Rapid Influenza Diagnostic Tests Research Articles

Synchronicity of influenza activity within Phoenix, AZ during the 2015-2016 seasonal epidemic

BackgroundVariability in the timing of influenza epidemics has been observed across global and regional scales, but this variability has not been studied extensively at finer spatial scales. As such, the aim of this study was to test whether influenza cases were synchronized across sites and/or age-groups within a major city.MethodsWe used influenza cases identified by rapid influenza tests from a network of clinics across Phoenix, AZ during the 2015–2016 influenza A season. We used a combination of KS tests and a bootstrapping approach to evaluate whether the temporal distribution of cases varied by site and/or age group.ResultsOur analysis indicates that the timing of influenza cases during the 2015–2016 seasonal influenza epidemic were generally synchronized across sites and age groups. That said, we did observe some statistically significant differences in the timing of cases across some sites, and by site and age group. We found no evidence that influenza activity consistently begins or peaks earlier in children than in adults.ConclusionsTo our knowledge, this is the first study to investigate differences in the intra-urban timing of influenza using influenza-specific case data. We were able to show evidence that influenza cases are not entirely synchronized across an urban area, but the differences we observed were relatively minor. It is important to understand the geographic scale at which influenza is synchronized in order to gain a better understanding of local transmission dynamics, and to determine the appropriate geographic scale that influenza surveillance data should be aggregated for prediction and warning systems.

Rapid Molecular Detection and Differentiation of Influenza Viruses A and B.

Influenza is a contagious respiratory illness caused by influenza viruses A and B in humans and causes a significant amount of morbidity and mortality every year. The Influenza A and B assay was the first CLIA-waived molecular rapid flu test available. The Influenza A and B test works by employing isothermal amplification with influenza-specific primers followed by target detection with molecular beacon probes. Here, the performance of the Influenza A and B assay on frozen, archived nasopharyngeal swab (NPS) specimens stored in viral transport medium (VTM) were compared to a respiratory panel assay. The performance of the Influenza A and B assay was evaluated by comparing the results to the respiratory panel reference method. The sensitivity for total influenza virus A was 67.5% (95% CI (CI), 56.6-78.5) and the specificity was 86.9% (CI, 71.0-100). For influenza virus B testing, the sensitivity and specificity were 90.2% (CI, 68.5-100) and 98.8% (CI, 68.5-100), respectively. This system has the advantage of a significantly shorter test time than any other currently available molecular assay and the simple, pipette-free procedure runs on a fully integrated, closed, small-footprint system. Overall, the Influenza A and B assay evaluated in this study has the potential to serve as a point-of-care rapid influenza diagnostic test.

The use of saliva specimens for detection of influenza A and B viruses by rapid influenza diagnostic tests

Background and objectivesDiagnostic tests for influenza infection commonly use nasopharyngeal swabs (NPS) even though these are invasive to obtain. As an alternative specimen, we evaluated the diagnostic usefulness of saliva samples with rapid influenza diagnostic tests (RIDTs). Study designBoth NPS and saliva samples were collected from 385 influenza suspected patients and analyzed using Sofia Influenza A+B Fluorescence Immunoassay (Quidel Corporation, San Diego, CA, USA), ichroma TRIAS Influenza A+B (Boditech, Chuncheon, Korea), SD Bioline Influenza Ag (Standard Diagnostic, Yonggin, Korea), BinaxNOW Influenza A/B antigen kit (Alere Inc., Waltham, MA, USA), and real-time reverse transcriptase PCR (RT-PCR). ResultsOf the 385 patients, 31.2% (120/385) were positive for influenza A, and 7.5% (29/385) were positive for influenza B virus with saliva or NPS by RT-PCR. The diagnostic sensitivity was slightly higher in NPS than in saliva samples for both influenza A and B by all of the four RIDTs. The diagnostic sensitivities of Sofia and ichroma TRIAS were significantly superior to those of the other conventional influenza RIDTs with both types of sample. The sensitivities of Sofia and ichroma TRIAS with saliva specimens were comparable to the sensitivities of the other two conventional RIDTs with NPS specimens. The simultaneous use of saliva and NPS samples exhibited improved sensitivity from 10.0% to 13.3% for influenza A and from 10.3% to 17.2% for influenza B compared to using NPS alone. ConclusionsThis study demonstrates that saliva is a useful specimen for influenza detection, and that the combination of saliva and NPS could improve the sensitivities of influenza RIDTs.

Evaluation of the point-of-care Becton Dickinson Veritor\u2122 Rapid influenza diagnostic test in Kenya, 2013\u20132014

BackgroundWe evaluated the performance of the Becton Dickinson Veritor™ System Flu A + B rapid influenza diagnostic test (RIDT) to detect influenza viruses in respiratory specimens from patients enrolled at five surveillance sites in Kenya, a tropical country where influenza seasonality is variable.MethodsNasal swab (NS) and nasopharyngeal (NP)/oropharyngeal (OP) swabs were collected from patients with influenza like illness and/or severe acute respiratory infection. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the RIDT using NS specimens were evaluated against nasal swabs tested by real time reverse transcription polymerase chain reaction (rRT-PCR). The performance parameter results were expressed as 95% confidence intervals (CI) calculated using binomial exact methods, with P < 0.05 considered significant. Two-sample Z tests were used to test for differences in sample proportions. Analysis was performed using SAS software version 9.3.ResultsFrom July 2013 to July 2014, 3,569 patients were recruited, of which 78.7% were aged <5 years. Overall, 14.4% of NS specimens were influenza-positive by RIDT. RIDT overall sensitivity was 77.1% (95% CI 72.8–81.0%) and specificity was 94.9% (95% CI 94.0–95.7%) compared to rRT-PCR using NS specimens. RIDT sensitivity for influenza A virus compared to rRT-PCR using NS specimens was 71.8% (95% CI 66.7–76.4%) and was significantly higher than for influenza B which was 43.8% (95% CI 33.8–54.2%). PPV ranged from 30%–80% depending on background prevalence of influenza.ConclusionAlthough the variable seasonality of influenza in tropical Africa presents unique challenges, RIDTs may have a role in making influenza surveillance sustainable in more remote areas of Africa, where laboratory capacity is limited.

Rapid Influenza Diagnostic Tests Improve Suitability of Antiviral Treatment in Hospitalized Children.

Influenza may have a complicated course in young children. The aim of the study was to analyze the suitability of influenza treatment among children younger than 5 years hospitalized due to an influenza-like illness. We conducted a comparison of the treatment among children hospitalized in two consecutive years: 2015, when no rapid influenza diagnostic tests (RIDT) were in use, and 2016, when RIDT were implemented into a routine practice in the pediatric ward. In both seasons, nasopharyngeal swabs were collected and examined with real time qRT-PCR. In the 2015 season, influenza was diagnosed in 15/52 (28 %) children and none of them received oseltamivir, while 14/15 (93 %) patients received antibiotics. In the 2016 season, influenza was diagnosed in 11/63 (17 %) children, 7/11 (64 %) of them received oseltamivir and another 7/11 (64 %) received antibiotics. In four cases antibiotics overlapped oseltamivir. These differences in the use of oseltamivir and antibiotics were statistically significant (p < 0.05). We conclude that the implementation of RIDT improves the suitability of influenza treatment and decreases the frequency of antibiotic therapy. RIDT should be available in pediatric departments to optimize influenza treatment.

Prevalence of co-infection between respiratory syncytial virus and influenza in children

BackgroundRespiratory syncytial virus (RSV) and influenza have varying degree of seasonal overlap. ObjectiveTo determine the prevalence of co-infection of RSV and influenza compared to the prevalence of those infections independently when both are in season. MethodsThis was a retrospective cross-sectional study of children evaluated between July 2010 and June 2013 for viral respiratory infection using multiplex PCR. Seasonality was defined retrospectively as weeks when >2% of the total annual positive tests were obtained and was calculated for influenza A, influenza B, and RSV independently. Periods of overlapping seasonality of RSV and influenza A and RSV and influenza B were identified. The expected incidences of co-infection were modeled as the product of the incidences of the individual viruses. Results13,664 specimens were sent for PCR during the study period. Over all 3 seasons, RSV overlapped with influenza A and B for 22 and 18weeks, respectively; in 2011–12, RSV overlapped with neither influenza A nor B. Based on modeling, there were 6–7 fold fewer cases of RSV/influenza co-infection observed than expected: RSV/influenza A 77 vs. 12, (p≤0.001; RSV/influenza B 76 vs. 11 (p≤0.001). ConclusionsThe observed incidence of co-infectivity of RSV and influenza was significantly less than the expected incidence even when both were co-circulating. In light of these data, it may be reasonable to forgo rapid influenza testing or empiric antiviral treatment for children whom rapid RSV testing is positive and who are at low risk of influenza-related complications, especially in times of antiviral therapy shortages.

Early Diagnosis of Influenza Virus A Using Surface‐enhanced Raman Scattering‐based Lateral Flow Assay

We report a surface‐enhanced Raman scattering (SERS)‐based lateral flow assay (LFA) kit for the rapid diagnosis of influenza virus A. Influenza virus A is highly infectious and causes acute respiratory diseases. Therefore, it is important to diagnose the virus early to prevent a pandemic and to provide appropriate treatment to the patient and vaccination of high‐risk individuals. Conventional diagnostic tests, including virus cell culture and real‐time polymerase chain reaction, take longer than 1 day to confirm the disease. In contrast, a commercially available rapid influenza diagnostic test can detect the infection within 30 min, but it is hard to confirm viral infection using only this test because of its low sensitivity. Therefore, the development of a rapid and simple test for the early diagnosis of influenza infection is urgently needed. To resolve these problems, we developed a SERS‐based LFA kit in which the gold nanoparticles in the commercial rapid kit were replaced with SERS‐active nano tags. It is possible to quantitatively detect the influenza virus A with high sensitivity by measuring the enhanced Raman signal of these SERS nano tags on the LFA strip. The limit of detection (LOD) using our proposed SERS‐based LFA kit was estimated to be 1.9 × 104 PFU/mL, which is approximately one order of magnitude more sensitive than the LOD determined from the colorimetric LFA kit.

Contribution of a rapid influenza diagnostic test to manage hospitalized patients with suspected influenza

AimTo evaluate the performances of the Alere i influenza A&B test and to appraise its contribution to patient management. MethodsIn total, 267 samples were tested. Influenza A and B PCR was performed as the reference. For each positive result, the supervising physician was contacted to collect data regarding patient management. FindingsThe overall sensitivity and specificity of the Alere i were 91.4% and 97.6% for influenza A and 54.5% and 98.8% for influenza B, respectively. More specifically, when used in the emergency room (ER), the test helped avoid 10.7% of hospitalizations, 46.4% of antibiotic prescriptions and 42.9% of additional investigations for positive patients. The test was also helpful in instituting the prescription of oseltamivir and patient isolation. ConclusionAlere i influenza A&B is a rapid, sensitive and specific diagnostic test for influenza A. Sensitivity for influenza B was poor. Its usefulness was more important when patients were still in the ER.

22: Outcomes of a negative rapid influenza diagnostic test among pregnant women

22: Outcomes of a negative rapid influenza diagnostic test among pregnant women

Influenza Pandemic Preparedness Training for Health Professionals and Rapid Influenza Testing Course in Spanish

Influenza Pandemic Preparedness Training for Health Professionals and Rapid Influenza Testing Course in Spanish

Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan

The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case–control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE.

Effectiveness of the 2013 and 2014 Southern Hemisphere Influenza Vaccines Against Laboratory-confirmed Influenza in Young Children Using a Test-negative Design, Bangkok, Thailand.

The Thai Advisory Committee on Immunization Practices recommends annual influenza vaccination for children 6 months through 2 years of age, although older children may be vaccinated on request. We evaluated the effectiveness of the 2013 and 2014 inactivated influenza vaccines to reduce medically attended, laboratory-confirmed influenza illness among Thai children aged 7-60 months. From September 2013-May 2015, children with influenza-like illness were screened with a rapid influenza diagnostic test. Enrolled children had nasal and throat swabs tested for influenza viruses using polymerase chain reaction. Cases and controls were subjects testing positive and negative, respectively, for influenza viruses by polymerase chain reaction. Vaccination status was ascertained from vaccination cards. Vaccine effectiveness (VE) was calculated as 100% × (1 - odds ratio of vaccination among cases vs. controls). Of the 1377 children enrolled, cases (n = 490) and controls (n = 887) were similar in demographic characteristics. Cases were less likely to receive influenza vaccine than controls in 2013 (6% vs. 14%; P = 0.02), but not in 2014 (6% vs. 7%; P = 0.57). Among cases, 126 (26%) were positive for influenza A(H1N1)pdm09 virus, 239 (49%) for influenza A(H3N2) and 124 (25%) for influenza B. One specimen was positive for both influenza A(H3N2) and B viruses. VE for full vaccination against all viruses was 64% (95% confidence interval: 21% to 84%) in 2013 and 26% (95% confidence interval: -47% to 63%) in 2014. Influenza vaccination was low among Thai children in this study, and VE varied by year, highlighting the need for annual monitoring of VE to better understand vaccine program effectiveness.

Classification and Regression Tree (CART) analysis to predict influenza in primary care patients.

BackgroundThe use of neuraminidase-inhibiting anti-viral medication to treat influenza is relatively infrequent. Rapid, cost-effective methods for diagnosing influenza are needed to enable appropriate prescribing. Multi-viral respiratory panels using reverse transcription polymerase chain reaction (PCR) assays to diagnose influenza are accurate but expensive and more time-consuming than low sensitivity rapid influenza tests. Influenza clinical decision algorithms are both rapid and inexpensive, but most are based on regression analyses that do not account for higher order interactions. This study used classification and regression trees (CART) modeling to estimate probabilities of influenza.MethodsEligible enrollees ≥ 5 years old (n = 4,173) who presented at ambulatory centers for treatment of acute respiratory illness (≤7 days) with cough or fever in 2011–2012, provided nasal and pharyngeal swabs for PCR testing for influenza, information on demographics, symptoms, personal characteristics and self-reported influenza vaccination status.ResultsAntiviral medication was prescribed for just 15 % of those with PCR-confirmed influenza. An algorithm that included fever, cough, and fatigue had sensitivity of 84 %, specificity of 48 %, positive predictive value (PPV) of 23 % and negative predictive value (NPV) of 94 % for the development sample.ConclusionsThe CART algorithm has good sensitivity and high NPV, but low PPV for identifying influenza among outpatients ≥5 years. Thus, it is good at identifying a group who do not need testing or antivirals and had fair to good predictive performance for influenza. Further testing of the algorithm in other influenza seasons would help to optimize decisions for lab testing or treatment.

Comparison of two new generation influenza rapid diagnostic tests with instrument-based digital readout systems for influenza virus detection

Introduction: Influenza rapid diagnostic tests (RDTs) have been developed to supply scientists with more sensitive and specific techniques. Newly developed digital reader-based techniques require test evaluations before their clinical application.Methods: Two types of digital influenza RDTs using a digital readout system and one conventional RDT were compared using 314 nasopharyngeal swabs of influenza. The swabs originated from symptomatic individuals suspected of influenza infection, and the presence of influenza was confirmed with influenza real-time polymerase chain reaction (PCR) testing and influenza subtyping. Methods were the Sofia® Influenza A + B Fluorescence Immunoassay (FIA), which uses a portable fluorescence analyser, the BD Veritor™ System Flu A + B, which uses a colorimetric immunochromatographic method with a reflectance-based measurement digital device, and the SD Bioline assay, which is based on a traditional immunochromatographic method.Results: The Sofia® Influenza A + B system, the BD Veritor™ System Flu A + B and the SD Bioline assay showed sensitivities in relative real-time PCR results of 74.2, 73.0 and 53.9%, respectively, for influenza A, and 82.5, 72.8 and 71.0%, respectively, for influenza B. All three RDTs showed 100% specificities for influenza A and influenza B. The Sofia® Influenza A + B Fluorescence Immunoassay showed sensitive and specific results for the detection of influenza B in contrast to the BD Veritor™ System Flu A + B. The two digital RDTs showed higher sensitivity and specificity than the conventional RDT in the detection of the influenza H3 subtype.Conclusions: Digital-based readout systems for the detection of the influenza virus can be applied for more sensitive diagnosis in clinical settings than conventional RDTs.

Oseltamivir Treatment for Children with Influenza-Like Illness in China: A Cost-Effectiveness Analysis.

BackgroundInfluenza is a common viral respiratory infection that causes epidemics and pandemics in the human population. Oseltamivir is a neuraminidase inhibitor—a new class of antiviral therapy for influenza. Although its efficacy and safety have been established, there is uncertainty regarding whether influenza-like illness (ILI) in children is best managed by oseltamivir at the onset of illness, and its cost-effectiveness in children has not been studied in China.ObjectiveTo evaluate the cost-effectiveness of post rapid influenza diagnostic test (RIDT) treatment with oseltamivir and empiric treatment with oseltamivir comparing with no antiviral therapy against influenza for children with ILI.MethodsWe developed a decision-analytic model based on previously published evidence to simulate and evaluate 1-year potential clinical and economic outcomes associated with three managing strategies for children presenting with symptoms of influenza. Model inputs were derived from literature and expert opinion of clinical practice and research in China. Outcome measures included costs and quality-adjusted life year (QALY). All the interventions were compared with incremental cost-effectiveness ratios (ICER).ResultsIn base case analysis, empiric treatment with oseltamivir consistently produced the greatest gains in QALY. When compared with no antiviral therapy, the empiric treatment with oseltamivir strategy is very cost effective with an ICER of RMB 4,438. When compared with the post RIDT treatment with oseltamivir, the empiric treatment with oseltamivir strategy is dominant. Probabilistic sensitivity analysis projected that there is a 100% probability that empiric oseltamivir treatment would be considered as a very cost-effective strategy compared to the no antiviral therapy, according to the WHO recommendations for cost-effectiveness thresholds. The same was concluded with 99% probability for empiric oseltamivir treatment being a very cost-effective strategy compared to the post RIDT treatment with oseltamivir.ConclusionIn the Chinese setting of current health system, our modelling based simulation analysis suggests that empiric treatment with oseltamivir to be a cost-saving and very cost-effective strategy in managing children with ILI.

Performance of rapid SOFIA Influenza A+B test compared to Luminex x-TAG respiratory viral panel assay in the diagnosis of influenza A, B, and subtype H3

Influenza is an acute respiratory illness caused by influenza A or B viruses that occur in outbreaks, mainly during the winter season. Rapid laboratory diagnosis of influenza can help guide...

A prospective study to assess the diagnostic performance of the Sofia® Immunoassay for Influenza and RSV detection.

BackgroundRespiratory viruses RSV and influenza A and B viruses are responsible for important disease outbreaks during the winter season in temperate climate regions. Rapid diagnostic tests (RDTs) are assays designed to yield a rapid diagnosis, which facilitates patient management. The Sofia Influenza A+B Fluorescence Immunoassay and Sofia RSV Fluorescence Immunoassay are RDTs for Influenza and RSV detection that employ a new technology to enhance their sensitivity. ObjectivesSensitivity, specificity and positive and negative predictive values of the assays were calculated compared with the reference diagnostic method: real-time RT-PCR. Study designA prospective evaluation was carried out on 1065 respiratory samples for Sofia Influenza A+B FIA and on 261 samples for Sofia RSV FIA from November 2013 to April 2014. ResultsThe sensitivities of the Sofia Influenza A+B FIA for influenza A and influenza B detection were, respectively, 75.3% (244/324) and 50.0% (8/16). The sensitivity of the Sofia RSV FIA was 92.1% (128/139). There were no differences in Sofia FIA performance depending on the virus subtype. ConclusionsThe results showed high sensitivity and specificity values for influenza A and RSV detection, but values were lower for influenza B. More information is needed regarding the performance for influenza B given the small number of positive samples assessed.

Survey of influenza and other respiratory viruses diagnostic testing in US hospitals, 2012-2013.

Little is known about laboratory capacity to routinely diagnose influenza and other respiratory viruses at clinical laboratories and hospitals. We sought to assess diagnostic practices for influenza and other respiratory virus in a survey of hospitals and laboratories participating in the US Influenza Hospitalization Surveillance Network in 2012-2013. All hospitals and their associated laboratories participating in the Influenza Hospitalization Surveillance Network (FluSurv-NET) were included in this evaluation. The network covers more than 80 counties in 15 states, CA, CO, CT, GA, MD, MN, NM, NY, OR, TN, IA, MI, OH, RI, and UT, with a catchment population of ~28 million people. We administered a standardized questionnaire to key personnel, including infection control practitioners and laboratory departments, at each hospital through telephone interviews. Of the 240 participating laboratories, 67% relied only on commercially available rapid influenza diagnostic tests to diagnose influenza. Few reported the availability of molecular diagnostic assays for detection of influenza (26%) and other viral pathogens (≤20%) in hospitals and commercial laboratories. Reliance on insensitive assays to detect influenza may detract from optimal clinical management of influenza infections in hospitals.

Rapid Influenza Diagnostic Tests - Indications, Clinical Implications and Usefulness

Rapid Influenza Diagnostic Tests - Indications, Clinical Implications and Usefulness

Effectiveness of a pharmacist-physician collaborative program to manage influenza-like illness

ObjectivesTo examine the effectiveness of collaborative physician–community pharmacist programs to treat influenza-like illness (ILI) with respect to clinical outcomes and health care utilization. DesignProspective multicenter cohort study. SettingFifty-five pharmacies in Michigan, Minnesota, and Nebraska. PatientsAdult patients presenting to the pharmacy with ILI during the 2013–14 influenza season (October 1, 2013 to May 30, 2014). InterventionPharmacists screened adult patients presenting with ILI, completed a brief physical assessment, performed a point-of-care rapid influenza diagnostic test (RIDT), and provided appropriate referral or treatment per an established collaborative practice agreement (CPA) with a licensed prescriber. Pharmacists followed-up with patients 24 to 48 hours after the encounter to assess patient status and possible need for further intervention. Main outcome measuresNumber of patients screened, tested, and treated for influenza. ResultsOf the 121 patients screened, 45 (37%) were excluded and referred to their primary care provider or an urgent care facility for management. Of the 75 patients (62%) eligible for participation, 8 (11%) had a positive RIDT and were managed according to the CPA. Of the patients tested, 34.6% had no primary care physician and 38.7% visited the pharmacy outside of normal office hours. Only 3% of patients reported feeling worse at follow-up. ConclusionThis study describes a physician-pharmacist collaborative model for treating ILI. Using an evidence-based CPA, pharmacists were able to provide timely treatment to patients with and without influenza.