Analytical performance of the BD veritor™ system for rapid detection of influenza virus A and B in a primary healthcare setting

Effectiveness of repeated influenza vaccination among the elderly population with high annual vaccine uptake rates during the three consecutive A/H3N2 epidemics

BACKGROUND

Annually, about 80% of the Korean elderly aged ≥65 years receive influenza vaccination. Repeated annual vaccination has been suggested as an important factor of poor influenza vaccine effectiveness (VE), though reported conflicting results.

METHODS

During the consecutive A/H3N2-dominant influenza seasons between 2012 and 2015, we comparatively evaluated the VE (repeated vs. current season only) against laboratory-confirmed influenza, pneumonia and hospitalization in the elderly aged ≥65 years with influenza-like illness (ILI). Clinical and demographic data were collected prospectively, and vaccination status of prior and current seasons was verified using the immunization registry data of Korean Centers for Disease Control and Prevention.

RESULTS

During the first A/H3N2-dominant season in 2012-2013, influenza vaccine showed statistically significant effectiveness against influenza A infection only and when vaccinated in the current season only (VE 53%, 95% CI 15-77). In the latter two seasons (2013-2015 years), the adjusted VE for influenza A was indistinguishable between repeated vaccination and vaccination in the current season only.

CONCLUSION

During consecutive influenza A/H3N2 epidemics, poor influenza vaccine effectiveness may be more pronounced among the elderly population with a high annual vaccine uptake rate.

Analytical performances of the BD Veritor™ System for the detection of respiratory syncytial virus and influenzaviruses A and B when used at bedside in the pediatric emergency department

This study aims to evaluate the analytical performance of the BD Veritor™ rapid diagnostic assays (RDTs) for respiratory syncytial virus (RSV) and influenzaviruses when performed 24/7 at bedside by nurses in the pediatric emergency department (PED). The study was performed between 14/10/2015 and 19/03/2016 on nasopharyngeal aspirates (NPAs) collected from children consulting at the PED of the University Hospital of Saint-Etienne for bronchiolitis (RSV detection) or flu-like syndrome (influenzaviruses A/B detection). NPAs were tested 24/7 at the PED with the RDT and then sent to the Infectious Agents Department for routine analyses, first by immunofluorescence assay (IFA), then by nucleic acid amplification test (NAAT) considered as the gold standard in case of discrepancy between RDT and IFA results. For RSV detection, 205 NPAs was analyzed; the overall concordance between RDT and routine assays was of 97.6% (200/205). The sensitivity (Se), specificity (Sp), negative predictive value (NPV) and positive predictive value (PPV) were of 97.6% (160/164), 97.6% (40/41), 90.9% (40/44) and 99.4% (160/161), respectively. A total of 419 NPA was tested for influenzaviruses. For influenzavirus A, the overall concordance was of 98.8% (414/419); Se, Sp, NPV and PPV were of 100% (41/41), 98.7% (373/378), 100% (373/373) and 89.1% (41/46), respectively. For influenzavirus B, the overall concordance was of 97.9% (410/419); Se, Sp, NPV and PPV were of 96.6% (172/178), 98.8% (238/241), 97.5% (238/244) and 98.3% (172/175), respectively. Due to their excellent performances and their easy handle by non-laboratory personnel, these RDTs can be warmly recommended as point of care assays at the PED.

Impact of bedside diagnosis of influenza in the paediatric emergency ward

OBJECTIVES

This prospective study performed in the paediatric emergency department of the University Hospital of Saint-Etienne aimed to measure the impact of the 24/7 bedside use of the Veritor™ System (Becton Dickinson) on the reduction of supplementary investigations, hospital stay and antimicrobial use.

METHODS

Influenza virus A and B antigens were detected with a rapid influenza digital immunoassay (DIA) on nasopharyngeal aspirates (NPAs) sampled from the children consulting at the paediatric emergency department between January and March 2016 for influenza-like illness. The same NPA was tested by immunofluorescence and/or molecular routine assays. Before performing the DIA, the clinician filled in a questionnaire listing the tests that he/she would have prescribed in the absence of the rapid testing. The prescription of complementary investigations, antimicrobial treatments and hospital stay were also compared to those of the 3 previous years.

RESULTS

A total of 514 children with flu-like symptoms were included. The use of the DIA at bedside decreased the prescription of blood puncture by 47.9% (21.2% to 6.6%), of chest X-rays by 69.0% (33.3% to 10.3%), of lumbar puncture by 77.8% (7.0% to 1.6%), of urine culture by 79.2% (23.3% to 4.9%), of antibiotic treatments by 70.1% (16.9% to 5.1%), and of hospital stay by 25.0% (27.2% to 20.4%), resulting in a reduction of medical costs estimated to more than €69 000 in a season.

CONCLUSIONS

In addition to delivering a rapid aetiological diagnosis, this strategy saves medical costs and favours an antimicrobial stewardship strategy. However, further prospective studies are needed to confirm our findings.

Detection Methods of Human and Animal Influenza Virus-Current Trends

The basic affairs connected to the influenza virus were reviewed in the article, highlighting the newest trends in its diagnostic methods. Awareness of the threat of influenza arises from its ability to spread and cause a pandemic. The undiagnosed and untreated viral infection can have a fatal effect on humans. Thus, the early detection seems pivotal for an accurate treatment, when vaccines and other contemporary prevention methods are not faultless. Public health is being attacked with influenza containing new genes from a genetic assortment between animals and humankind. Unfortunately, the population does not have immunity for mutant genes and is attacked in every viral outbreak season. For these reasons, fast and accurate devices are in high demand. As currently used methods like Rapid Influenza Diagnostic Tests lack specificity, time and cost-savings, new methods are being developed. In the article, various novel detection methods, such as electrical and optical were compared. Different viral elements used as detection targets and analysis parameters, such as sensitivity and specificity, were presented and discussed.

Point-of-care diagnostics for respiratory viral infections

Introduction: Successful treatment outcomes for viral respiratory tract infections presenting from primary health care to quaternary hospitals will only be achieved with rapid, sensitive and specific identification of pathogens to allow effective pathogen-specific antiviral therapy and infection control measures.

Areas covered: This review aims to explore the different point-of-care tests currently available to diagnose viral respiratory tract infections, discuss the advantages and limitations of point-of-care testing, and provide insights into the future of point-of-care tests. The following databases were searched: Medline (January 1996 to 30 September 2017) and Embase (1988 to 30 September 2017), using the following keywords: ‘point of care’, ‘respiratory virus’, ‘influenza’, ‘RSV’, ‘diagnostics’, ‘nucleic acid test’ and ‘PCR’.

Expert commentary: Viral respiratory tract infections cause significant morbidity and mortality worldwide, and point-of-care tests are facilitating the rapid identification of the pathogen responsible given the similarities in clinical presentation.

Comparison of the Alere i and BD Veritor Assays for the Rapid Detection of Influenza A and B Viruses

BACKGROUND

The use of point-of care testing (POCT) in patient management decisions is becoming increasingly common. Our goal was to evaluate the diagnostic performance of 2 commercially available rapid POCT devices for influenza viruses A and B: the Alere™ i Instrument (Alere, Scarborough) and the BD Veritor™ System (BD Diagnostics).

METHODS

Paired nasopharyngeal swabs were collected from patients (18-71 years) presenting with influenza-like symptoms at 3 outpatient clinics. A total of 65 samples were obtained. The Alere i and BD Veritor were performed according to the manufacturers' instructions. Discordant results were resolved using real-time reverse transcription PCR (RT-PCR).

RESULTS

In a head-to-head comparison involving symptomatic adult patients visiting outpatient clinics during the 2014-2015 and 2015-2016 influenza seasons, the Alere i and BD Veritor had 90.63% agreement in the detection of influenza A virus and a statistically significant observed κ coefficient of 0.754 (P <0.0001). Discordant results between the Alere i and BD Veritor were further investigated using RT-PCR, showing that the BD Veritor missed 5 positive influenza A virus results (false negatives) and detected 1 false positive, while the Alere i results agreed with all RT-PCR results. There were no discordant results between the Alere i and BD Veritor in the detection of influenza B virus.

CONCLUSIONS

Our data suggest that the Alere i has higher sensitivity and specificity than the BD Veritor in the detection of influenza A virus. Both assays showed equal performance in the detection of influenza B virus.