Evaluation of the ESPLINE® Influenza A & B-N assay for the detection of influenza A and B in nasopharyngeal aspirates

Influenza Virus Precision Diagnosis and Continuous Purification Enabled by Neuraminidase-Resistant Glycopolymer-Coated Microbeads

Rapid diagnosis and vaccine development are critical to prevent the threat posed by viruses. However, rapid tests, such as colloidal gold assays, yield false-negative results due to the low quantities of viruses; moreover, conventional virus purification, including ultracentrifugation and nanofiltration, is multistep and time-consuming, which limits laboratory research and commercial development of viral vaccines. A rapid virus enrichment and purification technique will improve clinical diagnosis sensitivity and simplify vaccine production. Hence, we developed the surface-glycosylated microbeads (glycobeads) featuring chemically synthetic glycoclusters and reversible linkers to selectively capture the influenza virus. The surface plasmon resonance (SPR) evaluation indicated broad spectrum affinity of S-linked glycosides to various influenza viruses. The magnetic glycobeads were integrated into clinical rapid diagnosis, leading to a 30-fold lower limit of detection. Additionally, the captured viruses can be released under physiological conditions, delivering purified viruses with >50% recovery and without decreasing their native infectivity. Notably, this glycobead platform will facilitate the sensitive detection and continuous one-step purification of the target virus that contributes to future vaccine production.

The Clinical Effect of Seasonal Flu Vaccination on Health-Related Quality of Life

Purpose

This study aimed to determine the clinical effect of seasonal flu vaccination in adult outpatients based on the effect on health-related quality of life (HRQOL).

Patients and Methods

We reviewed the clinical data of adult flu outpatients with mild symptoms who presented to the outpatient clinic of Teikyo University Hospital, Tokyo, Japan, from 2018 to 2020 winter season and were enrolled in the prospective observational study of the clinical efficacy of anti-flu agents (UMIN000034896). We evaluated influenza vaccination status, clinical symptoms, and the status of HRQOL as measured by Short Form-8^® (SF-8^®) at first visit. The SF-8^® survey generated two-component summaries; a physical component summary and a mental component summary.

Results

The data of 79 patients were evaluated in this study. Of the 79 patients, 37 were vaccinated for influenza at least three weeks before contracting seasonal influenza. Not every patient needed to be hospitalized for treatment. There were no significant differences in clinical backgrounds between vaccinated patients and non-vaccinated patients. Univariate analysis showed influenza vaccination was significantly associated with higher scores on the physical component summary of HRQOL (p=0.0011).

Conclusion

Influenza vaccinations would be clinically valuable for adult outpatients with seasonal flu and mild symptoms, because they can significantly inhibit the decrease of HRQOL due to influenza infection.

An HRP-labeled lateral flow immunoassay for rapid simultaneous detection and differentiation of influenza A and B viruses

Rapid and sensitive diagnosis of influenza is urgently needed to address the limitations of low sensitivity associated with current rapid tests available for clinics and on-site monitoring. A novel horseradish peroxidase (HRP)-labeled lateral flow immunoassay strip (HRP-LFIA) for rapid simultaneous detection and differentiation of influenza A (INF A) and influenza B (INF B) viruses were developed. This immunoassay was based on the signal amplification by the HRP-catalyzed oxidation of 3, 3', 5, 5'-tetramethylbenzidine forming a colored insoluble product, which was proportional to the analyte concentration. Compared with conventional gold-colloidal based strips, an analytical sensitivity enhancement of more than one order of magnitude for thirteen INF virus isolates was observed. A total of 1487 swabs obtained from persons with influenza-like illnesses were tested for the presence of INF A and B viruses using real-time reverse transcription polymerase chain reaction (rRT-PCR) as the reference criterion. The overall sensitivities of HRP-LFIA were 77.5% (100/129) and 71.2% (116/163) for INF A and INF B, respectively. The overall specificities were 99.8% (1144/1146) and 99.8% (918/920), respectively. The nasopharyngeal sampling method yielded higher sensitivity rates of 90.2% (55/61) and 82.6% (71/86). In conclusion, this user-friendly assay could be a promising rapid detection method for rapid screening of INF A and INF B viruses.

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.

Influenza in the Emergency Department: Vaccination, Diagnosis, and Treatment: Clinical Practice Paper Approved by American Academy of Emergency Medicine Clinical Guidelines Committee

BACKGROUND

Influenza is an acute respiratory virus that results in significant worldwide morbidity and mortality each year. As emergency physicians, we are often the first to encounter patients with seasonal influenza. It is therefore critical that we draw on the most recent and relevant research when we make clinical decisions regarding the diagnosis, treatment, and prophylaxis of this disease.

METHODS

A MEDLINE literature search from August 2009 to August 2015 was performed using the keywords influenza vaccination efficacy AND systematic, influenza AND rapid antigen testing, and Oseltamivir AND systematic, while limiting the search to human studies written in the English language. General review articles and case reports were omitted. Each of the selected articles then underwent a structured review.

RESULTS

We identified 163 articles through our literature search, of which 68 were found to be relevant to our clinical questions. These studies then underwent a rigorous review from which recommendations were given.

CONCLUSIONS

Influenza vaccine efficacy continues to range between 40% and 80%. Vaccination has the potential to decrease disease severity and is recommended for individuals older than 6 months of age. If resources permit, vaccination can be offered to patients presenting to the emergency department. Rapid antigen detection for influenza is a simple bedside test with high specificity, but generally low sensitivity. If a patient presents with a syndrome consistent with influenza and has negative rapid antigen detection, they should either receive a confirmatory reverse transcriptase polymerase chain reaction or be treated as if they have influenza. Treatment with neuraminidase inhibitors can decrease the duration of influenza and is recommended in hospitalized patients, or in those with high risk of complications.

Evaluation of Alere i Influenza A&B for rapid detection of influenza viruses A and B

Rapid and accurate diagnosis of influenza is important for infection control, as well as for patient management. Alere i Influenza A&B is an isothermal nucleic acid amplification-based integrated system for detection and differentiation of influenza virus A and influenza virus B. The performance of the Alere i Influenza A&B was screened using frozen nasopharyngeal-swab specimens collected in viral transport medium (VTM) that were originally tested fresh with the FilmArray Respiratory Panel (RP) assay during the 2012-2013 influenza outbreak. In total, 360 VTM specimens were selected for Alere i Influenza A&B testing: 40 influenza virus A H1N1-2009 (influenza virus A-1), 40 influenza virus A H3N2 (influenza virus A-3), 37 influenza virus A "equivocal" or "no subtype detected" (influenza virus A-u), 41 influenza virus B, and 202 influenza virus-negative specimens, as initially determined by the FilmArray RP assay. The Alere assay showed sensitivities of 87.2%, 92.5%, 25.0%, and 97.4% for influenza virus A-1, influenza virus A-3, influenza virus A-u, and influenza virus B, respectively, after discordant resolution by Prodesse ProFLU+ PCR. The specificities were 100% for both influenza virus A and influenza virus B. In general, the Alere i Influenza A&B provided good sensitivity, although the assay did show poorer sensitivity with samples determined to have low influenza virus A titers by Prodesse ProFlu+ PCR (a mean real-time PCR threshold cycle [CT] value of 31.9 ± 2.0), which included the majority of the samples called influenza virus A "equivocal" or "no subtype detected" by a single BioFire FilmArray RP test. The integrated, rapid, and simple characteristics of the Alere i Influenza A&B assay make it a potential candidate for point-of-care testing, with a test turnaround time of less than 15 min.

Identification of respiratory viruses with a novel point-of-care multianalyte antigen detection test in children with acute respiratory tract infection

BACKGROUND

Rapid etiological diagnosis of a respiratory virus infection may have impact on antiviral and antibiotic therapy, patient cohorting, and prediction of the clinical course. Most point-of-care tests for detection of respiratory viruses have limitations in diagnostic performance and clinical usability. A novel, multianalyte point-of-care antigen detection test system (mariPOC(®); ArcDia International Oy Ltd., Turku, Finland) detects eight respiratory viruses (influenza A and B viruses, respiratory syncytial virus (RSV), adenovirus, human metapneumovirus, and parainfluenza type 1, 2, and 3 viruses) from a single nasopharyngeal swab specimen by a fully automated, random-access immunoassay method.

OBJECTIVES

To evaluate mariPOC(®) point-of-care test system in comparison with reverse transcription polymerase chain reaction (RT-PCR) in a pediatric emergency department setting.

STUDY DESIGN

Prospectively collected samples from 158 children (mean age, 1.8 years) with respiratory symptoms and/or fever were analyzed both by mariPOC(®) and by multiplex RT-PCR.

RESULTS

The sensitivities and specificities (95% confidence intervals) of the mariPOC(®) test were for influenza A (n = 7), 71% (38-100) and 100%; influenza B (n = 22), 86% (72-100) and 98% (95-100); RSV (n = 35), 89% (78-99) and 100%; adenovirus (n = 12), 25% (1-50) and 97% (95-99); and for human metapneumovirus (n = 8), 50% (15-85) and 100%, respectively. Parainfluenzaviruses were detected only in five patients.

CONCLUSIONS

This novel point-of-care test system is a rapid, practical, and specific method for simultaneous detection of eight respiratory viruses. Compared with RT-PCR, its sensitivity is moderately high for detection of RSV and influenza viruses, and low for adenovirus.

Postexposure prophylaxis for influenza in pediatric wards oseltamivir or zanamivir after rapid antigen detection

BACKGROUND

Postexposure prophylaxis (PEP) using neuraminidase inhibitors against exposure to influenza virus has been well studied in household settings but not in nosocomial settings in pediatric wards.

METHODS

We used oseltamivir or zanamivir as PEP in our pediatric wards. All influenza cases were diagnosed by the influenza rapid diagnostic test.

RESULTS

Between 2003 and 2011, there were 20 nosocomial introductions of influenza (10 were A, 9 were B and 1 was undetermined). The index cases consisted of 17 inpatients, 2 parents and 1 medical staff member. The 17 inpatients had been admitted to the hospital for reasons other than infectious disease and they developed influenza after hospitalization. Among the 81 contacts, 28 (35%) were exposed to influenza A, and 52 (64%) were exposed to influenza B. The rate of secondary infection among contacts not given PEP was 29% (5/17), and the rate among contacts given PEP was significantly lower, 3% (2/63; P = 0.004). The 2 infected contacts who had been given PEP were both influenza B cases, and both had received oseltamivir. The contacts who received PEP within 24 hours (59), for influenza A (23) and those who received zanamivir (15) did not develop influenza. No adverse events were reported.

CONCLUSIONS

PEP using oseltamivir or zanamivir for unexpected occurrences of nosocomial influenza in pediatric wards is safe and effective. The influenza rapid diagnostic test that we used was helpful for detecting nosocomial influenza in children.