Consensus recommendation for prenatal, neonatal and postnatal management of congenital cytomegalovirus infection from the European congenital infection initiative (ECCI).

Congenital cytomegalovirus (cCMV) infection carries a significant burden with a 0.64% global prevalence and a 17-20% chance of serious long-term effects in children. Since the last guidelines, our understanding, particularly regarding primary maternal infections, has improved. A cCMV guidelines group was convened under the patronage of the European Society of Clinical Virology in April 2023 to refine these insights. The quality and validity of selected studies were assessed for potential biases and the GRADE framework was employed to evaluate quality of evidence across key domains. The resulting recommendations address managing cCMV, spanning prevention to postnatal care. Emphasizing early and accurate maternal diagnosis through serological tests enhances risk management and prevention strategies, including using valaciclovir to prevent vertical transmission. The guidelines also strive to refine personalized postnatal care based on risk assessments, ensuring targeted interventions for affected families.

Faster detection of asymptomatic COVID-19 cases among care home staff in England through the combination of SARS-CoV-2 testing technologies.

To detect SARS-CoV-2 amongst asymptomatic care home staff in England, a dual-technology weekly testing regime was introduced on 23 December 2020. A lateral flow device (LFD) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) test were taken on the same day (day 0) and a midweek LFD test was taken three to four days later. We evaluated the effectiveness of using dual-technology to detect SARS-CoV-2 between December 2020 to April 2021. Viral concentrations derived from qRT-PCR were used to determine the probable stage of infection and likely level of infectiousness. Day 0 PCR detected 1,493 cases of COVID-19, of which 53% were in the early stages of infection with little to no risk of transmission. Day 0 LFD detected 83% of cases that were highly likely to be infectious. On average, LFD results were received 46.3 h earlier than PCR, enabling removal of likely infectious staff from the workplace quicker than by weekly PCR alone. Demonstrating the rapidity of LFDs to detect highly infectious cases could be combined with the ability of PCR to detect cases in the very early stages of infection. In practice, asymptomatic care home staff were removed from the workplace earlier, breaking potential chains of transmission.

Rapid antigen testing for SARS-CoV-2 by lateral flow assay: A field evaluation of self- and professional testing at UK community testing sites.

BACKGROUND: The advent of lateral flow devices (LFDs) for SARS-CoV-2 detection enabled widespread use of rapid self-tests during the pandemic. While self-testing using LFDs is now common, whether self-testing provides comparable performance to professional testing was a key question that remained important for pandemic planning. METHODS: Three prospective multi-centre studies were conducted to compare the performance of self- and professional testing using LFDs. Participants tested themselves or were tested by trained (professional) testers at community testing sites in the UK. Corresponding qRT-PCR test results served as reference standard. The performance of Innova, Orient Gene and SureScreen LFDs by users (self) and professional testers was assessed in terms of sensitivity, specificity, and kit failure (void) rates. Impact of age, sex and symptom status was analysed using logistic regression modelling. RESULTS: 16,617 participants provided paired tests, of which 15,418 were included in the analysis. Self-testing with Innova, Orient Gene or SureScreen LFDs achieved sensitivities of 50 %, 53 % or 72 %, respectively, compared to qRT-PCR. Self and professional LFD testing showed no statistically different sensitivity with respect to corresponding qRT-PCR testing. Specificity was consistently equal to or higher than 99 %. Sex and age had no or only marginal impact on LFD performance while sensitivity was significantly higher for symptomatic individuals. Sensitivity of LFDs increased strongly to up to 90 % with higher levels of viral RNA measured by qRT-PCR. CONCLUSIONS: Our results support SARS-CoV-2 self-testing with LFDs, especially for the detection of individuals whose qRT-PCR tests showed high viral concentrations.

Swab pooling enables rapid expansion of high-throughput capacity for SARS-CoV-2 community testing.

BACKGROUND: The challenges of rapid upscaling of testing capacity were a major lesson from the COVID-19 pandemic response. The need for process adjustments in high-throughput testing laboratories made sample pooling a challenging option to implement. OBJECTIVE: This study aimed to evaluate whether pooling samples at source (swab pooling) was as effective as qRT-PCR testing of individuals in identifying cases of SARS-CoV-2 in real-world community testing conditions using the same high-throughput pipeline. METHODS: Two cohorts of 10 (Pool10: 1,030 participants and 103 pools) and 6 (Pool6: 1,284 participants and 214 pools) samples per pool were tested for concordance, sensitivity, specificity, and Ct value differences with individual testing as reference. RESULTS: Swab pooling allowed unmodified application of an existing high-throughput SARS-Cov-2 testing pipeline with only marginal loss of accuracy. For Pool10, concordance was 98.1% (95% Confidence interval: 93.3-99.8%), sensitivity was 95.7% (85.5-99.5%), and specificity was 100.0% (93.6-100.0%). For Pool6, concordance was 97.2% (94.0-99.0%), sensitivity was 97.5% (93.7-99.3%), and specificity was 96.4% (87.7-99.6%). Differences of outcomes measure between pool size were not significant. Most positive individual samples, which were not detected in pools, had very low viral concentration. If only individual samples with a viral concentration > 400 copies/ml (i.e. Ct value < 30) were considered positive, the overall sensitivity of pooling increased to 99.5%. CONCLUSION: The study demonstrated high sensitivity and specificity by swab pooling and the immediate capability of high-throughput laboratories to implement this method making it an option in planning of rapid upscaling of laboratory capacity for future pandemics.

Performance of antigen lateral flow devices in the UK during the alpha, delta, and omicron waves of the SARS-CoV-2 pandemic: a diagnostic and observational study.

BACKGROUND: Antigen lateral flow devices (LFDs) have been widely used to control SARS-CoV-2. We aimed to improve understanding of LFD performance with changes in variant infections, vaccination, viral load, and LFD use, and in the detection of infectious individuals. METHODS: In this diagnostic study, paired LFD and RT-PCR test results were prospectively collected from asymptomatic and symptomatic participants in the UK between Nov 4, 2020, and March 21, 2022, to support the National Health Service (NHS) England's Test and Trace programme. The LFDs evaluated were the Innova SARS-CoV-2 Antigen Rapid Qualitative Test, the Orient Gene Rapid Covid-19 (Antigen) Self-Test, and the Acon Flowflex SARS-CoV-2 Antigen Rapid Test (Self-Testing). Test results were collected across various community testing settings, including predeployment testing sites, routine testing centres, homes, schools, universities, workplaces, targeted community testing, and from health-care workers. We used multivariable logistic regression to analyse LFD sensitivity and specificity using RT-PCR as a reference standard, adjusting for viral load, LFD manufacturer, test setting, age, sex, test assistance, symptom status, vaccination status, and SARS-CoV-2 variant. National contact tracing data from NHS Test and Trace (Jan 1, 2021, to Jan 11, 2022) were used to estimate the proportion of transmitting index patients (with ≥1 RT-PCR-positive or LFD-positive contact) potentially detectable by LFDs (specifically Innova, as the most widely used LFD) with time, accounting for index viral load, variant, and symptom status. FINDINGS: We assessed 75 382 pairs of LFD and RT-PCR tests. Of these, 4131 (5·5%) were RT-PCR-positive. LFD sensitivity versus RT-PCR was 63·2% (95% CI 61·7-64·6) and specificity was 99·71% (95% CI 99·66-99·74). Increased viral load was independently associated with being LFD positive (adjusted odds ratio [aOR] 2·85 [95% CI 2·66-3·06] per 1 log10 copies per mL increase; p<0·0001). There was no evidence that LFD sensitivity differed for delta (B.1.617.2) infections versus alpha (B.1.1.7) or pre-alpha (B.1.177) infections (aOR 1·00 [0·69-1·45]; p=0·99), whereas omicron (BA.1 or BA.2) infections appeared more likely to be LFD positive (aOR 1·63 [1·02-2·59]; p=0·042). Sensitivity was higher in symptomatic participants (68·7% [95% CI 66·9-70·4]) than in asymptomatic participants (52·8% [50·1-55·4]). Among 347 374 unique index patients with probable onward transmission, 78·3% (95% CI 75·3-81·2) were estimated to have been detectable with LFDs (Innova), and this proportion was mostly stable with time and for successive variants. Overall, the estimated proportion of infectious index patients detectable by the Innova LFD was lower in asymptomatic patients (57·6% [53·6-61·9]) versus symptomatic patients (79·7% [76·7-82·5]). INTERPRETATION: LFDs remained able to detect most SARS-CoV-2 infections throughout vaccine roll-out and across different viral variants. LFDs can potentially detect most infections that transmit to others and reduce the risk of transmission. However, performance is lower in asymptomatic individuals than in symptomatic individuals. FUNDING: UK Health Security Agency, the UK Government Department of Health and Social Care, National Institute for Health Research (NIHR) Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, and the University of Oxford NIHR Biomedical Research Centre.

Genetic stability of SIV Gag/Tat gene inserted into Del-II in modified vaccinia virus ankara after serial passage of recombinant vector in pCEFs cells.

Modified vaccinia virus Ankara (MVA) is an attenuated vaccinia virus with restricted replication in human cells. The virus serves as an ideal vaccine vector suitable for safe use even in immune-compromised individuals. With its inherently large packaging capacity, expression cassettes encoding bulky genes can be inserted into deletion regions within the MVA genome. These deletion sites develop during the process of the attenuation of the virus by passage in Chicken Embryo Fibroblasts (pCEFs). Transgene stability in MVA is important to assure immunogenicity and efficacy. In the present study, we assessed the effect of substantial passage of recombinant MVA vectors on the stability of expression cassette encoding SIV Gag/Tat genes inserted at the Del-II site, as part of generating a vaccine to protect from HIV. Our data indicated that after 15 passages there was a significant loss or mutation of the inserted genes.

High throughput diagnostics and dynamic risk assessment of SARS-CoV-2 variants of concern.

BACKGROUND: The rise of new SARS-CoV-2 variants worldwide requires global molecular surveillance strategies to support public health control. Early detection and evaluation of their associated risk of spreading within the population are pivotal. METHODS: Between April 2020 and February 2021, the UK Lighthouse Labs Network at Alderley Park tested more than eight million nose and throat swab samples for the presence of SARS-CoV-2, via PCR. The assay targeted three genomic regions of the virus: N, Orf1ab and S. Whole-genome next-generation sequencing was used to confirm positive PCR results. Positive results were mapped using the postal district origin of samples to allow real-time tracking of the spread of a new variant through the UK. FINDINGS: In mid-November 2020, the assay identified an increasing number of S gene negative, N and Orf1ab positive samples. Whole-genome sequencing demonstrated that the loss of S gene detection was due to the appearance of a SARS-CoV-2 lineage (B.1.1.7) designated as Variant of concern (VOC) 202012/01. By the beginning of January 2021, the new SARS-CoV-2 VOC comprised 70% of daily positive samples tested at Alderley Park and ∼98% by the end of February 2021. INTERPRETATION: The timeline view identified the rapid spread of the new SARS-CoV-2 variant across England during the first three weeks of December. Coupling high-throughput diagnostics and molecular surveillance was pivotal to the early detection of the spread of this variant. The availability of real-time tracking of an emerging variant is an important new tool to inform decision-making authorities for risk mitigation. In a respiratory pandemic, a tool for the timely response to the emergence and spread of a novel variant is vital, even more so when a variant is associated with the enhanced transmission, as has occurred with VOC 202012/01. FUNDING: None.

Recommendations for the introduction of metagenomic high-throughput sequencing in clinical virology, part I: Wet lab procedure.

Metagenomic high-throughput sequencing (mHTS) is a hypothesis-free, universal pathogen detection technique for determination of the DNA/RNA sequences in a variety of sample types and infectious syndromes. mHTS is still in its early stages of translating into clinical application. To support the development, implementation and standardization of mHTS procedures for virus diagnostics, the European Society for Clinical Virology (ESCV) Network on Next-Generation Sequencing (ENNGS) has been established. The aim of ENNGS is to bring together professionals involved in mHTS for viral diagnostics to share methodologies and experiences, and to develop application recommendations. This manuscript aims to provide practical recommendations for the wet lab procedures necessary for implementation of mHTS for virus diagnostics and to give recommendations for development and validation of laboratory methods, including mHTS quality assurance, control and quality assessment protocols.

International external quality assessment for SARS-CoV-2 molecular detection and survey on clinical laboratory preparedness during the COVID-19 pandemic, April/May 2020.

Laboratory preparedness with quality-assured diagnostic assays is essential for controlling the current coronavirus disease (COVID-19) outbreak. We conducted an external quality assessment study with inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) samples to support clinical laboratories with a proficiency testing option for molecular assays. To analyse SARS-CoV-2 testing performance, we used an online questionnaire developed for the European Union project RECOVER to assess molecular testing capacities in clinical diagnostic laboratories.

Post-transplant lymphoproliferative disorder in adult renal transplant recipients: survival and prognosis.

Post-transplant lymphoproliferative disorder (PTLD) is a rare, serious complication following solid organ transplantation, with an incidence of 2.6 cases per 1000 patient years. Optimal treatment strategies and risk stratifications specific to kidney transplantation are lacking and PTLD mortality remains high. This study investigated survival and prognosis in 89 cases of PTLD presenting over 44 years at Manchester Royal Infirmary. Patient survival following diagnosis was 72% at 6 months, 67% at 1 year and 54% at 3 years. In multivariate analysis, a poorer 3 year survival was associated with acute kidney injury at diagnosis (p = 0.0001), impaired renal function (p = 0.04), early onset (p = 0.02), T cell disease (p = 0.02) and previous treatment with anti-thymocyte globulin (p = 0.04). The inclusion of graft function adds prognostic value to risk stratification and should be explored further. Strategies to improve survival should include timing and choice of immuno-chemotherapy, preparation for dialysis and aggressive surveillance for sepsis and treatment toxicity.

Single and multiple respiratory virus infections and severity of respiratory disease: a systematic review.

INTRODUCTION: There are suggestions that virus co-infections may influence the clinical outcome of respiratory virus illness. We performed a systematic review of the literature to summarise the evidence. METHODS: MEDLINE, EMBASE, Ovid and WEB of Science databases, major organisation websites and reference lists of published studies were searched. The quality of studies was assessed using the STROBE tool (von Elm et al., 1) Individual study data was analyzed using odds ratios and 95% confidence intervals as a measure of association between exposure (co-infection), patient outcome and results summarised using forest plots and tables RESULTS: Nineteen (19) studies from all over the world were identified and included in the review. Most of the studies 73.7% (14/19) recruited children ≤ 6 years old. Evidence on the role of co-infection in increasing disease severity was inconclusive. In five out of eight studies, co-infection significantly increased risk of admission to general ward (OR: 2.4, 95% CI: 1.3 - 4.4, p = 0.005; OR: 2.4, 95% CI: 1.1 - 7.7, P = 0.04; OR: 3.1, 95% CI: 2.0 - 5.1, p = <0.001; OR: 2.4, 95% CI: 1.7-3.4, p = <0.0001 and OR: 2.3, 95% CI: 1.1 - 5.1, p = 0.34), one found it did not (OR: 0.59, 95% CI: 0.4 - 0.9, p = 0.02) and the other 2 had insignificant results. Similarly on risk of admission to ICU, some studies found that co-infection significantly increased risk of admission to ICU (OR: 2.9, 95% CI: 1.4 - 5.9, p = 0.004 and OR: 3.0, 95% CI: 1.7 - 5.6, p = <0.0001), whereas others did not (OR: 0.18, 95% CI: 0.05 - 0.75, p = 0.02 and OR: 0.3, 95% CI: 0.2 - 0.6, p = <0.0001). There was no evidence for or against respiratory virus co-infections and risk of bronchiolitis or pneumonia. CONCLUSION: The influence of co-infections on severe viral respiratory disease is still unclear. The observed conflict in outcomes could be because they were conducted in different seasons and covered different years and periods. It could also be due to bias towards the null, especially in studies where only crude analysis was conducted. Future studies should employ stratified analysis.

Viral CNS infections in children from a malaria-endemic area of Malawi: a prospective cohort study.

BACKGROUND: Fever with reduced consciousness is an important cause of hospital admission of children in sub-Saharan Africa, with high mortality. Cerebral malaria, diagnosed when acute Plasmodium falciparum infection and coma are recorded with no other apparent reason, is one important cause. We investigated whether viruses could also be an important cause of CNS infection in such patients, and examined the relative contribution of viral pathogens and malaria parasitaemia. METHODS: We did a prospective cohort study in Blantyre, Malawi. From March 1, 2002, to Aug 31, 2004, we enrolled children aged between 2 months and 15 years who were admitted to hospital with suspected non-bacterial CNS infections. Children with a cerebrospinal fluid (CSF) white cell count of less than 1000 cells per µL and negative bacterial microscopy and culture were deemed to have suspected viral CNS infection. Blood was examined for asexual forms of P falciparum. PCR was done on CSF or on post-mortem brain biopsy specimens to detect 15 viruses known to cause CNS infection. FINDINGS: Full outcome data were available for 513 children with suspected viral CNS infection, of whom 94 (18%) died. 163 children (32%) had P falciparum parasitaemia, of whom 34 (21%) died. At least one virus was detected in the CNS in 133 children (26%), of whom 43 (33%) died. 12 different viruses were detected; adenovirus was the most common, affecting 42 children; mumps, human herpes virus 6, rabies, cytomegalovirus, herpes simplex virus 1, and enterovirus were also important. 45 (9%) of the 513 children had both parasitaemia and viral infection, including 27 (35%) of 78 diagnosed clinically with cerebral malaria. Children with dual infection were more likely to have seizures than were those with parasitaemia alone, viral infection only, or neither (p<0·0001). 17 (38%) of the 45 children with dual infection died, compared with 26 (30%) of 88 with viral infection only, 17 (14%) of 118 with parasitaemia only, and 34 (13%) of 262 with neither (p<0·0001). Logistic regression showed children with a viral CNS infection had a significantly higher mortality than did those who did not have a viral CNS infection (p=0·001). INTERPRETATION: Viral CNS infections are an important cause of hospital admission and death in children in Malawi, including in children whose coma might be attributed solely to cerebral malaria. Interaction between viral infection and parasitaemia could increase disease severity. FUNDING: Wellcome Trust, US National Institutes of Health, and UK Medical Research Council.

Influenza A viruses dual and multiple infections with other respiratory viruses and risk of hospitalisation and mortality.

INTRODUCTION: Recent literature suggests that dual or multiple virus infections may affect disease severity. However, few studies have investigated the effect of co-infection with influenza A viruses. OBJECTIVES: To identify the association between influenza A and respiratory viruses co-infections with disease outcome. METHODOLOGY: Data for samples from North West England tested between January 2007 and June 2011 was analysed for patterns of co-infection between influenza A viruses and eight respiratory viruses. Risk of hospitalisation to ICU or general ward in single versus co-infections was assessed using logistic regression. RESULTS: Of the 25,596 samples analysed for respiratory viruses 40·7% (10,501) were positive for any virus. Co-infections were detected in 4·7% (137/2879) of all patients with influenza A(H1N1)pdm09, and 7·3% (57/779) of those with other influenza A virus infections. Co-infection between seasonal influenza A viruses and influenza B virus was associated with a significant increase in the risk of admission to ICU/death (OR: 22·0, 95% CI: 2·21-219·8, P=0·008). Respiratory syncytial virus/influenza A (RSV/Flu A) co-infection also increased this risk but was not statistically significant. For influenza A(H1N1)pdm09, RSV and AdV co-infection increased risk of hospitalisation to general ward whereas Flu B increased risk of admission to ICU, but none of these were statistically significant. CONCLUSION: Co-infection is a significant predictor of disease outcome; combined treatment, introduction of an integrated vaccine for all respiratory viruses and development of multi-target rapid diagnostic tests is recommended. Integration of respiratory viruses' co-infections into public health reports could also contribute to the accumulation of evidence.

Epidemiology of posttransplantation lymphoproliferative disorder in adult renal transplant recipients.

BACKGROUND: There is little information in the literature describing the relationship between posttransplantation lymphoproliferative disorder (PTLD) incidence and presentation with both recipient Epstein-Barr virus (EBV) serostatus and EBV status of PTLD histology, particularly in the late posttransplantation period. METHODS: This study reports the largest UK single-center, single-organ analysis of PTLD to date in a retrospective cohort study of 80 cases occurring in 4189 adult renal transplant recipients. RESULTS: The incidence rate was 2.6 cases per 1000 patient-years (95% confidence interval [95% CI], 2.1-3.2) for PTLD, 1.8 (95% CI, 1.4-2.4) for non-Hodgkin's lymphoma, and 0.2 (95% CI, 0.07-4.2) for Hodgkin's lymphoma. Non-Hodgkin's lymphoma occurred at a rate 7.6 times that of the adult general population in England, whereas the rate for Hodgkin's lymphoma was 5.9 times. The incidence of PTLD was highest during the 10th to 14th posttransplantation years. Early-onset disease was associated with EBV-seronegative recipient status, EBV-positive histology, and the involvement of extranodal sites. PTLD occurring in EBV-seronegative recipients was associated with EBV nuclear antigen antibody deficiency, polymorphic disease, and the involvement of extranodal sites. EBV-negative histology occurred in 32% of cases at a median time to presentation of 109 months. PTLD involving the allograft, central nervous system, and skin was uncommon and occurred late. CONCLUSION: The incidence of PTLD is highest in the late posttransplantation period. Close clinical surveillance and education for transplant recipients is required for the duration of time while immunosuppressed. Failure to detect EBV DNA in blood should not reassure, particularly in patients with symptoms such as abdominal pain, oropharyngeal complaints, neck lumps, and B-symptoms.

Merkel cell polyomavirus DNA in immunocompetent and immunocompromised patients with respiratory disease.

Merkel cell polyomavirus (MCPyV) was identified originally in association with a rare but aggressive skin cancer, Merkel cell carcinoma. The virus has since been found in the respiratory tract of some patients with respiratory disease. However, the role of MCPyV in the causation of respiratory disease has not been established. To determine the prevalence of MCPyV in 305 respiratory samples from immunocompetent and immunocompromised patients and evaluate their contribution to respiratory diseases, specimens were screened for MCPyV using single, multiplex, or real-time PCR; co-infection with other viruses was examined. Of the 305 samples tested, 10 (3.27%) were positive for MCPyV. The virus was found in two groups of patients: in 6 (2%) nasopharyngeal aspirate samples from children aged 26 days to 7 months who were immunocompetent; and in 4 (1.3%) of nasopharyngeal aspirate samples taken from patients aged 41 to 69 years who were severely immunosuppressed from leukemia or transplant therapy. Both groups had upper or lower respiratory tract infection. Co-infections with other viruses were found in 30% of the MCPyV positive samples. The data present a pattern of infection similar to that seen with the polyomaviruses JC and BK in which the virus is acquired during childhood, probably by the respiratory route. The viruses then establish latency and become reactivated in the event of immunosuppression.

Evidence of simian virus 40 infection in multiple organ transplant recipients with renal dysfunction.

Electron microscopy (EM), real-time polymerase chain reaction (PCR) and conventional PCR were used to identify viruses associated with infection in 2 transplantation patients. An autologous haematopoietic stem cell, liver and renal transplant recipient was found to be positive for simian virus 40 (SV40). Dual BK virus and SV40 infection was found in a heart and renal transplantation patient. SV40 infection can occur in immunocompromised patients.

Planning for the healthcare burden of hepatitis C infection: Hepatitis C genotypes identified in England, 2002-2007.

BACKGROUND: Identification of HCV genotype is a prerequisite for anti-viral treatment in England. Treatment length and sustained virological response rates vary by genotype. Therefore knowledge of circulating HCV genotypes is important for health-care providers. OBJECTIVES: To describe the HCV genotypes identified in English laboratories and to investigate changes over time; sub-analysis of young adults (15-24 years) to provide information on recently circulating genotypes. STUDY DESIGN: Data from the national reference laboratory and 19 English laboratories participating in the sentinel surveillance of hepatitis testing study were analysed. Multinomial regression was used to investigate trends in genotypes identified between 2002 and 2007. RESULTS: HCV genotypes were available for 18,031 individuals. The majority (89%) of people were genotypes 1 and 3; 3a was the single largest subtype. Half of people born between 1960 and 1989 were genotype 3a and the majority of South Asian people were genotype 3a. People born pre-1940 were nine times more likely to have genotype 1b than 3a. The proportion of 1b infections, relative to 3a, declined over time, but, after adjusting for birth cohort, this effect disappeared. There was no evidence of a relative change in 1a infections. CONCLUSIONS: This is the largest study of genotypes identified in England to date. Changes in genotypes over time were due to decreased genotyping of older individuals. As the population ages, the proportion of more difficult to treat genotypes may decline, leading to possible cost-savings for health-care providers, with a higher chance of achieving sustained virological response.