Point-of-care tests for influenza A and B viruses and RSV in emergency departments - indications, impact on patient management and possible gains by syndromic respiratory testing, Capital Region, Denmark, 2018

Diagnostic utility of rapid antigen testing as point-of-care test for influenza and other respiratory viruses in patients with acute respiratory illness

This study investigates the prevalence and clinical characteristics of respiratory viruses among patients with acute respiratory illness (ARI) in a low-resource setting, using a rapid antigen test as a point-of-care test (POCT). We included 343 patients presenting with ARI symptoms at an outpatient pulmonary clinic from December 2023 to April 2024. Nasopharyngeal swabs were tested for SARS-CoV-2, influenza A/B, respiratory syncytial virus, and adenovirus using POCT. The overall prevalence of respiratory viruses was 21.2 %, with influenza A being the most common (11.4 %). Shorter duration of symptoms and lower lymphocyte counts were associated with higher influenza positivity. Patients who tested positive for influenza received significantly more antiviral therapy (98.1 % vs. 39.4 %, p<0.001) and less antibiotic therapy (1.9 % vs. 28.5 %, p<0.001) compared to those who tested negative. The study highlights the utility of rapid antigen testing in enhancing antiviral and antibiotic stewardship, thereby improving clinical decision-making and patient outcomes in resource-limited settings.

Understanding the Burden of Respiratory Syncytial Virus in Older Adults in Latin America: An Expert Perspective on Knowledge Gaps

Respiratory syncytial virus (RSV) is a significant global health concern and major cause of hospitalization, particularly among infants and older adults. The clinical impact of RSV is well characterized in infants; however, in many countries, the burden and risk of RSV in older populations are overlooked. In Latin America, there are limited data on RSV epidemiology and disease management in older adults. Therefore, the impact of RSV in this region needs to be addressed. Here, current insights on RSV infections in older populations in Latin America, including those with underlying health conditions, are discussed. We also outline the key challenges limiting our understanding of the burden of RSV in Latin America in a worldwide context and propose an expert consensus to improve our understanding of the burden of RSV in the region. By so doing, we aim to ultimately improve disease management and outcomes of those at risk and to alleviate the impact on healthcare systems.A graphical plain language summary is available with this article.

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

BACKGROUND

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

CONTENT

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

SUMMARY

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

Point-of-Care and Rapid Tests for the Etiological Diagnosis of Respiratory Tract Infections in Children: A Systematic Review and Meta-Analysis

Fever is one of the most common causes of medical evaluation of children, and early discrimination between viral and bacterial infection is essential to reduce inappropriate prescriptions. This study aims to systematically review the effects of point-of-care tests (POCTs) and rapid tests for respiratory tract infections on changing antibiotic prescription rate, length of stay, duration of therapy, and healthcare costs. Embase, MEDLINE, and Cochrane Library databases were systematically searched. All randomized control trials and non-randomized observational studies meeting inclusion criteria were evaluated using the NIH assessment tool. A meta-analysis was performed to assess the effects of rapid influenza diagnostic tests and film-array respiratory panel implementation on selected outcomes. From a total of 6440 studies, 57 were eligible for the review. The analysis was stratified by setting and POCT/rapid test type. The most frequent POCTs or rapid tests implemented were the Rapid Influenza Diagnostic Test and film-array and for those types of test a separate meta-analysis assessed a significant reduction in antibiotic prescription and an improvement in oseltamivir prescription. Implementing POCTs and rapid tests to discriminate between viral and bacterial infections for respiratory pathogens is valuable for improving appropriate antimicrobial prescriptions. However, more studies are needed to assess these findings in pediatric settings.

Emergence of circulating influenza A H3N2 viruses with genetic drift in the matrix gene: Be alert of false negative test results

In March 2022, we observed samples with a negative fluorescent signal (60.5%, n=43) for the influenza A matrix gene, and a stronger positive signal for subtype A(H3N2). Forty-three samples were positive in InfA (H3N2) (mean Cq 30.9, range 23.9-35.1) and 26 of the 43 samples were negative in InfA matrix (mean Cq 28.0, range 23.2-30.6). Our multiplex test is a laboratory developed four-target, four-color influenza A reverse-transcription PCR assay targeting the matrix gene, subtypes A(H3N2) and A(H1N1)pdm09. Several samples were negative when retested on commercial influenza Point-of-Care assays. As the matrix gene is a stand-alone target in most commercial diagnostic assays, we caution against false negative subtype A test results.

Effect of point-of-care influenza tests on antibiotic prescriptions by emergency physicians in a French hospital

BACKGROUND

Influenza is a public health issue worldwide. Although antibiotics should not be used to treat viral infections, they are often prescribed to patients with influenza-like illness (ILI). Such misuse promotes antibiotic resistance. The role of rapid point-of-care tests (POCT) in preventing antibiotic misuse in adults with ILI symptoms remains relatively unexplored.

AIM

To evaluate whether POCT implemented in 2018-2019 to detect influenza viruses lead to a decrease in antibiotic prescriptions compared to laboratory based influenza tests.

METHODS

Adult patients with ILI in one emergency department (ED) were retrospectively enrolled over three epidemic seasons (from 2016-2017 to 2018-2019). The primary outcome was the rate of antibiotic prescriptions, which was compared between the three seasons in bivariate and multivariate analyses. Prescriptions for ancillary laboratory tests, chest X-rays and oseltamivir were also compared, along with hospitalisations and length of stay (LOS) at the ED.

FINDINGS

Overall, 1849 patients were included. Median age was over 70 throughout all three seasons. The number of antibiotic prescriptions was significantly different between the three periods in bivariate analysis (48.3% in 2016/2017, 44% in 2017/2018 and 31.1% in 2018/2019; p<0,0001) and in multivariate analysis (adjusted Odds Ratio [aOR]=0.48, 95%CI=0.30-0.76 for 2018/2019 and aOR=0.99, 95%CI=0.67-1.46 for 2017/2018, compared to 2016/2017). There were significantly fewer prescriptions of ancillary laboratory tests, X-rays, hospitalisations and more oseltamivir prescriptions in 2018/2019, compared to the previous seasons. LOS was significantly lower in 2018/2019 only for influenza-positive patients.

CONCLUSION

ED influenza POCT decreased antibiotic use and lead to less ancillary testing, X-rays and hospitalisations among patients with ILI. However, medico-economic studies are necessary before formulating definite recommendations.

Point of care testing for infectious disease: ownership and quality

Traditionally, diagnosis of acute infections has been organism-growth based, which makes timely and actionable infection diagnosis a major challenge. In addition, traditional microbial detection methods, including direct microscopy, are not suited for outsourcing to clinical, non-laboratory-educated personnel. Optimal management of patients with known or suspected clinical infections, such as targeted (or no) antimicrobial treatment and correct use of single room contact isolation facilities, requires rapid identification of the causative infectious microorganism. We are now facing a new disruptive paradigm shift in diagnostic microbiology. The availability of small-footprint robust instruments with easy-to-use assay kits allows non-laboratory-trained nurses and physicians to perform high-quality molecular diagnostics in a near-patient setting with results available in <30 minutes. This technology is currently breaking the centralized laboratory monopoly on the delivery of gold-standard clinical microbiology diagnostics. There is clear potential for huge positive impacts on clinical patient management and antibiotic stewardship, especially in settings where access to timely laboratory test results is not possible, but there are also potentially huge risks. Moving diagnostic testing away from the controlled diagnostic laboratory environment will lead to risks such as increased risk of inappropriate use of the diagnostic tests, insufficient training of staff performing the tests, incorrect interpretation of the test results, lack of quality control procedures, failure to capture test results in electronic patient records and compromised local as well as national surveillance. To reap the upside and avoid the downside of point-of-care infectious disease testing, the diagnostic laboratory needs to maintain oversight, and each institution must have a clear strategy for implementation and execution. If we fail, the risks could outweigh the benefits.

Multicenter evaluation of molecular point-of-care testing and digital immunoassays for influenza virus A/B and respiratory syncytial virus in patients with influenza-like illness

INTRODUCTION

Digital immunoassays (DIAs) and molecular point-of-care (POC) tests for influenza were recently developed. We aimed to evaluate and compare the positive rate with molecular POC tests and DIAs in detecting influenza virus A, B and respiratory syncytial virus (RSV).

METHODS

A prospective observational study was conducted in 2019-2020. Nasopharyngeal swab samples were collected from adult outpatients with influenza-like illness who visited four hospitals and clinics in Japan. DIAs were performed at each facility. The clinical diagnosis was determined based on the findings of DIAs, history taking, and physical assessment. Molecular POC test and reverse transcription polymerase chain reaction (RT-PCR) were performed later.

RESULTS

A total of 182 patients were evaluated. The positive rate for influenza virus with molecular POC test was significantly higher than that with DIAs (51.6% versus 40.7%, p = 0.046). In patients who tested positive for influenza virus with only molecular POC test, the presence of influenza virus was confirmed by RT-PCR. In a comparison between the patients who were positive for influenza virus with only molecular POC test and those with both molecular POC test and DIA, the percentage of patients who sought consultation within 18 h after the onset of symptoms was significantly higher in the molecular POC test only group than in the both methods group (70.0% versus 43.2%, p = 0.044).

CONCLUSIONS

A molecular POC test could contribute to the accurate diagnosis of influenza in patients with influenza-like illness, especially those who visited a hospital immediately after the onset of symptoms.