Respiratory Syncytial Research Articles

Post-Pandemic Epidemiology of Respiratory Infections among Pediatric Inpatients in a Tertiary Hospital in Shanghai, China.

After the removal of the three-year epidemic control restrictions, Chinese children were confronted with heightened risks of respiratory infections. We aimed to investigate the post-pandemic (2023) epidemiology of respiratory infections among pediatric inpatients in a tertiary hospital in Shanghai, China, and compare it with the pre-pandemic (2019) levels. A total of 2644 pediatric inpatients were enrolled based on discharge time and divided into group 2019 (n = 1442) and group 2023 (n = 1202). Information on the demographic characteristics, diagnoses, and pathogen test results (Mycoplasma pneumoniae, MP; Chlamydia pneumoniae, CP; Legionella pneumophila, LP; Influenza A, IFA; Influenza B, IFB; Parainfluenza virus, PIV; respiratory syncytial virus, RSV; Coxsackie virus, COX; Adenovirus, ADV; Epstein-Barr virus, EBV) was collected and analyzed. Significant increases were found in the overall test positivity rates (64.6% vs. 46.7%), mixed infection rates (17.4% vs. 9%), and proportion of severe cases (25.5% vs. 3.7%) after the pandemic than those before it. Compared with 2019, the incidences of MP, IFA, LP, RSV, and ADV remarkably increased, while those of IFB and COX decreased, with no obvious differences noted for CP, PIV, and EBV in 2023. A significantly higher MP-positive detection rate was noticed in children aged 1-6 years in 2023 than in 2019. The incidence of RSV infection began to rise in August 2023, earlier than the conventional epidemic season. Compared with the pre-pandemic levels, the overall test positivity rates of atypical pathogens and viruses among pediatric inpatients significantly increased, and alterations in the disease spectrum, epidemic season, and age of prevalence were observed after the COVID-19 pandemic.

A clinical protocol for a German birth cohort study of the Maturation of Immunity Against respiratory viral Infections (MIAI).

Respiratory viral infections (RVIs) are a major global contributor to morbidity and mortality. The susceptibility and outcome of RVIs are strongly age-dependent and show considerable inter-population differences, pointing to genetically and/or environmentally driven developmental variability. The factors determining the age-dependency and shaping the age-related changes of human anti-RVI immunity after birth are still elusive. We are conducting a prospective birth cohort study aiming at identifying endogenous and environmental factors associated with the susceptibility to RVIs and their impact on cellular and humoral immune responses against the influenza A virus (IAV), respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The MIAI birth cohort enrolls healthy, full-term neonates born at the University Hospital Würzburg, Germany, with follow-up at four defined time-points during the first year of life. At each study visit, clinical metadata including diet, lifestyle, sociodemographic information, and physical examinations, are collected along with extensive biomaterial sampling. Biomaterials are used to generate comprehensive, integrated multi-omics datasets including transcriptomic, epigenomic, proteomic, metabolomic and microbiomic methods. The results are expected to capture a holistic picture of the variability of immune trajectories with a focus on cellular and humoral key players involved in the defense of RVIs and the impact of host and environmental factors thereon. Thereby, MIAI aims at providing insights that allow unraveling molecular mechanisms that can be targeted to promote the development of competent anti-RVI immunity in early life and prevent severe RVIs. https://drks.de/search/de/trial/, identifier DRKS00034278.

Comparison of clinical characteristics and outcomes in hospitalized adult patients infected with respiratory syncytial virus and influenza virus

Background Because patients infected with respiratory syncytial virus (RSV) have been reported to be older than patients infected with influenza virus, the more frequent incidence of complications in RSV-infected patients may be age-related. This study compared clinical characteristics and outcomes in hospitalized adults infected with RSV with findings in age- and sex-matched adults infected with influenza virus. Methods The medical records of hospitalized adult patients infected with RSV or influenza virus at two university hospitals from 2013 to 2022 were retrospectively analyzed. Virus infection was confirmed by real-time polymerase chain reaction. Each RSV-infected patient was matched by age and sex with two influenza virus-infected patients, and their clinical symptoms, laboratory parameters and hospital courses were compared. Results The study cohort consisted of 552 patients, 184 infected with RSV and 368 infected with influenza virus. Fever (71.2% vs. 79.9%, p = .022) and cough (70.1% vs. 80.4%, p = .007) were significantly less frequent in the RSV than in the influenza group, whereas white blood cell counts (9132/mm3 vs. 7616/mm3, p < .001) and C-reactive protein concentrations (10.25 vs. 8.88 mg/dL, p = .029) were significantly higher in the RSV group. The frequency of oxygen therapy was higher (60.3% vs. 48.6%, p = .010) and hospital stay was longer (8 vs. 6 days, p = .003) in RSV than in influenza virus-infected patients. Conclusions Clinical symptoms were less frequent, but disease was more severe, in hospitalized adult patients infected with RSV than in age- and sex-matched patients infected with influenza. Greater attention should be paid to diagnosing and preventing RSV infection in adults.

Complete Genomic Characterization of Global Pathogens, Respiratory Syncytial Virus (RSV), and Human Norovirus (HuNoV) Using Probe-based Capture Enrichment.

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in children worldwide, while human noroviruses (HuNoV) are a leading cause of epidemic and sporadic acute gastroenteritis. Generating full-length genome sequences for these viruses is crucial for understanding viral diversity and tracking emerging variants. However, obtaining high-quality sequencing data is often challenging due to viral strain variability, quality, and low titers. Here, we present a set of comprehensive oligonucleotide probe sets designed from 1,570 RSV and 1,376 HuNoV isolate sequences in GenBank. Using these probe sets and a capture enrichment sequencing workflow, 85 RSV positive nasal swab samples and 55 (49 stool and six human intestinal enteroids) HuNoV positive samples encompassing major subtypes and genotypes were characterized. The Ct values of these samples ranged from 17.0-29.9 for RSV, and from 20.2-34.8 for HuNoV, with some HuNoV having below the detection limit. The mean percentage of post-processing reads mapped to viral genomes was 85.1% for RSV and 40.8% for HuNoV post-capture, compared to 0.08% and 1.15% in pre-capture libraries, respectively. Full-length genomes were>99% complete in all RSV positive samples and >96% complete in 47/55 HuNoV positive samples-a significant improvement over genome recovery from pre-capture libraries. RSV transcriptome (subgenomic mRNAs) sequences were also characterized from this data. Probe-based capture enrichment offers a comprehensive approach for RSV and HuNoV genome sequencing and monitoring emerging variants.

Respiratory Syncytial Virus among People Living with HIV: Is There a Case for Rolling Out Prophylaxis? A Viewpoint Based on a Systematic Review.

Respiratory Syncytial Virus (RSV) is responsible for a considerable burden of respiratory disease among children and older adults. Several prophylactic strategies have recently been introduced. We review the available evidence on the interplay between RSV infection and HIV, looking at the specific role of RSV prophylactic strategies in individuals affected by or exposed to HIV. We conducted a systematic review on the association between HIV infection and RSV incidence and severity. We searched in PubMed/MEDLINE for clinical epidemiological studies covering outcomes such as RSV-associated illness, severity, and mortality in individuals affected by or exposed to HIV. A total of 36 studies met the inclusion criteria and were included, the majority conducted in sub-Saharan Africa. There was no compelling evidence suggesting a higher incidence of RSV illness among HIV-infected people. A higher risk of severe disease was consistent among both HIV-positive and HIV-exposed but uninfected (HEU) children. Case fatality rates were also higher for these groups. Evidence on a differing risk among adults was scarce. HIV-positive pregnant women should be given priority for recently approved RSV vaccination, for protection of their newborns. HIV-infected and HEU infants should be considered risk groups for nirsevimab prophylaxis in their first year of life and possibly beyond.

Sonication-Assisted Self-Assembled Resveratrol Nanoparticles with Enhanced Antiviral and Anti-inflammatory Activity against Respiratory Syncytial Virus-Induced Pneumonia.

Respiratory syncytial virus (RSV)-induced viral pneumonia in children is common worldwide. Its high occurrence and lack of an effective vaccine make it a leading cause of death in children. Severe RSV infection can trigger uncontrolled inflammatory responses in patients, so the development of small molecule drugs with the dual function of "direct antivirus" and "inflammatory response regulation" is welcome. Resveratrol (Res) has been reported to have antiviral and anti-inflammatory pharmacological effects, but its application is limited because of its poor water solubility and oral bioavailability. Based on small-molecule nanotechnology, we developed a sonication-assisted self-assembly method for preparing insoluble Res into highly soluble resveratrol nanoparticles (Res NPs). The obtained Res NPs exhibited a higher water solubility and a faster dissolution rate, which was more conducive to the effectiveness of Res in addressing RSV-induced viral pneumonia. In vitro studies had shown that Res NPs played an antiviral role by inhibiting RSV replication and reducing the production of pro-inflammatory cytokines. Nebulized inhalation administration of Res NPs prolonged the drug's residence time in the lungs, which appears to increase the accumulation and effectiveness of Res NPs. Additionally, in vivo studies had demonstrated significant benefits of Res NPs in inhibiting RSV viral load and improving the pulmonary microenvironment in RSV-infected mice. Both antiviral and anti-inflammatory experiments had confirmed that the pharmacological activity of Res NPs is superior to that of Res. This suggested that nanosizing Res was an effective way to enhance the original pharmacological activity of Res and also offered a new formulation strategy for treating viral pneumonia.

Epidemiology of respiratory viruses before and during the COVID-19 pandemic in a tertiary care hospital in Southern Brazil

BackgroundRespiratory viral infections affect millions of people worldwide and are life threatening for many of them. The viral seasonality leads to changes in the dynamics of respiratory infections and the importance of monitoring and surveillance of respiratory viruses becomes clearer. ObjectivesThis study aims to analyze data from respiratory virus testing at the Hospital de Clínicas de Porto Alegre (HCPA) to evaluate their epidemiology from 2018 to 2021, observing their occurrence and seasonality before and after the onset of the SARS-CoV-2 pandemic. Study designIn this study, data analysis was divided into four time periods, corresponding to 2018 to 2021. Anonymized patients diagnosed with influenza virus (FLU), human parainfluenza virus (HPIV), human respiratory syncytial virus (HRSV), SARS-CoV-2 virus, or human adenovirus (HAdV) were included. We conducted chi-square goodness-of-fit tests for each virus by year, and a p-value of <0.05 was considered statistically significant. ResultsAll analyzed respiratory viruses presented reduced case numbers during the COVID-19 pandemic, except FLU, which showed an increase of four cases in 2021 compared to 2019. For most viruses, the lowest incidence of confirmed cases was found in 2020. Furthermore, when excluding SARS-CoV-2, HRSV presented the most positive cases during the studied period, except in 2020. Besides SARS-CoV-2, the FLU was the only other respiratory virus that recorded deaths. It was also possible to observe that the number of SARS-CoV-2 cases reduced from April 2021. ConclusionsWe observed that most respiratory tract viral infections decreased during the COVID-19 pandemic, and this result may be associated with the public interventions for containing the COVID-19 pandemic. Moreover, the reduction of these other viruses may have resulted from the measures for prevention conducted by HCPA.

Implementing an Alert System for Communicating Actionable Wastewater Surveillance Results to School Communities, Houston, Texas, 2023-2024.

In 2020, the Houston Health Department (HHD) in Texas launched a citywide wastewater surveillance program, including a pilot program that monitored manholes at schools in Houston's largest school district (prekindergarten-12th grade). By 2022, the pilot program monitored wastewater for SARS-CoV-2, influenza A and B, and respiratory syncytial virus. To ensure effective communication of wastewater surveillance results to school communities, HHD designed and implemented a text- and email-based alert system using existing City of Houston resources. This alert program informs recipients about the presence of a virus at their schools and actions to protect themselves and others against that virus. To promote alert program sign-ups, a dedicated bilingual community involvement coordinator conducted in-person outreach geared toward school nurses and student caregivers. From September 2023 through February 2024, a combined 5178 alerts for 43 schools were sent following virus detections. As a supplemental initiative, HHD offered vaccination events to pilot program schools with consistent virus detection. As wastewater surveillance becomes more common across the United States, this alert program presents a framework for other public health agencies to scale and adapt according to their resources.

Transforming respiratory tract infection diagnosis in the kingdom of saudi arabia through point-of-care testing: A white paper for policy makers

With the evident increased prevalence of respiratory tract infections (RTIs) such as Respiratory Syncytial Virus (RSV), influenza, Group A Streptococcus (GAS), and COVID-19, the conventional diagnostic methods are considered sub-optimal in providing timely management to patients in the Kingdom of Saudi Arabia (KSA). Gaps in current diagnostics are magnified by the Kingdom's unique demographic composition, comprising 11.9 million foreign workers, and the annual influx of over 10 million pilgrims. Current gaps in timely diagnosis leads to delays in treatment, misuse of antibiotics, and protracted hospital stays, subsequently compromising patient care, and escalating healthcare costs. KSA healthcare stakeholders suggest that the integration of rapid molecular Point-of-Care Testing (POCT) into the Kingdom's healthcare infrastructure is an absolute necessity. This publication serves as an urgent call for action aimed at healthcare policymakers in Saudi Arabia, to review the existing diagnostic challenges and include rapid POCTs in the Saudi healthcare strategy for respiratory infections.

Characteristics of inpatient and outpatient respiratory syncytial virus mortality in Gavi-eligible countries

The current understanding of the RSV-related mortality age distribution in low- and lower-middle-income countries (LMICs) relies on a limited number of disease incidence studies reporting wide age bands, and lacking specificity to Gavi-eligible countries. Understanding the age distribution of RSV-related deaths is crucial for the implementation of RSV interventions in LMICs that rely on support from Gavi. This study aims to provide the age profile of RSV mortality specifically in Gavi-eligible countries.Utilizing data from the RSV GOLD project, an ongoing global online mortality registry focusing on children under the age of 5 with laboratory-confirmed RSV infection, we employed two models (Complete Data Model and Prospective Data Model) to estimate the age profiles. To mitigate biases related to age group representation, we applied post-stratification weighting in our analysis.We included 423 pediatric deaths, including 145 from the community, under 2 years of age from 15 Gavi-eligible countries. Both models identified a peak age at 1 month and found that the majority of RSV-related mortality cases (59–77 %) from Gavi-eligible countries occur before 6 months of life. However, the models exhibited disparities in other age-related metrics. We present fitted age-at-time-of-death probability distributions to aid impact and cost-effectiveness studies.We expect that implementing infant RSV immunization strategies, such as maternal vaccination or infant immunoprophylaxis, will have high impact on RSV-related mortality in Gavi-eligible countries. The divergent results from the two models underscore the importance of carefully considering potential biases in retrospective and surveillance data when interpreting the age profile of RSV mortality cases in future research.

The role of respiratory infections in the formation of airway hyperresponsiveness in children

Airway hyperresponsiveness (AHR) is a heterogeneous and complex disorder characterized by excessive narrowing of the airways in response to various exogenous and endogenous stimuli. This article presents information from the last five years, including 50 publications from PubMed and Google Scholar, on the most common viruses that provoke the development of airway hyperresponsiveness in children, including respiratory syncytial virus, rhinovirus, metapneumovirus, influenza and parainfluenza viruses, SARS-CoV-2 coronavirus, adenovirus, and bocavirus. It describes a number of pathophysiological mechanisms by which viruses damage the respiratory epithelium and lead to the formation of infectious and post-infectious bronchial hypersensitivity. The role of hyperexpression of cytokines and inflammatory mediators in the development of AHR, especially in early childhood, is emphasized. It is shown that the inflammatory process and a balanced immune response are crucial for mitigating the severity of the disease caused by viruses. Understanding the molecular mechanisms of inflammatory reactions and the immune response to acute respiratory viral infections can help develop more effective methods for the prevention and treatment of respiratory diseases in children.

Real-World Effectiveness of Nirsevimab Against Respiratory Syncytial Virus: A Test-Negative Case-Control Study.

Nirsevimab, a long-acting monoclonal antibody, has demonstrated efficacy against RSV-related lower respiratory tract infections (LRTIs) in clinical trials. Post-licensure monitoring is essential to confirm these benefits in real-world settings. To evaluate the real-world effectiveness of nirsevimab against medically attended RSV infections in infants and to assess how effectiveness varies by disease severity, dosage, and time since immunization. This test-negative case-control study used inpatient, outpatient, and emergency room data from the Yale New Haven Health System. Nirsevimab-eligible infants who were tested for RSV using polymerase chain reaction between October 1, 2023 and May 9, 2024 were included. Cases were infants with confirmed RSV infections; controls were those who tested negative. Nirsevimab immunization, verified through state immunization registries. Effectiveness was estimated using multivariable logistic regression, adjusting for age, calendar month, and individual risk factors. Separate models examined effectiveness by clinical setting, disease severity, dose, and time since immunization. Broader outcomes, including all-cause LRTI and LRTI-related hospitalization, were also analyzed, with stratification by early and late respiratory seasons. The analytic sample included 3,090 infants (median age 6.7 months, IQR 3.6-9.7), with 680 (22.0%) RSV-positive and 2,410 (78.0%) RSV-negative. 21 (3.1%) RSV-positive and 309 (12.8%) RSV-negative infants received nirsevimab. Effectiveness against RSV infection was 68.4% (95% CI, 50.3%-80.8%). Effectiveness was 61.6% (95% CI, 35.6%-78.6%) for outpatient visits and 80.5% (95% CI, 52.0%-93.5%) for hospitalizations. The highest effectiveness, 84.6% (95% CI, 58.7%-95.6%), was observed against severe RSV outcomes requiring ICU admission or high-flow oxygen. Although effectiveness against RSV infections declined over time, it remained significant at 55% (95% credible interval, 16%-75%) at 14 weeks post-immunization. Protective effectiveness was also observed against all-cause LRTI and LRTI-related hospitalizations during peak RSV season (49.4% [95% CI, 10.7%-72.9%] and 79.1% [95% CI, 27.6%-94.9%], respectively). However, from February to May, when RSV positivity was low, effectiveness against these broader outcomes was negligible. Nirsevimab provided substantial protection against RSV-related outcomes for at least three months. These findings support the continued use of nirsevimab and provide evidence that may help build public confidence in the immunization program. Question: What is the effectiveness of nirsevimab against medically attended respiratory syncytial virus (RSV) infections in infants?Findings: 680 RSV test-positive cases and 2,410 RSV test-negative controls were included in this test-negative case-control study. Nirsevimab's effectiveness was 69% against RSV infections, 81% against RSV-associated hospitalization, and 85% against severe RSV disease. Effectiveness against RSV infection declined from 79% at 2 weeks post-immunization to 55% at 14 weeks post-immunization.Meaning: Nirsevimab provides strong protection against a wide range of RSV outcomes, but its effectiveness diminishes over time. These data can be utilized to optimize nirsevimab's implementation and sustain its uptake.

Role of Poly(A)-Binding Protein Cytoplasmic 1, a tRNA-Derived RNA Fragment-Bound Protein, in Respiratory Syncytial Virus Infection.

Respiratory Syncytial Virus (RSV) is a significant cause of lower respiratory tract infections (LRTI) across all demographics, with increasing mortality and morbidity among high-risk groups such as infants under two years old, the elderly, and immunocompromised individuals. Although newly approved vaccines and treatments have substantially reduced RSV hospitalizations, accessibility remains limited, and response to treatment varies. This underscores the importance of comprehensive studies on host-RSV interactions. tRNA-derived RNA fragments (tRFs) are recently discovered non-coding RNAs, notable for their regulatory roles in diseases, including viral infections. Our prior work demonstrated that RSV infection induces tRFs, primarily derived from the 5'-end of a limited subset of tRNAs (tRF5), to promote RSV replication by partially targeting the mRNA of antiviral genes. This study found that tRFs could also use their bound proteins to regulate replication. Our proteomics data identified that PABPC1 (poly(A)-binding protein cytoplasmic 1) is associated with tRF5-GluCTC, an RSV-induced tRF. Western blot experimentally confirmed the presence of PABPC1 in the tRF5-GluCTC complex. In addition, tRF5-GluCTC is in the anti-PABPC1-precipitated immune complex. This study also discovered that suppressing PABPC1 with its specific siRNA increased RSV (-) genome copies without impacting viral gene transcription, but led to less infectious progeny viruses, suggesting the importance of PABPC1 in virus assembly, which was supported by its interaction with the RSV matrix protein. Additionally, PABPC1 knockdown decreased the production of the cytokines MIP-1α, MIP-1β, MCP-1, and TNF-α. This is the first observation suggesting that tRFs may regulate viral infection via their bound proteins.

Bovine respiratory syncytial virus: First identification in eastern Algeria based on direct immunofluorescence and ELISA tests

Bovine respiratory syncytial virus: First identification in eastern Algeria based on direct immunofluorescence and ELISA tests

Factors Associated With Hospitalization, Length of Stay, and Hospital Expenditures for Respiratory Syncytial Virus Infection in Japanese Infants and Children According to Palivizumab-indicated Underlying Conditions: The LIFE Study.

Respiratory syncytial virus (RSV) is a major cause of pediatric respiratory tract infections. In Japan, children with specific underlying conditions are eligible to receive palivizumab to prevent severe RSV disease. However, the association between palivizumab eligibility and RSV infection severity remains unclear. This study examined RSV infection severity and hospitalization outcomes in Japanese infants and children according to palivizumab eligibility and identified their associated factors. Using insurance claims data from 12 municipalities, we identified RSV cases aged ≤24 months between April 2017 and March 2022. The patients' characteristics and hospitalization status were analyzed according to the presence of palivizumab-indicated underlying conditions. Regression models were used to identify factors associated with hospitalization, length of stay (LOS), and hospital expenditures. We analyzed 1025 first-time RSV cases (860 infants <12 months and 165 children 12-24 months old). There were 777 (90.3%) palivizumab-ineligible infants and 83 (9.7%) palivizumab-eligible infants. Only 13 (15.7%) palivizumab-eligible infants had received palivizumab in the month before RSV infection, and 8 required hospitalization. RSV hospitalization was significantly associated with age (odds ratio: 0.84, 95% confidence interval: 0.79-0.88), palivizumab-indicated underlying conditions (1.82, 1.13-2.89), and non-indicated high-risk conditions (4.87, 2.28-10.99). These factors were also associated with LOS. Hospital expenditures were associated with age, high-risk conditions and LOS. Palivizumab-indicated underlying conditions, high-risk conditions, and younger age are risk factors for RSV hospitalization. Most hospitalized patients did not receive palivizumab in the month before RSV infection despite being eligible, suggesting that some hospitalizations were preventable through appropriate palivizumab use.

Safety and Pharmacokinetics of Nirsevimab in Immunocompromised Children.

Immunocompromised children may have increased risk for severe respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI), potentially leading to prolonged hospitalization, intensive care, and death. The open-label phase II MUSIC trial evaluated the safety and pharmacokinetics of nirsevimab, an extended half-life monoclonal antibody against RSV, in immunocompromised children aged ≤24 months. Participants received a single intramuscular injection of nirsevimab (first RSV season: 50 mg if <5 kg/100 mg if ≥5 kg; second season: 200 mg). Safety, antidrug antibodies, and pharmacokinetics were evaluated to day 361. Participants (n = 100) had ≥1 immunocompromising conditions: primary immunodeficiency (n = 33), previous transplantation (n = 16), HIV infection (n = 8) or treatment with high-dose systemic corticosteroids (n = 29), immunosuppressive chemotherapy (n = 20), or other immunosuppressive therapies (n = 15). Six children experienced eight treatment-related adverse events (none categorized as serious). Three deaths occurred, all were unrelated to treatment. Eleven children, developed antidrug antibodies, with minimal effects on pharmacokinetics and no apparent impact on safety. Nirsevimab serum concentrations at day 151 were similar to those effective in preventing medically attended RSV LRTI in healthy infants. Fourteen children had increased nirsevimab clearance. No protocol-defined medically attended RSV LRTIs occured through day 151. Among immunocompromised children aged ≤24 months, nirsevimab was well tolerated with no safety concerns and serum concentrations were supportive of efficacy. A subset of children with increased nirsevimab clearance, had conditions potentially associated with protein loss; however, the impact on efficacy is unknown.

The Role of the CX3CR1-CX3CL1 Axis in Respiratory Syncytial Virus Infection and the Triggered Immune Response.

Respiratory syncytial virus (RSV) is a common respiratory pathogen that causes respiratory illnesses, ranging from mild symptoms to severe lower respiratory tract infections in infants and older adults. This virus is responsible for one-third of pneumonia deaths in the pediatric population; however, there are currently only a few effective vaccines. A better understanding of the RSV-host relationship at the molecular level may lead to a more effective management of RSV-related symptoms. The fractalkine (CX3CL1) receptor (CX3CR1) is a co-receptor for RSV expressed by airway epithelial cells and diverse immune cells. RSV G protein binds to the CX3CR1 receptor via a highly conserved amino acid motif (CX3C motif), which is also present in CX3CL1. The CX3CL1-CX3CR1 axis is involved in the activation and infiltration of immune cells into the infected lung. The presence of the RSV G protein alters the natural functions of the CX3CR1-CX3CL1 axis and modifies the host's immune response, an aspects that need to be considered in the development of an efficient vaccine and specific pharmacological treatment.

Nirsevimab and Acute Bronchiolitis Episodes in Pediatric Emergency Departments.

In the 2023-2024 respiratory syncytial virus (RSV) season, Spain became one of the first countries to introduce universal RSV prophylaxis, during which all infants born at this time were eligible to receive nirsevimab. Locally, most Spanish regions also immunized infants younger than age 6 months at the start of the season (extended catch-up). The aim of this study was to assess how RSV prophylaxis affected the number of infants presenting to pediatric emergency departments with acute respiratory infections. A retrospective study was conducted in 15 Spanish pediatric emergency departments from 9 different regions between the 2018 and 2024 epidemic seasons (November-January). We compared the seasons occurring in 2018-2023 and the 2023-2024 season regarding the number of episodes of lower respiratory tract infection and acute bronchiolitis, acute bronchiolitis-related hospital admissions, and PICU admissions. A comparison with the average rates for the previous epidemic seasons revealed a 57.7% decrease in episodes of lower respiratory tract infection in 2023-2024 (95% CI, 56.5-58.8; P < .001; range among hospitals, 4.8-82.8), a 59.2% decrease in episodes of acute bronchiolitis (95% CI, 57.9-60.4; P < .001; range, 6.9-84.1), a 63.1% reduction in acute bronchiolitis-related hospital admissions (95% CI, 60.9-65.2; P < .001; range, 31.4-86.8), and a 63.1% reduction in PICU admissions (95% CI, 58.1-67.9; P < .001; range, 18.2-81.8). Hospitals in regions applying extended catch-up showed better results. Nirsevimab can protect a broad infant population against RSV infection with high effectiveness. Approaches including extended catch-up are the most effective, although cost- effectiveness must be considered.

Constructing a diagnostic prediction model to estimate the severe respiratory syncytial virus pneumonia in children based on machine learning.

Severe respiratory syncytial virus (RSV) pneumonia is a leading cause of hospitalization and morbidity in infants and young children. Early identification of severe RSV pneumonia is crucial for timely and effective treatment by pediatricians. Currently, no prediction model exists for identifying severe RSV pneumonia in children. This study aimed to construct a diagnostic prediction model for severe RSV pneumonia in children using a machine learning algorithm. We analyzed data from the Gene Expression Omnibus (GEO) Series, including training dataset GSE246622 and testing dataset GSE105450, to identify differential genes between severe and mild-to-moderate RSV pneumonia in children. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on the differential genes, followed by the construction of a protein-protein interaction (PPI) network. An artificial neural network (ANN) algorithm was then used to develop and validate a diagnostic prediction model for severe RSV pneumonia in children. We identified 34 differentially expressed genes between the severe and mild-to-moderate RSV pneumonia groups. Enrichment analysis revealed that these genes were primarily related to pathogenic infection and immune response. From the PPI network, we identified 10 hub genes and, using the random forest algorithm, screened out 20 specific genes. The ANN-based diagnostic prediction model achieved an area under the curve (AUC) value of 0.970 in the training group and 0.833 in the testing group, demonstrating the model's accuracy. This study identified specific biomarkers and developed a diagnostic model for severe RSV pneumonia in children. These findings provide a robust foundation for early identification and treatment of severe RSV pneumonia, offering new insights into its pathogenesis and improving pediatric care.

In vitro antiviral effect of sulfated pectin from Mangifera indica against the infection of the viral agent of childhood bronchiolitis (Respiratory Syncytial Virus - RSV)

The Human Respiratory Syncytial Virus (RSV) is the leading cause of acute respiratory infections in children. Currently, no safe, effective, or feasible option for pharmacological management of RSV exists. Hence, plant-derived natural compounds have been explored as promising antiviral agents. Mangifera indica is a globally distributed plant with reported anti-inflammatory, cardioprotective, and antiviral activities. Our study investigated the antiviral potential of a novel pectin from M. indica peels (PMi) and its chemically sulfated derivative (PSMi) against RSV in HEp-2 cells. The compounds were characterized using Fourier-transform infrared spectroscopy and nuclear magnetic resonance (NMR). NMR analysis revealed the presence of ester and carboxylic acid groups in PMi, and sulfation resulted in a sulfation degree of 0.5. PMi and PSMi showed no cytotoxic effects even at concentrations as high as 2000 μg/mL. PSMi completely inhibited RSV infectivity (100–1.56 μg/mL, 50 % inhibitory concentration of viral infectivity = 0.77 ± 0.11 μg/mL). The mechanism of action was investigated using the 50 % tissue culture infectious dose assay. PSMi displayed virucidal activity at concentrations from 100 to 6.25 μg/mL, and a significant reduction in viral infection was observed at all treatment times. Overall, PSMi is antiviral, cell-safe, and exhibits promising potential as an RSV treatment.