Detection Of Respiratory Viruses Research Articles

Design of Bio-Optical Transceiver for In Vivo Biomedical Sensor Applications.

This paper presents an enhanced version of our previously developed bio-optical transceiver, presenting a significant advancement in nanosensor technology. Using self-assembled polymers, this nanodevice is capable of electron detection while maintaining biocompatibility, an essential feature for in vivo medical biosensors. This enhancement finds significance in the field of infectious disease control, particularly in the early detection of respiratory viruses, including high-threat pathogens such as SARS-CoV-2. The proposed system harnesses bioluminescence by converting electric signaling to visible blue light, effectively opening the path of linking nano-sized mechanisms to larger-scale systems, thereby pushing the boundaries of in vivo biomedical sensing. The performance evaluation of our technology is analytical and is based on the use of Markov chains, through which we assess the bit error probability. The calculated improvements indicate that this technology qualifies as a forerunner in terms of supporting the communication needs of smaller, safer, and more efficient manufactured sensor technologies for in vivo medical applications.

Dynamic Patterns and Predominance of Respiratory Pathogens Post-COVID-19: Insights from a Two-Year Analysis

IntroductionRespiratory tract infections (RTIs) stand out as the most frequent causes leading to visits to the emergency department and hospitalizations. This study aims to assess the types and prevalence of respiratory infections across two years following the end of the COVID-19 pandemic.MethodsPatients presenting with an influenza-like illness (ILI) were tested using multiplex RT-PCR (QIAstat-Dx, Qiagen). The multiplexed RT- PCR test detects 21 respiratory viruses and bacteria.ResultsDuring the study period, PCR test was done on a total of 1,790 samples were tested, and 712 (40%) were positive for a total of 796 pathogens. The mean age (± SD) of the participants was 20.1 ± 28.4 years in 2022 and 21.9 ± 27.6 years in 2023. Among the detected pathogens, the most prevalent were Rhinovirus/Enterovirus 222 (12.4%), followed by RSV A&B (103 cases, 5.7%), and H1N1 Influenza (77 cases, 4.3%). Additionally, Influenza A/B constituted 172 (9.6%) while parainfluenza constituted (58, 3.2%). SARS-CoV-2 was identified in 3.97% of the samples. Over the two-year period, the monthly pattern of the identified pathogens exhibited fluctuations in the prevalence. Furthermore, variations were observed in the detected pathogens across different age groups.ConclusionIn addition to adding significant knowledge to the field of respiratory viral infections, this study emphasizes the necessity of ongoing research and surveillance for the detection and characterization of respiratory viruses, particularly those with the potential for emergence. Such studies would also require setting up a strategy for genotyping and/or sequencing of viruses.

Peptide-Based electrochemical potential Scanning: A novel approach for disulfide manipulation in pediatric Respiratory syncytial virus detection

Respiratory syncytial virus (RSV) poses a significant risk to children under two years old, necessitating rapid and accurate diagnostic methods. This study introduces an innovative approach using peptides and electrochemical potential scanning for RSV detection. By replacing enzymatic catalysis with electrochemical scanning, the method simplifies the process and reduces costs. Unbound peptides undergo potential-induced disulfide bridge opening, while target-bound peptides remain protected. After removing the target protein, copper ions and a reduced short peptide promote disulfide bridge formation, leading to crosslinking and passivation of the electrode surface. The degree of polymerization and passivation correlates with the target protein levels, generating a signal. This novel method offers enhanced sensitivity, specificity, and scalability, potentially revolutionizing RSV diagnostics in children under two years old. By addressing the limitations of traditional assays, it provides a cost-effective, rapid, and efficient approach for early RSV detection and improved clinical outcomes in this vulnerable population.

High Accuracy of Clinical Verification of Electrohydrodynamic-Driven Nanobox-on-Mirror Platform for Molecular Identification of Respiratory Viruses.

The molecular detection of multiple respiratory viruses provides evidence for the rational use of drugs and effective health management. Herein, we developed and tested the clinical performance of an electrohydrodynamic-driven nanobox-on-mirror platform (E-NoM) for the parallel, accurate, and sensitive detection of four respiratory viral antigens. The E-NoM platform uses gold-silver alloy nanoboxes as the core material with the deposition of a silver layer as a shell on the core surfaces to amplify and enable a reproducible Raman signal readout that facilitates accurate detection. Additionally, the E-NoM platform employs gold microelectrode arrays as the mirror with electrohydrodynamics to manipulate the fluid flow and enhance molecular interactions for an improved biosensing response. The presence of viral antigens binds the nanobox-based core-shell nanostructure on the gold microelectrode and creates the nanocavity with extremely strong "hot spots" to benefit sensitive analysis. Significantly, in a large clinical cohort with 227 patients, the designed E-NoM platform demonstrates the capability of screening respiratory infection with achieved clinical specificity, sensitivity, and accuracy of 100.0, 96.48, and 96.91%, respectively. It is anticipated that the E-NoM platform can find a position in clinical usage for respiratory disease diagnosis.

Factors Associated With Prolonged Respiratory Virus Detection From Polymerase Chain Reaction of Nasal Specimens Collected Longitudinally in Healthy Children in a US Birth Cohort.

Respiratory viral shedding is incompletely characterized by existing studies due to the lack of longitudinal nasal sampling and limited inclusion of healthy/asymptomatic children. We describe characteristics associated with prolonged virus detection by polymerase chain reaction (PCR) in a community-based birth cohort. Children were followed from birth to 2 years of age in the PREVAIL cohort. Weekly nasal swabs were collected and tested using the Luminex Respiratory Pathogen Panel. Weekly text surveys were administered to ascertain the presence of acute respiratory illnesses defined as fever and/or cough. Maternal reports and medical chart abstractions identified healthcare utilization. Prolonged virus detection was defined as a persistently positive test lasting ≥4 weeks. Factors associated with prolonged virus detection were assessed using mixed effects multivariable logistic regression. From a sub-cohort of 101 children with ≥70% weekly swabs collected, a total of 1489 viral infections were detected. Prolonged virus detection was found in 23.4% of viral infections overall, 39% of bocavirus infections, 33% of rhinovirus/enterovirus infections, 14% of respiratory syncytial virus (RSV) A infections, and 7% of RSV B infections. No prolonged detection was found for influenza virus A or B, coronavirus 229E or HKU1, and parainfluenza virus 2 or 4 infections. First-lifetime infection with each virus, and co-detection of another respiratory virus were significantly associated with prolonged detection, while symptom status, child sex, and child age were not. Prolonged virus detection was observed in 1 in 4 viral infections in this cohort of healthy children and varied by pathogen, occurring most often for bocavirus and rhinovirus/enterovirus. Evaluating the immunological basis of how viral co-detections and recurrent viral infections impact duration of virus detection by PCR is needed to better understand the dynamics of prolonged viral shedding.

Non-SARS-CoV-2 respiratory viral detection and whole genome sequencing from COVID-19 rapid antigen test devices: a laboratory evaluation study

There has been high uptake of rapid antigen test device use for point-of-care COVID-19 diagnosis. Individuals who are symptomatic but test negative on COVID-19 rapid antigen test devices might have a different respiratory viral infection. We aimed to detect and sequence non-SARS-CoV-2 respiratory viruses from rapid antigen test devices, which could assist in the characterisation and surveillance of circulating respiratory viruses in the community. We applied archival clinical nose and throat swabs collected between Jan 1, 2015, and Dec 31, 2022, that previously tested positive for a common respiratory virus (adenovirus, influenza, metapneumovirus, parainfluenza, rhinovirus, respiratory syncytial virus [RSV], or seasonal coronavirus; 132 swabs and 140 viral targets) on PCR to two commercially available COVID-19 rapid antigen test devices, the Panbio COVID-19 Ag Rapid Test Device and Roche SARS-CoV-2 Antigen Self-Test. In addition, we collected 31 COVID-19 rapid antigen test devices used to test patients who were symptomatic at The Royal Melbourne Hospital emergency department in Melbourne, Australia. We extracted total nucleic acid from the device paper test strips and assessed viral recovery using multiplex real-time PCR (rtPCR) and capture-based whole genome sequencing. Sequence and genome data were analysed through custom computational pipelines, including subtyping. Of the 140 respiratory viral targets from archival samples, 89 (64%) and 88 (63%) were positive on rtPCR for the relevant taxa following extraction from Panbio or Roche rapid antigen test devices, respectively. Recovery was variable across taxa: we detected influenza A in nine of 18 samples from Panbio and seven of 18 from Roche devices; parainfluenza in 11 of 20 samples from Panbio and 12 of 20 from Roche devices; human metapneumovirus in 11 of 16 from Panbio and 14 of 16 from Roche devices; seasonal coronavirus in eight of 19 from Panbio and two of19from Roche devices; rhinovirus in 24 of 28 from Panbio and 27 of 28 from Roche devices; influenza B in fourof 15 in both devices; and RSV in 16 of 18 in both devices. Of the 31 COVID-19 devices collected from The Royal Melbourne Hospital emergency department, 11 tested positive for a respiratory virus on rtPCR, including one device positive for influenza A virus, one positive for RSV, four positive for rhinovirus, and five positive for SARS-CoV-2. Sequences of target respiratory viruses from archival samples were detected in 55 (98·2%) of 56samples from Panbio and 48 (85·7%) of 56 from Roche rapid antigen test devices. 98 (87·5%) of 112 viral genomes were completely assembled from these data, enabling subtyping for RSV and influenza viruses. All 11samples collected from the emergency department had viral sequences detected, with near-complete genomes assembled for influenza A and RSV. Non-SARS-CoV-2 respiratory viruses can be detected and sequenced from COVID-19 rapid antigen devices. Recovery of near full-length viral sequences from these devices provides a valuable opportunity to expand genomic surveillance programmes for public health monitoring of circulating respiratory viruses. Australian Government Medical Research Future Fund and Australian National Health and Medical Research Council.

Ultrasensitive and Visible Detection of Influenza A Virus Based on Enzymatic Properties of Layered Gold Nanoparticles

Considering the urgent demand for reliable and rapid detection of infectious respiratory viruses during unpredictable pandemics, an innovative ultrasensitive colorimetric immunoassay for influenza A (H1N1) virus detection is developed herein. The proposed approach leverages dual amplification by combining layer‐by‐layer interactions with the nanozyme effect of biotinylated gold nanoparticles (BGNPs). BGNPs assemble around the target via repeated incubation cycles under optimized conditions, resulting in a layered structure that increases optical density, producing a more intense signal proportional to the viral titer. Additionally, the nanozyme effect of the layered BGNPs induces oxidation of 3,3',5,5'‐tetramethylbenzidine, which further enhances the visible signal detectable by the naked eye. This synergetic nanoprobe‐based system demonstrates remarkable sensitivity, with a limit of detection of 101.29 EID50 mL−1, which is 2500‐fold higher than that of commercial rapid kits and conventional enzyme‐linked immunosorbent assays, within a rapid 55 min timeframe. Furthermore, the anti‐interference capability and portability of the developed system reinforce its practicality, making it a promising tool for field diagnostic tests that offers advanced, ultrasensitive, and early detection of respiratory viruses.

Approach to hematopoietic cell transplant candidates with respiratory viral detection.

The management of respiratory viruses prior to hematopoietic cell transplant (HCT) can be controversial and requires special consideration of host factors, transplant parameters, and the specific respiratory virus (RV). In the setting of adenovirus (ADV), human metapneumovirus (HMPV), influenza, parainfluenza virus (PIV), and respiratory syncytial virus (RSV) detection prior to hematopoietic cell transplant (HCT), clinical practice guidelines recommend transplant delay when possible; however, there is much more ambiguity when other respiratory viruses, such as seasonal coronaviruses (CoVs), human rhinovirus (HRV), and SARS-CoV-2, are detected. Our aims for this review include detailing clinical practical guidelines and reviewing current literature on pre-transplant respiratory viral infections (RVIs), including antiviral therapies and prevention strategies, when available. We will center our discussion on three representative clinical scenarios, with the goal of providing practical guidance to clinicians.

First detection and molecular characterization of porcine reproductive and respiratory syndrome virus in Namibia, Africa.

The swine sector in Africa plays an important role in local economies, contributing to poverty alleviation and community subsistence. In addition, intensive farming is progressively becoming more important in the region. Therefore, any disease affecting swine populations can have detrimental effects on local communities. Porcine Reproductive and Respiratory Syndrome (PRRS) is among the most important infectious diseases affecting swine worldwide, but information on its epidemiology in Africa is extremely limited. In the present study, 147 healthy butchered pigs, originating from 15 Namibian intensive and rural farms were tested by RT-PCR and the ORF7 genes of positive samples were sequenced for further genetic characterization and phylogenetic analysis. Additionally, 55 warthogs were also evaluated using the same approach. Overall, 7 out of 147 pigs (4.76%) tested positive, all originating from 3 rural farms (with a within-herd detection frequency higher than 14%) characterized by strong epidemiological links. All industrial pig and warthog samples were negative. Sequence analysis revealed that all strains belonged to the Betaarterivirus suid1 species, previously known as PRRSV type I, and were likely imported from Europe at least 6 years ago, evolving independently thereafter. When and how the first introduction occurred could not be determined due to the absence of other African sequences for comparison. The present work provides the first detection and characterization of PRRSV molecular epidemiology in Namibia. Based on the present findings, the presence of the PPRSV appears marginal and limited to backyard farms. While biosecurity measures applied in industrial farms appear to be effective in preventing viral introduction, PRRSV circulation in rural settings still represents a potential threat, and considering the socio-economical implication of livestock diseases decreasing animal performances in rural areas, active monitoring should be encouraged to promptly act against emerging menaces and guarantee the welfare of local pig populations.

PDA-mediated colorimetric-fluorescence co-enhanced immunochromatography assay for the simultaneous and rapid detection of SARS-CoV-2 and HAdV

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human adenovirus (HAdV) are highly contagious to humans and cause similar symptoms, with HAdV occurring mostly in children. Therefore, a flexible, sensitive, and accurate immunochromatographic assay (ICA) capable of recognizing SARS-CoV-2 and HAdV is urgently needed in the face of infected pediatric patients. Here, we developed a colorimetric-fluorescent co-enhanced dual-mode ICA sensor for the rapid and accurate detection of SARS-CoV-2 and HAdV. A multilayered composite nanomaterial named polydopamine@dual shell quantum dots nanobead (PDQB), which consisted of a polydopamine core (colorimetric) and a two-layered shell (fluorescent) integrated with thousands of small quantum dots, was prepared to replace conventional colorimetric nanotags (colloidal gold, AuNPs) and fluorescent nanotags (quantum nanobeads, QBs) while providing an easily readable colorimetric signal and an easily quantifiable fluorescent signal. The sensitivities of the PDQB-based ICA for SARS-CoV-2 and HAdV were 0.1 ng/mL and 104 copies/mL in colorimetric mode, respectively, and 0.005 ng/mL and 500 copies/mL in fluorescent mode, respectively. The limit of detection (LOD) of the PDQB-based ICA in colorimetric mode was 5 times lower than that of conventional AuNP-ICA. The LOD of the PDQB-based ICA in fluorescent mode was 10 times lower than that of commercial QB-ICA. This work provides a novel strategy for the detection of respiratory viruses, that realizes the co-enhancement and integration of colorimetric and fluorescent methods with high accuracy and convenience. Excitingly, the co-enhancement of colorimetric and fluorescent modes can enable the detection of respiratory viruses in different scenarios, thus guiding epidemic prevention and control.

Evaluation of Severe Acute Respiratory Syndrome surveillance caused by respiratory viruses in a pediatric unit, 2013 to 2019.

To evaluate severe acute respiratory syndrome surveillance in a pediatric unit. Descriptive study of reported severe acute respiratory syndrome cases with the detection of respiratory viruses in the nasopharyngeal sample of patients hospitalized between 2013 and 2019, in a reference hospital in the Federal District, Brazil. A total of 269 children had one or more viruses detected, resulting in 280 viruses, of which 152 (54%) were respiratory syncytial virus. The detection of respiratory syncytial virus was higher during the autumn-winter period. Children´s median age was 6.9 months, 156 (58%) were male, 104 (39%) had comorbidity, 197 (73%) required mechanical ventilation, 241 (90%) received antibiotics, and 146 (54%) oseltamivir. There were 19 (7%) deaths. The median time from symptom onset to sample collection was 5 days and the median time from sample collection to final results was 6 days. The system needs to reduce the time to deliver results so that inappropriate use of antibiotics and antivirals can be avoided. Moreover, the burden of viral pneumonia was relevant and the system must be flexible enough to include emerging viruses in order to be useful in responding to public health emergencies caused by respiratory viruses.

Epidemiology and Disease Burden of Respiratory Syncytial Virus Infection in Adults.

Respiratory syncytial virus (RSV) constitutes a significant cause of respiratory illness and mortality among older adults, a demographic that is expanding with considerable impact on healthcare systems worldwide. The actual burden of RSV in this population may still be underestimated, owing to factors such as low awareness and suboptimal diagnostic sensitivity in adults, the lack of robust RSV surveillance systems, and the infrequent use of diagnostic testing. Recent advancements in respiratory virus detection have spurred further exploration into appropriate preventive and therapeutic strategies. The recent approval of two vaccines highlights the critical need for the precise estimation of the RSV disease burden to optimize the effectiveness and cost-efficiency of immunization programs. This narrative review aimed to summarize the existing knowledge of the RSV burden in adults with a particular focus on older adults, incorporating data from Korea. Overall, current estimates indicate that the annual RSV attack rate in the general adult population ranges from 1 - 7%, increasing to approximately 4 - 10% among elderly and high-risk groups. The in-hospital mortality rate can be estimated to be around 7 - 10%, rising up to 40% among intensive care unit-admitted patients. To elucidate RSV's disease burden, further continuing research, including population-based studies, is necessary.

A multiplex recombinase polymerase amplification assay combined with CRISPR/Cas12a for the detection of respiratory syncytial virus and respiratory adenovirus.

Respiratory syncytial virus (RSV) and respiratory adenovirus (ADV) are two common pathogens that cause acute respiratory tract infections in children. We aimed to develop a rapid method for detecting both pathogens simultaneously. The recombinase polymerase isothermal amplification (RPA) method was combined with the CRISPR/Cas detection system. The assay's specificity and sensitivity were explored by designing RPA primers and CRISPR RNAs (crRNAs) through multi-sequence comparisons, optimizing the reaction conditions, and using a fluorescent reading device. The consistency of the test results of 160 clinical pharyngeal swab samples was studied using quantitative polymerase chain reaction (qPCR) results as a comparative control. RSV and ADV could be detected at levels as low as 104 copies/mL and 103 copies/mL, respectively, within 50 minutes with no cross-reactivity with other similar pathogens. For the clinical samples, compared with the qPCR method, the sensitivities for RSV and ADV were 98.1% and 91.4%, respectively, and the detection specificities were both 100%. The Kappa values were greater than 0.95, suggesting a high degree of consistency. This method for detecting RSV and ADV is rapid, sensitive, and specific. It can accurately detect mixed infections in a timely manner, making it suitable for use in areas with scarce healthcare resources.

Epidemiology of Respiratory Viruses in Korean Children Before and After the COVID-19 Pandemic: A Prospective Study From National Surveillance System.

The coronavirus disease 2019 (COVID-19) pandemic led to a decrease in the seasonal incidence of many respiratory viruses worldwide due to the impact of nonpharmaceutical interventions (NPIs). However, as NPI measures were relaxed, respiratory viral infections re-emerged. We aimed to characterize the epidemiology of respiratory viruses in Korean children during post-COVID-19 pandemic years compared to that before the pandemic. A nationwide prospective ongoing surveillance study has been conducted for detection of respiratory viruses between January 2017 and June 2023. We included data on adenovirus (AdV), human bocavirus (HBoV), human coronavirus (HCoV), human metapneumovirus (HMPV), human rhinovirus (HRV), influenza virus (IFV), parainfluenza virus (PIV), and respiratory syncytial virus (RSV), which were detected in children and adolescents younger than 20 years. We analyzed the weekly detection frequency of individual viruses and the age distribution of the affected children. The study period was divided into prepandemic (2017-2019) and postpandemic (2021-2023) periods. A total of 19,589 and 14,068 samples were collected in the pre- and postpandemic periods, respectively. The overall detection rate of any virus throughout the study period was 63.1%, with the lowest occurring in the 2nd half of 2020 (50.6%) and the highest occurring in the 2nd half of 2021 (72.3%). Enveloped viruses (HCoV, HMPV, IFV, PIV, and RSV) almost disappeared, but nonenveloped viruses (AdV, HBoV, and HRV) were detected even during the peak of the COVID-19 pandemic. The codetection rate increased from 15.0% prepandemic to 19.1% postpandemic (P < 0.001). During the postpandemic period, a large out-of-season PIV and HMPV epidemic occurred, but the usual seasonality began to be restored in 2023. The mean age of children with each virus detected in 2023 was significantly greater than that in prepandemic years (P = 0.003 and 0.007 for AdV and HCoV, respectively; P < 0.001 for others). The mean age of children with IFV increased in 2022 (11.1 ± 5.2 years) from prepandemic years (7.9 ± 4.6 years) but decreased to 8.7 ± 4.1 years in 2023. With the relaxation of NPI measures, several seasonal respiratory viruses cocirculated with unusual seasonal epidemic patterns and were associated with increasing age of infected children.

Respiratory pathogens circulation among non-reactive sars-cov2 patients during the covid-19 pandemic in morocco

The SARS-CoV-2 pandemic has prompted the implementation of stringent measures to curb viral transmission, including mask mandates, hand hygiene practices, and social distancing. These interventions may also have a substantial impact on the prevalence of other respiratory infections, such as influenza and severe acute respiratory illness. This study aimed to assess the incidence of respiratory pathogens among SARS-CoV-2 negative patients admitted to healthcare facilities during the COVID-19 outbreak. From February to July 2021, nasopharyngeal swabs from 167 adults presenting with COVID-19 syndrome symptoms and negative SARS-CoV-2 tests were collected from seven regional sites across Morocco. Multiplexed nucleic acid testing was employed to simultaneously detect and differentiate 22 respiratory pathogens. Our findings revealed a 43% (n=72) overall prevalence of respiratory pathogens, with Human Rhinovirus (HRV) accounting for 38%, Human Coronavirus OC43 HCoV OC43) for 37%, and Human Parainfluenza3 (HPIV3) for 12%. In contrast to the decline in Influenza A/B, Respiratory Syncytial Virus (RSV) and Human Metapneumovirus (HMPV) detection, a significant increase was observed in HRV and HCoV OC43 prevalence. These observations suggest that SARS-CoV-2 prophylactic measures have significantly altered the dynamics of airborne transmission and epidemic patterns for respiratory pathogens. Our findings provide valuable insights into the impact of COVID-19 containment strategies on respiratory infection epidemiology and can inform future prevention and management strategies.

Syndromic surveillance performance in Canada throughout the COVID-19 pandemic, March 1, 2020 to March 4, 2023.

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the need for robust surveillance of respiratory viruses. Syndromic surveillance continues to be an important surveillance component recommended by the World Health Organization (WHO). While FluWatchers, Canada's syndromic surveillance system, has been in place since 2015, the COVID-19 pandemic provided a valuable opportunity to expand the program's scope and underlying technology infrastructure. Following some structural changes to FluWatchers syndromic questionnaire, participants are now able to contribute valuable data to the non-specific surveillance of respiratory virus activity across Canada. This article examines the performance of FluWatchers' syndromic surveillance over the three years of the COVID-19 pandemic in Canada. More specifically, this article examines FluWatchers' performance with respect to the correlation between the FluWatchers influenza-like illness (ILI) and acute respiratory infection (ARI) indicators and total respiratory virus detections (RVDs) in Canada, including influenza, respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and other respiratory viruses.

Multivalent nanobody-based sandwich enzyme-linked immunosorbent assay for sensitive detection of porcine reproductive and respiratory syndrome virus

The pandemic of the porcine reproductive and respiratory syndrome virus (PRRSV) has caused huge economic losses and continues to threaten the swine industry worldwide. Nucleocapsid protein (N protein) is the primary antigen of PRRSV for development of sensitive diagnostic assays. Two high affinity nanobodies against N protein, Nb12 and Nb35, were selected and employed to develop a sandwich ELISA. Further we improved the ELISA method to obtain greater sensitivity, a trivalent nanobody (3 × Nb35) and a bivalent nanobody-HRP fusion protein (2 × Nb12-HRP) were expressed and used. This modified ELISA was found to have high sensitivity for detecting PRRSV, with a detection limit of 10 TCID50/ml (median tissue culture infectious dose), which was approximately 200-fold greater than the single-copy nanobody-based sandwich ELISA. The developed assay shows high specificity and can detect almost all circulating lineages of PRRSV-2 in China. This study provides suggestions for reforming nanobodies and for the further development of multivalent nanobody-based ELISAs for other various viruses.

Respiratory virus detection among healthcare professionals in Brazil: work-related contact and episode recurrence during the COVID-19 pandemic

ObjectivesSince the beginning of the COVID-19 pandemic, changes in the circulation of respiratory viruses have been observed after measures to control the spread of SARS-CoV-2 were implemented. In this sense, we aimed to understand the circulation of the respiratory virus and its impact in a controlled healthy population of healthcare professional (HCP) volunteers in phase III of the clinical trial of the ChadOx nCoV1 conducted in São Paulo, Brazil. Study designThis was a nested observational cohort study within a clinical trial. MethodsWe performed RT-qPCR to detect SARS-CoV-2, influenza virus A and B (IVA and IVB), respiratory syncytial virus (RSV), human rhinovirus (HRV), human metapneumovirus (hMPV), human coronaviruses (hCoVs: HKU-1, NL63, OC43, and 229-E), parainfluenza virus (PiV) I–IV, and q-PCR for adenovirus in nasopharyngeal and oropharyngeal samples obtained from HCP enrolled in the clinical trial to assess respiratory viruses infection among vaccinated and non-vaccinated. ResultsFrom July 2020 to January 2022, 876 samples were included from 737 volunteers (median age: 33 years, 62.9% female). New episodes were registered for 119 individuals. We observed an overall positivity of 37.7% for SARS-CoV-2 and 16.4% for other respiratory viruses; HRV was the second most detected virus (8%), followed by RSV (2.4%). Fully vaccinated individuals accounted for 53.3% of collected samples, and 52.9% presented at least one respiratory virus infection, with SARS-CoV-2 being the most predominant etiologic agent (62.3%). Influenza and hMPV were not detected among the tested samples. Among the subjects that presented more than one episode, SARS-CoV-2 and HRV infections were related to direct contact with patients (P < 0.002). ConclusionsData show high infection rates among HCPs even under mask policies and contact precautions, highlighting the need for improvement in infection control measures in this population regardless of the vaccination program.

Evaluation of Multiplex Rapid Antigen Tests for the Simultaneous Detection of SARS-CoV-2 and Influenza A/B Viruses.

Single-target rapid antigen tests (RATs) are commonly used to detect highly transmissible respiratory viruses (RVs), such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses. The simultaneous detection of RVs presenting overlapping symptoms is vital in making appropriate decisions about treatment, isolation, and resource utilization; however, few studies have evaluated multiplex RATs for SARS-CoV-2 and other RVs. We assessed the diagnostic performance of multiplex RATs targeting both the SARS-CoV-2 and influenza A/B viruses with the GenBody Influenza/COVID-19 Ag Triple, InstaView COVID-19/Flu Ag Combo (InstaView), STANDARDTM Q COVID-19 Ag Test, and STANDARDTM Q Influenza A/B Test kits using 974 nasopharyngeal swab samples. The cycle threshold values obtained from the real-time reverse transcription polymerase chain reaction results showed higher sensitivity (72.7-100%) when the values were below, rather than above, the cut-off values. The InstaView kit exhibited significantly higher positivity rates (80.21% for SARS-CoV-2, 61.75% for influenza A, and 46.15% for influenza B) and cut-off values (25.57 for SARS-CoV-2, 21.19 for influenza A, and 22.35 for influenza B) than the other two kits, and was able to detect SARS-CoV-2 Omicron subvariants. Therefore, the InstaView kit is the best choice for routine screening for both SARS-CoV-2 and influenza A/B in local communities.

Water-stable perovskite-silica nanocomposites for encoded microbeads construction and multiplexed detection

All-inorganic lead halide perovskite nanocrystals exhibiting bright luminescence have great potential as fluorescence elements for optical encoding. However, their limited stability in water hinders the application in biosensing. In this study, novel optical encoded microbeads based on CsPbX3 (X = Cl, Br) nanocrystals are developed and applied in bead-based suspension arrays for the first time. Through the in-situ crystallization of CsPbX3 nanocrystals within mesoporous silica nano-templates (MSNs), accompanied by mesopores collapse after sintering, CsPbX3@MSNs (X3M) nanocomposites with uniform morphology and stable fluorescence intensity in aqueous solutions for up to 50 days are obtained. By assembling X3M with microspheres to form a host–guest structure, an optical encoding microbead (MX3M) library is established by varying the X3M ratio, halide composition, and the size of host microspheres, which can be easily decoded under multi-channel flow cytometer. As a result, MX3M exhibits outstanding capacity for specific target capture and negligible nonspecific absorption performance in the multiplex nucleic acid detection of respiratory viruses, with a low limit of detection (10 copies/rxn). This result highlights the tremendous potential of MX3M encoded microbeads constructed based on CsPbX3 nanocrystals for multiplexed bioassays.