Evaluation of Alere i RSV for Rapid Detection of Respiratory Syncytial Virus in Children Hospitalized with Acute Respiratory Tract Infection

A Genome-Wide Association Study of Respiratory Syncytial Virus Infection Severity in Infants

BACKGROUND

Respiratory syncytial virus (RSV) is a significant cause of infant morbidity and mortality worldwide. Most children experience at least one 1 RSV infection by the age of two 2 years, but not all develop severe disease. However, the understanding of genetic risk factors for severe RSV is incomplete. Consequently, we conducted a genome-wide association study of RSV severity.

METHODS

Disease severity was assessed by the ReSVinet scale, in a cohort of 251 infants aged 1 week to 1 year. Genotyping data were collected from multiple European study sites as part of the RESCEU Consortium. Linear regression models were used to assess the impact of genotype on RSV severity and gene expression as measured by microarray.

RESULTS

While no SNPs reached the genome-wide statistical significance threshold (P < 5 × 10-8), we identified 816 candidate SNPs with a P-value of <1 × 10-4. Functional annotation of candidate SNPs highlighted genes relevant to neutrophil trafficking and cytoskeletal functions, including LSP1 and RAB27A. Moreover, SNPs within the RAB27A locus significantly altered gene expression (false discovery rate, FDR P < .05).

CONCLUSIONS

These findings may provide insights into genetic mechanisms driving severe RSV infection, offering biologically relevant information for future investigations.

Summarizing Study Characteristics and Diagnostic Performance of Commercially Available Tests for Respiratory Syncytial Virus: A Scoping Literature Review in the COVID-19 Era

BACKGROUND

Nonpharmaceutical interventions to prevent the spread of coronavirus disease 2019 also decreased the spread of respiratory syncytial virus (RSV) and influenza. Viral diagnostic testing in patients with respiratory tract infections (RTI) is a necessary tool for patient management; therefore, sensitive and specific tests are required. This scoping literature review aimed to summarize the study characteristics of commercially available sample-to-answer RSV tests.

CONTENT

PubMed and Embase were queried for studies reporting on the diagnostic performance of tests for RSV in patients with RTI (published January 2005-January 2021). Information on study design, patient and setting characteristics, and published diagnostic performance of RSV tests were extracted from 77 studies that met predefined inclusion criteria. A literature gap was identified for studies of RSV tests conducted in adult-only populations (5.3% of total subrecords) and in outpatient (7.5%) or household (0.8%) settings. Overall, RSV tests with analytical time >30 min had higher published sensitivity (62.5%-100%) vs RSV tests with analytical time ≤30 min (25.7%-100%); this sensitivity range could be partially attributed to the different modalities (antigen vs molecular) used. Molecular-based rapid RSV tests had higher published sensitivity (66.7%-100%) and specificity (94.3%-100%) than antigen-based RSV tests (sensitivity: 25.7%-100%; specificity:80.3%-100%).

SUMMARY

This scoping review reveals a paucity of literature on studies of RSV tests in specific populations and settings, highlighting the need for further assessments. Considering the implications of these results in the current pandemic landscape, the authors preliminarily suggest adopting molecular-based RSV tests for first-line use in these settings.

[Association of temperament type and mother's emotional state with acute respiratory infection in children]

OBJECTIVE

To explore the correlation of temperament type and mother's emotional state with acute respiratory tract infections in children so as to provide evidence for comprehensive treatment of the infections.

METHODS

A total of 200 children aged between 3 and 6 were enrolled in this study from two kindergartens of Guangzhou and Hengyang. The mothers were invited to complete a questionnaire of the children's general information followed by assessment using children's temperament scale and the Depression-Anxiety-Stress Scale.

RESULTS

The total incidence of acute respiratory infection was significantly higher in children with a hard- to-raise temperament than the easy- to-raise children (P < 0.05); the incidences of acute rhinitis, acute pharyngitis, acute laryngitis and acute bronchitis were all significantly higher in the hard-to-raise children (P < 0.05). A significant positive correlation was identified between the total number of episodes of acute respiratory tract infection in children and their mothers' stress and anxiety levels (P < 0.01). Acute rhinitis and acute tracheitis in the children were both positively correlated with the mothers' stress scores (P < 0.05), while acute pharyngitis and acute laryngitis were positively correlated with the mothers' anxiety scores (P < 0.05), while acute bronchitis was positively correlated with the mothers' stress and anxiety scores (P < 0.05). Multiple linear regression analysis with the factors influencing the types of acute respiratory tract infections in children as the independent variables suggested that the easy-to-raise type of temperament was a protective factor against acute rhinitis in children (P < 0.05), while mothers' anxiety was a risk factor of acute laryngitis in children (P < 0.05); the mothers' stress was a risk factor for acute bronchitis in children (P < 0.05).

CONCLUSION

Acute respiratory tract infection in children is closely related to the temperament type of the children and the emotional state of the mothers, which are important therapeutic targets in comprehensive interventions of acute respiratory tract infection in children.

Investigating protein translocation in the presence of an electrolyte concentration gradient across a solid-state nanopore

Electrolyte chemistry plays an important role in the transport properties of analytes through nanopores. Here, we report the translocation properties of the protein human serum transferrin (hSTf) in asymmetric LiCl salt concentrations with either positive (C_trans /C_cis < 1) or negative chemical gradients (C_trans /C_cis > 1). The cis side concentration was fixed at 4 M for positive chemical gradients and at 0.5 M LiCl for negative chemical gradients, while the trans side concentration varied between 0.5 to 4 M which resulted in six different configurations, respectively, for both positive and negative gradient types. For positive chemical gradient conditions, translocations were observed in all six configurations for at least one voltage polarity whereas with negative gradient conditions, dead concentrations where no events at either polarity were observed. The flux of Li⁺ and Cl^- ions and their resultant cation or anion enrichment zones, as well as the interplay of electrophoretic and electroosmotic transport directions, would determine whether hSTf can traverse across the pore.

Advanced Point-of-Care Testing Technologies for Human Acute Respiratory Virus Detection

The ever-growing global threats to human life caused by the human acute respiratory virus (RV) infections have cost billions of lives, created a significant economic burden, and shaped society for centuries. The timely response to emerging RVs could save human lives and reduce the medical care burden. The development of RV detection technologies is essential for potentially preventing RV pandemic and epidemics. However, commonly used detection technologies lack sensitivity, specificity, and speed, thus often failing to provide the rapid turnaround times. To address this problem, new technologies are devised to address the performance inadequacies of the traditional methods. These emerging technologies offer improvements in convenience, speed, flexibility, and portability of point-of-care test (POCT). Herein, recent developments in POCT are comprehensively reviewed for eight typical acute respiratory viruses. This review discusses the challenges and opportunities of various recognition and detection strategies and discusses these according to their detection principles, including nucleic acid amplification, optical POCT, electrochemistry, lateral flow assays, microfluidics, enzyme-linked immunosorbent assays, and microarrays. The importance of limits of detection, throughput, portability, and specificity when testing clinical samples in resource-limited settings is emphasized. Finally, the evaluation of commercial POCT kits for both essential RV diagnosis and clinical-oriented practices is included.

Evaluation of the ImmuView RSV Test for Rapid Detection of Respiratory Syncytial Virus in Adult Patients with Influenza-Like Symptoms

Rapid antigen tests may enhance the diagnostic yield of respiratory syncytial virus (RSV) infections, but studies have shown low sensitivity in adults. We evaluated the novel ImmuView RSV test in adult patients with influenza-like symptoms who were prospectively enrolled at three emergency departments in two Swedish hospitals during two influenza seasons, 2017 to 2018 and 2018 to 2019. The ImmuView RSV test was performed on nasopharyngeal swabs and results were compared to those of the BinaxNOW RSV test. In the first season, tests were performed on frozen samples, while unfrozen samples were used in the second season. For comparison, tests were also performed on selected samples from children. Of 333 included adult patients, the sensitivity of ImmuView and BinaxNOW was 27% for both tests and specificities were 98% and 100%, respectively. The interassay agreement was good (κ = 0.61). There was no significant difference in test performance between frozen and unfrozen samples. In samples from children, the sensitivities of ImmuView and BinaxNOW were 67% and 70%, respectively. In conclusion, the ImmuView RSV test showed low sensitivity and high specificity for identifying RSV in adult patients with influenza-like symptoms, comparable with the BinaxNOW RSV test. Rapid RSV testing is of limited value for diagnosing RSV infection in adults. IMPORTANCE By timely RSV diagnosis among patients with influenza-like symptoms, especially when influenza diagnostics turn negative, it is possible to prevent unnecessary antibiotic usage as well as reduce diagnostic testing, nosocomial transmission, and hospital stay. Previous rapid RSV tests have demonstrated poor sensitivity in adults, and we could demonstrate that the novel ImmuView RSV test similarly showed limited value for diagnosing RSV infection in adult patients. However, in contrast to many other studies, we investigated patient characteristics in cases with false-positive tests and we compared the performance between unfrozen and frozen samples. Thus, our results are important, as they generate new knowledge about rapid antigen tests.

Analysis of the Effect of Nursing Intervention on Children with Respiratory Tract Infection Based on Comprehensive Nursing

Recurrent respiratory tract infections in children are common. It means that children are repeatedly exposed to external pathogens within a certain time, and the clinical symptoms are reciprocating. This article carries out nursing intervention on children's respiratory tract infection through comprehensive nursing methods and analyzes the intervention effect. Moreover, this paper uses a controlled trial to study the nursing methods of recurrent respiratory tract infections in children. In addition, this paper determines and screens test samples according to relevant standards, conducts different nursing methods on samples of different groups, and compares them with the same indicators. Finally, this paper combines mathematical statistics to make statistics of experimental results and draws tables and statistical graphs. By comparing multiple parameters, it can be seen that the comprehensive nursing intervention has a good effect on the nursing of children with respiratory tract infection compared with the traditional nursing intervention, so this nursing method can be expanded in the future.

Describing global pediatric RSV disease at intensive care units in GAVI-eligible countries using molecular point-of-care diagnostics: the RSV GOLD-III study protocol

Background

Respiratory syncytial virus (RSV) infection is an important cause of hospitalization and death in young children. The majority of deaths (99%) occur in low- and lower-middle-income countries (LMICs). Vaccines against RSV infection are underway. To obtain access to RSV interventions, LMICs depend on support from Gavi, the Vaccine Alliance. To identify future vaccine target populations, information on children with severe RSV infection is required. However, there is a lack of individual patient-level clinical data on instances of life-threatening RSV infection in LMICs. The RSV GOLD III—ICU Network study aims to describe clinical, demographic and socioeconomic characteristics of children with life-threatening RSV infection in Gavi-eligible countries.

Methods

The RSV GOLD-III—ICU Network study is an international, prospective, observational multicenter study and will be conducted in 10 Gavi-eligible countries at pediatric intensive care units and high-dependency units (PICUs/HDUs) during local viral respiratory seasons for 2 years. Children younger than 2 years of age with respiratory symptoms fulfilling the World Health Organization (WHO) “extended severe acute respiratory infection (SARI)” case definition will be tested for RSV using a molecular point-of-care (POC) diagnostic device. Patient characteristics will be collected through a questionnaire. Mortality rates of children admitted to the PICU and/or HDU will be calculated.

Discussion

This multicenter descriptive study will provide a better understanding of the characteristics and mortality rates of children younger than 2 years with RSV infection admitted to the PICU/HDU in LMICs. These results will contribute to knowledge on global disease burden and awareness of RSV and will directly guide decision makers in their efforts to implement future RSV prevention strategies.

Trial registration number: NL9519, May 27, 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06544-3.

Low Sensitivity of BinaxNOW RSV in Infants

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of hospitalization in infants. Early detection of RSV can optimize clinical management and minimize use of antibiotics. BinaxNOW RSV (BN) is a rapid antigen detection test that is widely used. We aimed to validate the sensitivity of BN in hospitalized and nonhospitalized infants against the gold standard of molecular diagnosis.

METHODS

We evaluated the performance of BN in infants with acute respiratory tract infections with different degrees of disease severity. Diagnostic accuracy of BN test results were compared with molecular diagnosis as reference standard.

RESULTS

One hundred sixty-two respiratory samples from 148 children from October 2017 to February 2019 were studied. Sixty-six (40.7%) samples tested positive for RSV (30 hospitalizations, 31 medically attended episodes not requiring hospitalization, and 5 nonmedically attended episodes). Five of these samples tested positive with BN, leading to an overall sensitivity of BN of 7.6% (95% confidence interval [CI], 3.3%-16.5%) and a specificity of 100% (95% CI, 96.2%-100%). Sensitivity was low in all subgroups.

CONCLUSIONS

We found a low sensitivity of BN for point-of-care detection of RSV infection. BinaxNOW RSV should be used and interpreted with caution.

Seasonality of Respiratory Syncytial Virus Hospitalization

Seasonality of respiratory syncytial virus (RSV) infection is an area of limited knowledge. In this study, we set out to get insight into the epidemic characteristics of RSV. We retrospectively evaluated medical files of 512 hospitalizations in children due to RSV infection from January 2010 to July 2017. In this cohort of patients, there were 96.3% of children below 1 year of age; the median age was 2.8 months. The influence of weather condition during the week of hospitalization (WH) and also the preceding week (WP) on the rate of hospitalizations was also assessed. An overview of morbidity data demonstrates that the epidemic RSV season started from Week 50 of a year and lasts until Week 15 of the following year, with a peak between Week 4 and Week 10. The average monthly percentage rate of morbidity per year was as follows: December, 12.3%; January, 24.5%; February, 29%; and March, 21.7%. Hospitalizations were positively associated with the minimum and maximum outside air temperature during the WH (62.5% and 59.7%, respectively) and the WP (64.3% and 63.4%, respectively) and with relative humidity (WH 23% and WP 29.8%). A weak association with the wind speed was also noticed (WH 22% and WP 21%), while there was no influence of the level of atmospheric pressure on RSV morbidity. We conclude that seasonality of RSV is present between December and April each year, and morbidity is mostly influenced by minimum-maximum outside air temperature changes. Further epidemiological exploration is required to get a better knowledge on both active and passive immunization against RSV.

Diagnostic and economic evaluation of a point-of-care test for respiratory syncytial virus

Respiratory syncytial virus is a common cause of bronchiolitis. Historically, point-of-care tests have involved antigen detection technology with limited sensitivity. The aim of this study was to prospectively evaluate the diagnostic accuracy and model the economic impact of the Roche cobas® Liat® point-of-care influenza A/B and respiratory syncytial virus test.

The “DEC-RSV” study was a multi-centre, prospective, observational study in children under 2 years presenting with viral respiratory symptoms. A nasopharyngeal aspirate sample was tested using the point-of-care test and standard laboratory-based procedures. The primary outcome was accuracy of respiratory syncytial virus detection. The cost implications of adopting a point-of-care test were modelled using study data.

A total of 186 participants were recruited, with both tests performed on 177 samples. The point-of-care test was invalid for 16 samples (diagnostic yield 91%) leaving 161 available for primary analysis. After resolving discrepancies, the cobas® Liat® respiratory syncytial virus test had 100.00% (95% CI 96.07%–100.00%) sensitivity and 98.53% (95% CI 92.08%–99.96%) specificity. Median time to result was 0.6 h (interquartile range (IQR) 0.5–1) for point-of-care testing and 28.9 h (IQR 26.3–48.1) for standard laboratory testing. Estimated non-diagnostic cost savings for 1000 patients, based on isolation decision-making on point-of-care test result, were £57 010, which would increase to £94 847 when cohort nursing is used.

In young children the cobas® Liat® point-of-care respiratory syncytial virus test has high diagnostic accuracy using nasopharyngeal aspirates (currently an off-licence sample type). Time to result is clinically important and was favourable compared to laboratory-based testing. The potential exists for cost savings when adopting the point-of-care test.

This prospective evaluation of the cobas Liat point-of-care RSV test in children demonstrated high diagnostic accuracy using nasopharyngeal aspirate samples, with favourable time to result compared to usual laboratory-based testing procedureshttps://bit.ly/2yKKmUB

Rapid diagnostic tests for infectious diseases in the emergency department

Background

Rapid diagnostic tests (RDTs) for infectious diseases, with a turnaround time of less than 2 hours, are promising tools that could improve patient care, antimicrobial stewardship and infection prevention in the emergency department (ED) setting. Numerous RDTs have been developed, although not necessarily for the ED environment. Their successful implementation in the ED relies on their performance and impact on patient management.

Objectives

The aim of this narrative review was to provide an overview of currently available RDTs for infectious diseases in the ED.

Sources

PubMed was searched through August 2019 for available studies on RDTs for infectious diseases. Inclusion criteria included: commercial tests approved by the US Food and Drug Administration (FDA) or Conformité Européenne (CE) in vitro diagnostic devices with data on clinical samples, ability to run on fully automated systems and result delivery within 2 hours.

Content

A nonexhaustive list of representative commercially available FDA- or CE-approved assays was categorized by clinical syndrome: pharyngitis and upper respiratory tract infection, lower respiratory tract infection, gastrointestinal infection, meningitis and encephalitis, fever in returning travellers and sexually transmitted infection, including HIV. The performance of tests was described on the basis of clinical validation studies. Further, their impact on clinical outcomes and anti-infective use was discussed with a focus on ED-based studies.

Implications

Clinicians should be familiar with the distinctive features of each RDT and individual performance characteristics for each target. Their integration into ED work flow should be preplanned considering local constraints of given settings. Additional clinical studies are needed to further evaluate their clinical effectiveness and cost-effectiveness.

Nosocomial Infections in Patients Hospitalized with Respiratory Syncytial Virus: A Practice Review

Viral testing is not always recommended in children with bronchiolitis due to doubts concerning its prognostic use. In this retrospective study, we investigated how the RSV testing would influence the frequency of nosocomial infections (NI). The files of 305 children, hospitalized due to the respiratory syncytial virus (RSV) infection in the period 2010-2014, were reviewed in the study. We found ten cases of NI. The RSV preventive measures did not vary in the consecutive years investigated, but the number of viral tests substantially varied. In 2010, 2012, and 2014, when ca. 2 tests per RSV(+) patient were performed, the risk of NI per patient was 1.3%, while in 2011 and 2013, when the RSV testing was less frequent, the accumulated risk per patient was 5.2%. There was a strong adverse relationship between the number of tests performed and the number of NI (rho = -0.975). The children with NI, when compared to those without NI, required a longer hospital stay, generating higher hospital costs regarding treatment, productivity loss, and indirect costs. The expenditure for RSV testing in the years of a low NI risk was higher than that in the high-risk years. Conversely, the expenditure related to NI management was lower in the years of a low NI risk. Each euro spent on RSV testing saved over 26 € from the NI management expenditure. We conclude that RSV testing is needed in the hospital setting to isolate the infected children and to prevent nosocomial RSV spread. This strategy is health advantageous and requires less resources than NI treatment.

Clinical microbiology

The clinical microbiology laboratory relies on traditional diagnostic methods such as culturing, Gram stains, and biochemical testing. Receipt of a high-quality specimen with an appropriate test order is integral to accurate testing. Recent technological advancements have led to decreased time to results and improved diagnostic accuracy. Examples of advancements discussed in this chapter include automation of bacterial culture processing and incubation, as well as introduction of mass spectrometry for the proteomic identification of microorganisms. In addition, molecular testing is increasingly common in the clinical laboratory. Commercially available multiplex molecular assays simultaneously test for a broad array of syndromic-related pathogens, providing rapid and sensitive diagnostic results. Molecular advancements have also transformed point-of-care (POC) microbiology testing, and molecular POC assays may largely supplant traditional rapid antigen testing in the future. Integration of new technologies with traditional testing methods has led to improved quality and value in the clinical microbiology laboratory.

After reviewing this chapter, the reader will be able to:•

List key considerations for specimen collection for microbiology testing.

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Discuss the advantages and limitations of automation in the clinical microbiology laboratory.

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Describe the evolution of microorganism identification methods.

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Discuss the benefits and limitations of molecular microbiology point-of-care testing.

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Summarize currently available multiplex molecular microbiology testing options.

RSVpredict: An Online Tool to Calculate the Likelihood of Respiratory Syncytial Virus Infection in Children Hospitalized With Acute Respiratory Disease

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection in young children. Early detection of RSV infection can avoid unnecessary diagnostic and therapeutic intervention and is required to prevent the nosocomial spread of RSV infection in pediatric hospitals. We developed a web tool to calculate the probability of RSV infection in children hospitalized with acute respiratory tract infection (ARTI) (RSVpredict).

METHODS

During winter seasons 2014/2015 to 2017/2018, 1545 children hospitalized with clinical symptoms of ARTI at the University Hospital Heidelberg/Germany were prospectively included. Medical information was reported on a standardized data sheet, and nasopharyngeal swabs were obtained for multiplex real-time polymerase chain reaction analyses. We applied logistic regression to develop a prediction model and developed a web-based application to predict the individual probability of RSV infection.

RESULTS

Duration of clinical symptoms ≥2 days on admission, calendar month of admission, admission for lower respiratory tract infection, the presence of cough and rale and younger age were associated with RSV infection (P < 0.05). Those data were included in the prediction model (RSVpredict, https://web.imbi.uni-heidelberg.de/rsv/). RSVpredict is a web-based application to calculate the risk of RSV infection in children hospitalized with ARTI. The prediction model is based on easily accessible clinical symptoms and predicts the individual probability of RSV infection risk immediately.

CONCLUSIONS

Pediatricians might use the RSVpredict to take informed decisions on further diagnostic and therapeutic intervention, including targeted RSV testing in children with relevant RSV infection risk.

Amplification chemistries in clinical virology

Molecular diagnostic methods have evolved and matured considerably over the last several decades and are constantly being evaluated and adopted by clinical laboratories for the identification of infectious pathogens. Advancement in other technologies such as fluorescence, electronics, instrumentation, automation, and sensors have made the overall diagnostic process more accurate, sensitive, and rapid. Nucleic acid based detection procedures, which rely on the fundamental principles of DNA replication have emerged as a popular and standard diagnostic method, and several commercial assays are currently available based on different nucleic acid amplification techniques. This review focuses on the major amplification chemistries that are used for developing commercial assays and discusses their application in the clinical virology laboratory.

Closed-type pre-treatment device for point-of-care testing of sputum

The procedures and protocols for the pre-treatment of sputum specimens, mainly used for the diagnosis of pneumonia, are complex, labor intensive, and require skilled specialists working in a biosafety containment laboratory because of sample infectivity. In this study, we developed the first portable, low-power pre-treatment device that carries out all sputum pre-treatment procedures (liquefaction, homogenization, dissolution, and inactivation) in an enclosed space. Designed to simultaneously employ chemical and mechanical dissolution in the enclosed chamber, this device eliminates the risk of transmission and improves the effectiveness of sputum dissolution and pathogen detection. This device is expected to allow for the pre-treatment of infectious sputum specimens outside of a biosafety containment laboratory. Used in conjunction with automated genome extraction and detection systems, this device should make the on-site diagnosis using infectious sputum specimens possible.

Laboratory Diagnosis of Respiratory Tract Infections in Children - the State of the Art

In the pediatric population, respiratory infections are the most common cause of physician visits. Although many respiratory illnesses are self-limiting viral infections that resolve with time and supportive care, it can be critical to identify the causative pathogen at an early stage of the disease in order to implement effective antimicrobial therapy and infection control. Over the last few years, diagnostics for respiratory infections have evolved substantially, with the development of novel assays and the availability of updated tests for newer strains of pathogens. Newer laboratory methods are rapid, highly sensitive and specific, and are gradually replacing the conventional gold standards, although the clinical utility of these assays is still under evaluation. This article reviews the current laboratory methods available for testing for respiratory pathogens and discusses the advantages and disadvantages of each approach.

Rapid and simple molecular tests for the detection of respiratory syncytial virus: a review

INTRODUCTION

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infections. The clinical manifestations of RSV are indistinguishable from other etiologies of acute respiratory infection. Therefore, accurate and timely laboratory testing is needed to impact clinical management. There are now multiple rapid, low-complexity, commercially available assays for RSV. These tests present significant performance advantages compared to older antigen detection tests. Accurate and rapid diagnosis of RSV has the potential for enabling timely cessation of unnecessary antibiotics and implementation of good infection control practices. Furthermore, a recently approved RSV diagnostic assay can reduce the test turnaround time to 13 min or less. Areas covered: The authors aim to review the importance of rapid and accurate testing for RSV and will describe the available molecular RSV diagnostic assays approved for use at the point-of-care. Expert commentary: Further independent evaluations are needed to confirm that the accuracy of the low-complexity assays is indeed similar to reverse transcriptase polymerase chain reaction across the age spectrum, and in immunosuppressed hosts. In the future, the challenge will be to achieve a balance between increasingly sophisticated multiplex diagnostic platforms and tests that are sufficiently simple to be used at the point-of-care.

Detection of Influenza A and B Viruses and Respiratory Syncytial Virus by Use of Clinical Laboratory Improvement Amendments of 1988 (CLIA)-Waived Point-of-Care Assays: a Paradigm Shift to Molecular Tests

An accurate laboratory diagnosis of influenza, respiratory syncytial virus (RSV), and other respiratory viruses can help to guide patient management, antiviral therapy, infection prevention strategies, and epidemiologic monitoring. Influenza has been the primary driver of rapid laboratory testing due to its morbidity and mortality across all ages, the availability of antiviral therapy, which must be given early to have an effect, and the constant threat of new pandemic strains. Over the past 30 years, there has been an evolution in viral diagnostic testing, from viral culture to rapid antigen detection, and more recently, to highly sensitive nucleic acid amplification tests (NAAT), as well as a trend to testing at the point of care (POC). Simple rapid antigen immunoassays have long been the mainstay for POC testing for influenza A and B viruses and respiratory syncytial virus (RSV) but have been faulted for low sensitivity. In 2015, the first POC NAAT for the detection of influenza was approved by the Food and Drug Administration (FDA), ushering in a new era. In 2017, the FDA reclassified rapid influenza diagnostic tests (RIDTs) from class I to class II devices with new minimum performance standards and a requirement for annual reactivity testing. Consequently, many previously available RIDTs can no longer be purchased in the United States. In this review, recent developments in Clinical Laboratory Improvement Amendments of 1988 (CLIA)-waived testing for respiratory virus infections will be presented, with the focus on currently available FDA-cleared rapid antigen and molecular tests primarily for influenza A and B viruses and RSV.

Profile of the Alere i Influenza A & B assay: a pioneering molecular point-of-care test

INTRODUCTION

The Alere i Influenza A & B assay incorporates the Nicking Enzyme Amplification Reaction technique on the Alere i instrument to detect and differentiate influenza virus (Flu) A and B nucleic acids in specific specimens. Areas covered: The Alere i Influenza A & B assay was cleared by the US Food and Drug Administration for use with nasal swabs (NS) and nasopharyngeal swabs, either directly or in viral transport medium. Notably, direct use on NS was the first ever CLIA-waived nucleic acid-based test. Previously published evaluations have reported sensitivities and specificities of 55.2-100% and 62.5-100% for Flu A and 45.2-100% and 53.6-100% for Flu B, respectively. Expert commentary: The Alere i Influenza A & B assay provides a rapid and simple platform for detection and differentiation of Flu A and B. Efforts are expected to further improve sensitivity and user-friendliness for effective and widespread use in the true point-of-care setting.

Clinical evaluation of a novel and simple-to-use molecular platform for diagnosis of respiratory syncytial virus

Rapid molecular diagnostic testing for respiratory infections can improve patient care and minimize unnecessary prescriptions of antibiotics. We present the preliminary clinical evaluation of Orion GenRead^® RSV, a novel, rapid, and easy-to-use molecular test for the diagnosis of respiratory syncytial virus (RSV) infection. The sensitivity and specificity of Orion GenRead RSV were 99% and 100%, respectively. Orion GenRead RSV detected RSV-positive specimens within 15 min. The performance of Orion GenRead RSV was similar to that of the reference method and this test could rapidly detect RSV within minutes. Orion GenRead RSV is applicable for near-patient testing.

Multicenter Clinical Evaluation of the Alere i Respiratory Syncytial Virus Isothermal Nucleic Acid Amplification Assay

The Alere i respiratory syncytial virus (RSV) assay is an isothermal nucleic acid amplification test capable of detecting RSV directly from respiratory specimens, with results being available in ≤13 min after test initiation. The objective of this study was to evaluate the performance characteristics of the Alere i RSV assay in a point-of-care setting by using direct nasopharyngeal (NP) swab specimens (direct NP) and nasopharyngeal swab specimens eluted and transported in viral transport medium (VTM NP). The study was a prospective, multicenter, clinical trial conducted at 9 sites across the United States to evaluate the clinical performance of the Alere i RSV assay with respiratory specimens obtained from both children (age, <18 years) and older adults (age, >60 years). The performance of the Alere i RSV assay was compared with that of the reference method, the Prodesse ProFlu+ real-time reverse transcriptase PCR (RT-PCR) assay. All specimens with discrepant test results were tested further by a second FDA-cleared PCR assay (the Verigene respiratory virus plus nucleic acid test; Luminex Inc., TX). A total of 554 subjects with signs and symptoms of respiratory infections were enrolled, and respiratory samples were collected in this study. In comparison with the ProFlu+ real-time RT-PCR, the overall sensitivity and specificity of Alere i RSV assay for the detection of RSV were 98.6% (95% confidence interval [CI], 94.4 to 99.7%) and 98.0% (95% CI, 95.8 to 99.1%), respectively, for direct NP and 98.6% (95% CI, 94.4 to 99.7%) and 97.8% (95% CI, 95.5 to 98.9%), respectively, for VTM NP. The Alere i RSV is a highly sensitive and specific molecular assay ideal for rapid RSV detection in patients in the point-of-care setting due to its minimal hands-on time and rapid result availability.

Point-of-care diagnostics for respiratory viral infections

Introduction: Successful treatment outcomes for viral respiratory tract infections presenting from primary health care to quaternary hospitals will only be achieved with rapid, sensitive and specific identification of pathogens to allow effective pathogen-specific antiviral therapy and infection control measures.

Areas covered: This review aims to explore the different point-of-care tests currently available to diagnose viral respiratory tract infections, discuss the advantages and limitations of point-of-care testing, and provide insights into the future of point-of-care tests. The following databases were searched: Medline (January 1996 to 30 September 2017) and Embase (1988 to 30 September 2017), using the following keywords: ‘point of care’, ‘respiratory virus’, ‘influenza’, ‘RSV’, ‘diagnostics’, ‘nucleic acid test’ and ‘PCR’.

Expert commentary: Viral respiratory tract infections cause significant morbidity and mortality worldwide, and point-of-care tests are facilitating the rapid identification of the pathogen responsible given the similarities in clinical presentation.

Performance of the Alere i RSV assay for point-of-care detection of respiratory syncytial virus in children

BACKGROUND

Respiratory syncytial virus (RSV) is the most important cause of severe acute respiratory tract infection in young children. Alere i RSV is a novel molecular rapid test which identifies respiratory syncytial virus in less than 13 min.

METHODS

We evaluated the clinical performance of the Alere i RSV assay in a pediatric point-of-care setting during winter season 2016 / 2017. Test results from 518 nasopharyngeal swab samples were compared to a real-time reverse transcription PCR reference standard.

RESULTS

The overall sensitivity and specificity of the Alere i RSV test assay was 93% (CI⁹⁵ 89% - 96%) and 96% (CI⁹⁵ 93% - 98%), respectively. Alere i RSV performed well in children of all age groups. An optimal sensitivity of 98% (CI⁹⁵ 94% - 100%) and specificity of 96% (CI⁹⁵ 90% - 99%) was obtained in children < 6 months. In children ≥ 2 years, sensitivity and specificity remained at 87% (CI⁹⁵ 73% - 96%) and 98% (CI⁹⁵ 92% - 100%), respectively. False negative Alere i RSV test results mostly occurred in samples with low viral load (mean CT value 31.1; CI⁹⁵ 29.6 - 32.6). The Alere i RSV assay is easy to use and can be operated after minimal initial training. Test results are available within 13 min, with most RSV positive samples being identified after approximately 5 min.

CONCLUSION

The Alere i RSV assay has the potential to facilitate the detection of RSV in pediatric point-of-care settings.