Xpert Flu for point-of-care diagnosis of human influenza in industrialized countries

Epidemiological Characterization of Respiratory Pathogens Using the Multiplex PCR FilmArray™ Respiratory Panel

Various pathogens can cause upper respiratory tract infections, presenting challenges in accurate diagnosis due to similar symptomatology. Therefore, rapid and precise diagnostic tests are crucial for effective treatment planning. Traditional culture-based methods for diagnosis are limited by their reliance on skilled personnel and lengthy processing times. In contrast, multiplex polymerase chain reaction (PCR) techniques offer enhanced accuracy and speed in identifying respiratory pathogens. In this study, we aimed to assess the efficacy of the FilmArray™ Respiratory Panel (RP), a multiplex PCR test capable of simultaneously screening 20 pathogens. This retrospective analysis was conducted at Dankook University Hospital, South Korea, between January 2018 and December 2022. Samples from patients with upper respiratory tract infections were analyzed. Results revealed adenovirus as the most prevalent pathogen (18.9%), followed by influenza virus A (16.5%), among others. Notably, a 22.5% co-infection rate was observed. The FilmArray™ RP method successfully identified 20 pathogens within 2 h, facilitating prompt treatment decisions and mitigating unnecessary antibiotic prescriptions. This study underscores the utility of multiplex PCR in respiratory pathogen identification, offering valuable insights for epidemiological surveillance and diagnosis.

Rhinothermy delivered by nasal high flow therapy in the treatment of the common cold: a randomised controlled trial

BACKGROUND

The common cold is the most common infectious disease affecting humans and has a substantial economic impact on society. Human rhinoviruses, which cause almost two-thirds of colds, have demonstrated temperature-dependent replication which is optimal between 33°C and 35°C.

METHODS

This randomised, single-blind, parallel-group trial completed at a single-centre in New Zealand, recruited 170 participants aged 18-75 years (mean age 27.5 years) who were within 48 hours of common cold symptom onset and had a symptom score (the Modified Jackson Score (MJS)) ≥7 and a negative point-of-care test for influenza. Participants were blinded to the intervention and randomised (1:1) to 5 days of either nasal high flow rhinothermy (rNHF) (100% humidified air delivered at 35 L/min and 41°C for 2 hours daily) (n=85) or 'sham' rhinothermy (100% humidified air delivered at 10 L/min and 31°C for 10 min daily) (n=85) and completed daily symptom diaries, which included the MJS, for 14 days, to investigate whether rNHF reduced common cold symptom severity and duration compared with 'sham' rhinothermy.

RESULTS

An intention-to-treat superiority analysis included all randomised participants and showed no difference between treatment groups for the primary outcome, the day 4 MJS analysed by analysis of covariance: mean (SD) 6.33 (3.97) for rNHF vs 5.8 (3.15) for 'sham'; estimated difference (95% CI) 0.37 (-0.69 to 1.42), p=0.49. There was no difference in time until resolution of symptoms: mean (SD) 5.96 (4.47) days for rNHF vs 6.42 (4.09) days for 'sham'; estimated difference (95% CI) 1.02 (0.75 to 1.38), p=0.91. There were no serious adverse events related to the study treatments.

CONCLUSIONS

This well-powered, single-blind randomised controlled trial does not provide evidence that 5 days of rNHF (100% humidified air heated to 41°C delivered at 35 L/min for 2 hours daily) reduces common cold symptom severity or duration. However, investigation of rNHF in the treatment of influenza is warranted.

TRIAL REGISTRATION NUMBER

ACTRN12617001340325.

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

We systematically reviewed available evidence from Embase, Medline, and the Cochrane Library on diagnostic accuracy and clinical impact of commercially available rapid (results <3 hours) molecular diagnostics for respiratory viruses as compared to conventional molecular tests. Quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies criteria for diagnostic test accuracy (DTA) studies, and the Cochrane Risk of Bias Assessment and Risk of Bias in Nonrandomized Studies of Interventions criteria for randomized and observational impact studies, respectively. Sixty-three DTA reports (56 studies) were meta-analyzed with a pooled sensitivity of 90.9% (95% confidence interval [CI], 88.7%-93.1%) and specificity of 96.1% (95% CI, 94.2%-97.9%) for the detection of either influenza virus (n = 29), respiratory syncytial virus (RSV) (n = 1), influenza virus and RSV (n = 19), or a viral panel including influenza virus and RSV (n = 14). The 15 included impact studies (5 randomized) were very heterogeneous and results were therefore inconclusive. However, we suggest that implementation of rapid diagnostics in hospital care settings should be considered.

Protocol for a randomised, single-blind, two-arm, parallel-group controlled trial of the efficacy of rhinothermy delivered by nasal high flow therapy in the treatment of the common cold

INTRODUCTION

The common cold is the most common infectious disease affecting humans. It is usually a self-limiting disease; however, the common cold can cause significant morbidity and has a substantial economic impact on society. Human rhinoviruses (HRVs), which cause up to two-thirds of colds, have temperature-dependent replication and most HRV strains replicate optimally at 33°C. Delivery of heated, humidified air to the upper airways has the potential to reduce viral replication, but evidence of the effectiveness of this treatment of the common cold is inconclusive. We plan to test the hypothesis that delivery of humidified air heated to 41°C at high flow, nasal high flow rhinothermy (rNHF), for 2 hours daily for five days is more effective in reducing common cold symptom severity and duration than five days of 'sham' rhinothermy.

METHODS AND ANALYSIS

This is a randomised, single-blind, parallel-group trial comparing rNHF to 'sham' rhinothermy in the treatment of common cold. We plan to recruit 170 participants within 48 hours of the onset of symptoms of common cold and randomise them 1:1 to receive one of the two treatments for five days. The study duration is 14 days, which includes clinic visits on the first day of randomisation and four days post-randomisation, and a phone call on the 14th day. Participants will complete daily symptom diaries which include a symptom score, the Modified Jackson Score (MJS). The primary outcome is the MJS after four days.

ETHICS AND DISSEMINATION

New Zealand Ethics Registration: 17/STH/174. Results will be published in a peer-reviewed medical journal, presented at academic meetings, and reported to participants.

TRIAL REGISTRATION NUMBER

U1111-1194-4345 and ACTRN12617001340325; Pre-results.

Zoonotic Influenza and Human Health-Part 2: Clinical Features, Diagnosis, Treatment, and Prevention Strategies

Purpose of Review

Zoonotic influenza viruses are those influenza viruses that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this second part of a two-part review, we discuss the clinical features, diagnostic modalities, and treatment of zoonotic influenza, and provide an overview of prevention strategies.

Recent Findings

Illnesses caused by novel reassortant avian influenza viruses continue to be detected and described; most recently, a human case of avian influenza A(H7N4) has been described from China. We continue to witness increasing rates of A(H7N9) infections, with the latest (fifth) wave, from late 2016 to 2017, being the largest to date. The case fatality rate for A(H7N9) and A(H5N1) infections among humans is much higher than that of seasonal influenza infections. Since the emergence of the A(H1N1) 2009 pandemic, and subsequently A(H7N9), testing and surveillance for novel influenzas have become more effective. Various newer treatment options, including peramivir, favipiravir (T-705), and DAS181, and human or murine monoclonal antibodies have been evaluated in vitro and in animal models.

Summary

Armed with robust diagnostic modalities, antiviral medications, vaccines, and advanced surveillance systems, we are today better prepared to face a new influenza pandemic and to limit the burden of zoonotic influenza than ever before. Sustained efforts and robust research are necessary to efficiently deal with the highly mutagenic zoonotic influenza viruses.

The Point-of-Care Laboratory in Clinical Microbiology

Point-of-care (POC) laboratories that deliver rapid diagnoses of infectious diseases were invented to balance the centralization of core laboratories. POC laboratories operate 24 h a day and 7 days a week to provide diagnoses within 2 h, largely based on immunochromatography and real-time PCR tests. In our experience, these tests are conveniently combined into syndrome-based kits that facilitate sampling, including self-sampling and test operations, as POC laboratories can be operated by trained operators who are not necessarily biologists. POC laboratories are a way of easily providing clinical microbiology testing for populations distant from laboratories in developing and developed countries and on ships. Modern Internet connections enable support from core laboratories. The cost-effectiveness of POC laboratories has been established for the rapid diagnosis of tuberculosis and sexually transmitted infections in both developed and developing countries.

Comparison of Cepheid Xpert Flu/RSV XC and BioFire FilmArray for Detection of Influenza A, Influenza B, and Respiratory Syncytial Virus

The Xpert Flu/RSV XC was compared to the FilmArray respiratory panel for detection of influenza (Flu) A, Flu B, and respiratory syncytial virus (RSV), using 128 nasopharyngeal swabs. Positive agreements were 100% for Flu A and RSV and 92.3% for Flu B. The Xpert may be useful in clinical situations when extensive testing is not required and may serve an important role in laboratories already performing broader respiratory panel testing.

Prospective and retrospective evaluation of the Cepheid Xpert® Flu/RSV XC assay for rapid detection of influenza A, influenza B, and respiratory syncytial virus

A total of 281 clinical specimens (nasal swabs and nasopharyngeal aspirates) were tested with the Xpert® Flu/RSV XC. The results were compared to those obtained with the real-time retro transcriptase-polymerase chain reaction assays routinely used in our laboratory. The Xpert® Flu/RSV XC showed sensitivity/specificity of 97.8%/100% and 97.9%/100% for flu and respiratory syncytial virus, respectively.

•

Real-time RT-PCR is gold standard for diagnosis of influenza and RSV in human samples.

•

Xpert® Flu/RSV XC assay sensitivity >97.75% and 100% specificity for both viruses.

•

Similar performances using nasal swabs or and nasopharyngeal aspirate specimens.

•

Turnaround time is 63 min, minimal training, suitable for point-of-care settings.

•

No need for confirmation of the results.

The Enigma ML FluAB-RSV assay: a fully automated molecular test for the rapid detection of influenza A, B and respiratory syncytial viruses in respiratory specimens

The Enigma(®) ML FluAB-RSV assay (Enigma Diagnostics, Porton Down, Salisbury, UK) is a CE-IVD marked multiplex molecular panel for the detection of influenza A, B and respiratory syncytial viruses in nasopharyngeal swabs. The assay runs on the fully automated Enigma ML platform without further specimen manipulation and provides a sample-to-answer result within 95 min. The reported sensitivity and specificity for influenza A are 100% (95% CI: 98.2-100) and 98.3% (95% CI: 95.5-99.4), respectively, for influenza B are 100% (95% CI: 98.2-100) and 98.7% (95% CI: 96-99.6), respectively, and for respiratory syncytial virus are 100% (95% CI: 98.2-100) and 99.4% (95% CI: 97.2-99.9), respectively.