Rapid Influenza Diagnostic Tests Research Articles

A(H3N2) antigenic variation of influenza is associated with low vaccine efficacy in the early 2018 influenza season in Mexico City

ObjectivesWe evaluated the VE and the mutations of the viruses present in the Mexican population at the beginning of 2018. MethodsWe diagnosed influenza in outpatients with a high-performance Rapid Influenza Diagnostic Test (RIDT) qRT–PCR. Descriptive statistics were used to describe the study population, while the chi-square test was used to determine clinical variables. VE was analyzed through a negative test design. We sequenced the hemagglutinin (HA) gene, performed a phylogenetic analysis, and analyzed the nonsynonymous substitutions both in and outside antigenic sites. ResultsOf the 240 patients analyzed, 42.5% received the trivalent vaccine, and 37.5% were positive for influenza. The VE for the general population for any influenza virus type or subtype was 37.0%, while the VE for the predominant influenza A(H3N2) subtype was the lowest (19.7%). The phylogenetic analysis of HA showed the co-circulation of clades and subclades 3C.2a1, 3C.2a1b, 3C.2a2, 3C.2a2re, 3C.2a3, and 3C.3a with identities approximately 97-98% similar to the vaccine composition. ConclusionLow VE was related to the co-circulation of multiple clades and subclades of influenza A(H3N2), with sufficient genetic and phenotypic distance to allow for the infection of vaccinated individuals.

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

IntroductionDespite 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. MethodsA 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. ResultsResponses 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. ConclusionMost 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.

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.

Clinical impact of the rapid molecular detection of RSV and influenza A and B viruses in the emergency department.

IntroductionUsing respiratory virus rapid diagnostic tests in the emergency department could allow better and faster clinical management. Point-of-care PCR instruments now provide results in less than 30 minutes. The objective of this study was to assess the impact of the use of a rapid molecular diagnostic test, the cobas® Influenza A/B & RSV Assay, during the clinical management of emergency department patients.MethodsPatients (adults and children) requiring admission or suffering from an underlying condition at risk of respiratory complications were prospectively recruited in the emergency department of four hospitals in the Brussels region. Physicians’ intentions regarding admission, isolation, antibiotic, and antiviral use were collected before and after performing the rapid molecular test. Additionally, a comparison of the analytical performance of this test against antigen rapid tests and viral culture was performed as well as a time-to-result evaluation.ResultsAmong the 293 patients recruited, 90 had a positive PCR, whereas 44 had a positive antigen test. PCR yielded a sensitivity of 100% for all targets. Antigen tests yielded sensitivities ranging from 66.7% for influenza B to 83.3% for respiratory syncytial virus (RSV). The use of PCR allowed a decrease in the overall need for isolation and treatment by limiting the isolation of negative patients and antibiotic use for positive patients. Meanwhile, antiviral treatments better targeted patients with a positive influenza PCR.ConclusionThe use of a rapid influenza and RSV molecular test improves the clinical management of patients admitted to the emergency department by providing a fast and reliable result. Their additional cost compared to antigen tests should be balanced with the benefit of their analytical performance, leading to efficient reductions in the need for isolation and antibiotic use.

A narrative review of nine commercial point of care influenza tests: an overview of methods, benefits, and drawbacks to rapid influenza diagnostic testing.

Rapid influenza diagnostic tests (RIDTs) are becoming increasingly accurate, available, and reliable as the first line of testing when suspecting influenza infections, although the global burden of influenza infections remains high. Rapid diagnosis of influenza infections has been shown to reduce improper or delayed treatment and to increase access to diagnostic measures in public health, primary care, and hospital-based settings. As the use of RIDTs continues to expand in all healthcare settings, there is a multitude of molecular techniques being employed by these various testing platforms. With this in mind, we compare the sensitivity, specificity, and time to diagnosis for nine highly utilized commercial RIDTs. Nine commercially available RIDTs were identified from the US Centers for Disease Control and Prevention (CDC) website, which were also referenced on PubMed by name within the title or abstract of peer-reviewed publications examining the sensitivity and specificity of each test against a minimum of three influenza A virus (IAV) strains as well as seasonal influenza B virus (IBV). Data from the peer-reviewed publications and manufacturers' websites were combined to discuss the sensitivity, specify, and time to diagnosis associated with each RIDT. The sensitivity and specificity across the examined RIDTs were greater than 85.0% for both IAV and IBV across all platforms, with the reverse transcriptase-polymerase chain reaction (RT-PCR) assays maintaining sensitivity and specificity greater than 95.0% for all viruses tested. However, the RT-PCR platforms were the longest in time to diagnosis when compared to the other molecular methods utilized in the examined RIDTs. Herein, we discussed the benefits and limitations of nine commercially available RIDTs and the molecular techniques upon which they are based, showing the relative accuracy and speed of each test for IAV and IBV detection as reported by the peer-reviewed literature and commercial manufacturers.

Patient perceptions of acute infectious disease point-of-care tests and treatment within community pharmacy settings

BackgroundCommunity pharmacies are well-positioned to help patients overcome many health care barriers they experience when trying to receive care. Community pharmacists are ready and equipped to provide patient care interventions like the test-and-treat model for acute infectious diseases. ObjectivesThe objective of this study was to determine patients’ experiences with rapid strep and influenza tests administered at community pharmacies, focusing on what impacted patients’ decisions to receive care, their perception of the care received, and if offering these tests in community pharmacies expanded their access to care. MethodsSeven independently owned pharmacies in Tennessee and Kentucky from November 2020 to April 2021 recruited study participants. Qualitative semi-structured key informant interviews were conducted using the theory of planned behavior as a theoretical framework. Participant interviews were audio recorded, transcribed, and independently coded by 2 investigators and reviewed by a third investigator. A qualitative analysis was completed, with a selection of supporting quotations for each theme. Qualitative analysis identified participant perceptions of rapid strep and flu POCT and treatments provided in community pharmacies, consistency and quality of patient care, and if these interventions expanded their access to care. ResultsA total of 11 patients participated in the interviews; of which, 9 (81.8%) participants were female, and participants ages ranged from 22 to 64 years (median, 40 years). Of 11, 7 participants received a strep test, 3 participants received a flu test, and 1 participant received both the tests. The analysis uncovered 10 major themes within the following 4 different categories: (1) convenience to patients, (2) quality of care received, (3) improved access to care, and (4) additional interventions for which patients want expanded access to care. ConclusionPharmacies offering services like rapid strep and flu tests provide convenience and quality care that can help expand patient access to health care and could help provide expanded access for underserved populations.

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

ObjectiveDuring 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.MethodsThis 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.ResultsA 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).ConclusionIn 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.

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

IntroductionThe 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.MethodsAt 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.ResultsOf 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.ConclusionsThe 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.

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

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. 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. 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. 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.

Factors associated with children’s seasonal influenza diagnosis by their guardians: a prospective observational study in Japan

Introduction Children's influenza diagnosis by their guardians has been reported to be highly accurate, but clinical factors that improve the reliability of a guardian's diagnosis are unclear. Aim To determine the accuracy of guardians' influenza diagnosis of their children, investigate clinical factors that improve the diagnostic accuracy, and determine the additional clinical value of the guardian's diagnosis. Methods A prospective observational study was conducted at a primary care clinic in Japan from December 2017 to April 2019. Pre-examination checklists completed by guardians accompanying children aged Results A total of 112 patient pairs of child (median age, 6 years) and guardian (mother, 81.2%; father, 16.1%; grandmother, 1.8%; other, 0.9%) were included in the analysis. The AUC for guardians' influenza diagnosis was higher in mothers (0.72), as well as pairs with children with a history of influenza (0.72), guardians who were aware of the influenza epidemic (0.71), and unvaccinated children (0.76), than in other guardians. After multivariate analysis, the AUC increased significantly from 0.79 to 0.85. Discussion Guardians' influenza diagnosis for their children was highly accurate. We identified factors that improve the accuracy of the guardians' diagnosis and demonstrated that the guardians' diagnosis can support physicians' diagnostic accuracy.

Trends in effectiveness of inactivated influenza vaccine in children by age groups in seven seasons immediately before the COVID-19 era

BackgroundWe have reported the vaccine effectiveness of inactivated influenza vaccine in children aged 6 months to 15 years between the 2013/14 and 2018/19 seasons. Younger (6–11 months) and older (6–15 years old) children tended to have lower vaccine effectiveness. The purpose of this study is to investigate whether the recent vaccine can be recommended to all age groups. MethodsThe overall adjusted vaccine effectiveness was assessed from the 2013/14 until the 2020/21 season using a test-negative case-control design based on rapid influenza diagnostic test results. Vaccine effectiveness was calculated by influenza type and by age group (6–11 months, 1–2, 3–5, 6–12, and 13–15 years old) with adjustments including influenza seasons. ResultsA total of 29,400 children (9347, 4435, and 15,618 for influenza A and B, and test-negatives, respectively) were enrolled. The overall vaccine effectiveness against influenza A, A(H1N1)pdm09, and B was significant (44% [95% confidence interval (CI), 41–47], 63% [95 %CI, 51–72], and 37% [95 %CI, 32–42], respectively). The vaccine was significantly effective against influenza A and B, except among children 6 to 11 months against influenza B. The age group with the highest vaccine effectiveness was 1 to 2 years old with both influenza A and B (60% [95 %CI, 55–65] and 52% [95 %CI, 41–61], respectively). Analysis for the 2020/21 season was not performed because no cases were reported. ConclusionsThis is the first report showing influenza vaccine effectiveness by age group in children for several seasons, including immediately before the coronavirus disease (COVID-19) era. The fact that significant vaccine effectiveness was observed in nearly every age group and every season shows that the recent vaccine can still be recommended to children for the upcoming influenza seasons, during and after the COVID-19 era.

Clinical manifestations and outcome of viral acute lower respiratory infection in hospitalised children in Myanmar

BackgroundAcute lower respiratory infection (ALRI) remains the leading cause of death in children worldwide, and viruses have been the major cause of ALRI. In Myanmar, ALRI is associated with high morbidity and mortality in children, and detailed information on ALRI is currently lacking.MethodsThis prospective study investigated the viral aetiologies, clinical manifestations, and outcomes of ALRI in hospitalised children aged 1 month to 12 years at the Yankin Children Hospital, Yangon, Myanmar from May 2017 to April 2019. The sample size was set to 300 patients for each year. Two nasopharyngeal swabs were obtained for the patients with suspected viral ALRI; one for rapid tests for influenza and respiratory syncytial virus (RSV), and the other for real-time PCR for the 16 ALRI-causing viruses. Pneumococcal colonization rates were also investigated using real-time PCR. Clinical information was extracted from the medical records, and enrolled patients were categorised by age and severity for comparison.ResultsAmong the 5463 patients admitted with a diagnosis of ALRI, 570 (10.4%) were enrolled in this study. The median age of the patients was 8 months (interquartile range, 4–15 months). The most common symptoms were cough (93%) and difficulty in breathing (73%), while the most common signs of ALRI were tachypnoea (78%) and chest indrawing (67%). A total of 16 viruses were detected in 502 of 570 patients’ samples (88%), with RSV B (36%) and rhinovirus (28%) being the most commonly detected. Multiple viruses were detected in 221 of 570 samples (37%) collected from 570 patients. Severe ALRI was diagnosed in 107 of 570 patients (19%), and RSV B and human rhinovirus were commonly detected. The mortality rate was 5%; influenza virus A (29%) and RSV B (21%) were commonly detected, and stunting and lack of immunization were frequently observed in such cases. Additionally, 45% (259/570) of the patients had pneumococcal colonization.ConclusionsViral ALRI in hospitalised children with a median of 8 months has significant morbidity and mortality rates in Myanmar. RSV and rhinovirus were the most commonly detected from nasopharyngeal swabs, while influenza virus and RSV were the most frequently associated with fatal cases.

Viral co-infections are associated with increased rates of hospitalization in those with influenza.

BackgroundInfluenza causes significant morbidity and mortality in the United States. Among patients infected with influenza, the presence of bacterial co‐infection is associated with worse clinical outcomes; less is known regarding the clinical importance of viral co‐infections. The objective of this study was to determine rates of viral co‐infections in emergency department (ED) patients with confirmed influenza and association of co‐infection with disease severity.MethodsSecondary analysis of a biorepository and clinical database from a parent study where rapid influenza testing was implemented in four U.S. academic EDs, during the 2014–2015 influenza season. Patients were systematically tested for influenza virus using a validated clinical decision guideline. Demographic and clinical data were extracted from medical records; nasopharyngeal specimens from influenza‐positive patients were tested for viral co‐infections (ePlex, Genmark Diagnostics). Patterns of viral co‐infections were evaluated using chi‐square analysis. The association of viral co‐infection with hospital admission was assessed using univariate and multivariate regression.ResultsThe overall influenza A/B positivity rate was 18.1% (1071/5919). Of the 999 samples with ePlex results, the prevalence of viral co‐infections was 7.9% (79/999). The most common viral co‐infection was rhinovirus/enterovirus (RhV/EV), at 3.9% (39/999). The odds of hospital admission (OR 2.33, 95% CI: 1.01–5.34) increased significantly for those with viral co‐infections (other than RhV/EV) versus those with influenza A infection only.ConclusionPresence of viral co‐infection (other than RhV/EV) in ED influenza A/B positive patients was independently associated with increased risk of hospital admission. Further research is needed to determine clinical utility of ED multiplex testing.

Flu@home: the Comparative Accuracy of an At-Home Influenza Rapid Diagnostic Test Using a Prepositioned Test Kit, Mobile App, Mail-in Reference Sample, and Symptom-Based Testing Trigger.

ABSTRACTAt-home testing with rapid diagnostic tests (RDTs) for respiratory viruses could facilitate early diagnosis, guide patient care, and prevent transmission. Such RDTs are best used near the onset of illness when viral load is highest and clinical action will be most impactful, which may be achieved by at-home testing. We evaluated the diagnostic accuracy of the QuickVue Influenza A+B RDT in an at-home setting. A convenience sample of 5,229 individuals who were engaged with an on-line health research platform were prospectively recruited throughout the United States. “Flu@home” test kits containing a QuickVue RDT and reference sample collection and shipping materials were prepositioned with participants at the beginning of the study. Participants responded to daily symptom surveys. If they reported experiencing cough along with aches, fever, chills, and/or sweats, they used their flu@home kit following instructions on a mobile app and indicated what lines they saw on the RDT. Of the 976 participants who met criteria to use their self-collection kit and completed study procedures, 202 (20.7%) were positive for influenza by qPCR. The RDT had a sensitivity of 28% (95% CI = 21 to 36) and specificity of 99% (98 to 99) for influenza A, and 32% (95% CI = 20 to 46) and 99% (95% CI = 98 to 99), for influenza B. Our results support the concept of app-supported, prepositioned at-home RDT kits using symptom-based triggers, although it cannot be recommended with the RDT used in this study. Further research is needed to determine ways to improve the accuracy and utility of home-based testing for influenza.

CLINICAL AND LABORATORY FINDINGS IN CHILDREN WITH INFLUENZA INFECTIONS

ABSTRACT Objective: We aimed to show the clinical characteristics of children with influenza infection and the relationship between influenza infections and hemogram parameters, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), neutrophil/monocyte ratio (NMR), and mean platelet volume (MPV). Methods: The data of patients who applied to Necmettin Erbakan University Meram Medical Faculty Pediatrics outpatient clinics and had positive rapid influenza test were scanned through the hospital information system. Results: The median age and neutrophil value in the influenza A group were significantly lower than in the influenza B group (p=.002, p=.008). The median MPV and monocyte value in the influenza A group were significantly higher than in influenza B (p&amp;lt;.00, p=.005). The mean WBC count was found to be significantly higher in hospitalized patients compared to outpatients. (p = .039). There were no significant difference between the groups in terms of NLR, PLR, NMR. Bacteremia was detected significantly more in hospitalized patients compared to outpatients. Underlying chronic diseases were significantly lower in outpatients than in inpatients.(p&amp;lt;.001) Conclusion: There were no difference in the severity of clinical severity between infleunza A and B subgroups and no significant difference was found in terms of hemogram parameters.

Reducing Unnecessary Respiratory Viral Testing to Promote High-Value Care.

Viral respiratory infections are common in children, and practice guidelines do not recommend routine testing for typical viral illnesses. Despite results often not impacting care, nasopharyngeal swabs for viral testing are frequently performed and are an uncomfortable procedure. The aim of this initiative was to decrease unnecessary respiratory viral testing (RVT) in the emergency department (ED) and the pediatric medicine wards (PMWs) by 50% and 25%, respectively, over 36 months. An expert panel reviewed published guidelines and appropriate evidence to formulate an RVT pathway using plan-do-study-act cycles. A multifaceted improvement strategy was developed that included implementing 2 newer, more effective tests when testing was deemed necessary; electronic order modifications with force functions; audit and feedback; and education. By using statistical process control charts, the outcomes analyzed were the percentage of RVT ordered in the ED and the rate of RVT ordered on the PMWs. Balancing measures included return visits leading to admission and inpatient viral nosocomial outbreaks. The RVT rate decreased from a mean of 3.0% to 0.5% of ED visits and from 44.3 to 30.1 per 1000 patient days on the PMWs and was sustained throughout the study. Even when accounting for the new rapid influenza test available in the ED, a 50% decrease in overall ED RVT was still achieved without any significant impact on return visits leading to admission or inpatient nosocomial infections. Through implementation of a standardized, electronically integrated RVT pathway, a decrease in unnecessary RVT was successfully achieved. Audit and feedback, reminders, and biannual education all supported long-term sustainability of this initiative.

A rapid influenza diagnostic test based on detection of viral neuraminidase activity

Current methods used for diagnosis of acute infection of pathogens rely on detection of nucleic acids, antigens, or certain classes of antibodies such as IgM. Here we report a virus enzyme assay as an alternative to these methods for detection of acute viral infection. In this method, we used a luciferin derivative as the substrate for detection of the enzyme activity of influenza viral neuraminidase as a means for diagnosis of influenza. The resulting commercial test, the qFLU Dx Test, uses a different supply chain that does not compete with those for the current tests. The assay reagents were formulated as a master mix that accommodated both the neuraminidase and luciferase reactions, thereby enabling rapid and prolonged production of stable light signal in the presence of influenza virus in the sample. The assay was evaluated using depository throat swab specimens. As expected, the assay exhibited similar detection rates for all influenza types and subtypes except for A(H7N9), which exhibited lower detection rate due to lower viral titer in the specimens. When throat swab specimens were diluted with the sample buffer of the test kit and tested with the qFLU Dx Test. The sensitivity and specificity were 82.41% (95% confidence interval: 79.66–85.84%) and 95.39% (95% confidence interval: 94.32–96.46%), respectively, for these diluted specimens in comparison to a real-time polymerase chain reaction assay. The uniqueness of the qFLU Dx Test as an enzymatic assay makes it highly complementary with currently available methods.

Performance of a Rapid Diagnostic Test for Influenza in a Tertiary Military Hospital, Philippines.

It is important to evaluate the performance of existing rapid influenza diagnostic tests (RIDTs) and the factors that can affect performance especially when the circulation dynamics of influenza strains change such as the displacement and replacement of the circulating seasonal influenza strains. Nasal swabs were collected from patients presenting at V Luna Medical Center, Armed Forces of the Philippines Health Service Command, with influenza-like illness (ILI) with one swab tested using Quickvue (QV) influenza A+B RIDT (Quidel) and the other swab tested using the ABI 7500 (Applied Biosystems) real-time reverse transcriptase-polymerase chain reaction. Sensitivity, specificity, positive predictive value, and negative predictive value were estimated. We identified clinical symptoms predictive of influenza subtype and evaluated the independence of QV sensitivity on (1) Cycle threshold (Ct) value, controlling for timing of collection; (2) timing of collection, controlling for Ct value; and (3) Ct value and timing of collection taken together. Between August 2011 and October 2016, patients presenting with ILI (n = 2333) underwent testing. Quickvue sensitivity across all subtypes was significantly correlated with lower Ct values (higher virus titers) (P <.001) and, except for flu A/H3 (P = .974), was also significantly associated with timing of specimen collection (P <.05). No statistically significant difference was noted in QV sensitivity for Flu A/H3 (P = .130), pandemic H1/N1 (P = .207), Flu A/H3 + pandemic H1/N1 (P = .341), and Flu B (P = .103) across different age groups but sensitivity of QV significantly differed (P <.001) across the different influenza subtypes. Overall specificity of QV was high across all flu subtypes, but overall sensitivity was low (Flu A/pdm H1) to moderate (Flu A/H3 and Flu B). The findings highlight the need to develop more sensitive influenza RDTs to detect circulating influenza strains and the use of the quadrivalent flu vaccine during the annual influenza vaccination.

Benign acute childhood myositis: Factors associated with muscle symptoms and resolution.

Benign acute childhood myositis (BACM) is associated with several viral infections. The aim of this study was to evaluate the progression of myositis symptoms, laboratory findings and oseltamivir treatment in children with influenza- and non-influenza-associated BACM. Patients aged 0-18 years old, admitted to the pediatric emergency department in the seasonal influenza period between 2018 and 2020 were retrospectively analyzed. Patients with acute onset calf tenderness, pain, difficulty in walking and elevated serum creatine phosphokinase were included and were grouped according to influenza rapid test kit results as influenza (A and B) positive, and influenza negative. The time to symptom resolution, laboratory data and the oseltamivir treatment were compared between the groups. There were 94 patients (67 male, 27 female) with a mean age of 77 ± 22 months. Influenza A was detected in 21, influenza B in 27, and neither were detected in 46 patients. Time to symptom resolution of BACM was shorter in the influenza-positive patients than in influenza-negative patients (2.9 ± 1.4 days and 3.5 ± 1.5 days, respectively, P = 0.027). Oseltamivir did not reduce the symptom resolution time in influenza patients. All children had normal hemoglobin and platelet counts, elevated creatine phosphokinase and 76% of them had leukopenia. Neither clinical recurrence nor metabolic disease were reported. Symptoms of BACM tended to resolve slightly earlier in influenza-positive patients and the duration of symptoms was not affected by oseltamivir treatment.

Provider views on rapid diagnostic tests and antibiotic prescribing for respiratory tract infections: A mixed methods study.

BackgroundRespiratory tract infections (RTIs) are often inappropriately treated with antibiotics. Rapid diagnostic tests (RDTs) have been developed with the aim of improving antibiotic prescribing but uptake remains low. The aim of this study was to examine provider knowledge, attitudes and behaviors regarding RDT use and their relationship to antibiotic prescribing decisions across multiple clinical departments in an urban safety-net hospital.MethodsWe conducted a mixed methods sequential explanatory study. Providers with prescribing authority (attending physicians, nurse practitioners and physician assistants) who had at least 20 RTI encounters from January 1, 2016 to December 31, 2018. Eighty-five providers completed surveys and 16 participated in interviews. We conducted electronic surveys via RedCap from April to July 2019, followed by semi-structured individual interviews from October to December 2019, to ascertain knowledge, attitudes and behaviors related to RDT use and antibiotic prescribing.ResultsSurvey findings indicated that providers felt knowledgeable about antibiotic prescribing guidelines. They reported high familiarity with the rapid streptococcus and rapid influenza tests. Familiarity with comprehensive respiratory panel PCR (RPP-respiratory panel PCR) and procalcitonin differed by clinical department. Qualitative interviews identified four main themes: providers trust their clinical judgment more than rapid test results; patient-provider relationships play an important role in prescribing decisions; there is patient demand for antibiotics and providers employ different strategies to address the demand and providers do not believe RDTs are implemented with sufficient education or evidence for clinical practice.ConclusionPrescribers are knowledgeable about prescribing guidelines but often rely on clinical judgement to make final decisions. The utility of RDTs is specific to the type of RDT and the clinical department. Given the low familiarity and clinical utility of RPP and procalcitonin, providers may require additional education and these tests may need to be implemented differently based on clinical department.