RT-RPA-PfAgo detection platform for one-tube simultaneous typing diagnosis of human respiratory syncytial virus.

Human respiratory syncytial virus (HRSV) is the most prevalent pathogen contributing to acute respiratory tract infections (ARTI) in infants and young children and can lead to significant financial and medical costs. Here, we developed a simultaneous, dual-gene and ultrasensitive detection system for typing HRSV within 60 minutes that needs only minimum laboratory support. Briefly, multiplex integrating reverse transcription-recombinase polymerase amplification (RT-RPA) was performed with viral RNA extracted from nasopharyngeal swabs as a template for the amplification of the specific regions of subtypes A (HRSVA) and B (HRSVB) of HRSV. Next, the Pyrococcus furiosus Argonaute (PfAgo) protein utilizes small 5'-phosphorylated DNA guides to cleave target sequences and produce fluorophore signals (FAM and ROX). Compared with the traditional gold standard (RT-qPCR) and direct immunofluorescence assay (DFA), this method has the additional advantages of easy operation, efficiency and sensitivity, with a limit of detection (LOD) of 1 copy/µL. In terms of clinical sample validation, the diagnostic accuracy of the method for determining the HRSVA and HRSVB infection was greater than 95%. This technique provides a reliable point-of-care (POC) testing for the diagnosis of HRSV-induced ARTI in children and for outbreak management, especially in resource-limited settings.

Systematic computer-aided disulfide design as a general strategy to stabilize prefusion class I fusion proteins.

Numerous enveloped viruses, such as coronaviruses, influenza, and respiratory syncytial virus (RSV), utilize class I fusion proteins for cell entry. During this process, the proteins transition from a prefusion to a postfusion state, undergoing substantial and irreversible conformational changes. The prefusion conformation has repeatedly shown significant potential in vaccine development. However, the instability of this state poses challenges for its practical application in vaccines. While non-native disulfides have been effective in maintaining the prefusion structure, identifying stabilizing disulfide bonds remains an intricate task. Here, we present a general computational approach to systematically identify prefusion-stabilizing disulfides. Our method assesses the geometric constraints of disulfide bonds and introduces a ranking system to estimate their potential in stabilizing the prefusion conformation. We hypothesized that disulfides restricting the initial stages of the conformational switch could offer higher stability to the prefusion state than those preventing unfolding at a later stage. The implementation of our algorithm on the RSV F protein led to the discovery of prefusion-stabilizing disulfides that supported our hypothesis. Furthermore, the evaluation of our top design as a vaccine candidate in a cotton rat model demonstrated robust protection against RSV infection, highlighting the potential of our approach for vaccine development.

Mucosal delivery of a prefusogenic-F, glycoprotein, and matrix proteins-based virus-like particle respiratory syncytial virus vaccine induces protective immunity as evidenced by challenge studies in mice.

RSV infection remains a serious threat to the children all over the world, especially, in the low-middle income countries. Vaccine delivery via the mucosa holds great potential for inducing local immune responses in the respiratory tract. Previously, we reported the development of highly immunogenic RSV virus-like-particles (RSV-VLPs) based on the conformationally stable prefusogenic-F protein (preFg), glycoprotein and matrix protein. Here, to explore whether mucosal delivery of RSV-VLPs is an effective strategy to induce RSV-specific mucosal and systemic immunity, RSV-VLPs were administered via the nasal, sublingual and pulmonary routes to BALB/c mice. The results demonstrate that immunization with the VLPs via the mucosal routes induced minimal mucosal response and yet facilitated modest levels of serum IgG antibodies, enhanced T cell responses and the expression of the lung-homing marker CXCR3 on splenocytes. Immunization with VLPs via all three mucosal routes provided protection against RSV challenge with no signs of RSV induced pathology.

Impact of the COVID-19 pandemic on the epidemiology of bronchiolitis at Hôpital du Jura in Delémont, Switzerland: a retrospective observational study.

BACKGROUND: Non-pharmaceutical interventions during the COVID-19 pandemic caused an unusual epidemiology in bronchiolitis hospitalisations, with a peak in the summer seasons of 2020 and 2021. AIM: The aim of this study was to analyse data from a 5-year period (2018-2022) at Hôpital du Jura in Delémont, Switzerland, regarding bronchiolitis hospitalisations before, during and towards the end of the COVID-19 pandemic in order to prepare for future changes in bronchiolitis epidemiology. MATERIALS AND METHODS: Anonymous retrospective data on bronchiolitis hospitalisations for children under 2 years of age with hospital admission date from 1 January 2018 to 31 December 2022 was obtained from the Health Records Coding Unit of our hospital. RESULTS: A clear shift in the peak of bronchiolitis is seen in 2021 compared to the three previous years. Starting in spring 2022, the trend begins to mimic pre-pandemic years. For respiratory syncytial virus (RSV) bronchiolitis hospitalisations specifically, an important peak in hospitalisations is seen in the summer months of 2021, with over 20 admissions, compared to zero admissions in the previous years. This peak shifts to the winter months in 2022. CONCLUSIONS: The non-pharmacological interventions implemented during 2020 and early 2021 did not cause a long-lasting seasonal shift in bronchiolitis. In 2022, when the non-pharmacological interventions were no longer in place in the non-hospital setting, the peak of bronchiolitis hospitalisations is seen once again in the winter months. We predict that hospitalisation patterns will gradually revert to those of pre-pandemic years.

Hospital surveillance of respiratory viruses during the COVID-19 pandemic and beyond: contribution to the WHO mosaic framework, Israel, 2020 to 2023.

BackgroundA new respiratory virus surveillance platform, based on nationwide hospital laboratory data, was established in Israel during the COVID-19 pandemic.AimWe aimed to evaluate the performance of this platform with respect to the detection of influenza and respiratory syncytial virus (RSV) from week 36 in 2020 to week 15 in 2023, and how it fits with the World Health Organization (WHO) mosaic surveillance framework.MethodsData of respiratory samples from hospitalised patients sent for laboratory confirmation of influenza virus or RSV from 25 general hospital laboratories nationwide were collected. We analysed the weekly number and percentage of samples positive for influenza virus or RSV vis-à-vis SARS-CoV-2 activity and compared data from the new surveillance platform with existing surveillance platforms. Using data in the new surveillance platform, we analysed early stages of a 2021 out-of-season RSV outbreak and evaluated the capabilities of the new surveillance system with respect to objectives and domains of the WHO mosaic framework.ResultsThe new hospital-laboratory surveillance platform captured the activity of influenza virus and RSV, provided crucial data when outpatient sentinel surveillance was not operational and supported an out-of-season RSV outbreak investigation. The new surveillance platform fulfilled important objectives in all three domains of the mosaic framework and could serve for gathering additional information to fulfil more domain objectives.ConclusionThe new hospital laboratory surveillance platform provided essential data during the COVID-19 pandemic and beyond, fulfilled important domain objectives of the mosaic framework and could be adapted for the surveillance of other viruses.

Implementation of the first respiratory syncytial (RSV) immunization campaign with nirsevimab in an autonomous community in Spain.

Respiratory syncytial virus (RSV) is the main cause of low respiratory tract infections in infants under one year of age. In the 2023/2024 season, the monoclonal antibody nirsevimab was available to protect children from RSV, and Spain has become one of the first countries worldwide to implement this strategy. It is essential to evaluate the results of this first campaign and different characteristics of the immunized population in order to plan next campaigns, especially for countries that are going to include this immunization. Our coverage was high (91.5% for those born during the season and 88.3% globally). For those born during the season, only 4.9% preferred not to immunize at the maternity hospital, which meant an average delay of 27.45 days. We observed a lower coverage in the population of immigrant origin. There was a rapid pace of immunization, since for those born before the beginning of the campaign the mean to be immunized was 15.63 days, without differences between healthy and at-risk children. This allows immunization before the RSV season (90% of the catch-up children had been immunized on November 3). The average age at which all the immunized children have received nirsevimab was lower in healthy children compared to those with risk conditions (49.65 versus 232.85 days). For those born during the campaign, the average age was also lower in healthy children (3.14 versus 14.58 days). In conclusion, we consider that the implementation of the immunization strategy with nirsevimab in the Region of Murcia, Spain, has been a success.

Respiratory syncytial virus immunization patterns in Germany, 2015-2020.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) in infants and young children worldwide. Using routine statutory health insurance claims data including patients from all regions of Germany, we investigated the health-care resource use and costs associated with RSV prophylaxis with palivizumab in Germany. In the database, infants from the birth cohorts 2015-2019 eligible for palivizumab immunization were identified using codes of the 10th revision of the International Classification of Diseases (ICD-10). Health-care resource use and costs related to immunization were determined by inpatient and outpatient administrations. Over the study period, only 1.3% of infants received at least one dose of palivizumab in their first year of life. The mean number of doses per immunized infant was 4.6. From a third-party payer perspective, the mean costs of palivizumab per infant who received at least one dose in the first year of life was €5,435 in the birth cohorts 2015-2019. Despite the substantial risk of severe RSV infection, we found low rates of palivizumab utilization. Novel preventive interventions, featuring broader indications and single-dose administration per season, contribute to mitigating the burden of RSV disease across a more extensive infant population.

Immunogenicity, safety and reactogenicity of Ad26.RSV.preF/RSV preF protein vaccine in adults aged 60 to 75 years: A comparison of phase 2b and phase 3 clinical trial material.

The Ad26.RSV.preF/RSV preF protein vaccine has previously demonstrated efficacyin protecting older adults against respiratory syncytial virus (RSV)-related lower respiratory tract disease in a phase 2b study. This study compared the immunogenicity of vaccine clinical trial material (CTM) representative of phase 2b clinical studies with CTM used in phase 3 clinical studies. A total of 248 adults aged 60-75 years, randomized in a 1:1 ratio, received one dose of either phase 3 CTM or phase 2b CTM. Solicited adverse events (AEs), unsolicited AEs, and serious AEs (SAEs) were assessed for 7-d, 28-d, and 6-month periods post-vaccination, respectively. RSV preF-ELISA antibody titers and RSV neutralizing titers were measured before and 14 d after vaccination. The phase 3 CTM-induced preF-ELISA response at Day 15, in terms of geometric mean titer, was shown to be non-inferior to that induced by phase 2b CTM. The RSV neutralizing antibody titers were also similar in the two groups at Day 15. The safety profile in terms of solicited AEs, unsolicited AEs, or SAEs was in general similar between the phase 3 CTM and phase 2b CTM groups, and solicited AEs were mostly mild to moderate in intensity. No related SAEs were reported, and no safety concerns were identified.

Nasal microRNA signatures for disease severity in infants with respiratory syncytial virus bronchiolitis: a multicentre prospective study.

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis contributes to a large morbidity and mortality burden globally. While emerging evidence suggests that airway microRNA (miRNA) is involved in the pathobiology of RSV infection, its role in the disease severity remains unclear. METHODS: In this multicentre prospective study of infants (aged<1 year) hospitalised for RSV bronchiolitis, we sequenced the upper airway miRNA and messenger RNA (mRNA) at hospitalisation. First, we identified differentially expressed miRNAs (DEmiRNAs) associated with higher bronchiolitis severity-defined by respiratory support (eg, positive pressure ventilation, high-flow oxygen therapy) use. We also examined the biological significance of miRNAs through pathway analysis. Second, we identified differentially expressed mRNAs (DEmRNAs) associated with bronchiolitis severity. Last, we constructed miRNA-mRNA coexpression networks and determined hub mRNAs by weighted gene coexpression network analysis (WGCNA). RESULTS: In 493 infants hospitalised with RSV bronchiolitis, 19 DEmiRNAs were associated with bronchiolitis severity (eg, miR-27a-3p, miR-26b-5p; false discovery rate<0.10). The pathway analysis using miRNA data identified 1291 bronchiolitis severity-related pathways-for example, regulation of cell adhesion mediated by integrin. Second, 1298 DEmRNAs were associated with bronchiolitis severity. Last, of these, 190 DEmRNAs were identified as targets of DEmiRNAs and negatively correlated with DEmiRNAs. By applying WGCNA to DEmRNAs, four disease modules were significantly associated with bronchiolitis severity-for example, microtubule anchoring, cell-substrate junction. The hub genes for each of these modules were also identified-for example, PCM1 for the microtubule anchoring module, LIMS1 for the cell-substrate junction module. CONCLUSIONS: In infants hospitalised for RSV bronchiolitis, airway miRNA-mRNA coexpression network contributes to the pathobiology of bronchiolitis severity.

Comparative efficacy of modified-live and inactivated vaccines in boosting responses to bovine respiratory syncytial virus, bovine parainfluenza virus Type 3, and bovine coronavirus following neonatal mucosal priming of beef calves.

Objective: This study compared clinical and immunological responses to coinfection challenge of beef calves mucosally primed and differentially boosted with commercial combination vaccines containing antigens against bovine coronavirus (BCoV), bovine parainfluenza virus Type 3 (BPIV3), and bovine respiratory syncytial virus (BRSV). Animals: Nineteen commercial beef heifers. Procedure: At birth, calves were mucosally (IN) primed with modified-live virus (MLV) vaccines, differentially boosted by injection of either combination MLV (IN-MLV) or inactivated virus (IN-KV) vaccines at a mean age of 44 d, and then challenged by coinfection with BCoV, BPIV3, and BRSV at weaning. Results: Both groups were similarly protected from clinical disease and had anamnestic neutralizing antibody responses to all 3 viruses. The IN-KV group shed more BCoV, and less BPIV3 and BRSV, than the IN-MLV group. Conclusion: These data indicated similar clinical and immunological protection between IN-MLV and IN-KV; however, shed of virus varied. Clinical relevance: Whereas boosting with KV or MLV appeared to have similar efficacy, viral shed differences may affect disease control.

Efficacité comparative des vaccins vivants modifiés et inactivés pour stimuler les réponses au virus respiratoire syncytial bovin, au virus parainfluenza bovin de type 3 et au coronavirus bovin après amorçage via la muqueuse de veaux de boucherie nouveau-nés. Objectif: Cette étude a comparé les réponses cliniques et immunologiques à une co-infection de veaux de boucherie amorcés par voie muqueuse et différentiellement stimulés avec des vaccins combinés commerciaux contenant des antigènes contre le coronavirus bovin (BCoV), le virus parainfluenza bovin de type 3 (BPIV3) et le virus respiratoire syncytial bovin (BRSV). Animaux: Dix-neuf génisses de boucherie commerciales. Procédure: À la naissance, les veaux ont été vaccinés au niveau des muqueuses (IN) avec des vaccins à virus vivants modifiés (MLV), stimulés de manière différentielle par l'injection de vaccins combinés MLV (IN-MLV) ou de virus inactivés (IN-KV) à un âge moyen de 44 jours. puis provoqué par une co-infection avec BCoV, BPIV3 et BRSV au sevrage. Résultats: Les deux groupes étaient protégés de la même manière contre la maladie clinique et présentaient des réponses anamnestiques en anticorps neutralisants contre les 3 virus. Le groupe IN-KV a excrété plus de BCoV et moins de BPIV3 et de BRSV que le groupe IN-MLV. Conclusion: Ces données indiquent une protection clinique et immunologique similaire entre IN-MLV et IN-KV; cependant, l'excrétion du virus variait. Pertinence clinique: Alors que le rappel avec KV ou MLV semble avoir une efficacité similaire, les différences d'excrétion virale peuvent affecter la limitation de la maladie.(Traduit par Dr Serge Messier).

Incidence of laboratory-confirmed influenza and RSV and associated presenteeism and absenteeism among healthcare personnel, Israel, influenza seasons 2016 to 2019.

BackgroundHealthcare personnel (HCP) are at high risk for respiratory infections through occupational exposure to respiratory viruses.AimWe used data from a prospective influenza vaccine effectiveness study in HCP to quantify the incidence of acute respiratory infections (ARI) and their associated presenteeism and absenteeism.MethodsAt the start and end of each season, HCP at two Israeli hospitals provided serum to screen for antibodies to influenza virus using the haemagglutination inhibition assay. During the season, active monitoring for the development of ARI symptoms was conducted twice a week by RT-PCR testing of nasal swabs for influenza and respiratory syncytial virus (RSV). Workplace presenteeism and absenteeism were documented. We calculated incidences of influenza- and RSV-associated ARI and applied sampling weights to make estimates representative of the source population.ResultsThe median age of 2,505 participating HCP was 41 years, and 70% were female. Incidence was 9.1 per 100 person-seasons (95% CI: 5.8-14.2) for RT-PCR-confirmed influenza and 2.5 per 100 person-seasons (95% CI: 0.9-7.1) for RSV illness. Each season, 18-23% of unvaccinated and influenza-negative HCP seroconverted. The incidence of seroconversion or RT-PCR-confirmed influenza was 27.5 per 100 person-seasons (95% CI: 17.8-42.5). Work during illness occurred in 92% (95% CI: 91-93) of ARI episodes, absence from work in 38% (95% CI: 36-40).ConclusionInfluenza virus and RSV infections and associated presenteeism and absenteeism were common among HCP. Improving vaccination uptake among HCP, infection control, and encouraging sick HCP to stay home are important strategies to reduce ARI incidence and decrease the risk of in-hospital transmission.

Disease Burden of RSV Infections and Bronchiolitis in Young Children (< 5 Years) in Primary Care and Emergency Departments: A Systematic Literature Review.

Respiratory syncytial virus (RSV) is the most common cause of acute respiratory infections in young children. Limited data are available on RSV disease burden in primary care and emergency departments (EDs). This review synthesizes the evidence on population-based incidence rates of RSV infections in young children (< 5 years) in primary care and EDs. A systematic literature review was performed in PubMed and Embase. Studies reporting yearly population-based RSV incidence rates in primary care and EDs were included. A total of 4244 records were screened and 32 studies were included, conducted between 1993 and 2019. Studies were mainly performed in high-income countries (n = 27), with 15 studies in North America and 10 studies in Europe. There was significant variability in study methodology and setting among studies, resulting in considerable variability in reported incidence rates. Incidence rates were higher in primary care-ranging from 0.8 to 330 (median = 109) per 1000 population-compared to EDs (7.5-144.0, median = 48). The highest incidence rates were reported in infants. Additionally, incidence rates were higher in high-income countries and in studies using laboratory-confirmed RSV cases compared to studies using bronchiolitis ICD-codes (non-laboratory confirmed). Our study found that a substantial number of children under 5 years of age attend primary care settings and EDs, every year for RSV infections. Due to the considerable heterogeneity in study methodology, it was impossible to draw definitive conclusions regarding factors explaining differences in reported incidence rates. Additionally, more studies in low- and middle-income countries are recommended.

[Development and validation of an individual risk prediction tool for severe respiratory syncytial virus infection among children under five years in China].

Objective: To construct a predictive model to assess the risk of severe respiratory syncytial virus infection among children under five years in China, conduct preliminary validation of this model by using external data, and develop an individual risk assessment tool available for their parents. Methods: The admission after RSV infection was used as a marker of severe infection. Based on the evidence of RSV hospitalization-related risk factors and real-world data, such as the prevalence of various risk factors in children under five years old in China, a Monte Carlo-based individual RSV hospitalization risk prediction model for children under five years old was constructed. Taking Suzhou City as an example, the model was externally validated, and an interactive risk prediction tool (RSV HeaRT) was developed on the WeChat mini-program platform. Results: The estimation model showed that in children under five years old in China if the population did not have any risk factors for severe RSV infection, the RSV annual hospitalization rate was 2.2/1 000 (95%CI: 0.9/1 000-7.5/1 000). Based on this baseline hospitalization rate and the prevalence of related risk factors in Suzhou, the model predicted an RSV hospitalization rate of 8.0/1 000 (95%CI: 4.6/1 000-24.4/1 000) for children under five years old annually in Suzhou, which was close to the reported RSV hospitalization rate in literature (10/1 000-20/1 000). In the developed RSV HeaRT WeChat mini-program, target users (such as parents of children) could input basic information, disease history, and social environmental factors of the child into the mini-program, and the tool could provide real-time feedback on the following predicted results: First, the relative risk of hospitalization due to RSV infection in current children compared to general children; Second, the probability of hospitalization due to RSV infection within the next year; Third, the relative risk of adverse outcomes during hospitalization in the event of RSV infection. Conclusion: This study is based on real-world evidence related to RSV hospitalization risk and constructs an RSV hospitalization risk prediction model suitable for Chinese children based on the combination of the current prevalence of risk factors in children under five years old in China. The accuracy of the prediction model results has been preliminarily demonstrated. Based on this design, the RSV HeaRT developed can facilitate parents to evaluate the hospitalization risk of children.

[Epidemiological characteristics of human respiratory syncytial virus in Hubei Province from 2016 to 2023].

Objective: To analyze the epidemiological characteristics of human respiratory syncytial virus (HRSV) in patients with acute respiratory infection (ARIs) in sentinel hospitals of the Hubei influenza surveillance network from 2016 to 2023. Methods: ARIs samples [including influenza-like cases (ILI) and severe acute respiratory infection (SARI)] were collected from influenza surveillance sentinel hospitals in Hubei Province from 2016 to 2023, and case information was collected. HRSV virus nucleic acid typing was performed by fluorescence quantitative PCR method, and the data were collated, plotted and analyzed. Results: From 2016 to 2023, 12 779 cases of ILI and 9 166 cases of SARI were collected. The positive rate of HRSV was the highest in<5 years of age group [15.77% (168/1 065)], among which the positive rate was the highest in 2 to 5 years of age group of ILI cases [13.60% (31/228)], and the positive rate was the highest in 0 to 2 years of age group of SARI cases [25.97% (60/231)] (all P values<0.001). The positive rate of HRSV in SARI cases was 2.31%-25.97%, higher than that in ILI cases (0-13.60%) (P=0.016). HRSV was prevalent in autumn and winter from 2016 to 2020 and in spring in 2023. Alternating epidemics of HRSV virus type A and B in Hubei Province from 2016 to 2023 (dominant epidemics of type B in 2016 and 2020; dominant epidemics of type A in 2017-2019 and 2023). Conclusion: SARI and ILI patients under five years old are the main infection groups of HRSV. The seasonal prevalence characteristics of HRSV in Hubei Province from 2016 to 2023 shift from autumn and winter to spring.

[Research progress on detection methods for human respiratory syncytial virus].

Human respiratory syncytial virus (HRSV) can infect individuals of all ages, with children under five years old, the elderly, and immunocompromised persons as the main high-risk groups. Although older children and adults often exhibit mild or no symptoms, they may still be potential carriers of the virus. Therefore, employing efficient, accurate, and rapid detection methods to timely identify infection sources and quickly halt transmission is an important means to curb the potential spread of the epidemic. However, the clinical manifestations of HRSV infection are difficult to distinguish from acute respiratory infections caused by other respiratory viruses, and the identification relies on the results of pathogen testing. This article summarizes four commonly used detection methods for HRSV based on detection principles: antigen detection, nucleic acid testing, antibody detection, and virus isolation. The advantages, disadvantages, principles, and applicable scenarios of these four methods are summarized and compared. Furthermore, the research progress and prospects of HRSV detection methods are reviewed.

[Epidemiological characteristics of human respiratory syncytial virus in influenza-like illness in Shenzhen City from 2019 to 2023].

Objective: To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among cases presenting with influenza-like illness (ILI) in Shenzhen City from 2019 to 2023. Methods: Respiratory specimens were collected from two national sentinel hospitals in Shenzhen from March 2019 to December 2023, specifically targeting cases of ILI. The real-time PCR method was used for the detection and genotyping of HRSV. Basic demographic information was collected and used for the epidemiological analysis. Results: A total of 9 278 respiratory specimens of influenza-like cases were collected and detected, with a total positive rate of 4.77% (443/9 278) for HRSV. In 2021 (8.48%, 167/1 970), the positive rate of HRSV was significantly higher than in 2019 (3.35%, 52/1 552), 2022 (1.80%, 39/2 169), and 2023 (4.49%, 133/2 960), and the difference was statistically significant (χ2=102.395, P<0.001). The prevalence of HRSV was mainly in summer and early autumn (September), and there was an abnormal increase in the positive rate of HRSV in winter 2022. The highest positive rate of HRSV was in children under five years old (9.84%, 330/335). The typing results showed that in 2022, the prevalence of HRSV-A was predominant (71.79%, 28/39), and in 2023, HRSV-A and HRSV-B subtypes coexisted. Conclusions: The prevalence of HRSV in Shenzhen from 2019 to 2023 has obvious seasonality, mainly in summer and early autumn. Children under five years old are the main population of HRSV infections.