Comparison of four clinical specimen types for detection of influenza A and B viruses by optical immunoassay (FLU OIA test) and cell culture methods

Differential detection of H1N1 virus spiker proteins by two hexaphenylbutadiene isomers based on size-matching principle

As one of the high pathogenic influenza viruses, H1N1 virus easily induces to serious diseases, even leading to death. To date, all detection methods for H1N1 virus had shortcomings, including high equipment cost, time consumption, and etc. Therefore, a novel detection method should be established to achieve more convenient, rapid, and low-cost detection. In this work, an isomer of HPBmN-I with aggregation-induced emission characteristic was firstly synthesized on the basis of our previous reported HPBpN-I. The results showed that HPBmN-I only selectively binds to N1 in the presence of H1, while HPBpN-I can exhibit total fluorescence response to H1 and N1 in H1/N1 mixture. The limited of detection (LOD) of HPBmN-I to N1 was estimated to be 20.82 ng/mL in normal saline (NS) according to the IUPAC-based approach. The simulation calculations based on molecular docking revealed that four HPBmN-I molecules combine well with the hydrophobic cavity of N1 and achieve the fluorescence enhancement due to size matching with each other. The combination of HPBpN-I and HPBmN-I as probes was successfully used to quantitatively detect H1 and N1 in real H1N1 virus. Compared to enzyme-linked immunosorbent assay (ELISA) method, the established method not only showed the same detection accuracy but also had the advantages of real-time, ease of preparation, and low-cost, demonstrating potential market prospects.

Seasonal influenza viruses decay more rapidly at intermediate humidity in droplets containing saliva compared to respiratory mucus

Expulsions of virus-laden aerosols or droplets from the oral and nasal cavities of an infected host are an important source of onward respiratory virus transmission. However, the presence of infectious influenza virus in the oral cavity during infection has not been widely considered, and thus, little work has explored the environmental persistence of influenza virus in oral cavity expulsions. Using the ferret model, we detected infectious virus in the nasal and oral cavities, suggesting that the virus can be expelled into the environment from both anatomical sites. We also assessed the stability of two influenza A viruses (H1N1 and H3N2) in droplets of human saliva or respiratory mucus over a range of relative humidities. We observed that influenza virus infectivity decays rapidly in saliva droplets at intermediate relative humidity, while viruses in airway surface liquid droplets retain infectivity. Virus inactivation was not associated with bulk protein content, salt content, or droplet drying time. Instead, we found that saliva droplets exhibited distinct inactivation kinetics during the wet and dry phases at intermediate relative humidity, and droplet residue morphology may lead to the elevated first-order inactivation rate observed during the dry phase. Additionally, distinct differences in crystalline structure and nanobead localization were observed between saliva and airway surface liquid droplets. Together, our work demonstrates that different respiratory fluids exhibit unique virus persistence profiles and suggests that influenza viruses expelled from the oral cavity may contribute to virus transmission in low- and high-humidity environments.IMPORTANCEDetermining how long viruses persist in the environment is important for mitigating transmission risk. Expelled infectious droplets and aerosols are composed of respiratory fluids, including saliva and complex mucus mixtures, but how well influenza viruses survive in such fluids is largely unknown. Here, we find that infectious influenza virus is present in the oral cavity of infected ferrets, suggesting that saliva-containing expulsions can play a role in onward transmission. Additionally, influenza virus in droplets composed of saliva degrades more rapidly than virus within respiratory mucus. Droplet composition impacts the crystalline structure and virus localization in dried droplets. These results suggest that viruses from distinct sites in the respiratory tract could have variable persistence in the environment, which will impact viral transmission fitness.

Comparison of "hock-a-loogie" saliva versus nasopharyngeal and oropharyngeal swabs for detecting common respiratory pathogens

Self-collection of saliva samples has attracted considerable attention in recent years, particularly during the coronavirus disease 2019 pandemic. However, studies investigating the detection of other common respiratory pathogens in saliva samples are limited. In this study, nasopharyngeal swabs (NPS), oropharyngeal swabs (OPS), and "hock-a-loogie" saliva (HLS) were collected from 469 patients to detect 13 common respiratory pathogens. Overall positivity rates for NPS (66.1 %), HLS (63.5 %), and OPS (57.8 %) were statistically different (P = 0.028), with an overall concordance of 72.7 %. Additionally, detection rates for NPS (85.9 %) and HLS (83.2 %) for all pathogens were much higher than for OPS (73.3 %). Coronavirus and human rhinovirus were most frequently detected pathogens in NPS (P < 0.001). Mycoplasma pneumoniae was significantly more prevalent in the HLS group (P = 0.008). In conclusion, NPS was a reliable sample type for detecting common respiratory pathogens. HLS was more easily collected and can be used in emergencies or specific conditions. Mixed NPS/OPS and NPS/HLS specimens have the potential to improve detection rates, although OPS testing alone has a relatively high risk for missed detection.

Vaccination for seasonal flu, pneumococcal infection, and SARS-CoV-2 in patients with solid tumors: recommendations of the Associazione Italiana di Oncologia Medica (AIOM)

Patients with cancer have a well-known and higher risk of vaccine-preventable diseases (VPDs). VPDs may cause severe complications in this setting due to the immune system impairment, malnutrition and oncological treatments. Despite this evidence, vaccination rates are inadequate. The Italian Association of Medical Oncology (AIOM) has been involved in vaccination awareness since 2014. Based on a careful review of the available data about the immunogenicity, effectiveness and safety of flu, pneumococcal and anti-SARS-CoV-2 vaccines, we report the recommendations of the Associazione Italiana di Oncologia Medica about these vaccinations in adult patients with solid tumors. AIOM recommends comprehensive education on the issue of VPDs. We believe that a multidisciplinary care model may improve the vaccination coverage in immunocompromised patients. Continued surveillance, implementation of preventive practices and future well-designed immunological prospective studies are essential for a better management of our patients with cancer.

Next Generation Sequencing Approaches to Characterize the Respiratory Tract Virome

The COVID-19 pandemic and heightened perception of the risk of emerging viral infections have boosted the efforts to better understand the virome or complete repertoire of viruses in health and disease, with a focus on infectious respiratory diseases. Next-generation sequencing (NGS) is widely used to study microorganisms, allowing the elucidation of bacteria and viruses inhabiting different body systems and identifying new pathogens. However, NGS studies suffer from a lack of standardization, in particular, due to various methodological approaches and no single format for processing the results. Here, we review the main methodological approaches and key stages for studies of the human virome, with an emphasis on virome changes during acute respiratory viral infection, with applications for clinical diagnostics and epidemiologic analyses.

Association between lipid profiles and viral respiratory infections in human sputum samples

Background

Respiratory infections such as influenza account for significant global mortality each year. Generating lipid profiles is a novel and emerging research approach that may provide new insights regarding the development and progression of priority respiratory infections. We hypothesized that select clusters of lipids in human sputum would be associated with specific viral infections (Influenza (H1N1, H3N2) or Rhinovirus).

Methods

Lipid identification and semi-quantitation was determined with liquid chromatography and high-resolution mass spectrometry in induced sputum from individuals with confirmed respiratory infections (influenza (H1N1, H3N2) or rhinovirus). Clusters of lipid species and associations between lipid profiles and the type of respiratory viral agent was determined using Bayesian profile regression and multinomial logistic regression.

Results

More than 600 lipid compounds were identified across the sputum samples with the most abundant lipid classes identified as triglycerides (TG), phosphatidylethanolamines (PE), phosphatidylcholines (PC), Sphingomyelins (SM), ether-PC, and ether-PE. A total of 12 lipid species were significantly different when stratified by infection type and included acylcarnitine (AcCar) (10:1, 16:1, 18:2), diacylglycerols (DG) (16:0_18:0, 18:0_18:0), Lysophosphatidylcholine (LPC) (12:0, 20:5), PE (18:0_18:0), and TG (14:1_16:0_18:2, 15:0_17:0_19:0, 16:0_17:0_18:0, 19:0_19:0_19:0). Cluster analysis yielded three clusters of lipid profiles that were driven by just 10 lipid species (TGs and DGs). Cluster 1 had the highest levels of each lipid species and the highest prevalence of influenza A H3 infection (56%, n = 5) whereas cluster 3 had lower levels of each lipid species and the highest prevalence of rhinovirus (60%; n = 6). Using cluster 3 as the reference group, the crude odds of influenza A H3 infection compared to rhinovirus in cluster 1 was significantly (p = 0.047) higher (OR = 15.00 [95% CI: 1.03, 218.29]). After adjustment for confounders (smoking status and pulmonary comorbidities), the odds ratio (OR) became only marginally significant (p = 0.099), but the magnitude of the effect estimate was similar (OR = 16.00 [0.59, 433.03]).

Conclusions

In this study, human sputum lipid profiles were shown to be associated with distinct types of viral infection. Better understanding the relationship between respiratory infections of global importance and lipids contributes to advancing knowledge of pathogenesis of infections including identifying populations with increased susceptibility and developing effective therapeutics and biomarkers of health status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02091-w.

Advanced Point-of-Care Testing Technologies for Human Acute Respiratory Virus Detection

The ever-growing global threats to human life caused by the human acute respiratory virus (RV) infections have cost billions of lives, created a significant economic burden, and shaped society for centuries. The timely response to emerging RVs could save human lives and reduce the medical care burden. The development of RV detection technologies is essential for potentially preventing RV pandemic and epidemics. However, commonly used detection technologies lack sensitivity, specificity, and speed, thus often failing to provide the rapid turnaround times. To address this problem, new technologies are devised to address the performance inadequacies of the traditional methods. These emerging technologies offer improvements in convenience, speed, flexibility, and portability of point-of-care test (POCT). Herein, recent developments in POCT are comprehensively reviewed for eight typical acute respiratory viruses. This review discusses the challenges and opportunities of various recognition and detection strategies and discusses these according to their detection principles, including nucleic acid amplification, optical POCT, electrochemistry, lateral flow assays, microfluidics, enzyme-linked immunosorbent assays, and microarrays. The importance of limits of detection, throughput, portability, and specificity when testing clinical samples in resource-limited settings is emphasized. Finally, the evaluation of commercial POCT kits for both essential RV diagnosis and clinical-oriented practices is included.

Comparison of detection rate of 16 sampling methods for respiratory viruses: a Bayesian network meta-analysis of clinical data and systematic review

BACKGROUND

Respiratory viruses (RVs) is a common cause of illness in people of all ages, at present, different types of sampling methods are available for respiratory viral diagnosis. However, the diversity of available sampling methods and the limited direct comparisons in randomised controlled trials (RCTs) make decision-making difficult. We did a network meta-analysis, which accounted for both direct and indirect comparisons, to determine the detection rate of different sampling methods for RVs.

METHODS

Relevant articles were retrieved comprehensively by searching the online databases of PubMed, Embase and Cochrane published before 25 March 2020. With the help of R V.3.6.3 software and 'GeMTC V.0.8.2' package, network meta-analysis was performed within a Bayesian framework. Node-splitting method and I ² test combined leverage graphs and Gelman-Rubin-Brooks plots were conducted to evaluate the model's accuracy. The rank probabilities in direct and cumulative rank plots were also incorporated to rank the corresponding sampling methods for overall and specific virus.

RESULTS

16 sampling methods with 54 438 samples from 57 literatures were ultimately involved in this study. The model indicated good consistency and convergence but high heterogeneity, hence, random-effect analysis was applied. The top three sampling methods for RVs were nasopharyngeal wash (NPW), mid-turbinate swab (MTS) and nasopharyngeal swab (NPS). Despite certain differences, the results of virus-specific subanalysis were basically consistent with RVs: MTS, NPW and NPS for influenza; MTS, NPS and NPW for influenza-a and b; saliva, NPW and NPS for rhinovirus and parainfluenza; NPW, MTS and nasopharyngeal aspirate for respiratory syncytial virus; saliva, NPW and MTS for adenovirus and sputum; MTS and NPS for coronavirus.

CONCLUSION

This network meta-analysis provides supporting evidences that NPW, MTS and NPS have higher diagnostic value regarding RVs infection, moreover, particular preferred methods should be considered in terms of specific virus pandemic. Of course, subsequent RCTs with larger samples are required to validate our findings.

Epidemiology, Diagnosis, Treatment, and Prevention of Influenza Infection in Oncology Patients

Influenza infection causes increased morbidity and higher mortality in patients receiving treatment of underlying cancer, particularly in those with hematological malignancy or patients who have undergone hematopoietic stem-cell transplantation. The illness is characterized by seasonality and nonspecific clinical manifestations of upper respiratory infection at a time when other respiratory illnesses are common in the community, making the diagnosis challenging. However, accurate and timely diagnosis by new molecular techniques is crucial in the management of immunocompromised patients, because delays in initiating appropriate therapy can have devastating consequences. Emergence of viral resistance to currently used antiviral agents is of concern, particularly in immunocompromised hosts, and warrants continued monitoring and surveillance. Early and effective treatment improves outcomes, but optimal therapeutic strategies in patients with cancer are not well defined. Health care and research efforts should focus on defining treatment guidelines in patients with cancer and attempt to improve on current vaccination strategies.

Feasibility study for the use of self-collected nasal swabs to identify pathogens among participants of a population-based surveillance system for acute respiratory infections (GrippeWeb-Plus)-Germany, 2016

Background

Internet‐based participatory surveillance systems, such as the German GrippeWeb, monitor the frequency of acute respiratory illnesses on population level. In order to interpret syndromic information better, we devised a microbiological feasibility study (GrippeWeb‐Plus) to test whether self‐collection of anterior nasal swabs is operationally possible, acceptable for participants and can yield valid data.

Methods

We recruited 103 GrippeWeb participants (73 adults and 30 children) and provided them with a kit, instructions and a questionnaire for each sample. In the first half of 2016, participants took an anterior nasal swab and sent it to the Robert Koch Institute whenever an acute respiratory illness occurred. Reporting of illnesses through the GrippeWeb platform continued as usual. We analysed swabs for the presence of human c‐myc‐DNA and 22 viral and bacterial pathogens. After the study, we sent participants an evaluation questionnaire. We analysed timeliness, completeness, acceptability and validity.

Results

One hundred and two participants submitted 225 analysable swabs. Ninety per cent of swabs were taken within 3 days of symptom onset. Eighty‐nine per cent of swabs had a corresponding reported illness in the GrippeWeb system. Ninety‐nine per cent of adults and 96% of children would be willing to participate in a self‐swabbing scheme for a longer period. All swabs contained c‐myc‐DNA. In 119 swabs, we identified any of 14 viruses but no bacteria. The positivity rate of influenza was similar to that in the German physician sentinel.

Conclusion

Self‐collection of anterior nasal swabs proofed to be feasible, was well accepted by participants, gave valid results and was an informative adjunct to syndromic data.

Prevalence of Common Respiratory Viral Infections and Identification of Adenovirus in Hospitalized Adults in Harbin, China 2014 to 2017

Background: Respiratory infections pose a great challenge in global health, and the prevalence of viral infection in adult patients has been poorly understood in northeast China. Harbin is one of the major cities in northeast China, and more than half of any given year in Harbin is occupied by winter. To reveal the viral etiology and seasonality in adult patients from Harbin, a 4-year consecutive survey was conducted in Harbin, China.

Methods: From January 2014 to December 2017, specimens were obtained from adult patients admitted to the Second Affiliated Hospital of Harbin Medical University with lower respiratory tract infections. Sputum samples were examined by direct immunofluorescence assays to detect seven common respiratory viruses, including influenza virus (type A and B), parainfluenza virus (type 1 to 3), respiratory syncytial virus and adenovirus. Adenovirus positive samples were seeded onto A549 cells to isolate viral strains. Phylogenetic analysis was conducted on the highly variable region of adenoviral hexon gene.

Results: A total of 1,300 hospitalized adult patients with lower respiratory tract infections were enrolled, in which 189 patients (14.5%) were detected as having at least one viral infection. The co-infection rate in this study was 25.9% (49/189). The dominant viral pathogen from 2014 to 2017 was parainfluenza virus, with a detection rate of 7.2%, followed by influenza virus, respiratory syncytial virus and adenovirus. Based on the climate seasons determined by daily average temperature, the highest overall viral detection rate was detected in spring (22.0%, 52/236), followed by winter (13.4%, 109/813), autumn (11.4%, 13/114) and summer (10.9%, 15/137). Adenovirus type 3 strains with slight variations were isolated from positive cases, which were closely related to the GB strain from the United States, as well as the Harbin04B strain isolated locally.

Conclusion: This study demonstrated that common respiratory viruses were partially responsible for hospitalized lower respiratory tract infections in adult patients from Harbin, China, with parainfluenza virus as the dominant viral pathogen. Climate seasons could be rational indicators for the seasonality analysis of airborne viral infections. Future surveillance on viral mutations would be necessary to reveal the evolutionary history of respiratory viruses.

Human respiratory syncytial virus load normalized by cell quantification as predictor of acute respiratory tract infection

Human respiratory syncytial virus (HRSV) is a common cause of respiratory infections. The main objective is to analyze the prediction ability of viral load of HRSV normalized by cell number in respiratory symptoms. A prospective, descriptive, and analytical study was performed. From 7307 respiratory samples processed between December 2014 to April 2016, 1019 HRSV-positive samples, were included in this study. Low respiratory tract infection was present in 729 patients (71.54%). Normalized HRSV load was calculated by quantification of HRSV genome and human β-globin gene and expressed as log10 copies/1000 cells. HRSV mean loads were 4.09 ± 2.08 and 4.82 ± 2.09 log10 copies/1000 cells in the 549 pharyngeal and 470 nasopharyngeal samples, respectively (P < 0.001). The viral mean load was 4.81 ± 1.98 log10 copies/1000 cells for patients under the age of 4-year-old (P < 0.001). The viral mean loads were 4.51 ± 2.04 cells in patients with low respiratory tract infection and 4.22 ± 2.28 log10 copies/1000 cells with upper respiratory tract infection or febrile syndrome (P < 0.05). A possible cut off value to predict LRTI evolution was tentatively established. Normalization of viral load by cell number in the samples is essential to ensure an optimal virological molecular diagnosis avoiding that the quality of samples affects the results. A high viral load can be a useful marker to predict disease progression.

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

BACKGROUND AND OBJECTIVES

Diagnostic 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 DESIGN

Both 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).

RESULTS

Of 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.

CONCLUSIONS

This 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.

Enhanced detection of respiratory pathogens with nanotrap particles

The Influenza virus is a leading cause of respiratory disease in the United States each year. While the virus normally causes mild to moderate disease, hospitalization and death can occur in many cases. There are several methodologies that are used for detection; however problems such as decreased sensitivity and high rates of false-negative results may arise. There is a crucial need for an effective sample preparation technology that concentrates viruses at low abundance while excluding resident analytes that may interfere with detection. Nanotrap particles are hydrogel particles that are coupled to chemical dye affinity baits that bind a broad range of proteins and virions. Within minutes (<30 minutes), Nanotrap particles concentrate low abundant proteins and viruses from clinically complex matrices. Nanotrap particles with reactive red baits concentrated numerous respiratory viruses including various strains and subtypes of Influenza virus, Coronavirus, and Respiratory Syncytial Virus from saliva, nasal fluid swab specimens, and nasal aspirates. Detection was enhanced more than 10-fold when coupled to plaque assays and qRT-PCR. Importantly, Nanotrap particle can efficiently capture and concentrate multiple viral pathogens during a coinfection scenario. These results collectively demonstrate that Nanotrap particles are an important tool that can easily be integrated into various detection methodologies.

Community acquired respiratory virus infections in cancer patients-Guideline on diagnosis and management by the Infectious Diseases Working Party of the German Society for haematology and Medical Oncology

Background

Community acquired viruses (CRVs) may cause severe disease in cancer patients. Thus, efforts should be made to diagnose CRV rapidly and manage CRV infections accordingly.

Methods

A panel of 18 clinicians from the Infectious Diseases Working Party of the German Society for Haematology and Medical Oncology have convened to assess the available literature and provide recommendations on the management of CRV infections including influenza, respiratory syncytial virus, parainfluenza virus, human metapneumovirus and adenovirus.

Results

CRV infections in cancer patients may lead to pneumonia in approximately 30% of the cases, with an associated mortality of around 25%. For diagnosis of a CRV infection, combined nasal/throat swabs or washes/aspirates give the best results and nucleic acid amplification based-techniques (NAT) should be used to detect the pathogen. Hand hygiene, contact isolation and face masks have been shown to be of benefit as general infection management. Causal treatment can be given for influenza, using a neuraminidase inhibitor, and respiratory syncytial virus, using ribavirin in addition to intravenous immunoglobulins. Ribavirin has also been used to treat parainfluenza virus and human metapneumovirus, but data are inconclusive in this setting. Cidofovir is used to treat adenovirus pneumonitis.

Conclusions

CRV infections may pose a vital threat to patients with underlying malignancy. This guideline provides information on diagnosis and treatment to improve the outcome.

•

Community acquired viral respiratory tract infections can be life-threatening in cancer patients.

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Respiratory virus infections need early and appropriate management to improve outcome and avoid outbreaks.

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This guideline summarises recommendations by the AGIHO on community acquired respiratory viruses in cancer patients.

A two-step protocol for isolation of influenza A (H7N7) virions and their RNA for PCR diagnostics based on modified paramagnetic particles

Annual epidemics of influenza cause death of hundreds of thousands people and they also have a significant economic impact. Hence, a need for fast and cheap influenza diagnostic method is arising. The conventional methods for an isolation of the viruses are time-consuming and require expensive instrumentation as well as trained personnel. In this study, we modified the surface of nanomaghemite (γ-Fe2 O3 ) paramagnetic core with tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane and the resulting particles were utilized for the isolation of H7N7 influenza virions. Consequently, we designed γ-Fe2 O3 paramagnetic core modified with calcium tripolyphosphate which was employed for the isolation of viral nucleic acid after virion's lysis. Both of these procedures can be performed rapidly in less than 10 min and, in combination with the RT-PCR, the whole influenza detection can be shortened to few hours. Moreover, the whole protocol could be easily automated and/or miniaturized, and thus can serve as a basis for use in a lab-on-a-chip device. We assume that magnetic isolation is an exceptional procedure which can significantly accelerate the diagnostic possibilities of a broad spectrum of diseases.

Light Weight and Flexible High-Performance Diagnostic Platform

A flexible diagnostic platform is realized and its performance is demonstrated for early detection of avian influenza virus (AIV) subtype H1N1 DNA sequences. The key component of the platform is high-performance biosensors based on high output currents and low power dissipation Si nanowire field effect transistors (SiNW-FETs) fabricated on flexible 100 μm thick polyimide foils. The devices on a polymeric support are about ten times lighter compared to their rigid counterparts on Si wafers and can be prepared on large areas. While the latter potentially allows reducing the fabrication costs per device, the former makes them cost efficient for high-volume delivery to medical institutions in, e.g., developing countries. The flexible devices withstand bending down to a 7.5 mm radius and do not degrade in performance even after 1000 consecutive bending cycles. In addition to these remarkable mechanical properties, on the analytic side, the diagnostic platform allows fast detection of specific DNA sequences of AIV subtype H1N1 with a limit of detection of 40 × 10(-12) m within 30 min suggesting its suitability for early stage disease diagnosis.

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

BACKGROUND

The test-negative design is a variant of the case-control study being increasingly used to study influenza vaccine effectiveness (VE). In these studies, patients with influenza-like illness are tested for influenza. Vaccine coverage is compared between those testing positive versus those testing negative to estimate VE.

OBJECTIVES

We reviewed features in the design, analysis and reporting of 85 published test-negative studies.

DATA SOURCES

Studies were identified from PubMed, reference lists and email updates. Study eligibility: All studies using the test-negative design reporting end-of-season estimates were included.

STUDY APPRAISAL

Design features that may affect the validity and comparability of reported estimates were reviewed, including setting, study period, source population, case definition, exposure and outcome ascertainment and statistical model.

RESULTS

There was considerable variation in the analytic approach, with 68 unique statistical models identified among the studies.

CONCLUSION

Harmonization of analytic approaches may improve the potential for pooling VE estimates.

Evaluation of the Sofia Influenza A + B fluorescent immunoassay for the rapid diagnosis of influenza A and B

Rapid influenza diagnostic tests (RIDTs) can facilitate the appropriate prescription of antivirals for influenza, obviate the need for unnecessary testing and antibacterial agents and allow the implementation of infection control measures. However, the reported sensitivities and specificities of different RIDTs vary widely in clinical settings, as does assay ability to distinguish between influenza types and subtypes. To evaluate the performance of the Sofia Influenza A + B fluorescent immunoassay (FIA) for the detection of influenza A and B during the 2013 Southern Hemisphere influenza season, a total of 209 consecutive respiratory tract swabs from adult patients with an influenza-like illness were tested by both Sofia Influenza A + B and an in-house real-time, reverse transcription-polymerase chain reaction (RT-PCR) assay. Compared to RT-PCR, the sensitivity and specificity of the Sofia Influenza A + B FIA for detection of influenza A was 72.4% and 98.3%, respectively. Too few influenza B positive samples were available during the study to accurately assess the Sofia's performance for influenza B detection. The sensitivity of Sofia Influenza A + B FIA for both influenza A and B detection correlated with the amount of influenza RNA present in the sample as indicated indirectly by the RT-PCR cycle threshold (Ct ). In conclusion, the Sofia Influenza A + B FIA continues to perform well as a RIDT with the circulating influenza strains of the 2013 Southern Hemisphere influenza season.

Comparison among nasopharyngeal swab, nasal wash, and oropharyngeal swab for respiratory virus detection in adults with acute pharyngitis

BACKGROUND

Acute pharyngitis is frequently seen in primary care. Acute viral pharyngitis may be easily misdiagnosed as acute bacterial pharyngitis. Laboratory-confirmed diagnosis of respiratory viruses is recommended. The purpose of this study was to compare the sensitivities among oropharyngeal swab (OPS), nasopharyngeal swab (NPS), and nasal wash (NW) in adults with acute pharyngitis.

METHODS

OPS, NPS, and NW were obtained from each participant with acute pharyngitis. The specimens were tested for 15 respiratory viruses by TaqMan real-time polymerase chain reaction. A sample was considered to be a true positive if any of the specimens was positive. The sensitivities among samples were compared by chi-square test or Fisher's exact test, as appropriate.

RESULTS

One hundred three triple samples collected consecutively by OPS, NPS, and NW were obtained. In 73 patients, one or more viruses were detected by any of the three methods. Among all viruses, the sensitivity of NPS was significantly higher than that of NW (74% vs. 49%, respectively; p < 0.01) and OPS (74% vs. 49%, respectively; p < 0.01).

CONCLUSIONS

Flocked NPS collection may be the most effective alternative to NW and OPS for detection of respiratory viruses in adults with acute pharyngitis using TaqMan real-time polymerase chain reaction.

Symptomatic predictors for 2009 influenza A virus (H1N1) infection with an emphasis for patients with a negative rapid diagnostic test

Background

The clinical diagnosis of influenza is difficult because it shares nonspecific symptoms with a variety of diseases. Emergency departments and clinics were overwhelmed by a surge of anxious patients during the 2009 influenza A virus (H1N1) outbreak. Our objective was to identify symptomatic predictors of influenza virus infection for patients with a negative rapid diagnostic test.

Methodology/Principal Findings

We conducted a retrospective review of 805 patients who presented at Chang Gung Memorial Hospital, from August 1, 2009, to September 30, 2009. Respiratory specimens from these patients were subjected to rapid influenza tests and reverse-transcription polymerase chain reactions. In total, 36% of 308 children and 23% of 497 adults were positive for 2009 influenza A virus (H1N1) infection by polymerase chain reaction or virus culture. For pediatric patients, sore throat and influenza-like illness significantly increased the odds of having 2009 influenza A virus (H1N1) infection, by more than 3-fold (95% confidence interval (CI): 1.9–7.3) and 7-fold (95% CI: 4.00–14.2), respectively. For adult patients, cough and constitutional symptoms increased the odds of having 2009 influenza A virus (H1N1) by greater than 5-fold (95% CI: 3.1–10.2) and 3-fold (95% CI: 2.1–6.7), respectively. The negative likelihood ratio of the combination of fever and cough was 0.096 (95% CI: 0.01–0.69) for children with negative results of rapid influenza diagnostic tests.

Conclusion/Significance

In influenza epidemic settings, clinicians should be aware that rapid influenza diagnostic tests are relatively insensitive for the diagnosis of influenza virus infection. For patients with negative rapid influenza diagnostic tests, those lacking fever and cough have a low probability of influenza virus infection. The management strategy should be made individually and depend on the severity of illness.

Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests

BACKGROUND

The performance of rapid influenza diagnostic tests (RIDTs) in detecting influenza A(H1N1) 2009 has varied widely. Evaluations of RIDTs among infected individuals across all age groups have not been described in depth.

OBJECTIVES

Determine RIDT clinical sensitivity in comparison with influenza detection using real-time RT-PCR among patients infected with influenza A(H1N1) 2009 across all age groups.

STUDY DESIGN

This study analyzed respiratory specimens received by the New Hampshire Public Health Laboratories (NHPHL) from September 1, 2009, through December 31, 2009. RIDT performance was evaluated among different age groups of patients determined to be infected with influenza A (H1N1) 2009, and the association between age and RIDT sensitivity was determined.

RESULTS

Of 1373 specimens examined, 269 tested positive for influenza A(H1N1) 2009 by real-time RT-PCR (rRT-PCR) and had RIDT results available. Overall clinical sensitivity and specificity of RIDTs were 53·9 and 98·5%, respectively. By age group, clinical sensitivity was 85·7% in patients <2 years old, 60·3% in patients between 2- and 39 years old, and 33·3% in patients aged 40 and older. Logistic regression analysis indicated that increasing age was negatively associated with RIDT performance.

CONCLUSION

Rapid influenza diagnostic test sensitivity decreased significantly with increasing age. Findings from this study may impact a clinician's interpretation of RIDT test results and ultimately have implications in clinical decision-making.

Comparison of nasopharyngeal and oropharyngeal swabs for the diagnosis of eight respiratory viruses by real-time reverse transcription-PCR assays

Background

Many acute respiratory illness surveillance systems collect and test nasopharyngeal (NP) and/or oropharyngeal (OP) swab specimens, yet there are few studies assessing the relative measures of performance for NP versus OP specimens.

Methods

We collected paired NP and OP swabs separately from pediatric and adult patients with influenza-like illness or severe acute respiratory illness at two respiratory surveillance sites in Kenya. The specimens were tested for eight respiratory viruses by real-time reverse transcription-polymerase chain reaction (qRT-PCR). Positivity for a specific virus was defined as detection of viral nucleic acid in either swab.

Results

Of 2,331 paired NP/OP specimens, 1,402 (60.1%) were positive for at least one virus, and 393 (16.9%) were positive for more than one virus. Overall, OP swabs were significantly more sensitive than NP swabs for adenovirus (72.4% vs. 57.6%, p<0.01) and 2009 pandemic influenza A (H1N1) virus (91.2% vs. 70.4%, p<0.01). NP specimens were more sensitive for influenza B virus (83.3% vs. 61.5%, p = 0.02), parainfluenza virus 2 (85.7%, vs. 39.3%, p<0.01), and parainfluenza virus 3 (83.9% vs. 67.4%, p<0.01). The two methods did not differ significantly for human metapneumovirus, influenza A (H3N2) virus, parainfluenza virus 1, or respiratory syncytial virus.

Conclusions

The sensitivities were variable among the eight viruses tested; neither specimen was consistently more effective than the other. For respiratory disease surveillance programs using qRT-PCR that aim to maximize sensitivity for a large number of viruses, collecting combined NP and OP specimens would be the most effective approach.

Diagnosis of 2009 pandemic influenza A (pH1N1) and seasonal influenza using rapid influenza antigen tests, San Antonio, Texas, April-June 2009

Clinicians frequently use influenza rapid antigen tests for diagnostic testing. We tested nasal wash samples from 1 April to 7 June 2009 from 1538 patients using the QuickVue Influenza A+B (Quidel) rapid influenza antigen test and compared the results with real-time reverse transcription polymerase chain reaction (rRT-PCR) assay (gold standard). The prevalence of 2009 pandemic influenza A (pH1N1) was 1.98%, seasonal influenza type A .87%, and seasonal influenza type B 2.07%. The sensitivity and specificity of the rapid test for pH1N1 was 20% (95% CI, 8-39) and 99% (95% CI, 98-99), for seasonal influenza type A 15% (95% CI, 2-45) and 99% (95% CI, 98-99), and for influenza type B was 31% (95% CI, 9-61) and 99% (95% CI, 98-99.7). Rapid influenza antigen tests were of limited use at a time when the prevalence of pH1N1 and seasonal influenza in the United States was low. Clinicians should instead rely on clinical impression and laboratory diagnosis by rRT-PCR.

Viral etiologies of acute respiratory infections among hospitalized Vietnamese children in Ho Chi Minh City, 2004-2008

BACKGROUND

The dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized children in resource-limited tropical countries where morbidity and mortality caused by ARIs are highest. Improved etiological insight is needed to improve clinical management and prevention.

OBJECTIVES

We conducted a three-year prospective descriptive study of severe respiratory illness among children from 2 months to 13 years of age within the largest referral hospital for infectious diseases in southern Vietnam.

METHODS

Molecular detection for 15 viral species and subtypes was performed on three types of respiratory specimens (nose, throat swabs and nasopharyngeal aspirates) using a multiplex RT-PCR kit (Seeplex™ RV detection, Seegene) and additional monoplex real-time RT-PCRs.

RESULTS

A total of 309 children were enrolled from November 2004 to January 2008. Viruses were identified in 72% (222/309) of cases, including respiratory syncytial virus (24%), influenza virus A and B (17%), human bocavirus (16%), enterovirus (9%), human coronavirus (8%), human metapneumovirus (7%), parainfluenza virus 1-3 (6%), adenovirus (5%), and human rhinovirus A (4%). Co-infections with multiple viruses were detected in 20% (62/309) of patients. When combined, diagnostic yields in nose and throat swabs were similar to nasopharyngeal aspirates.

CONCLUSION

Similar to other parts in the world, RSV and influenza were the predominant viral pathogens detected in Vietnamese hospitalized children. Combined nasal and throat swabs are the specimens of choice for sensitive molecular detection of a broad panel of viral agents. Further research is required to better understand the clinical significance of single versus multiple viral coinfections and to address the role of bacterial (co-)infections involved in severe respiratory illness.

Respiratory syncytial virus and human rhinoviruses are the major causes of severe lower respiratory tract infections in Kuwait

Respiratory infections are very common in Kuwait, yet little is known about the cause of severe lower respiratory tract infections. This study was designed to investigate the viral cause of lower respiratory tract infections using sensitive molecular methods. PCR was applied to investigate 10 respiratory viruses in respiratory samples from 1,014 patients aged between 3 days to 76 years with acute lower respiratory tract infections. Of the 1,014 patients with lower respiratory tract infections, 288 (28.4%) had a viral infection. One hundred fifty‐five (53.8%) presented with bronchiolitis, 100 (43.7%) with pneumonia, and 33 (11.5%) with croup. One hundred six (36.8%) and 99 (34.4%) patients had evidence of respiratory syncytial virus and human rhinoviruses infections, respectively. Adenoviruses were detected in 44 (15.2%) patients, while influenza A virus in 21 (7.3%) patients. The majority of respiratory syncytial virus infections (84%) were among patients aged <1 year. Similarly, of the 99 patients infected by human rhinoviruses, 50 (50.5%) were also among this age group. In contrast, most of influenza A virus infections, 12 of 21 (57.1%), were among patients aged over 16 years. Parainfluenza virus‐2 and human coronaviruses were not detected in any of the patients' samples. Over the 3‐year period, most of the hospitalized patients were seen during the autumn and winter months from October through March. These data show that respiratory syncytial virus and human rhinoviruses may be the major causes of lower respiratory tract infections in children admitted to hospital in Kuwait. J. Med. Virol. 82:1462–1467, 2010. © 2010 Wiley‐Liss, Inc.

Viral pneumonias in immunocompromised adult hosts

Viral infections have always been considered pediatric diseases. However, viral pneumonia has become an important cause of morbidity and mortality in immuncompromised adults. Improved diagnostic techniques, such as the introduction of highly sensitive nucleic acid amplification tests, have not only allowed us to discover new viruses but also to determine the etiology of viral pneumonia in immunocompromised adult hosts. Unfortunately, only a few antiviral agents are available. Thus, early diagnosis and treatment are crucial to patient outcome. In this article, we review the most common viruses that have been implicated as etiologic agents of viral pneumonia in immunocompromised adults. We discuss the epidemiologic characteristics and clinical presentation of these viral infections and the most appropriate diagnostic approaches and therapies when available.

Shedding and transmission of novel influenza virus A/H1N1 infection in households--Germany, 2009

Essential epidemiologic and virologic parameters must be measured to provide evidence for policy/public health recommendations and mathematical modeling concerning novel influenza A/H1N1 virus (NIV) infections. Therefore, from April through August of 2009, the authors collected nasopharyngeal specimens and information on antiviral medication and symptoms from households with NIV infection on a daily basis in Germany. Specimens were analyzed quantitatively by using reverse transcriptase-polymerase chain reaction. In 36 households with 83 household contacts, 15 household contacts became laboratory-confirmed secondary cases of NIV. Among 47 contacts without antiviral prophylaxis, 12 became cases (secondary attack rate of 26%), and 1 (8%) of these was asymptomatic. The mean and median serial interval were 2.6 and 3 days, respectively (range: 1-3 days). On average, the authors detected viral RNA copies for 6.6 illness days (treated in time = 5.7 days, not treated in time = 7.1 days; P = 0.06), but they estimated that most patients cease to excrete viable virus by the fifth illness day. Shedding profiles were consistent with the number and severity of symptoms. Compared with other nasopharyngeal specimen types, nasal wash was the most sensitive. These results support the notion that epidemiologic and virologic characteristics of NIV are in many aspects similar to those of seasonal influenza.

Antigen-based assays for the identification of influenza virus and respiratory syncytial virus: why and how to use them in pediatric practice

This article describes the clinical and socioeconomic relevance of influenza (IV) and respiratory syncytial virus (RSV) in pediatrics, the characteristics and limitations of currently available assays, and the impact of rapid diagnostic tests. This article shows that rapid tests for the detection and identification of IV and RSV in the respiratory secretions of infants and children are useful in the diagnosis of common, and possibly severe diseases, such as influenza and bronchiolitis. The tests' specificity and sensitivity make them most reliable when the prevalence of influenza or RSV infection is high, which suggests that their routine use should be restricted to the peak periods of viral circulation. The most recently marketed tests are similarly effective in identifying viruses, and so pediatricians should choose those that are less expensive, less time consuming, and easier to perform and to interpret.

Difficulty with mumps diagnosis: what is the contribution of mumps mimickers?

BACKGROUND

Mumps is a vaccine preventable disease that typically presents with unilateral or bilateral parotitis. In February 2007, mumps re-emerged in university students in Nova Scotia. Despite highly sensitive methods for mumps virus detection, only 14% (298/2082) of cases during the peak of the outbreak were laboratory confirmed.

OBJECTIVES

Due to the low positivity rate, this study investigated whether infection with other viral pathogens caused mumps-like presentations during the outbreak.

STUDY DESIGN

148 buccal specimens from patients who presented with unilateral or bilateral parotitis but had negative laboratory tests for mumps virus were tested for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) by quantitative PCR and 21 different viral markers using the Luminex xTAG Respiratory Virus Panel (RVP). Companion sera to each buccal specimen were available for EBV and CMV serology to differentiate acute infection from reactivation.

RESULTS

No correlation was observed since viral pathogens were detected in both the parotitis and non-parotitis groups.

CONCLUSION

Although there was co-circulation of other viral pathogens during the mumps outbreak, no difference was observed in the prevalence between patients who presented with or without parotitis. The low positivity rate for specimens submitted for mumps diagnostics was likely the result of increased Public Health messaging and physician inexperience in recognizing mumps infection, suggesting the clinical acumen for mumps diagnosis based solely on clinical presentation is low.

Identification of respiratory viruses in adults: nasopharyngeal versus oropharyngeal sampling

The optimal method for identifying respiratory viruses in adults has not been established. The objective of the study was to compare the sensitivities of three sampling methods for this purpose. One thousand participants (mean age, 63.1 +/- 17.8 years) were included. Of these, 550 were patients hospitalized for acute febrile lower respiratory tract infections and 450 were controls. Oropharyngeal swabs (OPS), nasopharyngeal swabs (NPS), and nasopharyngeal washings (NPW) were obtained from each participant and were tested for 12 respiratory viruses by a multiplex hydrolysis probes-based quantitative real-time reverse transcription-PCR. Patients were defined as positive for a specific virus if the virus was identified by at least one sampling method. In all, 251 viruses were identified in 244 participants. For the detection of any virus, the sensitivity rates for OPS, NPS, and NPW were 54.2%, 73.3%, and 84.9%, respectively (for OPS versus NPS and NPW, P < 0.00001; for NPS versus NPW, P < 0.003). Maximal sensitivity was obtained only with sampling by all three methods. The same gradation of sensitivity for the three sampling methods was found when influenza viruses, coronaviruses, and rhinoviruses were analyzed separately. The three sampling methods yielded equal sensitivity rates for respiratory syncytial virus. We conclude that nasopharyngeal sampling has a higher rate of sensitivity than oropharyngeal sampling and that the use of NPW has a higher rate of sensitivity than the use of NPS with a rigid cotton swab for the identification of respiratory viruses in adults. Sampling by all three methods is required for the maximal detection of respiratory viruses.

The detection of influenza A and B viruses in clinical specimens using a quartz crystal microbalance

Current methods for the accurate diagnosis of influenza based on culture of the virus or PCR are highly sensitive and specific but require specialised laboratory facilities and highly trained personnel and, in the case of viral culture, can take up to 14 days to obtain a definitive result. In this study, a quartz crystal microbalance-based immunosensor (QCM) has been developed and its potential evaluated for the rapid and sensitive detection of both influenza A and B viruses in laboratory-cultured preparations and clinical samples. The effective limit for detection by QCM for stock preparations of both A/PR/8/34 and B/Lee/40 viruses was 1 × 10⁴ pfu/mL, associated with observed frequency shifts of 30 (±5) and 37 (±6.5) Hz, respectively. Conjugation of 13 nm gold nanoparticles to the detecting antibody improved the mass sensitivity of the immunosensor, resulting in a 10-fold increase in sensitivity and a detection limit of 1 × 10³ pfu/mL for both preparations, with resulting frequency shifts of 102 (±11) and 115 (±5) Hz, respectively. Detection of virus in nasal washes with this technique was achieved by overnight passage in MDCK cultures prior to analysis. A comparison of results obtained from 67 clinical samples using existing RT-PCR, shell vial, cell culture and ELISA methods showed that QCM techniques were comparable in sensitivity and specificity to cell culture methods.

The limitations of point of care testing for pandemic influenza: what clinicians and public health professionals need to know

As the world prepares for the next influenza pandemic, governments have made significant funding commitments to vaccine development and antiviral stockpiling. While these are essential components to pandemic response, rapid and accurate diagnostic testing remains an often neglected cornerstone of pandemic influenza preparedness. Clinicians and Public Health Practitioners need to understand the benefits and drawbacks of different influenza tests in both seasonal and pandemic settings. Culture has been the traditional gold standard for influenza diagnosis but requires from 1-10 days to generate a positive result, compared to nucleic acid detection methods such as real time reverse transcriptase polymerase chain reaction (RT-PCR). Although the currently available rapid antigen detection kits can generate results in less than 30 minutes, their sensitivity is suboptimal and they are not recommended for the detection of novel influenza viruses. Until point-of-care (POC) tests are improved, PILPN recommends that the best option for pandemic influenza preparation is the enhancement of nucleic acid-based testing capabilities across Canada.

Field performance of a rapid diagnostic test for influenza in an ambulatory setting

Provided test characteristics are adequate, point-of-care rapid antigen detection tests for influenza could improve the timeliness and appropriateness of clinical decisions. Our objective was to estimate the field sensitivity and specificity of the Quidel QuickVue Influenza A+B test in an ambulatory setting. The sensitivity and specificity of the Quidel QuickVue test was evaluated against reverse-transcriptase PCR (RT-PCR) on nasopharyngeal specimens collected over two consecutive influenza seasons from ambulatory patients consulting for influenza-like illness (ILI) within 7 days of ILI onset. A total of 491 patients with ILI (180 in 2006 to 2007 and 311 in 2007 to 2008) provided specimens that were tested both by PCR and by the Quidel QuickVue test. Among the 267 patients positive by PCR (55%), 52 were also positive by the QuickVue test, for an overall sensitivity of 19.5% (95% confidence interval [95% CI], 14.7% to 24.2%). Among the 221 PCR-negative patients, 2 were positive for influenza B virus by the rapid test (<1%), for an overall specificity of 99.1% (95% CI, 97.9 to 100%). The field sensitivity of the test varied little with the age or gender of the patient, immunization status, delay since the onset of symptoms, or influenza season. The sensitivity of the test was slightly but nonsignificantly higher for influenza B virus (23%) than for influenza A virus (18%). Despite its high specificity, the low sensitivity of the Quidel QuickVue Influenza A+B test is too poor to direct clinical decisions for ambulatory patients with ILI. Negative results cannot rule out the diagnosis of influenza, and in that context, this test is of questionable utility for routine application in the clinical setting.

Influenza virus infection and the risk of serious bacterial infections in young febrile infants

OBJECTIVE

We aimed to determine the risk of SBIs in febrile infants with influenza virus infections and compare this risk with that of febrile infants without influenza infections.

PATIENTS AND METHODS

We conducted a multicenter, prospective, cross-sectional study during 3 consecutive influenza seasons. All febrile infants <or=60 days of age evaluated at any of 5 participating pediatric EDs between October and March of 1998 through 2001 were eligible. We determined influenza virus status by rapid antigen detection. We evaluated infants with blood, urine, cerebrospinal fluid, and stool cultures. Urinary tract infection (UTI) was defined by single-pathogen growth of either >or=5 x 10(4) colony-forming units per mL or >or=10(4) colony-forming units per mL in association with a positive urinalysis. Bacteremia, bacterial meningitis, and bacterial enteritis were defined by growth of a known bacterial pathogen. SBI was defined as any of the 4 above-mentioned bacterial infections.

RESULTS

During the 3-year study period, 1091 infants were enrolled. A total of 844 (77.4%) infants were tested for the influenza virus, of whom 123 (14.3%) tested positive. SBI status was determined in 809 (95.9%) of the 844 infants. Overall, 95 (11.7%) of the 809 infants tested for influenza virus had an SBI. Infants with influenza infections had a significantly lower prevalence of SBI (2.5%) and UTI (2.4%) when compared with infants who tested negative for the influenza virus. Although there were no cases of bacteremia, meningitis, or enteritis in the influenza-positive group, the differences between the 2 groups for these individual infections were not statistically significant.

CONCLUSIONS

Febrile infants <or=60 days of age with influenza infections are at significantly lower risk of SBIs than febrile infants who are influenza-negative. Nevertheless, the rate of UTI remains appreciable in febrile, influenza-positive infants.

Antigen detection using polymerization-based amplification

The influenza virus has been subtyped from crude lysates using polymerization-based amplification. In this novel chemical approach to detection, signal amplification was achieved by coupling a polymerization reaction to a protein-protein recognition event. This particular method shows promise due to its advantages over the techniques currently employed in commercial assays in terms of cost, robustness, and unambiguity of test results. Instrumentation is not required to see the crosslinked hydrogel "readout", and no false positives or false negatives were observed above the limit of detection.

Comparison of four nasal sampling methods for the detection of viral pathogens by RT-PCR-A GA(2)LEN project

The aim of this study was to compare the efficacy and patient discomfort between four techniques for obtaining nasal secretions. Nasal secretions from 58 patients with symptoms of a common cold, from three clinical centers (Amsterdam, Lodz, Oslo), were obtained by four different methods: swab, aspirate, brush, and wash. In each patient all four sampling procedures were performed and patient discomfort was evaluated by a visual discomfort scale (scale 1–5) after each procedure. Single pathogen RT-PCRs for Rhinovirus (RV), Influenza virus and Adenovirus, and multiplex real-time PCR for RV, Enterovirus, Influenza virus, Adenovirus, Respiratory Syncytial Virus (RSV), Parainfluenza virus, Coronavirus, Metapneumovirus, Bocavirus and Parechovirus were performed in all samples. A specific viral cause of respiratory tract infection was determined in 48 patients (83%). In these, the detection rate for any virus was 88% (wash), 79% (aspirate), 77% (swab) and 74% (brush). The degree of discomfort reported was 2.54 for swabs, 2.63 for washes, 2.68 for aspirates and 3.61 for brushings. Nasal washes yielded the highest rate of viral detection without excessive patient discomfort. In contrast, nasal brushes produced the lowest detection rates and demonstrated the highest level of discomfort.

Comparison of respiratory virus detection rates for infants and toddlers by use of flocked swabs, saline aspirates, and saline aspirates mixed in universal transport medium for room temperature storage and shipping

A nylon flocked swab/universal transport medium collection method developed for bacterial sexually transmitted infections was adapted to detect respiratory viruses in infants and toddlers. This method significantly outperformed the traditional use of nasal aspirates in terms of PCR-based virus detection (P = 0.016), and the samples were easier for clinicians to evaluate, store, and transport.

Rapid diagnosis of influenza infection in older adults: influence on clinical care in a routine clinical setting

BACKGROUND

Laboratory diagnosis of influenza has previously relied on viral isolation in culture. Rapid antigen tests (RATs) are now available but few studies have examined their use in older adults under routine clinical conditions.

OBJECTIVES

To determine the utility of the RAT in older adults presenting to a large medical center and how test results impacted clinical care.

STUDY DESIGN

Retrospective chart review of patients tested for influenza during the 2003--2004 and 2004--2005 influenza seasons. Clinical data were correlated with the results of laboratory testing.

RESULTS

Eighty-four adults tested positive for influenza. Adding the results of the RAT to symptom complexes predictive of influenza significantly enhanced the ability to diagnose influenza in the acute setting. The positive predictive value of fever plus cough increased from 32% to 92% with a positive RAT. The RAT also directed appropriate antiviral therapy. 20/22 (91%) patients with a positive RAT and symptoms < or =48 h received antiviral treatment compared to only 1/12 (8%) patients with a negative RAT and a positive culture.

CONCLUSIONS

Under routine clinical conditions rapid influenza testing enhances the ability to quickly diagnose influenza and can be used to guide early treatment decisions in older adults.