Performance of rapid influenza diagnostic tests (QuickVue) for influenza A and B Infection in India

An overview of advancement in aptasensors for influenza detection

INTRODUCTION

The platforms for early identification of infectious diseases such as influenza has seen a surge in recent years as delayed diagnosis of such infections can lead to dreadful effects causing large numbers of deaths. The time taken in detection of an infectious disease may vary from a few days to a few weeks depending upon the choice of the techniques. So, there is an urgent need for advanced methodologies for early diagnosis of the influenza.

AREAS COVERED

The emergence of "Aptasensor" synergistically with biosensors for diagnosis has opened a new era for sensitive, selective and early detection approaches. This review described various conventional as well as advanced methods based on artificial immunogenic nucleotide sequences complementing a part of the virus, i.e., aptamers based aptasensors for influenza diagnosis and the challenges faced in their commercialization.

EXPERT OPINION

Although numerous traditional methods are available for influenza detection but mostly associated with low sensitivity, specificity, high cost, trained personnel, and animals required for virus culture/ antibody raising as the major drawbacks. Aptamers can be manufactured invitro as 'chemical antibodies' at commercial level, no animal required. Following these advantages, aptamers can pave the way for an efficient diagnostic technique as compared to other existing conventional methods..

Assessment of potential factors associated with the sensitivity and specificity of Sofia Influenza A+B Fluorescent Immunoassay in an ambulatory care setting

Background

Seasonal influenza leads to an increase in outpatient clinic visits. Timely, accurate, and affordable testing could facilitate improved treatment outcomes. Rapid influenza diagnostic tests (RIDTs) provide results in as little as 15 minutes and are relatively inexpensive, but have reduced sensitivity when compared to RT-PCR. The contributions of multiple factors related to test performance are not well defined for ambulatory care settings. We assessed clinical and laboratory factors that may affect the sensitivity and specificity of Sofia Influenza A+B Fluorescence Immunoassay.

Study design

We performed a post-hoc assessment of surveillance data amassed over seven years from five primary care clinics. We analyzed 4,475 paired RIDT and RT-PCR results from specimens collected from patients presenting with respiratory symptoms and examined eleven potential factors with additional sub-categories that could affect RIDT sensitivity.

Results

In an unadjusted analysis, greater sensitivity was associated with the presence of an influenza-like illness (ILI), no other virus detected, no seasonal influenza vaccination, younger age, lower cycle threshold value, fewer days since illness onset, nasal discharge, stuffy nose, and fever. After adjustment, presence of an ILI, younger age, fewer days from onset, no co-detection, and presence of a nasal discharge maintained significance.

Conclusion

Clinical and laboratory factors may affect RIDT sensitivity. Identifying potential factors during point-of-care testing could aid clinicians in appropriately interpreting negative influenza RIDT results.

Evaluating an app-guided self-test for influenza: lessons learned for improving the feasibility of study designs to evaluate self-tests for respiratory viruses

Background

Seasonal influenza leads to significant morbidity and mortality. Rapid self-tests could improve access to influenza testing in community settings. We aimed to evaluate the diagnostic accuracy of a mobile app-guided influenza rapid self-test for adults with influenza like illness (ILI), and identify optimal methods for conducting accuracy studies for home-based assays for influenza and other respiratory viruses.

Methods

This cross-sectional study recruited adults who self-reported ILI online. Participants downloaded a mobile app, which guided them through two low nasal swab self-samples. Participants tested the index swab using a lateral flow assay. Test accuracy results were compared to the reference swab tested in a research laboratory for influenza A/B using a molecular assay.

Results

Analysis included 739 participants, 80% were 25–64 years of age, 79% female, and 73% white. Influenza positivity was 5.9% based on the laboratory reference test. Of those who started their test, 92% reported a self-test result. The sensitivity and specificity of participants’ interpretation of the test result compared to the laboratory reference standard were 14% (95%CI 5–28%) and 90% (95%CI 87–92%), respectively.

Conclusions

A mobile app facilitated study procedures to determine the accuracy of a home based test for influenza, however, test sensitivity was low. Recruiting individuals outside clinical settings who self-report ILI symptoms may lead to lower rates of influenza and/or less severe disease. Earlier identification of study subjects within 48 h of symptom onset through inclusion criteria and rapid shipping of tests or pre-positioning tests is needed to allow self-testing earlier in the course of illness, when viral load is higher.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06314-1.

Socioeconomic costs of influenza complications in hospitalized children

Introduction

Influenza may be correlated with a high number of complications and generate high costs of treatment. The study aimed to estimate the socioeconomic significance of hospitalized influenza cases.

Material and methods

In the 2015-2016 flu season 157 children (median age 17 months) were hospitalized in the Department of Pediatrics. The diagnosis was confirmed with the rapid influenza diagnostic test (RIDT), polymerase chain reaction (PCR) or both. The study assessed the direct and indirect costs of hospitalization, including the cost of treatment, work absence and the related income lost.

Results

The frequency of complications among the children hospitalized was 57.3% (90/157), mainly due to pneumonia (31%) and bronchitis (23%). Patients with complications required longer hospital treatment (8 vs. 6 days, p < 0.01) and generated a higher total cost (€ 1042 vs. € 779, p < 0.01), including the patient's and systemic costs (€123 vs. € 94, p < 0.01 and € 916 vs. € 690, p < 0.01, respectively). Patients with complications had a 3.5-fold higher risk of generating higher (i.e., above median) costs. The difference in the costs between children aged under 2 and those over 2 years old was greater than the difference between children aged under 5 and those over 5 years old (€ 358 vs. € 253).

Conclusions

Influenza complications generate higher systemic and patient's costs, both direct and indirect. The group of children for whom the difference is especially marked is under 2 years of age.

Quick assessment of influenza a virus infectivity with a long-range reverse-transcription quantitative polymerase chain reaction assay

BACKGROUND

The polymerase chain reaction (PCR) is commonly used to detect viral pathogens because of its high sensitivity and specificity. However, conventional PCR methods cannot determine virus infectivity. Virus infectivity is conventionally examined with methods such as the plaque assay, even though such assays require several days. Long-range reverse-transcription quantitative PCR (RT-qPCR) has previously been suggested for the rapid assessment of RNA virus infectivity where the loss of infectivity is attributable to genomic fragmentation.

METHODS

IAV was irradiated with 253.7 nm ultraviolet (UV) rays to induce genomic strand breaks that were confirmed by a full-length RT-PCR assay. The IAV was then subjected to plaque assay, conventional RT-qPCR and long-range RT-qPCR to examine the relationship between infectious titer and copy number. A simple linear regression analysis was performed to examine the correlation between the results of these assays.

RESULTS

A long-range RT-qPCR assay was developed and validated for influenza A virus (IAV). Although only a few minutes of UV irradiation was required to completely inactivate IAV, genomic RNA remained detectable by the conventional RT-qPCR and the full-length RT-PCR for NS of viral genome following inactivation. A long-range RT-qPCR assay was then designed using RT-priming at the 3' termini of each genomic segment and subsequent qPCR of the 5' regions. UV-mediated IAV inactivation was successfully analyzed by the long-range RT-qPCR assay especially when targeting PA of the viral genome. This was also supported by the regression analysis that the long-range RT-qPCR is highly correlated with plaque assay (Adjusted R² = 0.931, P = 0.000066).

CONCLUSIONS

This study suggests that IAV infectivity can be predicted without the infectivity assays. The rapid detection of pathogenic IAV has, therefore, been achieved with this sensing technology.

Very high sensitivity of a rapid influenza diagnostic test in adults and elderly individuals within 48 hours of the onset of illness

During influenza epidemics, Japanese clinicians routinely perform rapid influenza diagnostic tests (RIDTs) in the examination of patients who have an influenza-like illness, and patients with positive test results, including otherwise healthy individuals, are treated with anti-influenza drugs. However, it was recently reported that the sensitivity of RIDTs was extremely low in adult patients. We examined the sensitivity and specificity of an RIDT that is widely used in Japan, ImunoAce Flu (TAUNS, Shizuoka, Japan), in comparison to reverse transcriptase polymerase chain reaction (RT-PCR). The sensitivity and specificity of the ImunoAce Flu test were 97.1% (95%CI: 93.8–98.9) and 89.2% (95%CI: 84.1–93.1), respectively. The ImunoAce Flu test is designed to not only detect influenza A or B, but also to detect H1N1pdm09 with the use of an additional test kit (Linjudge FluA/pdm). Its sensitivity and specificity for A/H1N1pdm09 were 97.6% (95%CI: 87.4–99.9) and 92.6% (95%CI: 82.1–97.9), respectively. Thus, by consecutively testing patients with the ImunoAce Flu test followed by the Linjudge FluA/pdm test, we are able to diagnose whether a patient has A/H1N1pdm09 or A/H3N2 infection within a short time. The reliability of rapid test results seems to be much higher in Japan than in other countries, because approximately 90% of influenza patients are tested and treated within 48 hours after the onset of illness, when the influenza viral load in the upper respiratory tract is high. From the Japanese experience, RIDTs are sufficiently sensitive and highly useful, if patients are tested within 48 hours after the onset of illness.

Clinical Impact of Rapid Point-of-Care PCR Influenza Testing in an Urgent Care Setting: a Single-Center Study

Seasonal influenza virus causes significant morbidity and mortality each year. Point-of-care (POC) testing using rapid influenza diagnostic tests (RIDTs), immunoassays that detect viral antigens, are often used for diagnosis by physician offices and urgent care centers. These tests are rapid but lack sensitivity, which is estimated to be 50 to 70%. Testing by PCR is highly sensitive and specific, but historically these assays have been performed in centralized clinical laboratories necessitating specimen transport and increasing the time to result. Recently, Clinical Laboratory Improvement Amendments (CLIA)-waived, POC PCR influenza assays have been developed with >95% sensitivity and specificity compared to centralized PCR assays. To determine the clinical impact of a POC PCR test for influenza, we compared antimicrobial prescribing patterns of one urgent care location using the Cobas LIAT Influenza A/B assay (LIAT assay; Roche Diagnostics, Indianapolis, IN) to other urgent care centers in our health system using traditional RIDT, with negative specimens being reflexed to PCR. Antiviral prescribing was lower in patients with a negative LIAT PCR result (2.3%) than in patients with a negative RIDT result (25.3%; P < 0.005). Antivirals were prescribed more often in patients that tested positive by LIAT PCR (82.4%) than in those testing positive by either RIDT or reflex PCR (69.9%; P < 0.05). Antibacterial prescriptions for patients testing negative by LIAT PCR were higher (44.5%) than for those testing negative by RIDT (37.7%), although the difference was not statistically significant. In conclusion, having results from a PCR POC test during the clinic visit improved antiviral prescribing practices compared to having rapid results from an RIDT.

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.

Influenza: Underestimated in Children Below 2 Years of Age

Children under 2 years of age may receive antiviral therapy when influenza is suspected. Signs of influenza are frequently unclear and testing is indicated. The aim of the study was to assess the usefulness of clinical signs and the rapid influenza diagnostic test (RIDT) in diagnosing influenza and in choosing the appropriate treatment. In the 2015-2016 influenza season, 89 children under 2 years of age (56.7% of 157 children diagnosed with influenza) were hospitalized. There were 74 RIDT and 70 reverse transcription polymerase chain reactions (RT-PCR) performed for the purpose of diagnosis, either test per child. Eighty-three percent of children (74/89) presented with fever, 55.1% (49/89) with cough, and 39.3% (35/89) with both cough and fever. The RIDT was positive in 31.1% (23/74) of cases. The highest percentage of positive RIDT was within the first 24 h of disease, decreasing dramatically thereafter (70% vs. 13-17%, respectively). The RIDT shortened the time to diagnosis by 43.8 h/patient (an average €149 gain in treatment costs). The mean delay for RT-PCR-based diagnosis was 33.5 h/patient (an average €114 loss in treatment costs). We conclude that clinical signs have a low diagnostic sensitivity in children under 2 years of age. Likewise, RIDT is of low sensitivity, being diagnostically useful only in the first 24 h. The PCR is recommended for the diagnosis, but that requires a constant access to the method.

Rapid Tests for Influenza, Respiratory Syncytial Virus, and Other Respiratory Viruses: A Systematic Review and Meta-analysis

Rapid diagnosis of respiratory virus infections contributes to patient care. This systematic review evaluates the diagnostic accuracy of rapid tests for the detection of respiratory viruses. We searched Medline and EMBASE for studies evaluating these tests against polymerase chain reaction as the reference standard. Of 179 studies included, 134 evaluated rapid tests for influenza viruses, 32 for respiratory syncytial virus (RSV), and 13 for other respiratory viruses. We used the bivariate random effects model for quantitative meta-analysis of the results. Most tests detected only influenza viruses or RSV. Summary sensitivity and specificity estimates of tests for influenza were 61.1% and 98.9%. For RSV, summary sensitivity was 75.3%, and specificity, 98.7%. We assessed the quality of studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. Because of incomplete reporting, the risk of bias was often unclear. Despite their intended use at the point of care, 26.3% of tests were evaluated in a laboratory setting. Although newly developed tests seem more sensitive, high-quality evaluations of these tests are lacking.