Clearance of HBV DNA in immunized children born to HBsAg-positive mothers, years after being diagnosed with occult HBV infection.

In a previous study, we observed immunoprophylaxis failure due to occult hepatitis B virus (HBV) infection (OBI) despite the presence of adequate levels of anti-HBs in 21 (28%) of 75 children born to HBsAg-positive mothers. The aim of the study was to explore the maintenance of this cryptic condition in this population. Of 21 OBI-positive children, 17 were enrolled. HBV serological profiles were determined by enzyme-linked immunosorbent assay. Highly sensitive real-time and standard PCR followed by direct sequencing were applied in positive cases. The mean age (±SD) of studied patients was 6.57 ± 2.75 years. All children still were negative for HBsAg. All but one (94%) were negative for HBV DNA. Only two children were positive for anti-HBc. The results of the most recent anti-HBs titration showed that 4 (23.5%) and 13 (76.5%) had low (<10 IU/mL) and adequate (>10 IU/mL) levels of anti-HBs, respectively. The only still OBI-positive patient had an HBV DNA level of 50 copy/mL, carried the G145R mutation when tested in 2009 and again in 2013 in the 'a' determinant region of the surface protein. Further follow-up showed that after 18 months, he was negative for HBV DNA. In high-risk children, the initial HBV DNA positivity early in the life (vertical infection) does not necessarily indicate a prolonged persistence of HBV DNA (occult infection). Adequate levels of anti-HBs after vaccine and hepatitis B immune globulin immunoprophylaxis following birth could eventually clear the virus as time goes by. Periodic monitoring of these children at certain time intervals is highly recommended.

Performance characteristics of the VERSANT hepatitis C virus RNA 1.0 (kPCR) assay.

HCV RNA assays are of central importance for virological diagnostics and for clinical planning and monitoring of an antiviral combination treatment of chronic HCV infections. The objective of the pre-market evaluation of the VERSANT HCV RNA 1.0 Assay (kPCR) was to collect analytical performance data for this new method of HCV RNA quantification and to compare them with the high standards that exist in this context. The assay exhibited a specificity of 100%. The mean intra- and inter-assay imprecision was 14.1% and 14.6%, respectively. The detection limit was determined to be 16IU/ml (95% confidence interval: 11.9-30.6IU/ml) and consequently corresponded to the manufacturer's claims (i.e. 15IU/ml). The test exhibited linearity for all HCV genotypes in a broad range from 15 to 10(8)IU HCV RNA/ml. Hence, the kPCR assay in general is well suitable for HCV RNA determinations in clinical practice. However, in a methodological comparison, a considerable under-quantification of the concentrations of HCV genotype 2 and 3 isolates was detected. Provided that the assay's manufacturer will quickly remedy this shortcoming, the VERSANT HCV RNA 1.0 (kPCR) can be called a completely reliable technique for HCV RNA quantification in routine virological diagnostics.

Adhesive luting of new CAD/CAM materials.

OBJECTIVE: To evaluate the adhesive bonding performance of recently introduced tooth-colored CAD/CAM materials after different pretreatment protocols and using different luting materials. MATERIALS AND METHODS: The CAD/CAM materials under investigation were e.max CAD (lithium disilicate glass ceramic; Ivoclar Vivadent, Schaan, Liechtenstein), Celtra Duo (zirconia-reinforced lithium disilicate ceramic; Dentsply DeTrey, Konstanz, Germany), Lava Ultimate (resin nano ceramic; 3M ESPE, Neuss, Germany), and Enamic (resin infiltrated ceramic; Vita, Bad Säckingen, Germany). A total of 240 blocks (n = 5) received various pretreatments (no pretreatment, silane, sandblasting, sandblasting + silane, hydrofluoric acid, hydrofluoric acid + silane), and then different classes of adhesive luting composites were applied (adhesive: Prime&Bond XP + SCA + Calibra; Dentsply DeTrey; self adhesive: RelyX Unicem; 3M ESPE). After 24 h water storage and 10,000 thermocycles (5°C/55°C), specimens were cut into beams and microtensile bond strengths were recorded. RESULTS: Bonding performance of recent CAD/CAM materials was clearly influenced by the pretreatment method (P < 0.05). In general, significantly higher µ-TBS values were recorded for the ceramic materials compared to the hybrid materials (P < 0.05). Among the hybrid materials, Enamic exhibited higher bond strengths than Lava Ultimate (P < 0.05). However, despite the differences found, all materials showed a high level of bonding performance, being sufficient to withstand intraoral chewing forces during mastication. CONCLUSION: When pretreated as recommended by the manufacturers, recent tooth-colored CAD/CAM materials show an encouraging bonding performance for adhesive luting.

[Combined hepatitis A/B vaccination: evaluation of a vaccination schedule in facilities for handicapped people]. / Hepatitis A/B-Kombinationsimpfung: Evaluation eines Impfprogramms in Werkstätten für Menschen mit Behinderung.

AIM OF THE STUDY: People with mental and physical disabilities have a higher risk of infection with hepatitis viruses. Studies conducted so far show contradictory results on the success of vaccination in this population. These people live and work under special conditions and sometimes have immune defects. METHODS: We investigated the antibody response after combined vaccination against hepatitis A and B in facilities for handicapped people in the city of Essen/Germany. Antibodies were determined in people with disabilities (n=949) and also in social workers taking care of handicapped people (n=115). RESULTS: Protective antibodies against hepatitis A were detected in 98.9% in people with disabilities and social workers. The seroconversion rate against hepatitis B in handicapped people was 90.2% and was comparable to the seroconversion rate in social workers (91.3%). Re-vaccinations were offered to all people with anti-HBs titres below 100 IU/L (28% of handicapped and 23.5% of social workers). In the group of low responders in handicapped people about 50% developed anti-HBs concentration above 100 IU/L. Non-responders showed 30-40% seroconversion rate after re-vaccination. CONCLUSION: Based on this study we would recommend serological tests about 4-8 weeks after vaccination to confirm seroconversion. By this procedure people who need a booster vaccination will be recognized and non-responders should be offered another HBV vaccination. In about 20% of the non-responders included in this study HBs antigen was detected.

Hepatitis B virus carrier rate, prevalence and susceptibility and impact of immunization program among households in the city of Taiz, Yemen.

OBJECTIVE: To examine the carrier rate, prevalence and susceptibility to hepatitis B virus infection in the city of Taiz, Yemen. METHODS: In a community-based household survey 521 subjects from 98 randomly selected households were enrolled. Carrier rate, prevalence and susceptibility of hepatitis B virus infection in the city of Taiz, Yemen were examined. RESULTS: The median age of the subjects was 19 years (range <1-85 years), 219 (42.0%) of whom were males and 305 (58.0%) were females. The HBsAg carrier rate was 4.2% (22/521), the prevalence was 16.9% (88/521) and the susceptibility rate was 57.5% (287/499). Male vs female carrier rate, prevalence and susceptibility rate were comparable. Children (age ≤ 18 years) vs adults had carrier rates of 2.7% vs 5.7% (odds ratio=2.2) and a prevalence of 5.1% vs 28.4% (OR: 5.6). The carrier rate, prevalence and immunity to HBV among subjects who reported vaccination vs those unvaccinated was; 2.1% vs 5.5%, 11.3 vs 20.8% and 53.1% vs 18.8%. A proportion of 47.2% of subjects who aged ≤ 10 years had isolated anti-HBs. Of 142 of the cohort born after full implementation of vaccination program (age:≤ 9 years) 72 (50.7%) were immune and 70 (49.3%) were susceptible whereas of 357 subjects borne before program implementation (Age:≥ 10 years) 140 (39.2%) were immune and 217 (60.8%) were susceptible (p<0.02 (Pearson) OR: 1.6 CI=0.42-0.93). CONCLUSIONS: An intermediate endimicity was identified in Taiz city. Vaccination reduced carrier rate prevalence and susceptibility among vaccinated subjects. The high rate of subjects with isolated anti- HBs together with the reduced susceptibility rate among the cohort born after inclusion of HBV vaccine to EPI reflects impact of the program. Improving vaccination coverage will further reduce susceptibility rate.

Pandemic A/H1N1(2009) influenza infections in very-low-birth-weight infants--a case series from the German Neonatal Network.

6 cases of clinical influenza A/H1N1(2009) infections were reported within the multi-center German Neonatal Network (GNN) during the primary hospital stay in the pandemic season 2009/2010 and 2010/2011. Clinical symptoms varied from transient hyperthermia to apnea and severe respiratory distress. 1 fatal course with systemic inflammatory response after perinatal transmission of A/H1N1(2009) was observed. Oseltamivir treatment in 3/6 infants was without side effects. The reported cases have major implications for the management of VLBW infants: i) fatal courses after perinatal transmission are possible, ii) postnatal A/H1N1(2009) infection may result in life threatening events at a time when the infant is otherwise stable, iii) vaccination should be recommended for parents and medical staff to avoid nosocomial transmission, iv) more data are needed on the benefit and harm of antiviral drugs in preterm infants, v) neonatologists should suspect A/H1N1(2009) infection when unexplained sepsis-like or respiratory symptoms occur in VLBW infants.

[Rate of influenza vaccination among medical staff working at a university hospital]. / Die Influenza-Impfrate bei Mitarbeitern eines Universitätsklinikums.

UNLABELLED: BACKGROUND AND OBJEKTIVES: In 1988 the German Vaccination Board (STIKO) at the Robert-Koch-Institute (RKI) in Berlin, recommended that German health care workers should be vaccinated annually against influenza. Despite this, vaccination rates have remained low (20 %). Between January and March 2009 a study was performed at the University Clinical Centre in Essen to determine reasons for low influenza vaccination rates and to assess improvement strategies. METHODS: All employees and staff members of the University Hospital (n = 5349) were asked to fill in a questionnaire anonymously. The completed questionnaires were digitalized and the results analysed electronically. RESULTS: 1 670 of the 5 349 (31 %) questionnaires were found to be satisfactory for evaluation. The vaccination rate among this cohort was 29 %. Vaccination rates varied widely between different departments (4 - 71 %). The most common reason for not undergoing vaccination was "forgotten" (32 %). The second most common reason was the fear of side effects (30 %). Only 32 % of the employees stated that the quality of the information about influenza vaccination provided by their employer was "good" or "very good". CONCLUSION: The vaccination rate of 29 % among this group of health care workers was higher than the average (20 %) in German hospitals and highest among medical doctors. Strikingly enough employees of theoretic departments were vaccinated to a higher percentage than those providing nursing care and thus had more frequent contact to patients. A number of comparatively basic and inexpensive measures would be enough to increase vaccination rates significantly.

Elimination of hepatitis B virus surface antigen and appearance of neutralizing antibodies in chronically infected patients without viral clearance.

Seroconversion from hepatitis B surface antigen (HBsAg) to antibodies against HBsAg (anti-HBs) usually indicates resolution of hepatitis B virus (HBV) infection. Here, two HBV-infected patients with seroconversion to anti-HBs were found to be persistently positive for HBeAg and HBV DNA. Immunohistology of liver biopsies confirmed the expression of HBV proteins in the liver of one patient. The neutralizing ability of anti-HBs in patient sera was demonstrated by blocking HBV infection of primary tupaia hepatocytes. Analysis of the HBsAg-encoding region of HBV isolates from patients indicated the coexistence of heterogeneous HBV genomes in patients. The majority of recombinant variant HBsAg was reactive in HBsAg assays and was able to bind to anti-HBs. Circulating immune complexes (CIC) of HBsAg in patient sera could be detected by polyethylene glycol precipitation and trypsin digestion. Thus, neutralizing anti-HBs may appear in chronic HBV carriers for long periods but does not necessarily lead to complete viral clearance.

Hepatocyte apoptotic bodies encasing nonstructural HCV proteins amplify hepatic stellate cell activation: implications for chronic hepatitis C.

Chronic hepatitis C infection leads to increased hepatocyte apoptosis. Because engulfment of apoptotic bodies (ABs) by hepatic stellate cells (HSC) is profibrogenic, we compared the effects of ABs derived from hepatitis C virus (HCV)-negative vs HCV-infected (Con1+) Huh7 hepatoblastoma cells on fibrogenic and activation-related mRNA expression by a human HSC line (LX2). Uptake of Huh7(Con1+) ABs by LX2 cells dose dependently upregulated profibrotic genes (COL1A1, TGFB1; TIMP1; TIMP2). When normalized to the apoptotic cytokeratin-18 M30 neoepitope, HCV(+) ABs exhibited a more pronounced effect than HCV(-) ABs. In contrast, neither noningested ABs nor nucleic acids obtained from Huh7, Huh7(Con1+) or HepG2 cells triggered those AB-dependent effects. Both the engulfment of Huh7(Con1+) ABs and their effects were partially blocked by masking of phosphatidylserine with annexin V and completely inhibited by the class-A scavenger receptor ligand, polyinosinic acid. Our findings demonstrate that AB uptake stimulates HSCs and indicate that HCV infection leads to amplified fibrogenic mRNA expression and enhanced HSC activation.

Characterization of CD8+ T-cell response in acute and resolved hepatitis A virus infection.

BACKGROUND & AIMS: In contrast to the infection with other hepatotropic viruses, hepatitis A virus (HAV) always causes acute self-limited hepatitis, although the role for virus-specific CD8 T cells in viral containment is unclear. Herein, we analyzed the T cell response in patients with acute hepatitis by utilizing a set of overlapping peptides and predicted HLA-A2 binders from the polyprotein. METHODS: A set of 11 predicted peptides from the HAV polyprotein, identified as potential binders, were synthesized. Peripheral blood mononuclear cells (PBMCs) from patients were tested for IFNγ secretion after stimulation with these peptides and ex vivo with HLA-A2 tetramers. Phenotyping was carried out by staining with the activation marker CD38 and the memory marker CD127. RESULTS: Eight out of 11 predicted HLA-A2 binders showed a high binding affinity and five of them were recognized by CD8+ T cells from patients with hepatitis A. There were significant differences in the magnitude of the responses to these five peptides. One was reproducibly immunodominant and the only one detectable ex vivo by tetramer staining of CD8+ T cells. These cells have an activated phenotype (CD38hi CD127lo) during acute infection. Three additional epitopes were identified in HLA-A2 negative patients, most likely representing epitopes restricted by other HLA-class I-alleles (HLA-A11, B35, B40). CONCLUSIONS: Patients with acute hepatitis A have a strong multi-specific T cell response detected by ICS. With the tetramer carrying the dominant HLA-A2 epitope, HAV-specific and activated CD8+ T cells could be detected ex vivo. This first description of the HAV specific CTL-epitopes will allow future studies on strength, breadth, and kinetics of the T-cell response in hepatitis A.

Effectiveness of four electronic apex locators to determine distance from the apical foramen.

AIM: To evaluate the accuracy of four electronic apex locators (EAL) in the apical region (0-3 mm short of the foramen) and to compare the precision of the readings on the display with the real position of the file in the root canal. METHODOLOGY: Twenty single-rooted extracted teeth with round root canals were used. The canal orifices were preflared, and the length to the major foramen was determined visually under a microscope. Canals were enlarged, so that a size 15 file fitted well inside the canal. Teeth were mounted in acrylic test tubes filled with physiologic saline solution. Electronic length was determined in the region between the major foramen and 3 mm short of it in 0.5 mm steps with the Dentaport ZX, Root ZX mini, Elements Diagnostic Unit and Apex Locator and Raypex 5 using files of size 10 and size 15. The data were analysed using linear regression between true length and EAL reading, Bland-Altman plots and nonparametric tests at a significance level of alpha = 0.05. RESULTS: The major foramen was detected by all EALs. With a measurement file positioned directly at the major foramen, meter readings were equivalent to a position 0.01-0.38 mm away. For the Dentaport ZX, a better accuracy using the size 15 file for the area 0-1.5 mm short of the apex was found. The differences in measurements between the two files were smaller for the other EALs. In linear regression, a good linearity for Dentaport ZX and Root ZX mini and moderate linearity for Elements Diagnostic Unit and Apex Locator and Raypex 5 were found. The slope of the measurement curve was too low (0.37-0.57) for the Raypex 5 and almost optimal for the Dentaport ZX (1.01-1.05). The Root ZX mini and the Elements Obturation Unit produced lower slope values and especially the Elements Obturation Unit revealed much higher SDs at the different measurement levels. CONCLUSION: Amongst the four EALs, the Dentaport ZX and Root ZX mini had the best agreement between true lengths and meter readings. For the Raypex 5, an interpretation of the colour-coded zones as distance to the foramen cannot be recommended and might lead to erroneous interpretations.

Outbreak of influenza virus A/H1N1 in a hospital ward for immunocompromised patients.

In February 2008, five patients were infected with the H1N1 subtype of influenza A virus in one hospital ward for immunocompromised patients at a hospital in North Rhine-Westphalia, Germany. All of these patients had an established haematologic disease and tested positive either for viral RNA or antigen shortly after the beginning of respiratory illness. In three of the patients, influenza virus was repeatedly detected, and four of the patients died in coincidence with the virus infection. Sequencing of the amplified (HA1) haemagglutinin yielded identical nucleotide sequences in isolates from three of the patients, whereas one nucleotide difference was found in the isolate of the fourth patient, resulting in an amino acid substitution (G153R). To investigate the source of infection, the medical staff (n = 104) of the hospital unit was tested and found negative for influenza virus RNA and antigen in pharyngeal lavages. Testing for influenza virus antibodies by immunofluorescence assay revealed that 12 staff members were positive for influenza virus A IgA antibodies. These findings suggest that wild-type influenza virus infections occurred within the medical staff at the same time the patients were infected and that the staff might have contributed to the circulation of virus in the hospital ward.

Spotlight on measles 2010: measles outbreak in a mainly unvaccinated community in Essen, Germany, March-June 2010.

On 15 March 2010, a case of measles was reported to the District Health Office in Essen. In total 71 cases occurred from 15 March to 19 May (four cases hospitalised), with the majority linked to a Waldorf school. Only one case had been vaccinated twice, two cases had been vaccinated once. Immediate and consequent exclusion of non-immune children from classes for two weeks as well as the adjacent spring break prevented the wider spread of the virus.

The woodchuck: a model for therapeutic vaccination against hepadnaviral infection.

Interferon-alpha and nucleoside analogues are available for the treatment of chronic hepatitis B virus (HBV) infection but do not lead to a satisfactory result. New findings about the immunological control of HBV during acute infection suggest the pivotal role of T-cell mediated immune responses. Several preclinical and clinical trials were undertaken to explore the possibility of stimulating specific immune responses in chronically infected animals and patients by vaccination. However, vaccination with commercially available HBV vaccines in patients and immunization in woodchucks with core or surface proteins of woodchuck hepatitis virus (WHV) did not result in effective control of HBV and WHV infection, suggesting that new formulations of therapeutic vaccines are needed. Some new approaches combining antiviral treatments with nucleoside analogues, DNA vaccines and protein vaccines were tested in the woodchuck model. It could be shown that therapeutic vaccinations are able to stimulate specific B- and T-cell responses and to achieve transient suppression of viral replication. These results suggest the great potential of therapeutic vaccination in combination with antivirals to reach an effective and sustained control of HBV infection.

SEM evaluation of root canal debridement with Sonicare CanalBrush irrigation.

AIM: To determine the efficacy of Sonicare CanalBrush irrigation for root canal cleaning. METHODOLOGY: Fifty human molar root canals were shaped with sequential NiTi rotary instruments up to size F3 (size 30, 0.09 taper; ProTaper system) and then enlarged apically with a Profile size 40, 0.04 taper. Five different irrigation protocols were tested (n = 10 canals per group) with 2 mL of distilled water (control, group I) or 2.5% NaOCl (control group II and test groups III, IV and V) between instrument size changes. Group III-IV received a final rinse with 17% EDTA for one min. This was extended by 30 s in group IV, whereas group V received this additional 30 s of 17% EDTA sonically dispersed with a Sonicare CanalBrush. For cleanliness evaluations, roots were split longitudinally, examined with scanning electron microscopy and scored according to Hülsmann et al. (1997) for debris and smear layer on the surface of the root canal wall. Walls were assessed at the coronal, middle and apical thirds. Data were analysed with the Kruskal-Wallis and Mann-Whitney tests. RESULTS: Irrigation with 17% EDTA significantly reduced debris and smear layer scores (P < 0.05) compared to controls. The coronal and middle thirds had lower debris and smear layer scores than the apical third (P < 0.05). In all thirds, sonic agitation of the irrigant with a CanalBrush (group V) resulted in significantly cleaner canal walls compared to all other groups (P < 0.05). CONCLUSIONS: Irrigation by agitation with the Sonicare CanalBrush improved root canal debridement in the coronal, middle and particularly the apical thirds of the root canal.

Management and outcomes after multiple corneal and solid organ transplantations from a donor infected with rabies virus.

BACKGROUND: This article describes multiple transmissions of rabies via transplanted solid organ from a single infected donor. The empirical Milwaukee treatment regimen was used in the recipients. METHODS: Symptomatic patients were treated by deep sedation (ketamine, midazolam, and phenobarbital), ribavirin, interferon, and active and passive vaccination. Viral loads and antibodies were continuously monitored. RESULTS: Recipients of both cornea and liver transplants developed no symptoms. The recipient of the liver transplant had been vaccinated approximately 20 years before transplantation. Two recipients of kidney and lung transplants developed rabies and died within days of symptomatic disease. Another kidney recipient was treated 7 weeks before he died. The cerebrospinal fluid viral load remained at constant low levels (<10,000 copies/mL) for approximately 5 weeks; it increased suddenly by almost 5 orders of magnitude thereafter. After death, no virus was found in peripheral compartments (nerve tissue, heart, liver, or the small intestine) in this patient, in contrast to in patients in the same cohort who died early. CONCLUSIONS: Our report includes, to our knowledge, the longest documented treatment course of symptomatic rabies and the first time that the virus concentration was measured over time and in different body compartments. The postmortem virus concentration in the periphery was low, but there was no evidence of a reduction of virus in the brain.

Micro-CT evaluation of residual material in canals filled with Activ GP or GuttaFlow following removal with NiTi instruments.

AIM: To assess the efficacy of removing Activ GP or GuttaFlow from canals using NiTi instruments. METHODOLOGY: Root canals in 55 extracted pre-molars were prepared to apical size 40, 0.04 taper. The teeth were imaged with micro-CT, and 30 teeth selected that had consistent apical size and taper of the shaped canals. They were randomly assigned to root filling with either the glass-ionomer-based ActivGP system (n = 15) or the polyvinylsiloxane-based GuttaFlow system (n = 15). After 2 weeks, canals were retreated stepwise with size 40-50 EndoSequence 0.04 taper instruments. Micro-CT scans (8 mum) were taken after use of each instrument to detect root filling residue in the coronal, middle and apical segment, and the retreatment time recorded. Residue, expressed as percentage of canal surface area, was compared between groups with t-tests, and within groups with repeated measures anova and Bonferroni-adjusted pairwise comparisons. Retreatment time was analysed with one-way anova. RESULTS: The percentage of sealer residue-coated canal surface was consistently highest (P < 0.001) in the apical third of canals, and it did not differ significantly between the two root filling groups. Stepwise enlargement from size 40 to 50 significantly decreased the amount of sealer residue in both groups (P < 0.001). Retreatment time did not differ significantly between groups. CONCLUSIONS: Both root fillings with ActivGP and GuttaFlow were removed with nickel-titanium rotary instruments. Enlargement of canals up to two sizes beyond the pre-retreatment size was necessary to minimize the amount of sealer remaining.

Analytical performance characteristics and clinical utility of a novel assay for total hepatitis C virus core antigen quantification.

The detection and quantification of hepatitis C virus (HCV) core antigen in serum or plasma by the use of different assay formats have previously been shown to represent useful markers of viral replication. In the present study, the intrinsic performance characteristics and the potential clinical utility of a novel assay for the quantification of total HCV core antigen were comprehensively assessed by using clinical serum samples and specimens contained in various evaluation panels. The Architect HCV Ag assay showed a specificity of 100%. The intra- and interassay coefficients of variation ranged from 3.6 to 8.0% and from 4.7 to 9.5%, respectively. Except for HCV genotype 2 isolates, the analytical sensitivity was always less than 10 fmol core antigen/liter, corresponding to approximately 500 to 3,000 IU of HCV RNA/ml. Linearity was guaranteed throughout the dynamic range (10 to 20,000 fmol/liter). When seroconversion panels were tested, the assay was not inferior to HCV RNA detection and reduced the preseroconversion period by 4 to 16 days. The results obtained by core antigen and HCV RNA quantification for 385 clinical specimens were correlated by regression analysis (r = 0.857), but the calculated conversion equation differed significantly from the line of identity. Monitoring of viral kinetics by use of either core antigen or RNA concentrations in 38 HCV-infected patients undergoing antiviral combination therapy resulted in very similarly shaped curves in all cases. Finally, the Architect HCV Ag assay was also shown to enable high-throughput screening of in vitro HCV RNA replication. With these results taken together, the Architect HCV Ag assay proved to be a specific, reproducible, highly sensitive, and clinically applicable test format which will find its future place in the context of virological HCV diagnostics.

Lack of de novo hepatitis C virus infections and absence of nosocomial transmissions of GB virus C in a large cohort of German haemodialysis patients.

To determine the prevalence and incidence of hepatitis C virus (HCV) infections among haemodialysis patients, a large prospective multicentre trial was conducted in the German Federal State of North Rhine-Westphalia. Sera obtained from the recruited patients in two separate sampling rounds run 1 year apart were analysed for both anti-HCV antibodies and HCV RNA. HCV RNA positive samples were also genotyped by direct sequencing of an HCV core fragment. In the first and second rounds, 150 (5.2%) of 2909 and 114 (5.4%) of 2100 patients were anti-HCV positive, respectively, and 4% of individuals were viraemic. Evaluation of potential risk factors in a case-control study indicated that the factors 'foreign country of birth', 'blood transfusions given before 1991' and 'duration of treatment on haemodialysis' were associated with the risk of HCV infection. Among the 2100 patients of whom 'paired' serum samples from both rounds were available for testing, not a single 'de novo' HCV infection could be recorded. The fact that in a subset of about 20% of these patients no nosocomial GB virus C (GBV-C) transmission occurred during the observational period suggests that the lack of HCV seroconversions was not only attributable to the isolation of HCV-infected patients but also to the strict adherence to so-called universal hygienic precautions for infection control maintained in the participating dialysis centres.