Rapid Molecular Tests for Influenza, Respiratory Syncytial Virus, and Other Respiratory Viruses: A Systematic Review of Diagnostic Accuracy and Clinical Impact Studies

Diagnostic accuracy of point-of-care tests for acute respiratory infection: a systematic review of reviews

Background

Acute respiratory infections are a common reason for consultation with primary and emergency healthcare services. Identifying individuals with a bacterial infection is crucial to ensure appropriate treatment. However, it is also important to avoid overprescription of antibiotics, to prevent unnecessary side effects and antimicrobial resistance. We conducted a systematic review to summarise evidence on the diagnostic accuracy of symptoms, signs and point-of-care tests to diagnose bacterial respiratory tract infection in adults, and to diagnose two common respiratory viruses, influenza and respiratory syncytial virus.

Methods

The primary approach was an overview of existing systematic reviews. We conducted literature searches (22 May 2023) to identify systematic reviews of the diagnostic accuracy of point-of-care tests. Where multiple reviews were identified, we selected the most recent and comprehensive review, with the greatest overlap in scope with our review question. Methodological quality was assessed using the Risk of Bias in Systematic Reviews tool. Summary estimates of diagnostic accuracy (sensitivity, specificity or area under the curve) were extracted. Where no systematic review was identified, we searched for primary studies. We extracted sufficient data to construct a 2 × 2 table of diagnostic accuracy, to calculate sensitivity and specificity. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies version 2 tool. Where possible, meta-analyses were conducted. We used GRADE to assess the certainty of the evidence from existing reviews and new analyses.

Results

We identified 23 reviews which addressed our review question; 6 were selected as the most comprehensive and similar in scope to our review protocol. These systematic reviews considered the following tests for bacterial respiratory infection: individual symptoms and signs; combinations of symptoms and signs (in clinical prediction models); clinical prediction models incorporating C-reactive protein; and biological markers related to infection (including C-reactive protein, procalcitonin and others). We also identified systematic reviews that reported the accuracy of specific tests for influenza and respiratory syncytial virus. No reviews were found that assessed the diagnostic accuracy of white cell count for bacterial respiratory infection, or multiplex tests for influenza and respiratory syncytial virus. We therefore conducted searches for primary studies, and carried out meta-analyses for these index tests. Overall, we found that symptoms and signs have poor diagnostic accuracy for bacterial respiratory infection (sensitivity ranging from 9.6% to 89.1%; specificity ranging from 13.4% to 95%). Accuracy of biomarkers was slightly better, particularly when combinations of biomarkers were used (sensitivity 80-90%, specificity 82-93%). The sensitivity and specificity for influenza or respiratory syncytial virus varied considerably across the different types of tests. Tests involving nucleic acid amplification techniques (either single pathogen or multiplex tests) had the highest diagnostic accuracy for influenza (sensitivity 91-99.8%, specificity 96.8-99.4%).

Limitations

Most of the evidence was considered low or very low certainty when assessed with GRADE, due to imprecision in effect estimates, the potential for bias and the inclusion of participants outside the scope of this review (children, or people in hospital).

Future work

Currently evidence is insufficient to support routine use of point-of-care tests in primary and emergency care. Further work must establish whether the introduction of point-of-care tests adds value, or simply increases healthcare costs.

Funding

This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number NIHR159948.

Enhancing efficiency in detection of COVID-19 through AI-driven colorimetric isothermal detection with multiplex primers

COVID-19 has afflicted millions of lives worldwide. Although there are many rapid methods to detect it based on colorimetric loop-mediated isothermal amplification, there remains room for improvement. This study aims to 1) integrate multiple primers into a singleplex assay to enhance the diagnostic sensitivity, and 2) utilize a high-throughput smartphone-operatable AI-driven color reading tool to enable a rapid result analysis. This setup can improve the sensitivity by 10-100 times and can analyze approximately 6700 samples per minute. The assay is simpler than RT-qPCR, with a turnaround time of less than 75 min. It can detect various types of SARS-CoV-2 by targeting 3 genes, increasing the likelihood that it will remain effective even if the virus undergoes mutations in any single target gene. In summary, it affords potential for adaptation to detection of new/re-emerging diseases with the visual readout for maximum assay simplicity and AI-operated mode for large-scale testing.

Healthcare as a driver, reservoir and amplifier of antimicrobial resistance: opportunities for interventions

Antimicrobial resistance (AMR) is a global health challenge that threatens humans, animals and the environment. Evidence is emerging for a role of healthcare infrastructure, environments and patient pathways in promoting and maintaining AMR via direct and indirect mechanisms. Advances in vaccination and monoclonal antibody therapies together with integrated surveillance, rapid diagnostics, targeted antimicrobial therapy and infection control measures offer opportunities to address healthcare-associated AMR risks more effectively. Additionally, innovations in artificial intelligence, data linkage and intelligent systems can be used to better predict and reduce AMR and improve healthcare resilience. In this Review, we examine the mechanisms by which healthcare functions as a driver, reservoir and amplifier of AMR, contextualized within a One Health framework. We also explore the opportunities and innovative solutions that can be used to combat AMR throughout the patient journey. We provide a perspective on the current evidence for the effectiveness of interventions designed to mitigate healthcare-associated AMR and promote healthcare resilience within high-income and resource-limited settings, as well as the challenges associated with their implementation.

Transforming respiratory tract infection diagnosis in the kingdom of saudi arabia through point-of-care testing: A white paper for policy makers

With the evident increased prevalence of respiratory tract infections (RTIs) such as Respiratory Syncytial Virus (RSV), influenza, Group A Streptococcus (GAS), and COVID-19, the conventional diagnostic methods are considered sub-optimal in providing timely management to patients in the Kingdom of Saudi Arabia (KSA). Gaps in current diagnostics are magnified by the Kingdom's unique demographic composition, comprising 11.9 million foreign workers, and the annual influx of over 10 million pilgrims. Current gaps in timely diagnosis leads to delays in treatment, misuse of antibiotics, and protracted hospital stays, subsequently compromising patient care, and escalating healthcare costs. KSA healthcare stakeholders suggest that the integration of rapid molecular Point-of-Care Testing (POCT) into the Kingdom's healthcare infrastructure is an absolute necessity. This publication serves as an urgent call for action aimed at healthcare policymakers in Saudi Arabia, to review the existing diagnostic challenges and include rapid POCTs in the Saudi healthcare strategy for respiratory infections.

Impact of respiratory pathogens detection by a rapid multiplex polymerase chain reaction assay on the management of community-acquired pneumonia for children at the paediatric emergency department. A randomized controlled trial, the Optimization of Pneumonia Acute Care (OPTIPAC) study

OBJECTIVES

The pathogen of community-acquired pneumonia (CAP) in children is typically uncertain during initial treatment, leading to systematic empiric antibiotic use. This study investigates if having rapid multiplex PCR results in the emergency department (ED) improves empiric treatment.

METHODS

OPTIPAC, a French multicentre study (2016-2018), enrolled patients consulting for CAP at the paediatric ED in 11 centres. Patients were randomized to either receive a multiplex PCR test plus usual care or usual care alone and followed for 15 days. The primary outcome was the appropriateness of initial antimicrobial management, determined by a blinded committee.

RESULTS

Of the 499 randomized patients, 248 were tested with the multiplex PCR. Appropriateness of the antibiotic treatment was higher in the PCR group (168/245, 68.6% vs. 120/249, 48.2%; Relative risk 1.42 [1.22-1.66]; p < 0.0001), chiefly by reducing unnecessary antibiotics in viral pneumonia (RR 3.29 [2.20-4.90]). No adverse events were identified.

DISCUSSION

The multiplex PCR assay result at the ED improves paediatric CAP's antimicrobial stewardship, by both reducing antibiotic prescriptions and enhancing treatment appropriateness.

Resurgence of common respiratory viruses in patients with community-acquired pneumonia (CAP)-A prospective multicenter study

BACKGROUND

Community-acquired pneumonia (CAP) is a major global cause of death and hospitalization. Bacteria or community-acquired viruses (CARVs) cause CAP. COVID-19 associated restrictions effectively reduced the circulation of CARVs.

OBJECTIVES

The aim of this study was to analyze the proportion of CARVs in adult patients with CAP from mid-2020 to mid-2023. Specifically, we aimed to compare the rate of influenza virus, SARS-CoV-2, and RSV detections in patients aged 18-59 years and ≥60 years.

STUDY DESIGN

We analyze the proportion of 21 community-acquired respiratory viruses (CARVs) and three atypical bacteria (Bordetella pertussis, Legionella pneumophila, and Mycoplasma pneumoniae) in nasopharyngeal swab samples using molecular multiplex methods within the prospective, multicentre, multinational study of the German study Group CAPNETZ. We used stringent inclusion criteria throughout the study.

RESULTS

We identified CARVs in 364/1,388 (26.2 %) patients. In detail, we detected SARS-CoV-2 in 210/1,388 (15.1 %), rhino-/enterovirus in 64/1,388 (4.6 %), influenza virus in 23/1,388 (1.6 %) and RSV in 17/1,388 (1.2 %) of all patients. We detected RSV and influenza more frequently in patients ≥60 years, especially in 22/23 compared to the previous season. None of the atypical bacteria were detected.

CONCLUSIONS

Beginning in 2023, we demonstrate a re-emergence of CARVs in CAP patients. Effective vaccines or specific antiviral therapies for more than two thirds of the detected viral infections are currently available. High detection rates of vaccine-preventable viruses in older age groups support targeted vaccination campaigns.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Clinical impact of rapid molecular diagnostic tests in patients presenting with viral respiratory symptoms: A systematic literature review

BACKGROUND

Molecular tests can detect lower concentrations of viral genetic material over a longer period of respiratory infection than antigen tests. Delays associated with central laboratory testing can result in hospital-acquired transmission, avoidable patient admission, and unnecessary use of antimicrobials, all which may lead to increased cost of patient management. The aim of this study was to summarize comparisons of clinical outcomes associated with rapid molecular diagnostic tests (RMDTs) versus other diagnostic tests for viral respiratory infections.

METHODS

A systematic literature review (SLR) conducted in April 2023 identified studies evaluating clinical outcomes of molecular and antigen diagnostic tests for patients suspected of having respiratory viral infections.

RESULTS

The SLR included 21 studies, of which seven and 14 compared RMDTs (conducted at points of care or at laboratories) to standard (non-rapid) molecular tests or antigen tests to detect SARS-CoV-2 and influenza, respectively. In studies testing for SARS-CoV-2, RMDTs led to reductions in time to test results versus standard molecular tests (range of the reported medians: 0.2-3.8 hours versus 4.3-35.9 hours), with similar length of emergency department stay (3.2-8 hours versus 3.7-28.8 hours). Similarly, in studies testing for influenza, RMDTs led to reductions in time to test results versus standard molecular tests (1-3.5 hours versus 18.2-29.2 hours), with similar length of emergency department stay (3.7-11 hours versus 3.8-11.9 hours). RMDTs were found to decrease exposure time of uninfected patients, rate of hospitalization, length of stay at the hospitals, and frequency of unnecessary antiviral and antibacterial therapy, while improving patient flow, compared to other tests.

CONCLUSIONS

Compared to other diagnostic tests, RMDTs improve clinical outcomes, test turnaround time, and stewardship by decreasing unnecessary use of antibiotics and antivirals. They also reduce hospital admission and length of stay, which may, in turn, reduce unnecessary exposure of patients to hospital-acquired infections and their associated costs.

Clinical Outcomes of Rapid Respiratory Virus Testing in Emergency Departments: A Systematic Review and Meta-Analysis

Importance

Rapid tests for respiratory viruses, including multiplex panels, are increasingly available in emergency departments (EDs). Their association with patient outcomes remains unclear.

Objective

To determine if ED rapid respiratory virus testing in patients with suspected acute respiratory infection (ARI) was associated with decreased antibiotic use, ancillary tests, ED length of stay, and ED return visits and hospitalization and increased influenza antiviral treatment.

Data Sources

Ovid MEDLINE, Embase (Ovid), Scopus, and Web of Science from 1985 to November 14, 2022.

Study Selection

Randomized clinical trials of patients of any age with ARI in an ED. The primary intervention was rapid viral testing.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines were followed. Two independent reviewers (T.S. and K.W.) extracted data and assessed risk of bias using the Cochrane Risk of Bias, version 2.0. Estimates were pooled using random-effects models. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations framework.

Main Outcomes and Measures

Antibiotic use and secondary outcomes were pooled separately as risk ratios (RRs) and risk difference estimates with 95% CIs.

Results

Of 7157 studies identified, 11 (0.2%; n = 6068 patients) were included in pooled analyses. Routine rapid viral testing was not associated with antibiotic use (RR, 0.99; 95% CI, 0.93-1.05; high certainty) but was associated with higher use of influenza antivirals (RR, 1.33; 95% CI, 1.02-1.75; moderate certainty) and lower use of chest radiography (RR, 0.88; 95% CI, 0.79-0.98; moderate certainty) and blood tests (RR, 0.81; 95% CI, 0.69-0.97; moderate certainty). There was no association with urine testing (RR, 0.95; 95% CI, 0.77-1.17; low certainty), ED length of stay (0 hours; 95% CI, -0.17 to 0.16; moderate certainty), return visits (RR, 0.93; 95%, CI 0.79-1.08; moderate certainty) or hospitalization (RR, 1.01; 95% CI, 0.95-1.08; high certainty). Adults represented 963 participants (16%). There was no association of viral testing with antibiotic use in any prespecified subgroup by age, test method, publication date, number of viral targets, risk of bias, or industry funding.

Conclusions and Relevance

The results of this systematic review and meta-analysis suggest that there are limited benefits of routine viral testing in EDs for patients with ARI. Further studies in adults, especially those with high-risk conditions, are warranted.

Implementation of point-of-care molecular testing for respiratory viruses in congregate living settings

OBJECTIVE

To implement and evaluate a point-of-care (POC) molecular testing platform for respiratory viruses in congregate living settings (CLS).

DESIGN

Prospective quality improvement study.

SETTING

Seven CLS, including three nursing homes and four independent-living facilities.

PARTICIPANTS

Residents of CLS.

METHODS

A POC platform for COVID-19, influenza A and B, and respiratory syncytial virus was implemented at participating CLS from December 1, 2022 to April 15, 2023. Residents with respiratory symptoms underwent paired testing, with respiratory specimens tested first with the POC platform and then delivered to an off-site laboratory for multiplex respiratory virus panel (MRVP) polymerase chain reaction (PCR) as per standard protocol. Turn-around time and diagnostic accuracy of the POC platform were compared against MRVP PCR. In an exploratory analysis, time to outbreak declaration among participating CLS was compared against a convenience sample of 19 CLS that did not use the POC platform.

RESULTS

A total of 290 specimens that underwent paired testing were included. Turn-around time to result was significantly shorter with the POC platform compared to MRVP PCR, with median difference of 36.2 hours (interquartile range 21.8-46.4 hours). The POC platform had excellent diagnostic accuracy compared to MRVP PCR, with area under the curve statistic of .96. Time to outbreak declaration was shorter in CLS that used the POC platform compared to CLS that did not.

CONCLUSION

Rapid POC testing platforms for respiratory viruses can be implemented in CLS, with high diagnostic accuracy, expedited turn-around times, and shorter time to outbreak declaration.

Viral Pneumonia: From Influenza to COVID-19

Respiratory viruses are increasingly recognized as a cause of community-acquired pneumonia (CAP). The implementation of new diagnostic technologies has facilitated their identification, especially in vulnerable population such as immunocompromised and elderly patients and those with severe cases of pneumonia. In terms of severity and outcomes, viral pneumonia caused by influenza viruses appears similar to that caused by non-influenza viruses. Although several respiratory viruses may cause CAP, antiviral therapy is available only in cases of CAP caused by influenza virus or respiratory syncytial virus. Currently, evidence-based supportive care is key to managing severe viral pneumonia. We discuss the evidence surrounding epidemiology, diagnosis, management, treatment, and prevention of viral pneumonia.

A cost-consequence analysis of the Xpert Xpress CoV-2/Flu/RSV plus test strategy for the diagnosis of influenza-like illnesses

AIMS

Influenza-like illnesses (ILI) affect millions each year in the United States (US). Determining definitively the cause of symptoms is important for patient management. Xpert Xpress CoV-2/Flu/RSV plus (Xpert Xpress) is a rapid, point-of-care (POC), multiplex real-time polymerase chain reaction (RT-PCR) test intended for the simultaneous qualitative detection and differentiation of SARS-CoV-2, influenza A/B, and respiratory syncytial virus (RSV). The objective of our analysis was to develop a cost-consequence model (CCM) demonstrating the clinico-economic impacts of implementing PCR testing with Xpert Xpress compared to current testing strategies.

METHODS

A decision tree model, with a 1-year time horizon, was used to compare testing with Xpert Xpress alone to antigen POC testing and send-out PCR strategies in the US outpatient setting from a payer perspective. A hypothetical cohort of 1,000,000 members was modeled, a portion of whom develop symptomatic ILIs and present to an outpatient care facility. Our main outcome measure is cost per correct treatment course.

RESULTS

The total cost per correct treatment course was $1,131 for the Xpert Xpress strategy compared with a range of $3,560 to $5,449 in comparators. POC antigen testing strategies cost more, on average, than PCR strategies.

LIMITATIONS

Simplifying model assumptions were used to allow for modeling ease. In clinical practice, treatment options, costs, and diagnostic test sensitivity and specificity may differ from what is included in the model. Additionally, the most recent incidence and prevalence data was used within the model, which is not reflective of historical averages due to the SARS-CoV-2 pandemic.

CONCLUSION

The Xpert Xpress CoV-2/Flu/RSV plus test allows for rapid and accurate diagnostic results, leading to reductions in testing costs and downstream healthcare resource utilization compared to other testing strategies. Compared to POC antigen testing strategies, PCR strategies were more efficient due to improved diagnostic accuracy and reduced use of confirmatory testing.

Fully integrated sample-in-answer-out platform for viral detection using digital reverse transcription recombinase polymerase amplification (dRT-RPA)

Recombinase polymerase amplification (RPA) is one of the most promising diagnostic methods for pathogen detection, owing to the simplified isothermal amplification technique. Using one-step digital reverse transcription RPA (dRT-RPA) to detect viral RNA provides a fast diagnosis and absolute quantification. Here, we present a chip that purifies, digitalizes, and detects viral RNA of SARS-CoV-2 in a fully automated and sensitive manner. The chip purifies the RNA using the surface charge concept of magnet bead-RNA binding, then mixes the RNA with the amplification reagents, digitalizes the amplification mixture, and performs dRT-RPA. RNA-bead complex is transported among purification buffers that are separated by an oil phase. For reagent manipulation and mixing, a magnetic valve system is integrated on the chip, where an external magnet controls the reagent direction and time of addition. Besides, a novel vacuum system is suggested to drive and regulate the reagents into two fluid systems simultaneously in ∼2 min. We also developed a cost-effective way to perform fluorescent detection for dRT-RPA on chip by using EvaGreen® dye. With integrated heating and optical detection system, the on-chip dRT-RPA presents a sample-to-answer detection platform for absolute viral RNA quantitation in 37 min and a sensitivity as low as 10 RNA copies/μL. Hence, this platform is expected to be a useful tool for accurate and automated diagnosis of infectious diseases.

Respiratory Syncytial Virus Infections in Neonates: A Persisting Problem

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections in young infants. It is an enveloped, single-stranded, nonsegmented, negative-strand RNA virus, a member of the family Pneumoviridae. Globally, RSV is responsible for 2.3% of deaths among neonates 0-27 days of age. Respiratory syncytial virus infection is most common in children aged below 24 months. Neonates present with cough and fever. Respiratory syncytial virus-associated wheezing is seen in 20% infants during the first year of life of which 2-3% require hospitalization. Reverse transcriptase polymerase chain reaction (RT-PCR) gives fast results and has higher sensitivity compared with culture and rapid antigen tests and are not affected by passively administered antibody to RSV. Therapy for RSV infection of the LRT is mainly supportive, and preventive measures like good hygiene and isolation are the mainstay of management. Standard precautions, hand hygiene, breastfeeding and contact isolation should be followed for RSV-infected newborns. Recent AAP guidelines do not recommend pavilizumab prophylaxis for preterm infants born at 29-35 weeks without chronic lung disease, hemodynamically significant congenital heart disease and coexisting conditions. RSV can lead to long-term sequelae such as wheezing and asthma, associated with increased healthcare costs and reduced quality of life.

Trends in Molecular Diagnosis of Nosocomial Pneumonia Classic PCR vs. Point-of-Care PCR: A Narrative Review

Nosocomial pneumonia is one of the most frequent hospital-acquired infections. One of the types of nosocomial pneumonia is ventilator-associated pneumonia, which occurs in endotracheally intubated patients in intensive care units (ICU). Ventilator-associated pneumonia may be caused by multidrug-resistant pathogens, which increase the risk of complications due to the difficulty in treating them. Pneumonia is a respiratory disease that requires targeted antimicrobial treatment initiated as early as possible to have a good outcome. For the therapy to be as specific and started sooner, diagnostic methods have evolved rapidly, becoming quicker and simpler to perform. Polymerase chain reaction (PCR) is a rapid diagnostic technique with numerous advantages compared to classic plate culture-based techniques. Researchers continue to improve diagnostic methods; thus, the newest types of PCR can be performed at the bedside, in the ICU, so-called point of care testing-PCR (POC-PCR). The purpose of this review is to highlight the benefits and drawbacks of PCR-based techniques in managing nosocomial pneumonia.

Single centre experience: Managing seasonal influenza without a point-of-care test

Background

The use of point-of-care testing (POCT) for influenza is not routine in many hospitals in the United Kngdom and testing is currently by laboratory-based polymerase chain reaction (PCR) tests. This review aims to evaluate patients who were tested positive for influenza in the last winter season and project if future POCT usage at initial point of patient assessment could assist in better utilisation of healthcare resources.

Methods

Retrospective review in a district general hospital without POCT facility for influenza. Medical records of patients who tested positive for influenza during a 4-month period from 1 October 2019 to 31 January 2020 in the paediatric department were reviewed and analysed.

Results

Thirty patients had laboratory-confirmed cases of influenza of which 63% (n = 19) were admitted to the ward. 56% of patients were not isolated at first instance on admission and 50% (n = 9) of admitted patients did not require inpatient management which totalled up to 224 h length of stay in ward.

Conclusions

Routine POCT for influenza can potentially improve management of patients presenting with respiratory symptoms and allocation of healthcare resources. We recommend its use to be introduced in diagnostic pathways for acute respiratory illness in the paediatric population in the next winter season in all hospitals.

Rapid Multiplex PCR for Respiratory Viruses Reduces Time to Result and Improves Clinical Care: Results of a Systematic Review and Meta-Analysis

OBJECTIVES

The clinical impact of rapid sample-to-answer 'syndromic' multiplex polymerase chain reaction (PCR) testing for respiratory viruses is not clearly established. We performed a systematic literature review and meta-analysis to evaluate this impact for patients with possible acute respiratory tract infection in the hospital setting.

METHODS

We searched EMBASE, MEDLINE, and Cochrane databases from 2012 to present and conference proceedings from 2021 for studies comparing clinical impact outcomes between multiplex PCR testing and standard testing.

RESULTS

Twenty-seven studies with 17,321 patient encounters were included in this review. Rapid multiplex PCR testing was associated with a reduction of -24.22hours (95% CI -28.70 to -19.74hours) in the time to results. Hospital length of stay was decreased by -0.82 days (95% CI -1.52 to -0.11 days). Among influenza positive patients, antivirals were more likely to be given (RR 1.25, 95% CI 1.06 to 1.48) and appropriate infection control facility use was more common with rapid multiplex PCR testing (RR 1.55, 95% CI 1.16 to 2.07).

CONCLUSIONS

Our systematic review and meta-analysis demonstrates a reduction in time to results and length of stay for patients overall along with improvements in appropriate antiviral and infection control management among influenza positive patients. This evidence supports the routine use of rapid sample-to-answer multiplex PCR testing for respiratory viruses in the hospital setting.

Practice patterns and perceptions of influenza testing amongst pediatric urgent care providers

INTRODUCTION

Despite a sensitivity of 50% to 70% the rapid influenza diagnostic test (RIDT) continues to play an important role in clinical decision-making due to its quick turn-around time, high specificity, relative simplicity of use, and low cost.

METHODS

A quantitative study using a web-based survey was distributed to 110 members of the Society of Pediatric Urgent Care aimed to assess RIDT use for diagnosis and management of influenza in outpatient pediatric patients.

RESULTS

Responses from 61 providers were received. Forty-two percent (95% CI 29.5-54.5%) of respondents report higher confidence in their diagnosis of influenza with the aid of a positive RIDT. 28% of respondents (95% CI 16.6-39.4%) report a higher likelihood of prescribing antiviral medications to low-risk patients if an RIDT is positive than without laboratory confirmation.

CONCLUSION

Most pediatric urgent care respondents reported higher confidence in their diagnosis and higher likelihood of prescribing antivirals with a positive RIDT rather than by clinical symptoms alone.

Measuring clinical outcomes of highly multiplex molecular diagnostics for respiratory infections: A systematic review and conceptual framework

Objectives

To review methodologies and outcomes reporting among these studies and to develop a conceptual framework of outcomes to assist in guiding studies and production of clinical metrics.

Data sources

PubMed and Embase from January 1, 2012, thru December 1, 2021.

Study eligibility criteria

Studies evaluating highly multiplex molecular respiratory diagnostics and their impact on either clinical or economic outcomes.

Methods

A systematic literature review (SLR) of methodologies and outcomes reporting was performed. A qualitative synthesis of identified SLRs and associated primary studies was conducted to develop conceptual framework for outcomes.

Results

Ultimately, 4 systemic literature reviews and their 12 associated primary studies were selected for review. Most primary studies included patient outcomes focusing on antimicrobial exposure changes such as antibiotic (80%) and antiviral use (50%) or occupancy changes such as hospital length of stay (60%). Economic outcomes were infrequently reported, and societal outcomes, such as antibiotic resistance impact, were absent from the reviewed literature. Qualitative evidence synthesis of reported outcomes yielded a conceptual framework of outcomes to include operational, patient, economic, and societal domains.

Conclusions

Our review highlights the significant heterogeneity in outcomes reporting among clinical impact studies for highly multiplex molecular respiratory diagnostics. Furthermore, we developed a conceptual framework of outcomes domains that may act as a guide to improve considerations in outcomes selection and reporting when evaluating clinical impact of these tests. These improvements may be important in synthesizing the evidence for informing clinical decision making, guidelines, and financial reimbursement.

Respiratory viruses: their importance and lessons learned from COVID-19

Respiratory virus infection can cause severe illnesses capable of inducing acute respiratory failure that can progress rapidly to acute respiratory distress syndrome (ARDS). ARDS is related to poor outcomes, especially in individuals with a higher risk of infection, such as the elderly and those with comorbidities, i.e. obesity, asthma, diabetes mellitus and chronic respiratory or cardiovascular disease. Despite this, effective antiviral treatments available for severe viral lung infections are scarce. The coronavirus disease 2019 (COVID-19) pandemic demonstrated that there is also a need to understand the role of airborne transmission of respiratory viruses. Robust evidence supporting this exists, but better comprehension could help implement adequate measures to mitigate respiratory viral infections. In severe viral lung infections, early diagnosis, risk stratification and prognosis are essential in managing patients. Biomarkers can provide reliable, timely and accessible information possibly helpful for clinicians in managing severe lung viral infections. Although respiratory viruses highly impact global health, more research is needed to improve care and prognosis of severe lung viral infections. In this review, we discuss the epidemiology, diagnosis, clinical characteristics, management and prognosis of patients with severe infections due to respiratory viruses.

A pragmatic randomized controlled trial of rapid on-site influenza and respiratory syncytial virus PCR testing in paediatric and adult populations

Background

Rapid/point-of-care respiratory virus nucleic acid tests (NAT) may improve oseltamivir, antibiotic, diagnostic test, and hospital bed utilization. Previous randomized controlled trials (RCT) on this topic have not used standard procedures of an accredited healthcare and laboratory system.

Methods

We conducted a parallel RCT at two hospitals [paediatric = Alberta Children’s Hospital (ACH); primarily adult = Peter Lougheed Centre (PLC)]. Patients with a respiratory viral testing order were randomized to testing at either a central accredited laboratory (standard arm) or with a rapid polymerase chain reaction test at an on-site accredited laboratory followed by standard testing [rapid on-site test (ROST) arm] based on day of specimen receipt at the laboratory. Patients and clinicians were blinded to assignment.

The primary outcome for ACH was inpatient length of stay (LOS) and for PLC was the proportion of inpatients prescribed oseltamivir.

Results

706 patient encounters were included at ACH; 322 assigned to ROST (181 inpatients) and 384 to the standard arm (194 inpatients). 422 patient encounters were included at PLC; 200 assigned to ROST (157 inpatients) and 222 to the standard arm (175 inpatients).

The rate of oseltamivir prescription and number of doses given was reduced in PLC inpatients negative for influenza in the ROST arm compared to standard arm [mean 14.9% (95% CI 9.87–21.9) vs. 27.5% (21.0–35.2), p = 0.0135; mean 2.85 doses (SEM 2.39–3.32) vs. 4.17 doses (3.85–4.49) p = 0.022, respectively]. ROST also significantly reduced oseltamivir use at ACH, reduced chest radiographs (ACH), and laboratory test ordering (PLC), but not antibiotic prescriptions. ROST also reduced the median turnaround time by > 24 h (ACH and PLC).

The LOS at ACH was not significantly different between the ROST and standard arms [median 4.05 days (SEM 1.79–18.2) vs 4.89 days (2.07–22.9), p = 0.062, respectively].

No adverse events were reported.

Conclusions

In a RCT representing implementation of ROST in an accredited laboratory system, we found that a ROST improved oseltamivir utilization and is the first RCT to show reduced ancillary testing in both paediatric and adult populations. A larger study is required to assess reduction in paediatric LOS as ACH was underpowered. These findings help justify the implementation of rapid on-site respiratory virus testing for inpatients.

Trial registration ISRCTN, number 10110119, Retrospectively Registered, 01/12/2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07796-3.

Comparing the cobas Influenza A/B Nucleic acid test for use on the cobas Liat System (Liat) with rapid antigen tests for clinical management of Japanese patients at the point of care

Background

Rapid diagnosis of influenza is critical in preventing the spread of infection and ensuring patients quickly receive antiviral medication to reduce the severity and duration of influenza symptoms, whilst controlling the spread of the causative virus. In Japan patients are often administered anti-influenza medication following a positive rapid antigen detection test (RADT) result. However, the sensitivity of RADTs can lead to false negative results. The cobas^® Influenza A/B Nucleic acid test for use on the cobas Liat^® System (Liat) is a molecular point-of-care method that can provide a more sensitive alternative to RADTs for rapid influenza diagnosis and treatment.

Methods

In this prospective multicenter study, diagnostic performance of the Liat test was compared with RADTs in patients presenting with influenza-like-illness. Test performance was also assessed by time since symptom onset.

Results

Of 419 patients enrolled, 413 were evaluable for all designated tests. Most patients had type-A infection, and only one patient had influenza type B. In 413 patients, the sensitivity and specificity (95% CI) of the Liat test were 99.5% (97.2–99.9%) and 99.5% (97.4–99.9%), respectively, and were 79.7% (73.5–84.7%) and 95.4% (91.7–97.5%) for RADTs. For patients tested <12 hours from symptom onset, the Liat test had significantly higher sensitivity than RADTs (p<0.0001).

Conclusion

Overall, compared with standard of care RADTs, the Liat test was more sensitive and specific in children and adults, particularly in the early stages of infection. Greater sensitivity can enable earlier diagnosis and may better inform appropriate antiviral treatment decisions.

Rapid influenza molecular testing in secondary care and influenza surveillance in England: Any impact?

INTRODUCTION

The use of rapid molecular testing for influenza diagnosis is becoming increasingly popular. Used at the point of care or in a clinical laboratory, these tests detect influenza A and B viruses, though many do not distinguish between influenza A subtypes. The UK Severe Influenza Surveillance System (USISS) collects surveillance data on laboratory-confirmed influenza admissions to secondary care in England. This study set out to understand how rapid influenza molecular testing was being used and how it might influence the availability of subtyping data collected on influenza cases admitted to secondary care in England.

METHODS

At the end of the 2017/2018 and 2018/2019 influenza seasons, a questionnaire was sent to all National Health Service Hospital Trusts in England to evaluate the use of rapid influenza testing. Surveillance data collected through USISS was analysed from 2011/2012 to 2020/2021.

RESULTS

Of responding trusts, 42% (13/31) in 2017/2018 and 55% (9/17) in 2018/2019 used rapid influenza molecular tests, either alone or in combination with other testing. The majority of rapid tests used did not subtype the influenza A result, and limited follow-up testing occurred. Surveillance data showed significant proportions of influenza A hospital and intensive care unit/high dependency unit admissions without subtyping information, increasing by approximately 35% between 2012/2013 and 2020/2021.

CONCLUSIONS

The use of rapid influenza molecular tests is a likely contributing factor to the large proportion of influenza A hospitalisations in England that were unsubtyped. Given their clear clinical advantages, further work must be done to reinforce these data for public health through integrated genomic surveillance.

Respiratory virus testing and clinical outcomes among children hospitalized with pneumonia

BACKGROUND

Despite the increased availability of diagnostic tests for respiratory viruses, their clinical utility for children with community-acquired pneumonia (CAP) remains uncertain.

OBJECTIVE

To identify patterns of respiratory virus testing across children's hospitals prior to the COVID-19 pandemic and to determine whether hospital-level rates of viral testing were associated with clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter retrospective cohort study of children hospitalized for CAP at 19 children's hospitals in the United States from 2010-2019.

MAIN OUTCOMES AND MEASURES

Using a novel method to identify the performance of viral testing, we assessed time trends in the use of viral tests, both overall and stratified by testing method. Adjusted proportions of encounters with viral testing were compared across hospitals and were correlated with length of stay, antibiotic and oseltamivir use, and performance of ancillary laboratory testing.

RESULTS

There were 46,038 hospitalizations for non-severe CAP among children without complex chronic conditions. The proportion with viral testing increased from 38.8% to 44.2% during the study period (p < .001). Molecular testing increased (27.2% to 40.0%, p < .001) and antigen testing decreased (33.2% to 7.8%, p < .001). Hospital-specific adjusted proportions of testing ranged from 10.0% to 83.5% and were not associated with length of stay, antibiotic use, or antiviral use. Hospitals that performed more viral testing did not have lower rates of ancillary laboratory testing.

CONCLUSIONS

Viral testing practices varied widely across children's hospitals and were not associated with clinically important process or outcome measures. Viral testing may not influence clinical management for many children hospitalized with CAP.

Development of an efficient veterinary rabies vaccine production process in the avian suspension cell line AGE1.CR.pIX

Background

Mass vaccination of dogs as important rabies reservoir is proposed to most effectively reduce and eliminate rabies also in humans. However, a minimum coverage of 70% needs to be achieved for control of the disease in zoonotic regions. In numerous developing countries, dog vaccination rate is still dangerously low because of economic constraints and due to a high turnover in dog populations. Improved vaccine production processes may help to alleviate cost and supply limitations. In this work, we studied and optimized the replication and vaccine potency of PV rabies virus strain in the muscovy-duck derived AGE1.CR and AGE1.CR.pIX suspension cell lines.

Results

The BHK-21-adapted PV rabies virus strain replicated efficiently in the avian cell lines without requirement for prior passaging. CR.pIX was previously shown to augment heat shock responses and supported slightly higher infectious titers compared to the parental CR cell line. Both cell lines allowed replication of rabies virus also in absence of recombinant IGF, the only complex component of the chemically defined medium that was developed for the two cell lines. After scale-up from optimization experiments in shake flask to production in 7-l bioreactors peak virus titers of 2.4 × 10⁸ FFU/ml were obtained. The potency of inactivated rabies virus harvest according to the NIH test was 3.5 IU/ml. Perfusion with the chemically defined medium during the virus replication phase improved the potency of the vaccine twofold, and increased the number of doses 9.6 fold.

Conclusion

This study demonstrates that a rabies vaccine for animal vaccination can be produced efficiently in the AGE1.CR.pIX suspension cell line in a scalable process in chemically defined medium.

Optimal use of procalcitonin to rule out bacteremia in patients with possible viral infections

Objective

During the winter, many patients present with suspected infection that could be a viral or a bacterial (co)infection. The aim of this study is to investigate whether the optimal use of procalcitonin (PCT) is different in patients with and without proven viral infections for the purpose of excluding bacteremia. We hypothesize that when a viral infection is confirmed, this lowers the probability of bacteremia and, therefore, influences the appropriate cutoff of procalcitonin.

Methods

This study was conducted in the emergency department of an academic medical center in The Netherlands in the winter seasons of 2019 and 2020. Adults (>18 years) with suspected infection, in whom a blood culture and a rapid polymerase chain reaction test for influenza was performed were included.

Results

A total of 546 patients were included of whom 47 (8.6%) had a positive blood culture. PCT had an area under the curve of 0.85, 95% confidence interval (95% CI) 0.80-0.91, for prediction of bacteremia. In patients with a proven viral infection (N = 212) PCT < 0.5 μg/L had a sensitivity of 100% (95% CI 63.1-100) and specificity of 81.2% (95% CI 75.1-86.3) to exclude bacteremia. In patients without a viral infection, the procalcitonin cutoff point of < 0.25 μg/L showed a sensitivity of 87.2% (95% CI 72.6-95.7) and specificity of 64.1 % (95% CI 58.3-69.6).

Conclusion

In patients with a viral infection, our findings suggest that a PCT concentration of <0.50 μg/L makes bacteremia unlikely. However, this finding needs to be confirmed in a larger population of patients with viral infections, especially because the rate of coinfection in our cohort was low.

Clinical characteristics and outcomes of mixed virus or bacterial infection in children with laboratory-confirmed influenza infection

BACKGROUND/PURPOSE

This study investigated the demographic characteristics and influenza complications of paediatric patients and explored the association of different influenza virus types and viral and bacterial coinfections with disease severity.

METHODS

This retrospective cohort study used data collected in 2010-2016 from the Chang Gung Research Database (CGRD), the largest collection of multi-institutional electronic medical records in Taiwan. Data were retrieved for children aged 0-18 years with laboratory-confirmed influenza. We extracted and analysed the demographic characteristics and the data on clinical features, complications, microbiological information, and advanced therapies of each case.

RESULTS

We identified 6193 children with laboratory-confirmed influenza, of whom 1964 (31.7%) were hospitalised. The age of patients with influenza A infection was lower than that of patients with influenza B (4.48 vs. 6.68, p < 0.001). Patients with influenza B infection had a higher incidence of myositis or rhabdomyolysis (4.4%, p < 0.001) and a higher need for advanced therapies (OR, 1.96; 95% CI, 1.32-2.9, p < 0.001). In addition to bacterial (OR, 9.07; 95% CI, 5.29-15.54, p < 0.001) and viral coinfection (OR, 7.73; 95% CI, 5.4-11.07, p < 0.001), dual influenza A and B infection was also a risk factor for influenza complications (OR, 2.13; 95% CI, 1.47-3.09, p < 0.001).

CONCLUSION

Dual influenza A and B infection and bacterial coinfection can contribute to influenza complications. Early recognition of any influenza complication is critical for the timely initiation of organ-specific advanced therapies to improve influenza-associated outcomes.

A review on colorimetric assays for DNA virus detection

Early detection is one of the ways to deal with DNA virus widespread prevalence, and it is necessary to know new diagnostic methods and techniques. Colorimetric assays are one of the most advantageous methods in detecting viruses. These methods are based on color change, which can be seen either with the naked eye or with special devices. The aim of this study is to introduce and evaluate effective colorimetric methods based on amplification, nanoparticle, CRISPR/Cas, and Lateral flow in the diagnosis of DNA viruses and to discuss the effectiveness of each of the updated methods. Compared to the other methods, colorimetric assays are preferred for faster detection, high efficiency, cheaper cost, and high sensitivity and specificity. It is expected that the spread of these viruses can be prevented by identifying and developing new methods.

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.

Viral Respiratory Infections: New Tools for a Rapid Diagnosis

Respiratory tract infection is one of the most common diseases in human worldwide. Many viruses are implicated in these infections, including emerging viruses, such as the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Identification of the causative viral pathogens of respiratory tract infections is important to select a correct management of patients, choose an appropriate treatment, and avoid unnecessary antibiotics use. Different diagnostic approaches present variable performance in terms of accuracy, sensitivity, specificity, and time-to-result, that have to be acknowledged to be able to choose the right diagnostic test at the right time, in the right patient. This review describes currently available rapid diagnostic strategies and syndromic approaches for the detection of viruses commonly responsible for respiratory diseases.

A Valve-Enabled Sample Preparation Device with Isothermal Amplification for Multiplexed Virus Detection at the Point-of-Care

Early and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses at the point-of-care is crucial for reducing disease transmission during the current pandemic and future flu seasons. To prepare for potential cocirculation of these two viruses, we report a valve-enabled, paper-based sample preparation device integrated with isothermal amplification for their simultaneous detection. The device incorporates (1) virus lysis and RNA enrichment, enabled by ball-based valves for sequential delivery of reagents with no pipet requirement, (2) reverse transcription loop-mediated isothermal amplification, carried out in a coffee mug, and (3) colorimetric detection. We have used the device for simultaneously detecting inactivated SARS-CoV-2 and influenza A H1N1 viruses in 50 min, with limits of detection at 2 and 6 genome equivalents, respectively. The device was further demonstrated to detect both viruses in environmental samples.

Advances and insights in the diagnosis of viral infections

Viral infections are the most common among diseases that globally require around 60 percent of medical care. However, in the heat of the pandemic, there was a lack of medical equipment and inpatient facilities to provide all patients with viral infections. The detection of viral infections is possible in three general ways such as (i) direct virus detection, which is performed immediately 1-3 days after the infection, (ii) determination of antibodies against some virus proteins mainly observed during/after virus incubation period, (iii) detection of virus-induced disease when specific tissue changes in the organism. This review surveys some global pandemics from 1889 to 2020, virus types, which induced these pandemics, and symptoms of some viral diseases. Non-analytical methods such as radiology and microscopy also are overviewed. This review overlooks molecular analysis methods such as nucleic acid amplification, antibody-antigen complex determination, CRISPR-Cas system-based viral genome determination methods. Methods widely used in the certificated diagnostic laboratory for SARS-CoV-2, Influenza A, B, C, HIV, and other viruses during a viral pandemic are outlined. A comprehensive overview of molecular analytical methods has shown that the assay's sensitivity, accuracy, and suitability for virus detection depends on the choice of the number of regions in the viral open reading frame (ORF) genome sequence and the validity of the selected analytical method.

Influenza Antiviral Treatment and Length of Stay

BACKGROUND

Antiviral treatment is recommended for hospitalized patients with suspected and confirmed influenza, but evidence is limited among children. We evaluated the effect of antiviral treatment on hospital length of stay (LOS) among children hospitalized with influenza.

METHODS

We included children <18 years hospitalized with laboratory-confirmed influenza in the US Influenza Hospitalization Surveillance Network. We collected data for 2 cohorts: 1 with underlying medical conditions not admitted to the ICU (n = 309, 2012-2013) and an ICU cohort (including children with and without underlying conditions; n = 299, 2010-2011 to 2012-2013). We used a Cox model with antiviral receipt as a time-dependent variable to estimate hazard of discharge and a Kaplan-Meier survival analysis to determine LOS.

RESULTS

Compared with those not receiving antiviral agents, LOS was shorter for those treated ≤2 days after illness onset in both the medical conditions (adjusted hazard ratio: 1.37, P = .02) and ICU (adjusted hazard ratio: 1.46, P = .007) cohorts, corresponding to 37% and 46% increases in daily discharge probability, respectively. Treatment ≥3 days after illness onset had no significant effect in either cohort. In the medical conditions cohort, median LOS was 3 days for those not treated versus 2 days for those treated ≤2 days after symptom onset (P = .005).

CONCLUSIONS

Early antiviral treatment was associated with significantly shorter hospitalizations in children with laboratory-confirmed influenza and high-risk medical conditions or children treated in the ICU. These results support Centers for Disease Control and Prevention recommendations for prompt empiric antiviral treatment in hospitalized patients with suspected or confirmed influenza.

Antiviral Use in Canadian Children Hospitalized for Influenza

OBJECTIVES

Antivirals are recommended for children hospitalized with influenza but are underutilized. We describe antiviral prescribing during influenza admissions in Canadian pediatric centers and identify factors associated with antiviral use.

METHODS

We performed active surveillance for laboratory-confirmed influenza hospitalizations among children ≤16 years old at the 12 Canadian Immunization Monitoring Program Active hospitals, from 2010-2011 to 2018-2019. Logistic regression analyses were used to identify factors associated with antiviral use.

RESULTS

Among 7545 patients, 57.4% were male; median age was 3 years (interquartile range: 1.1-6.3). Overall, 41.3% received antiviral agents; 72.8% received antibiotics. Antiviral use varied across sites (range, 10.2% to 81.1%) and influenza season (range, 19.9% to 59.6%) and was more frequent in children with ≥1 chronic health condition (52.7% vs 36.7%; P < .001). On multivariable analysis, factors associated with antiviral use included older age (adjusted odds ratio [aOR] 1.04 [95% confidence interval (CI), 1.02-1.05]), more recent season (highest aOR 9.18 [95% CI, 6.70-12.57] for 2018-2019), admission during peak influenza period (aOR 1.37 [95% CI, 1.19-1.58]), availability of local treatment guideline (aOR 1.54 [95% CI, 1.17-2.02]), timing of laboratory confirmation (highest aOR 2.67 [95% CI, 1.97-3.61] for result available before admission), presence of chronic health conditions (highest aOR 4.81 [95% CI, 3.61-6.40] for cancer), radiographically confirmed pneumonia (aOR 1.39 [95% CI, 1.20-1.60]), antibiotic treatment (aOR 1.51 [95% CI, 1.30-1.76]), respiratory support (1.57 [95% CI, 1.19-2.08]), and ICU admission (aOR 3.62 [95% CI, 2.88-4.56]).

CONCLUSIONS

Influenza antiviral agents were underused in Canadian pediatric hospitals, including among children with high-risk chronic health conditions. Prescribing varied considerably across sites, increased over time, and was associated with patient and hospital-level characteristics. Multifaceted hospital-based interventions are warranted to strengthen adherence to influenza treatment guidelines and antimicrobial stewardship practices.

Engineered nanomaterials as fighters against SARS-CoV-2: The way to control and treat pandemics

In this editorial trend, we aim to collect and present recently available data about the characteristics of SARS-CoV-2 virus, severity, infection, replication, diagnosis, and current medications. In addition, we propose the role of nanomaterials in controlling and treating COVID-19 through their antiviral and antibacterial potential with suggested action mechanisms indicating the capability of interaction between these nanomaterials and SARS-CoV-2. These nanomaterials might be among the possible and most effective cures against coronavirus.

Leveraging Existing and Soon-to-Be-Available Novel Diagnostics for Optimizing Outpatient Antibiotic Stewardship in Patients With Respiratory Tract Infections

Respiratory tract infections (RTIs) drive many outpatient encounters and, despite being predominantly viral, are associated with high rates of antibiotic prescriptions. With rising antibacterial resistance, optimization of prescribing of antibiotics in outpatients with RTIs is a critical need. Fortunately, this challenge arises at a time of increasing availability of novel RTI diagnostics to help discern which patients have bacterial infections warranting treatment. Effective implementation of antibiotic stewardship is needed, but optimal approaches for ambulatory settings are unknown. Future research needs are reviewed in this summary of a research summit convened by the Infectious Diseases Society of America in the fall of 2019.

Use of point-of-care molecular tests reduces hospitalization and oseltamivir administration in children presenting with influenza-like illness

Influenza is associated with increased morbidity, healthcare costs, hospitalization rates, and mortality in children. Rapid immunochromatography assay (ICA), a test with low sensitivity, is often used as point-of-care (POC) test. Recently, the rapid syndromic molecular test FilmArray has become available. This observational study aims to evaluate whether the use of FilmArray would decrease the use of antivirals and hospitalization rates among children presenting to the emergency room (ER) with influenza-like illness (ILI) symptoms. Nasopharyngeal swabs were prospectively collected from children, aged 0-16 years, presenting with ILI at the ER of a tertiary hospital during the peak endemic period. Patients were allocated to be tested by either FilmArray or ICA. The use of antivirals and hospitalization rates were noted. Logistic regression models were used to investigate the impact of testing methods on decision-making. Overall, 80 children were included (mean age: 5 years). Admissions were more likely to occur if an ICA test was performed (OR, 3.16; 95% CI, 1.01-9.82; p = .046). Oseltamivir administration was more likely among children who had undergone the ICA test (OR, 4.67; 95% CI, 1.06-20.43; p = .041). The implementation of rapid molecular test had no impact on complementary diagnostic testing or antibacterial prescription. The use of FilmArray significantly reduced both hospitalization and oseltamivir administration in children. Further knowledge on the use of POC tests is required to improve current management of children presenting with ILI and decrease associated healthcare costs.

Clinical impact of a routine, molecular, point-of-care, test-and-treat strategy for influenza in adults admitted to hospital (FluPOC): a multicentre, open-label, randomised controlled trial

BACKGROUND

Diagnosis of influenza in patients admitted to hospital is delayed due to long turnaround times with laboratory testing, leading to inappropriate and late antiviral treatment and isolation facility use. Molecular point-of-care tests (mPOCTs) are highly accurate, easy to use, and generate results in less than 1 h, but high-quality evidence for their effect on management and clinical outcomes is needed. The aim of this study was to assess the clinical impact of an mPOCT on influenza detection, antiviral use, infection control measures, and clinical outcomes in adults admitted to hospital with acute respiratory illness.

METHODS

In this multicentre, pragmatic, open-label, randomised controlled trial (FluPOC), we recruited adults admitted to hospital with acute respiratory illness during influenza seasons from two hospitals in Hampshire, UK. Eligible patients were aged 18 years and older, with acute respiratory illness of 10 days or fewer duration before admission to hospital, who were recruited within 16 h of admission to hospital. Participants were randomly assigned (1:1), using random permuted blocks of varying sizes (4, 6 and 8), to receive mPOCT for influenza or routine clinical care (control group). The primary outcome was the proportion of patients infected with influenza who were treated appropriately with antivirals (neuraminidase inhibitors) within 5 days of admission. Safety was assessed in all patients. Secondary outcomes included time to antivirals, isolation facility use, and clinical outcomes. This study is registered with the ISRCTN registry, ISRCTN17197293, and is now complete.

FINDINGS

Between Dec 12, 2017, and May 3, 2019, over two influenza seasons, 613 patients were enrolled, of whom 307 were assigned to the mPOCT group and 306 to the control group, and all were analysed. Median age was 62 years (IQR 45-75) and 332 (54%) of 612 participants with data were female. 100 (33%) of 307 patients in the mPOCT group and 102 (33%) of 306 in the control group had influenza. 100 (100%) of 100 patients with influenza were diagnosed in the mPOCT group and 60 (59%) of 102 were diagnosed though routine clinical care in the control group (relative risk 1·7, 95% CI 1·7-1·7; p<0·0001). 99 (99%) of 100 patients with influenza in the mPOCT group were given antiviral treatment within 5 days of admission versus 63 (62%) 102 in the control group (relative risk 1·6, 95% CI 1·4-1·9; p<0·0001). Median time to antivirals was 1·0 h (IQR 0·0 to 2·0) in the mPOCT group versus 6·0 h (0·0 to 12·0) in the control group (difference of 5·0 h [95% CI 0·0-6·0; p=0·0039]). 70 (70%) of 100 patients with influenza in the mPOCT group were isolated to single-room accommodation versus 39 (38%) of 102 in the control group (relative risk 1·8 [95% CI 1·4-2·4; p<0·0001]). 19 adverse events occurred among patients with influenza in the mPOCT group compared with 34 events in the control group. No patients with influenza died in the mPOCT group and two (2%) died in the control group (p=0·16).

INTERPRETATION

Routine mPOCT for influenza was associated with improved influenza detection and improvements in appropriate and timely antiviral and isolation facility use. Routine mPOCT should replace laboratory-based diagnostics for acute admissions to hospital during the influenza season.

FUNDING

National Institute for Health Research.

Comparative practicability and analytical performances of Credo VitaPCR™ Flu A&B and Cepheid Xpert® Xpress Flu/RSV platforms

To compare the practicability (usability and satisfaction) and analytical performances of VitaPCR™ Flu A&B Assay (Credo Diagnostics Biomedical Pte. Ltd., Singapore, Republic of Singapore) and Xpert® Xpress Flu/RSV kit (Cepheid, Sunnyvale, USA), two rapid point-of-care (POC) nucleic acid amplification tests (NAATs) by reference to multiplex RT-PCR for respiratory viruses. Nasopharyngeal swabs (n=117) were collected from patients with influenza-like illness in Paris, France. Thawed specimens were further analyzed with both NAATs. The usability was comparable for both NAATs. Satisfaction questionnaire was better for the VitaPCR™ platform for the short time of test result in 20 minutes. Both NAATs showed comparable sensitivities (VitaPCR^TM: 95.0%; Xpert® Xpress: 97.5%) and specificities (100%) for influenza A/B RNA detection, with excellent reliability and accuracy between both NAATs. Both VitaPCR™ and Xpert® Xpress NAATs can be implemented in hospital setting as POC NAATs to rapidly detect influenza A/B RNA in symptomatic patients.

Using Point of Care Testing to estimate influenza vaccine effectiveness in the English primary care sentinel surveillance network

Introduction

Rapid Point of Care Testing (POCT) for influenza could be used to provide information on influenza vaccine effectiveness (IVE) as well as influencing clinical decision-making in primary care.

Methods

We undertook a test negative case control study to estimate the overall and age-specific (6 months-17 years, 18–64 years, ≥65 years old) IVE against medically attended POCT-confirmed influenza. The study took place over the winter of 2019–2020 and was nested within twelve general practices that are part of the Oxford-Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC), the English sentinel surveillance network.

Results

648 POCT were conducted. 193 (29.7%) of those who were swabbed had received the seasonal influenza vaccine. The crude unadjusted overall IVE was 46.1% (95% CI: 13.9–66.3). After adjusting for confounders the overall IVE was 26.0% (95% CI: 0–65.5). In total 211 patients were prescribed an antimicrobial after swab testing. Given a positive influenza POCT result, the odds ratio (OR) of receiving an antiviral was 21.1 (95%CI: 2.4–182.2, p = <0.01) and the OR of being prescribed an antibiotic was 0.6 (95%CI: 0.4–0.9, p = <0.01).

Discussion

Using influenza POCT in a primary care sentinel surveillance network to estimate IVE is feasible and provides comparable results to published IVE estimates. A further advantage is that near patient testing of influenza is associated with improvements in appropriate antiviral and antibiotic use. Larger, randomised studies are needed in primary care to see if these trends are still present and to explore their impact on outcomes.

Multinational evaluation of the BioFire® FilmArray® Pneumonia plus Panel as compared to standard of care testing

This study compared standard of care testing (SOC) to BioFire® FilmArray® Pneumonia plus Panel (PNplus). PNplus detects 15 bacteria with semiquantitative log bin values, 7 antibiotic resistance markers, three atypical bacteria (AB), and eight viral classes directly from bronchoalveolar lavage-like specimens (BLS) and sputum-like specimens (SLS). Fifty-two laboratories from 13 European countries and Israel tested 1234 BLS and 1242 SLS with PNplus and SOC. Detection rates and number of pathogens/samples were compared for PNplus pathogens. PNplus bin values and SOC quantities were compared. Three thousand two hundred sixty-two bacteria in PNplus were detected by PNplus and/or SOC. SOC detected 57.1% compared to 95.8% for PNplus (p ≤ 0.0001). PNplus semiquantitative bin values were less than SOC, equal to SOC, or greater than SOC in 5.1%, 25.4%, and 69.6% of results, respectively. PNplus bin values were on average ≥ 1 log than SOC values (58.5% 1–2 logs; 11.0% 3–4 logs). PNplus identified 98.2% of MRSA and SOC 55.6%. SOC detected 73/103 AB (70.9%) and 134/631 viruses (21.2%). PNplus detected 93/103 AB (90.3%) and 618/631 viruses (97.9%) (p ≤ 0.0001). PNplus and SOC mean number of pathogens/samples were 1.99 and 1.44, respectively. All gram-negative resistance markers were detected. PNplus and SOC results were fully or partially concordant for 49.1% and 26.4% of specimens, respectively. PNplus was highly sensitive and detected more potential pneumonia pathogens than SOC. Semiquantification may assist in understanding pathogen significance. As PNplus generates results in approximately 1 h, PNplus has potential to direct antimicrobial therapy in near real time and improve antimicrobial stewardship and patient outcomes.

Update in Viral Infections in the Intensive Care Unit

The advent of highly sensitive molecular diagnostic techniques has improved our ability to detect viral pathogens leading to severe and often fatal infections that require admission to the Intensive Care Unit (ICU). Viral infections in the ICU have pleomorphic clinical presentations including pneumonia, acute respiratory distress syndrome, respiratory failure, central or peripheral nervous system manifestations, and viral-induced shock. Besides de novo infections, certain viruses fall into latency and can be reactivated in both immunosuppressed and immunocompetent critically ill patients. Depending on the viral strain, transmission occurs either directly through contact with infectious materials and large droplets, or indirectly through suspended air particles (airborne transmission of droplet nuclei). Many viruses can efficiently spread within hospital environment leading to in-hospital outbreaks, sometimes with high rates of mortality and morbidity, thus infection control measures are of paramount importance. Despite the advances in detecting viral pathogens, limited progress has been made in antiviral treatments, contributing to unexpectedly high rates of unfavorable outcomes. Herein, we review the most updated data on epidemiology, common clinical features, diagnosis, pathogenesis, treatment and prevention of severe community- and hospital-acquired viral infections in the ICU settings.

Evaluation of Diagnostic Tests

As technology advances, diagnostic tests continue to improve and each year, we are presented with new alternatives to standard procedures. Given the plethora of diagnostic alternatives, diagnostic tests must be evaluated to determine their place in the diagnostic armamentarium. The first step involves determining the accuracy of the test, including the sensitivity and specificity, positive and negative predictive values, likelihood ratios for positive and negative tests, and receiver operating characteristic (ROC) curves. The role of the test in a diagnostic pathway has then to be determined, following which the effect on patient outcome should be examined.

The relationship between cyclonic weather regimes and seasonal influenza over the Eastern Mediterranean

The prediction of the occurrence of infectious diseases is of crucial importance for public health, as clearly seen in the ongoing COVID-19 pandemic. Here, we analyze the relationship between the occurrence of a winter low-pressure weather regime - Cyprus Lows - and the seasonal Influenza in the Eastern Mediterranean. We find that the weekly occurrence of Cyprus Lows is significantly correlated with clinical seasonal Influenza in Israel in recent years (R = 0.91; p < .05). This result remains robust when considering a complementary analysis based on Google Trends data for Israel, the Palestinian Authority and Jordan. The weekly occurrence of Cyprus Lows precedes the onset and maximum of Influenza occurrence by about one to two weeks (R = 0.88; p < .05 for the maximum occurrence), and closely follows their timing in eight out of ten years (2008-2017). Since weather regimes such as Cyprus Lows are more robustly predicted in weather and climate models than individual climate variables, we conclude that the weather regime approach can be used to develop tools for estimating the compatibility of the transmission environment for Influenza occurrence in a warming world. Furthermore, this approach may be applied to other regions and climate sensitive diseases. This study is a new cross-border inter-disciplinary regional collaboration for appropriate adaptation to climate change in the Eastern Mediterranean.

Molecular Testing for Acute Respiratory Tract Infections: Clinical and Diagnostic Recommendations From the IDSA's Diagnostics Committee

The clinical signs and symptoms of acute respiratory tract infections (RTIs) are not pathogen specific. Highly sensitive and specific nucleic acid amplification tests have become the diagnostic reference standard for viruses, and translation of bacterial assays from basic research to routine clinical practice represents an exciting advance in respiratory medicine. Most recently, molecular diagnostics have played an essential role in the global health response to the novel coronavirus pandemic. How best to use newer molecular tests for RTI in combination with clinical judgment and traditional methods can be bewildering given the plethora of available assays and rapidly evolving technologies. Here, we summarize the current state of the art with respect to the diagnosis of viral and bacterial RTIs, provide a practical framework for diagnostic decision making using selected patient-centered vignettes, and make recommendations for future studies to advance the field.

Point-of-care diagnostic tests for influenza in the emergency department: A cost-effectiveness analysis in a high-risk population from a Canadian perspective

BACKGROUND

Our objective was to assess the cost-effectiveness of novel rapid diagnostic tests: rapid influenza diagnostic tests (RIDT), digital immunoassays (DIA), rapid nucleic acid amplification tests (NAAT), and other treatment algorithms for influenza in high-risk patients presenting to hospital with influenza-like illness (ILI).

METHODS

We developed a decision-analytic model to assess the cost-effectiveness of diagnostic test strategies (RIDT, DIA, NAAT, clinical judgement, batch polymerase chain reaction) preceding treatment; no diagnostic testing and treating everyone; and not treating anyone. We modeled high-risk 65-year old patients from a health payer perspective and accrued outcomes over a patient's lifetime. We reported health outcomes, quality-adjusted life years (QALYs), healthcare costs, and net health benefit (NHB) to measure cost-effectiveness per cohort of 100,000 patients.

RESULTS

Treating everyone with no prior testing was the most cost-effective strategy, at a cost-effectiveness threshold of $50,000/QALY, in over 85% of simulations. This strategy yielded the highest NHB of 15.0344 QALYs, but inappropriately treats all patients without influenza. Of the novel rapid diagnostics, NAAT resulted in the highest NHB (15.0277 QALYs), and the least number of deaths (1,571 per 100,000). Sensitivity analyses determined that results were most impacted by the pretest probability of ILI being influenza, diagnostic test sensitivity, and treatment effectiveness.

CONCLUSIONS

Based on our model, treating high-risk patients presenting to hospital with influenza-like illness, without performing a novel rapid diagnostic test, resulted in the highest NHB and was most cost-effective. However, consideration of whether treatment is appropriate in the absence of diagnostic confirmation should be taken into account for decision-making by clinicians and policymakers.