virus (SEN) has been assumed to be responsible for posttransfusion hepatitis in humans. Phylogenetic analysis of SEN virus has revealed the existence of 8 different strains. Two of them (SEN virus strain H (SENV-H) and SENV-D) have been described as possible candidate viruses for inducing posttransfusion hepatitis. Until now, it is unclear whether patients on maintenance hemodialysis are on increased risk for acquiring SEN virus.

OBJECTIVES

To investigate the prevalence of SENV-H among patients on maintenance hemodialysis and to examine whether special measures have to be taken to prevent nosocomial spreading of the virus.

STUDY DESIGN

Serum samples derived from 78 chronically hemodialysed patients were examined for SENV-H viremia by seminested polymerase chain reaction. A panel of 226 samples from healthy blood donors served as a control group.

RESULTS

The prevalence of SENV-H was determined to be 12.8% (n=10) among patients on maintenance hemodialysis. This is nearly the same prevalence as in healthy blood donors (16.8%; n=38). None of the solely SENV-H-viremic individuals had clinical or biochemical signs of liver disease. Enhanced severity of liver disease could not be observed in patients coinfected with hepatitis C virus and SENV-H.

CONCLUSION

We conclude that SENV-H viremia is widespread among hemodialysis patients. Since no viremic patient had clinical or biochemical signs of liver disease, in our setting the hepatitis-inducing capacity of SENV-H remains unclear. On the basis of our results, at present, we do not regard it as necessary to dialyse SENV-H-viremic patients on separate machines.

Impact of dedicated space, dialysis equipment, and nursing staff on the transmission of hepatitis C virus in a hemodialysis unit of the middle east

BACKGROUND

Infection with the hepatitis C virus (HCV) is endemic in hemodialysis (HD) units, especially in Middle Eastern countries. The meticulous isolation policy recommended for patients with the hepatitis B virus (HBV) in an HD unit resulted in a significant drop in HBV incidence globally. This study was developed to prospectively investigate the impact of an identical isolation policy on incidence of nosocomial HCV infection in this HD unit of the Middle East.

METHODS

In phase I of the study, we retrospectively reviewed the records of 189 patients with a mean age of 47.5 +/- 11.4 years (range, 15-85 years) who were receiving maintenance HD from December 7, 1995, to December 6, 2000, for the mean duration of 73 +/- 6.3 months (range, 3-144 months) to record the prevalence of HCV. Factors such as blood transfusions and dialytic age (time span that patient has received dialysis since its initiation) implicated in transmission of HCV in the HD unit also were recorded. Phase II involved stringent isolation of anti-HCV positive patients detected during phase I through provision of dedicated space, dialysis equipment, and nursing staff from December 7, 2000, to December 6, 2001. Liver function and anti-HCV tests were repeated for all the 198 patients every 6 months to identify new HCV seroconversions.

RESULTS

An HCV prevalence rate of 43.9% (83/189) and an annual HCV seroconversion rate of 6.8% were identified in this cohort. No significant association with blood tranfusion was observed. Eighty-three anti-HCV positive (43.9%) patients had a mean dialytic age of 48.5 +/- 14.2 months compared with 25.0 +/- 8.6 months among 106 (56.1%) anti-HCV negative patients (relative risk [RR], 1.89; 95% confidence interval [CI], 1.39-5.86; P <.001). Only 2 new HCV seroconversions (1.01% [2/198]) were identified.

CONCLUSIONS

Evidently, the sharing of facilities in a high-risk HD environment for a prolonged dialytic age facilitates the nosocomial transmission of HCV infection. A significant decline of annual seroconversion rate from 6.8% to 1.01% (odds ratio [OR], 7.535; 95% CI, 1.598-48.89; P <.005) suggests that a comprehensive, strictly enforced isolation policy for HCV-positive patients may play a significant role in limiting HCV transmission in HD units, just as it has in drastically reducing HBV transmission in these settings.

Nosocomial hepatitis C virus infection in a renal transplantation center

Nosocomial hepatitis C virus (HCV) infections were recorded in the renal transplantation unit of the university hospital. There were cases of acute HCV infection with aggressive clinical courses diagnosed from a positive HCV RNA test in the early post-transplantation period and which remained anti-HCV negative. Their anti-HCV seronegativity was attributed to them having acquired HCV under intense immunosuppressive therapy and suggested that the aggressive clinical course could be due to the deficient immune response resulting in an inability to limit viral replication. There were also donors diagnosed as having acute HCV infection in the early post-operative period. Genotyping and sequence analysis for HCV were performed on the isolates of eight of these patients who were consecutively transplanted and of three donors whose recipients were infected with HCV prior to transplantation, and who acquired acute HCV infection after transplantation. Of the eight recipients in the first group three were genotype 1a, three were genotype 1b, one was genotype 3a, and the last one was genotype 4 according to Simmond's classification. Of the three donor-recipient couples both the HCV isolates from one couple were genotyped as 1b and the phylogenetic analysis indicated that the patients were infected with a common variant of HCV, but the genotypes of HCV isolates from the other couples were different. Recipients were genotype 1b and the donors were genotype 1a in these couples. Genotype results of the first group and donor-recipient couples, and sequence analysis of genotype 1b and 1a isolates, showed that the source of infection was not a unique strain and there were multiple breaks in universal precautions while managing these patients.

Outbreak of nosocomial hepatitis C virus infection resolved by genetic analysis of HCV RNA

In July 2000, symptomatic acute hepatitis C was diagnosed in five patients who had attended the emergency room of a municipal hospital on the same day, about 6 weeks before. Investigation of the remaining 65 patients visited at the emergency room on that day disclosed that 8 patients had a positive anti-hepatitis C virus (anti-HCV) test and 4 of them had biochemical evidence of acute anicteric hepatitis. HCV RNA was detected in 12 of the 13 anti-HCV-positive patients. Phylogenetic analysis of the nonstructural 5A (NS5A) and E2 regions showed that 10 patients, including all 9 with acute hepatitis, were infected with a closely related HCV strain, while the remaining 2 patients harbored unrelated strains. Flushing of intravenous catheters with heparin retrieved from a multidose heparin solution in saline was carried out for all the patients involved in the hepatitis outbreak but in only 1 of 23 (4%) matched controls recruited among HCV-noninfected patients attending the emergency room on the same day, and this was the only significant difference concerning risk factors for HCV infection between patients and controls. Thus, accidental contamination of a multidose heparin solution with blood from an unrecognized HCV carrier was identified as the source of this nosocomial outbreak of hepatitis C.

Low prevalence of hepatitis C virus infection in hemodialysis units: effect of isolation?

Hepatitis C virus (HCV) infection has recently become the major cause of chronic liver disease among patients on chronic hemodialysis. The use of erythropoietin for treatment of anemia has reduced the number of blood transfusions, but the frequency of HCV infection has not declined in hemodialysis units. The exact mode of transmission of HCV within dialysis units is as yet incompletely defined, but there is evidence to support nosocomial transmission by sharing dialysis machines in the hemodialysis unit. We performed a study to estimate the prevalence of HCV infection in our hemodialysis unit and to evaluate the effect of patient isolation and use of devoted dialysis machines for HCV-positive patients on the spread of HCV infection. A total of 168 patients on chronic hemodialysis (92 males and 76 females; mean age 54 +/- 12) were screened for HCV-antibodies (HCV-Ab) before their admission to the dialysis unit. Seropositive patients were isolated and confined to dedicated dialysis machines. Aminotransferases were measured monthly and HCV-Ab screening was performed second or third generation ELISA test every two months. Seropositive patients were tested by the PCR for the detection of HCV-RNA. Between March 1992 and August 2000, eight of 168 patients showed seroconversion. Seropositive patients were also found HCV-RNA positive. Four of these patients have become seropositive after they had undergone hemodialysis in other dialysis centers on holiday, two patients had received blood transfusions within the six months preceding seroconversion. The prevalence of HCV positivity in our hemodialysis unit is 4.7%. The low prevalence of HCV infection of our unit suggests that patient isolation and use of dedicated dialysis machines for seropositive patients decrease the transmission of HCV infection in hemodialysis units.

Outbreak of hepatitis C virus infection in a hemodialysis unit: potential transmission by the hemodialysis machine?

OBJECTIVE

To identify the routes of transmission during an outbreak of infection with hepatitis C virus (HCV) genotype 2a/2c in a hemodialysis unit.

DESIGN

A matched case-control study was conducted to identify risk factors for HCV seroconversion. Direct observation and staff interviews were conducted to assess infection control practices. Molecular methods were used in a comparison of HCV infecting isolates from the case-patients and from patients infected with the 2a/2c genotype before admission to the unit.

SETTING

A hemodialysis unit treating an average of 90 patients.

PATIENTS

A case-patient was defined as a patient receiving hemodialysis with a seroconversion for HCV genotype 2a/2c between January 1994 and July 1997 who had received dialysis in the unit during the 3 months before the onset of disease. For each case-patient, 3 control-patients were randomly selected among all susceptible patients treated in the unit during the presumed contamination period of the case-patient.

RESULTS

HCV seroconversion was associated with the number of hemodialysis sessions undergone on a machine shared with (odds ratio [OR] per additional session, 1.3; 95% confidence interval [CI95], 0.9 to 1.8) or in the same room as (OR per additional session, 1.1; CI95, 1.0 to 1.2) a patient who was anti-HCV (genotype 2a/2c) positive. We observed several breaches in infection control procedures. Wetting of transducer protectors in the external pressure tubing sets with patient blood reflux was observed, leading to a potential contamination by blood of the pressure-sensing port of the machine, which is not accessible to routine disinfection. The molecular analysis of HCV infecting isolates identified among the case-patients revealed two groups of identical isolates similar to those of two patients infected before admission to the unit.

CONCLUSIONS

The results suggest patient-to-patient transmission of HCV by breaches in infection control practices and possible contamination of the machine. No additional cases have occurred since the reinforcement of infection control procedures and the use of a second transducer protector.