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A globally implemented unified phylogenetic classification for human respiratory syncytial virus (HRSV) below the subgroup level remains elusive. We formulated global consensus of HRSV classification on the basis of the challenges and limitations of our previous proposals and the future of genomic surveillance. From a high-quality curated dataset of 1,480 HRSV-A and 1,385 HRSV-B genomes submitted to GenBank and GISAID (https://www.gisaid.org) public sequence databases through March 2023, we categorized HRSV-A/B sequences into lineages based on phylogenetic clades and amino acid markers. We defined 24 lineages within HRSV-A and 16 within HRSV-B and provided guidelines for defining prospective lineages. Our classification demonstrated robustness in its applicability to both complete and partial genomes. We envision that this unified HRSV classification proposal will strengthen HRSV molecular epidemiology on a global scale.

Since its discovery in 1957, respiratory syncytial virus (RSV) has been widely recognized as a common and deadly pathogen. Although early studies focused on the impact of RSV on the health of children, more recent data show that RSV imposes a significant burden on individuals aged ≥ 70 years. RSV also substantially harms the health of individuals with cardiopulmonary diseases. Early efforts to develop an RSV vaccine were hampered by toxicity due to antibody-enhanced viral pneumonia and a lack of efficacy in vaccines that targeted the postfusion configuration of the F fusion protein, which is crucial to the pathogenesis of RSV-mediated injury. A newer wave of vaccines has targeted a stabilized prefusion F protein, generating effective neutralizing antibodies and reducing the burden of mild and severe RSV lower respiratory tract injury. This review focuses on the burden of RSV in patients with pulmonary diseases, highlights the tumultuous path from the early days of RSV vaccine development to the modern era, and offers insights into key gaps in knowledge that must be addressed to adequately protect the vulnerable population of patients with severe pulmonary diseases. RSV vaccination with bivalent RSVPreF or RSVPreF3OA, which target the stabilized prefusion F protein, can be broadly recommended to adults aged ≥ 60 years with pulmonary diseases. However, more data are needed to understand how these vaccinations affect key clinical outcomes in individuals with pulmonary disease. [ABSTRACT FROM AUTHOR]

This retrospective study aims to analyze the baseline characteristics and factors associated with poor outcomes in patients with necrotizing enterocolitis (NEC) complicating respiratory syncytial virus (RSV) infection. Using the Virtual Pediatric Systems data registry, patients under 2 years admitted to the pediatric intensive care unit (PICU) were screened. Patients with documented RSV infection and NEC, intestinal perforation, noninfectious gastroenteritis/colitis, or pneumatosis intestinalis occurring around the timing of RSV bronchiolitis diagnosis were included. Out of the screened patients, 41 were analyzed. Most patients (93%) were aged 30 days to 2 years, one-third had baseline anatomical cardiac defects, and 20% history of prematurity. Median PICU length of stay was 11.7 days. Seven patients died before hospital discharge. While not statistically significant, nonsurvivors tended to exhibit higher PRISM-3 scores, more acidemia, and lower systolic blood pressure. These findings emphasize the need for cautious assessment of gastrointestinal symptoms in critically ill patients with RSV infection. [ABSTRACT FROM AUTHOR]

• SARS-CoV-2 bronchiolitis had more severe outcomes than RSV bronchiolitis. • During the SARS-CoV-2 pandemic, RSV bronchiolitis was not severe during the first delayed RSV season. • For the second RSV season during the pandemic, RSV bronchiolitis was not severe, but SARS-CoV-2 bronchiolitis was. Severe acute respiratory syndrome related coronavirus (SARS-CoV-2) bronchiolitis has arisen with the SARS-CoV-2 pandemic. There is a paucity of literature on SARS-CoV-2 bronchiolitis. The purpose of our paper was to review and compare outcomes in bronchiolitis due to severe acute respiratory syndrome related coronavirus 2 (SARS- CoV-2) and Respiratory Syncytial Virus (RSV). We also performed a subgroup analysis of two disrupted RSV seasons during the pandemic. This was a retrospective study from a US TriNetX database from March 1, 2020-January 1, 2023. Propensity matching was utilized for confounders. There was a total of 3,592 patients (1,796 in each group) after propensity matching. There was an increased risk of oxygen saturation ≤95 % (RR=1.50 95 % CI 1.58–1.94, p = 0.002) and ICU admission (RR=1.44 95 % CI 1.06–1.94, p = 0.02) in those with SARS- CoV-2 but not for oxygen saturation ≤90 % (RR=1.03 95 %CI 0.75–1.42, p = 0.85) or intubation (RR=0.73 95 % CI 0.35–1.47, p = 0.37). There was a decreased risk of a patient with SARS- CoV-2 bronchiolitis being hospitalized (RR=0.65 95 % CI 0.57–0.74, p < 0.0001), respiratory rate ≥60 (RR=0.64 95 % CI 0.48–0.88, p < 0.001) or ≥70 (RR=0.64 95 % CI 0.43–0.96, p = 0.03) when compared to RSV bronchiolitis. Specifically examining SARS- CoV-2 versus RSV bronchiolitis during the delayed RSV seasons, during the first season both infections were not severe, but during the second RSV bronchiolitis season, patients infected with RSV had less risk of ICU admission compared to those infected with SARS- CoV-2. SARS- CoV-2 bronchiolitis patients appeared to have more severe outcomes since the risk of ICU admission was higher for these patients. Also, during the second delayed RSV season, SARS- CoV-2 bronchiolitis was more severe than RSV bronchiolitis. [ABSTRACT FROM AUTHOR]

Background: Recently, several novel RSV immunisation products that protect infants and older adults against RSV disease have been licensed in Europe. We estimated the effectiveness and efficiency of introducing these RSV immunisation strategies in Germany. Methods: We used a Bayesian framework to fit a deterministic age-structured dynamic transmission model of RSV to sentinel surveillance and RSV-specific hospitalisation data in Germany from 2015 to 2019. The calibrated model was used to evaluate different RSV intervention strategies over 5 years: long-acting, single-dose monoclonal antibodies (mAbs) in high-risk infants aged 1–5 months; long-acting mAbs in all infants aged 1–5 months; seasonal vaccination of pregnant women and one-time seasonal vaccination of older adults (75 + /65 + /55 + years). We performed sensitivity analysis on vaccine uptake, seasonal vs. year-round maternal vaccination, and the effect of under-ascertainment for older adults. Results: The model was able to match the various RSV datasets. Replacing the current short-acting mAB for high-risk infants with long-acting mAbs prevented 1.1% of RSV-specific hospitalisations in infants per year at the same uptake. Expanding the long-acting mAB programme to all infants prevented 39.3% of infant hospitalisations per year. Maternal vaccination required a larger number to be immunised to prevent one additional hospitalisation than a long-acting mAB for the same uptake. Vaccination of adults older than 75 years at an uptake of 40% in addition to Nirsevimab in all infants prevented an additional 4.5% of all RSV hospitalisations over 5 years, with substantial uncertainty in the correction for under-ascertainment of the RSV burden. Conclusions: Immunisation has the potential to reduce the RSV disease burden in Germany. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) causes severe infections in infants, immunocompromised or elderly individuals resulting in annual epidemics of respiratory disease. Currently, limited clinical surveillance and the lack of predictable seasonal dynamics limit the public health response. Wastewater-based epidemiology (WBE) has recently been used globally as a key metric in determining prevalence of severe acute respiratory syndrome coronavirus 2 in the community, but its application to other respiratory viruses is limited. In this study, we present an integrated genomic WBE approach, applying reverse-transcription quantitative polymerase chain reaction and partial G-gene sequencing to track RSV levels and variants in the community. We report increasing detection of RSV in wastewater concomitant with increasing numbers of positive clinical cases. Analysis of wastewater-derived RSV sequences permitted identification of distinct circulating lineages within and between seasons. Altogether, our genomic WBE platform has the potential to complement ongoing global surveillance and aid the management of RSV by informing the timely deployment of pharmaceutical and nonpharmaceutical interventions. [ABSTRACT FROM AUTHOR]

Background: Identifying risk factors for respiratory syncytial virus (RSV)–associated severe acute respiratory illness (SARI) will assist with targeting vaccine interventions. Methods: Using surveillance data from South Africa (2012–2018), we compared the characteristics of individuals with RSV-associated influenza-like illness (ILI) (reference group) to those with RSV-associated SARI to describe factors associated with SARI using a multivariable analysis. Results: RSV was detected in 6% (483/7792) of ILI cases and 15% (844/5672) of SARI cases. Factors associated with SARI in children included age < 2 months, compared to age 2–4 years (adjusted odds ratio (aOR) 54.4; 95% confidence interval (CI) 23.5–125.8), malnutrition (aOR 1.9; 95% CI 1.2–3.2), prematurity (aOR 2.4; 95% CI 1.3–4.6) and living with HIV (LWH) (aOR 22.5; 95% CI 2.9–174.3). In individuals ≥ 5 years, factors associated with SARI included age ≥ 65 years compared to age 5–24 years (aOR 10.7; 95% CI 1.1–107.5), symptom duration ≥ 5 days (aOR 2.7; 95% CI 1.1–6.3), underlying illness (aOR 2.7; 95% CI 1.5–26.1) and LWH (aOR 16.8, 95% CI: 4.8–58.2). Conclusion: Individuals at the extremes of age and those with identified risk factors might benefit most from RSV prevention interventions. Clinical trial number: Not applicable, this is not a clinical trial. [ABSTRACT FROM AUTHOR]

Background: The coronavirus disease 2019 (COVID-19) pandemic has highlighted the urgent need for rapid and accurate diagnostic tools for upper respiratory tract infections (URTIs). Nucleic acid amplification tests (NAATs) have transformed URTI diagnostics by enabling the rapid detection of multiple pathogens simultaneously, thereby improving patient management and infection control. This study aimed to evaluate the diagnostic accuracy of the LabTurbo QuadAIO Common Flu Assay compared to that of the Xpert Xpress CoV-2/Flu/RSV Plus Assay for detecting SARS-CoV-2, Influenza A, Influenza B, and respiratory syncytial virus (RSV). Methods: A retrospective diagnostic accuracy study was conducted using nasopharyngeal samples from patients. Samples were tested using the LabTurbo QuadAIO Common Flu Assay and the comparator Xpert Xpress CoV-2/Flu/RSV Plus Assay. Positive and negative percent agreements (PPA and NPA) were calculated. Results: The LabTurbo Assay demonstrated a PPA of 100% and an NPA of 100% for SARS-CoV-2, Influenza A, and Influenza B, whereas it showed a PPA of 100% and an NPA of 98.3% for RSV. Conclusions: The LabTurbo QuadAIO Assay exhibited high diagnostic accuracy for detecting multiple respiratory pathogens, including SARS-CoV-2, Influenza A, Influenza B, and RSV. Despite the slight discrepancy in the NPA for RSV, the overall performance of the LabTurbo Assay supports its integration into routine diagnostic workflows to enhance patient management and infection control. [ABSTRACT FROM AUTHOR]

Respiratory diseases (RDs) constitute a common public health problem both in industrialized and developing countries. The comprehension of the pathophysiological mechanisms underlying these conditions and the development of new therapeutic strategies are critical for improving the quality of life of affected patients. β2-adrenergic receptor (β2AR) and transient receptor potential vanilloid 1 (TRPV1) are both involved in physiological responses in the airways. β2AR is implicated in bronchodilation, mucociliary clearance, and anti-inflammatory effects, while TRPV1 is involved in the mediation of pain and cough reflexes. In RDs, such as respiratory infections, asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, the concentration and expression of these receptors can be altered, leading to significant consequences. In this review, we provided an update on the literature about the role of β2AR and TRPV1 in these conditions. We reported how the diminished or defective expression of β2AR during viral infections or prolonged therapy with β2-agonists can increase the severity of these pathologies and impact the prognosis. Conversely, the role of TRPV1 was pivotal in neuroinflammation, and its modulation could lead to innovative treatment strategies in specific patients. We indicate future perspectives and potential personalized treatments in RDs through a comprehensive analysis of the roles of these receptors in the physiological and pathological mechanisms of these pathologies. [ABSTRACT FROM AUTHOR]

Introduction: Respiratory syncytial virus (RSV) leads to significant morbidity in newborn infants in the United Kingdom (UK). Nirsevimab, a long-acting monoclonal antibody, received approval from the European Medicines Agency and has been licensed by the Medicines and Healthcare products Regulatory Agency for preventing RSV lower respiratory tract disease (LRTD) in neonates and infants during their first RSV season. The objective of this study was to assess the potential impact of nirsevimab on RSV-associated LRTDs, related costs, and loss of quality-adjusted life years (QALYs) in infants experiencing their first RSV season. Methods: The impact of administering nirsevimab across all infant populations compared to palivizumab in the high-risk palivizumab-eligible population was assessed via a static decision-analytic model specified for a UK birth cohort experiencing their first RSV season. The RSV-related health events of interest included primary care (PC), accident and emergency (A&E) visits, hospitalizations [including hospitalizations alone and those resulting in intensive care unit (ICU) admissions], recurrent wheezing in infants who were previously hospitalized, and all-cause LRTD hospitalizations. Results: Under the current standard of practice (SoP), RSV was estimated to result in 329,425 RSV LRTDs annually, including 24,381 hospitalizations and ICU admissions, representing £117.8 million (2024 GBP) in costs. Comparatively, universal immunization of all infants with nirsevimab could avoid 198,886 RSV LRTDs, including 16,657 hospitalizations and ICU admissions, resulting in savings of £77.2 million in RSV treatment costs. Considering the impact on all-cause LRTD of a universal immunization strategy, nirsevimab could be valued between £243 and £274, assuming willingness-to-pay (WTP) thresholds of £20,000 and £30,000 per QALY saved, respectively. Conclusions: This analysis demonstrated that the health and economic burden of RSV would be substantially reduced in all infants experiencing their first RSV season in the UK (including term, preterm, and palivizumab-eligible infants) as a result of a universal immunization strategy with nirsevimab. [ABSTRACT FROM AUTHOR]

Background: Interferon epsilon (IFN-ε) is a type I IFN that plays a critical role in the host immune response against pathogens. Despite having demonstrated antiviral activity in macrophages and mucosal tissues such as the female reproductive tract and the constitutive expression in mucosal tissues such as the lung, the relevance of IFN-ε against respiratory viral infections remains elusive. Results: We present, for the first time, the expression of IFN-ε in alveolar epithelial cells and primary human bronchial epithelial cells grown in an air–liquid interface (ALI) in response to human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) infection. The molecular characterization of the IFN-ε induction by the viruses indicates that the expression of RIG-I is necessary for an optimal IFN-ε expression. Furthermore, treatment of the airway epithelial cells with rhIFN-ε induced the expression of IFN-stimulated genes (ISGs) and significantly restricted the viral replication of HMPV and RSV. Conclusions: These findings underscore the relevance of IFN-ε against viral infections in the respiratory tract. [ABSTRACT FROM AUTHOR]

Background: Mixed infections can worsen disease symptoms. This study investigated the impact of mixed infections with viral and bacterial pathogens in patients positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Using the in-house multiplex PCR method, we tested 337 SARS-CoV-2 positive samples for co-infections with three bacterial and 14 other viral pathogens. Results: Between August 2021 and May 2022, 8% of 337 SARS-CoV-2-positive patients had bacterial co-infections, 5.6% had viral co-infections, and 1.4% had triple mixed infections. The most common causes of mixed infections were Haemophilus influenzae (5.93%) and respiratory syncytial virus (RSV) (1.18%). Children < 5 years old had more frequent co-infections than adults < 65 years old (20.8% vs. 16.4%), while adults showed a more severe clinical picture with a higher C-reactive protein (CRP) level (78.1 vs.16.2 mg/L; p = 0.033), a lower oxygen saturation (SpO2) (89.5 vs. 93.2%), and a longer hospital stay (8.1 vs. 3.1 days; p = 0.025) (mean levels). The risk of a fatal outcome was 41% in unvaccinated patients (p = 0.713), which increased by 2.66% with co-infection with two pathogens (p = 0.342) and by 26% with three pathogens (p = 0.005). Additionally, 50% of intensive care unit (ICU) patients had a triple infection, compared with only 1.3% in the inpatient unit (p = 0.0029). The risk of death and/or ICU admission was 12 times higher (p = 0.042) with an additional pathogen and increased by 95% (p = 0.003) with a third concomitant pathogen. Conclusions: Regular multiplex testing is important for prompt treatment and targeted antibiotic use. [ABSTRACT FROM AUTHOR]

Introduction: 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. Methods: 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. Discussion: 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. Clinical trial registration: https://drks.de/search/de/trial/, identifier DRKS00034278. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionsBecause 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.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.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.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. [ABSTRACT FROM AUTHOR]

The UK is launching a new free vaccination programme against respiratory syncytial virus (RSV) in adults aged 75 or over. This follows the development of safe and effective vaccines against RSV and the growing realisation of the burden of RSV-related disease in older adults—estimated at circa 8000 deaths and 175 000 GP episodes every year in the UK. It is likely that the full burden of RSV-related illness is under-appreciated and under-reported due to a lack of testing and awareness of its dangers in older adults. Healthcare professionals working with older people should be aware of the evidence base and be in a position to advise patients on the risks and benefits of vaccination and nonvaccination. We briefly review the evidence for the safety and effectiveness of the two licensed vaccines against RSV with a special focus on what geriatricians and others working with frailer, older people need to know. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) and rotavirus infections are long-standing infectious diseases that affect children worldwide. RSV and rotavirus were first discovered in clinical specimens in 1955 and 1973, respectively. From their discovery to the present day, significant progress has been made in understanding these two infections. The introduction of a simple and rapid antigen diagnostic test into clinical settings in the 1990s offered new insight into the clinical characteristics and epidemiology of these infections. Regarding therapeutics, symptomatic treatments have remained the mainstay; however, prophylactic humanized anti-RSV monoclonal antibodies have been developed and advances in structural biology may allow for more effective human anti-RSV monoclonal antibodies and novel RSV vaccines to be developed soon. For rotavirus, two vaccines have been licensed and broadly applied over the past 10 years, which have been successful clinically and have changed the epidemiology of rotavirus infections in Japan. [ABSTRACT FROM AUTHOR]

Aim: Respiratory syncytial virus (RSV) represents a significant cause of morbidity for children worldwide, especially for newborns. As RSV vaccines are not routinely used for children yet, non‐pharmaceutical interventions (NPIs) represent the main strategy for prevention. The objective of this study was to investigate the correlation between school holidays and RSV transmission. Methods: Data were collected from the weekly reports on RSV incidence for the 2021/2022 and 2022/2023 seasons in Sweden. The 7‐day cumulative incidence of RSV was compared before and after the designated school holidays (Fall, Christmas, and Winter holidays). Results: Our findings reveal an immediate (−1.7%, p < 0.001, 95% CI [−3.1%, −0.4%]) and gradual (−1.4%/week, p < 0.001, 95%CI [−1.8, −1.0]) reduction in RSV incidence following the Fall holiday in 2021, especially among children under 1 year of age, both immediately (−107.6%, p < 0.05, 95% CI [−203.7, −11.5]) and gradually afterwards (−58.5%/week, p < 0.001, 95% CI [−72.7, −44.3]). Mixed results were obtained for the Fall in 2022/2023 and for the Winter and holidays in both the studied years. Conclusions: While the Fall holiday in 2021/2022 was associated with a decrease in RSV incidence in Sweden, our results do not support a universal effect of school holidays on reducing RSV transmission. [ABSTRACT FROM AUTHOR]

Introduction: Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection, especially in children and older people. However, no effective treatment is currently available. Type I interferons (IFNs) are a group of cytokines that help regulate the activity of the immune system. GB05, human IFNα1b inhalation solution, was developed under US Food and Drug Administration (FDA) standard guidelines to combat RSV infection. This randomized, double-blind, placebo-controlled, dose-escalation phase I trial evaluated the safety, tolerability, and pharmacokinetics of nebulized GB05. Methods: A total of 35 eligible healthy Chinese adult volunteers were enrolled in this study. In the single ascending dose (SAD) study, volunteers were randomized into 0.2, 0.6, 1.2, and 1.8 million IU of GB05 or placebo. In the multiple ascending dose (MAD) study, volunteers received 1.2 or 1.8 million IU of GB05 or placebo for four consecutive days. Safety, tolerability, immunogenicity, and plasma pharmacokinetics were assessed for all groups. Results: All adverse events were mild or moderate and resolved spontaneously. The most common adverse event was decreased white blood cell count (8.6% in SAD and 10% in MAD). No serious adverse events, deaths, or adverse events that reached the termination criteria occurred during the study. In SAD, the maximum concentration and area under the curve increased across the dose range of 1.2–1.8 million IU in a non-linear relationship. The maximum plasma concentration after GB05 nebulization (1.06 IU/ml in the 1.8 million IU group) reflected a low concentration in the blood, suggesting a better lung uptake of GB05 and reduced incidence or risks of adverse events. In MAD, a steady state was reached after continuous administrations of twice daily for 3 days. Conclusions: Overall, nebulized GB05 exhibited satisfactory safety, tolerability, and favorable pharmacokinetic (PK) profiles in healthy adult volunteers, supporting further clinical investigation in patients infected with respiratory syncytial virus. Clinical Trial Registration: ClinicalTrials.gov Identifier NCT06277167. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus is a major causative agent of lower respiratory tract infection in children, especially infants with substantial morbidity and mortality implications. The virus undergoes continuous evolution documented by accumulation of mutations in the glycoprotein gene necessitating vigilant surveillance to provide essential data to epidemiologists and researchers involved in development of vaccines. This study was aimed to perform molecular characterization of respiratory syncytial virus (RSV) among children ≤ 5 years admitted in hospital. In the current study we observed RSV‐A (2019 (n = 95) and 2021 (n = 61) seasons) and RSV‐B (2022 season (n = 68)). Phylogenetic analysis revealed all RSV‐A strains (n = 47) to be GA.2.3.5 and RSV‐B (n = 22) were classified as GB.5.0.5a. Selection pressure analysis identified one positive (P274L/V) and one negative site (P230T) in RSV–A, while in RSV‐B there was only one negatively selected site (S295). This study spanning over three seasons contributes to RSV evolutionary dynamics in India emphasizing the importance of on‐going surveillance to inform effective public health strategies and vaccine development efforts. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection amongst all ages, causing a significant global health burden. Preventative and therapeutic options for RSV infection have long been under development, and recently, several widely‐publicised vaccines targeting older adult and maternal populations have become available. Promising monoclonal antibody (mAb) and antiviral (AV) therapies are also progressing in clinical trials, with the prophylactic mAb nirsevimab recently approved for clinical use in infant populations. A systematic review on current progress in this area is lacking. We performed a systematic literature search (PubMed, Embase, Web of Science, ClinicalTrials.gov, EudraCT, ANZCTR—searched Nov 29th, 2023) to identify studies on all RSV‐specific mAbs and AV therapies that has undergone human clinical trials since year 2000. Data extraction focused on outcomes related to the therapeutic efficacy and safety of the intervention on trial, and all studies were graded against the OCEBM Levels of Evidence Table. Results from 59 studies were extracted, covering efficacy and safety data on six mAbs (motavizumab, motavizumab‐YTE, nirsevimab, ALX‐0171, suptavumab, clesrovimab) and 12 AV therapies (ALN‐RSV01, RSV604, presatovir, MDT‐637, lumicitabine, IFN‐α1b, rilematovir, enzaplatovir, AK0529, sisunatovir, PC786, EDP‐938). Of the mAbs reviewed, nirsevimab and clesrovimab hold considerable promise. The timeline for RSV‐specific AV availability is less advanced, although EDP‐938 and AK0529 have reported promising phase 2 efficacy and safety data. Moving forward, passive immunisation and treatment options for RSV infection will play a significant role in reducing the health burden of RSV, complementing recent advancements in vaccine development. Trial Registration: PROSPERO registration: CRD42022376633 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Background Recently, several novel RSV immunisation products that protect infants and older adults against RSV disease have been licensed in Europe. We estimated the effectiveness and efficiency of introducing these RSV immunisation strategies in Germany. Methods We used a Bayesian framework to fit a deterministic age-structured dynamic transmission model of RSV to sentinel surveillance and RSV-specific hospitalisation data in Germany from 2015 to 2019. The calibrated model was used to evaluate different RSV intervention strategies over 5 years: long-acting, single-dose monoclonal antibodies (mAbs) in high-risk infants aged 1–5 months; long-acting mAbs in all infants aged 1–5 months; seasonal vaccination of pregnant women and one-time seasonal vaccination of older adults (75 + /65 + /55 + years). We performed sensitivity analysis on vaccine uptake, seasonal vs. year-round maternal vaccination, and the effect of under-ascertainment for older adults. Results The model was able to match the various RSV datasets. Replacing the current short-acting mAB for high-risk infants with long-acting mAbs prevented 1.1% of RSV-specific hospitalisations in infants per year at the same uptake. Expanding the long-acting mAB programme to all infants prevented 39.3% of infant hospitalisations per year. Maternal vaccination required a larger number to be immunised to prevent one additional hospitalisation than a long-acting mAB for the same uptake. Vaccination of adults older than 75 years at an uptake of 40% in addition to Nirsevimab in all infants prevented an additional 4.5% of all RSV hospitalisations over 5 years, with substantial uncertainty in the correction for under-ascertainment of the RSV burden. Conclusions Immunisation has the potential to reduce the RSV disease burden in Germany.

Abstract Background Identifying risk factors for respiratory syncytial virus (RSV)–associated severe acute respiratory illness (SARI) will assist with targeting vaccine interventions. Methods Using surveillance data from South Africa (2012–2018), we compared the characteristics of individuals with RSV-associated influenza-like illness (ILI) (reference group) to those with RSV-associated SARI to describe factors associated with SARI using a multivariable analysis. Results RSV was detected in 6% (483/7792) of ILI cases and 15% (844/5672) of SARI cases. Factors associated with SARI in children included age

In a population-based birth cohort study of respiratory syncytial virus surveillance in the United States, 897/1,680 (53.4%) children were infected during infancy; 25 (2.8%) of those were hospitalized. Among symptomatic infants, 143/324 (44.1%) had lower respiratory tract infections. These data provide benchmarks to monitor effects of maternal vaccines and extended half-life monoclonal antibodies.

The burden of respiratory syncytial virus (RSV) disease is widely recognized. Main risk factors for severe disease, such as extreme ages, chronic cardiopulmonary conditions, and immunosuppression, typically coincide with poorer outcomes. While the majority of RSV hospitalizations involve healthy children, a higher proportion of hospitalized adults with underlying conditions need intensive care. Presently, treatment primarily consists of supportive measures. RSV-induced wheezing should be distinguished from respiratory tract thickening, without response to bronchodilators. Obstructive RSV disease frequently overlaps with viral pneumonia. Non-invasive mechanical ventilation and high-flow oxygen therapy represented significant advancements in the management of severe RSV disease in children and may also hold considerable importance in specific phenotypes of RSV disease in adults. Most severe infections manifest with refractory hypoxemia necessitating more advanced ventilatory support and/or extracorporeal membrane oxygenation therapy. Although bacterial co-infection rates are low, they have been associated with worse outcomes. Antibiotic prescription rates are high. Accurately diagnosing bacterial co-infections remains a challenge. Current evidence and antibiotic stewardship policies advise against indiscriminate antibiotic usage, even in severe cases. The role of currently developing antiviral therapies in severe RSV disease will be elucidated in the coming years, contingent upon the success of new vaccines and immune passive strategies involving nirsevimab.

Abstract Introduction Respiratory syncytial virus (RSV) leads to significant morbidity in newborn infants in the United Kingdom (UK). Nirsevimab, a long-acting monoclonal antibody, received approval from the European Medicines Agency and has been licensed by the Medicines and Healthcare products Regulatory Agency for preventing RSV lower respiratory tract disease (LRTD) in neonates and infants during their first RSV season. The objective of this study was to assess the potential impact of nirsevimab on RSV-associated LRTDs, related costs, and loss of quality-adjusted life years (QALYs) in infants experiencing their first RSV season. Methods The impact of administering nirsevimab across all infant populations compared to palivizumab in the high-risk palivizumab-eligible population was assessed via a static decision-analytic model specified for a UK birth cohort experiencing their first RSV season. The RSV-related health events of interest included primary care (PC), accident and emergency (A&E) visits, hospitalizations [including hospitalizations alone and those resulting in intensive care unit (ICU) admissions], recurrent wheezing in infants who were previously hospitalized, and all-cause LRTD hospitalizations. Results Under the current standard of practice (SoP), RSV was estimated to result in 329,425 RSV LRTDs annually, including 24,381 hospitalizations and ICU admissions, representing £117.8 million (2024 GBP) in costs. Comparatively, universal immunization of all infants with nirsevimab could avoid 198,886 RSV LRTDs, including 16,657 hospitalizations and ICU admissions, resulting in savings of £77.2 million in RSV treatment costs. Considering the impact on all-cause LRTD of a universal immunization strategy, nirsevimab could be valued between £243 and £274, assuming willingness-to-pay (WTP) thresholds of £20,000 and £30,000 per QALY saved, respectively. Conclusions This analysis demonstrated that the health and economic burden of RSV would be substantially reduced in all infants experiencing their first RSV season in the UK (including term, preterm, and palivizumab-eligible infants) as a result of a universal immunization strategy with nirsevimab.

Respiratory infections with respiratory syncytial virus (RSV) account for an important part of hospital admissions for acute respiratory infections. Nirsevimab has been developed to reduce the hospital burden of RSV infections. Compared with the product previously used, it has a stronger binding capacity to RSV F protein and a high affinity for FcRn (neonatal receptor for the Fc fragment of IgG), which extends its lifespan. Nirsevimab has been shown to be highly effective in reducing hospitalization rates of RSV infections but a large or unknown number of treated subjects have been excluded in clinical and post-marketing studies. However, analysis of these studies cannot exclude that, in rare cases, nirsevimab facilitates and worsens RSV infection (or other respiratory infections). This could be attributable to antibody-dependent enhancement (ADE) which has been observed with RSV F protein antibodies in inactivated vaccine trials. This risk has been incompletely assessed in pre-clinical and clinical trials (incomplete exploration of nirsevimab effector functions and pharmacokinetics). ADE by disruption of the immune system (not studied and due to FcRn binding) could explain why there is no reduction in all-cause hospital admissions in treated age groups. Given the high price of nirsevimab, the cost-effectiveness of mass immunization campaigns may therefore be debated from an economic as well as a scientific point of view.

Abstract Introduction Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection, especially in children and older people. However, no effective treatment is currently available. Type I interferons (IFNs) are a group of cytokines that help regulate the activity of the immune system. GB05, human IFNα1b inhalation solution, was developed under US Food and Drug Administration (FDA) standard guidelines to combat RSV infection. This randomized, double-blind, placebo-controlled, dose-escalation phase I trial evaluated the safety, tolerability, and pharmacokinetics of nebulized GB05. Methods A total of 35 eligible healthy Chinese adult volunteers were enrolled in this study. In the single ascending dose (SAD) study, volunteers were randomized into 0.2, 0.6, 1.2, and 1.8 million IU of GB05 or placebo. In the multiple ascending dose (MAD) study, volunteers received 1.2 or 1.8 million IU of GB05 or placebo for four consecutive days. Safety, tolerability, immunogenicity, and plasma pharmacokinetics were assessed for all groups. Results All adverse events were mild or moderate and resolved spontaneously. The most common adverse event was decreased white blood cell count (8.6% in SAD and 10% in MAD). No serious adverse events, deaths, or adverse events that reached the termination criteria occurred during the study. In SAD, the maximum concentration and area under the curve increased across the dose range of 1.2–1.8 million IU in a non-linear relationship. The maximum plasma concentration after GB05 nebulization (1.06 IU/ml in the 1.8 million IU group) reflected a low concentration in the blood, suggesting a better lung uptake of GB05 and reduced incidence or risks of adverse events. In MAD, a steady state was reached after continuous administrations of twice daily for 3 days. Conclusions Overall, nebulized GB05 exhibited satisfactory safety, tolerability, and favorable pharmacokinetic (PK) profiles in healthy adult volunteers, supporting further clinical investigation in patients infected with respiratory syncytial virus. Clinical Trial Registration ClinicalTrials.gov Identifier NCT06277167.

Abstract Introduction In Germany, the estimation of the disease burden of respiratory syncytial virus (RSV) in older adults is limited. This makes it challenging for public health decision-makers to develop evidence-based recommendations for newly available vaccines against RSV for individuals aged 60 years and older (60+). This study investigates publicly available data sources in Germany to address the current gaps in evidence regarding the burden of RSV. Methods Hospitalisation databases from the German Federal Statistical Office and national mortality statistic between 2000 and 2023, as well as regular surveillance reports from the national public health institute since 2014, were utilised to extract, combine and analyse data on RSV-related morbidity and mortality. These data were used to triangulate the age-specific burden of RSV. Results The data indicate that the number of RSV-related outpatient consultations ranges between 1,313,100 and 3,911,800 cases per season from 2014/2015 to 2022/2023 for all age groups, with approximately 13.0% of outpatient consultations occurring in adults 60+. The significant increase in hospitalisations over time suggests that heightened testing due to the coronavirus disease 2019 (COVID-19) pandemic revealed the underdetection of inpatient RSV cases in pre-pandemic seasons. In the most recent season recorded, 2022/2023, the data show 12,800 RSV-related hospitalisations in adults 60+ (24% of all RSV-related hospitalisations) and 1340 in-hospital deaths in adults 60+ (93% of all RSV-related deaths). Conclusion The comparison of pre- to post-pandemic seasons strongly suggest up to a sevenfold underdetection of RSV in individuals 60+, and the analysis of in-hospital mortality reveals higher mortality rates compared with the general German mortality statistics. These findings highlight the urgent need to improve surveillance and implement targeted prevention strategies to mitigate the impact of RSV in older adults.

Abstract Background Respiratory viral illnesses among children are a prominent cause of morbidity and mortality in the developing world. The aim of this study is to understand the seasonal pattern and surge of respiratory viruses among the Nicobarese tribe. Methods Respiratory specimens were collected from both ARI and SARI cases attended the BJR district hospital in Car Nicobar Island, India, between 2021 and 2022. Respiratory viruses were identified from the specimens by using the qRT-PCR assay. Meteorological parameters were collected and evaluated using Microsoft Excel and SPSS 21. The significant association between the surge of respiratory viruses and each climatic parameter was evaluated. Results In this hospital-based cross-sectional study, 471 ILI cases were enrolled, and 209 of these were positive for respiratory viral infections. Of these respiratory virus infections, 201 (96.2%) were infected with a single respiratory virus infection, and 8 (3.8%) had mixed viral infections. Fever, cough, and chills were the most common symptoms of respiratory illness among this indigenous population. There was a significant link between respiratory viruses and influenza-like illness in children (below 5 years and 6 to 15 years). Conclusion This prevalence study revealed that viral respiratory infections were more common in children than adults. Among these respiratory viruses, respiratory syncytial virus A (RSV) and influenza B virus were predominantly reported among tribal children up to age five years. In the year 2021, these viruses were recorded frequently during the winter season. Climate factors such as high humidity, high precipitation, moderate temperature, and moderate rainfall are found to be correlated with respiratory viral infections. This study implicates important information for preventing a further outbreak of respiratory viral infections in Car Nicobar Island.

Abstract Background Respiratory syncytial virus (RSV) affects 60–80% of children below 1 year and it’s the first cause of acute bronchiolitis. The aim of this study was to assess the trend and characteristics of hospitalizations for RSV infections in Italy. Methods This is a retrospective study based on the Italian Hospital Discharge Record (HDR) database. We analysed HDRs from June 2015 to May 2019, considering two groups of infants: Group 1 had a confirmed diagnosis of RSV; Group 2 had a diagnosis of acute bronchiolitis not RSV-coded. Results There were 67,746 overall hospitalizations (40.1% Group 1, and 59.9% Group 2). Hospitalization rate increased for Group 1 from 125 to 178 per 10,000 infants (+ 42.4%), and for Group 2 from 210 to 234 per 10,000 (+ 11.4%). The mean hospitalization length was 6.3 days in Group 1, longer than Group 2 (+ 1.0 day). A further analysis revealed that infants with heart disease or born premature had longer mean hospital stay compared to infants without risk factors (10.7 days versus 6.1 days, p

Abstract Background Respiratory Syncytial Virus (RSV) disease in young children ranges from mild cold symptoms to severe symptoms that require hospitalization and sometimes result in death. Studies have shown a statistical association between RSV subtype or phylogenic lineage and RSV disease severity, although these results have been inconsistent. Associations between variation within RSV gene coding regions or residues and RSV disease severity has been largely unexplored. Methods Nasal swabs from children (

This study comprehensively evaluated the DNA/RNA Defend Pro (DRDP) sample collection buffer, designed to inactivate and stabilize patient samples. The primary objectives were to assess DRDP's efficacy in ensuring sample stability, facilitating extraction-free polymerase chain reaction (PCR), and ensuring compatibility with rapid antigen testing (RAT). Ninety-five diagnostic nasopharyngeal swab samples tested for influenza virus (influenza A), respiratory syncytial virus (RSV A), and/or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were 10-fold diluted with DRDP and anonymized. Initial characterization and retesting of these samples using cobas Liat confirmed 88 samples as positive, validating the presence of viral targets. Results from rapid antigen testing showed lower sensitivity compared to nucleic acid amplification testing (NAAT) but maintained perfect specificity, with 40 out of 88 positive samples by cobas Liat also testing positive for RAT. Direct RT-qPCR of DRDP-diluted samples demonstrated robust compatibility, with 72 out of 88 samples positive for cobas Liat also testing positive by direct RT-qPCR. Non-concordant results could be explained by the 200-fold lower input of extraction-free NAAT. Stability testing involved incubating 31 positive samples at 4 °C, 20 °C, and 37 °C for 7 days, with extraction-free NAAT. DRDP guaranteed viral RNA stability at all temperatures for influenza A, SARS-CoV-2, and RSV A, showing stability up to 7 days at 4 °C. In conclusion, DRDP is an effective stabilizing medium compatible with direct RT-qPCR and rapid antigen testing and shows great potential for optimizing diagnostic processes, particularly in resource-limited or time-sensitive scenarios. [ABSTRACT FROM AUTHOR]

Background Worldwide, respiratory syncytial virus (RSV) infections are among the most common causes of infant hospitalization. Host genetic factors influencing the risk and severity of RSV infection are not well known. Methods We conducted a genome-wide association study (GWAS) to investigate single-nucleotide polymorphisms (SNPs) associated with severe RSV infections using a nested case-control design based on 2 Danish cohorts. We compared SNPs from 1786 children hospitalized with RSV to 45 060 controls without an RSV-coded hospitalization. We performed gene-based testing, tissue enrichment, gene-set enrichment, and a meta-analysis of the 2 cohorts. Finally, an analysis of potential associations between the severity of RSV infection and genetic markers was performed. Results We did not detect any significant genome-wide associations between SNPs and RSV infection or the severity of RSV. We did find potential loci associated with RSV infections on chromosome 5 in 1 cohort but failed to replicate any signals in both cohorts. Conclusions Despite being the largest GWAS of severe RSV infection, we did not detect any genome-wide significant loci. This may be an indication of a lack of power or an absence of signal. Future studies might include mild illness and need to be larger to detect any significant associations. [ABSTRACT FROM AUTHOR]

Introduction: Off-season upsurge of respiratory syncytial virus (RSV) infection with changed characteristics and heightened clinical severity during the postCOVID-19 era are raising serious concerns. This study aimed to develop and validate a nomogram for predicting the risk of severe acute lower respiratory tract infection (SALRTI) in children hospitalized for RSV infection during the postCOVID-19 era using machine learning techniques. Methods: A multicenter retrospective study was performed in nine tertiary hospitals in Yunnan, China, enrolling children hospitalized for RSV infection at seven of the nine participating hospitals during January–December 2023 into the development dataset. Thirty-nine variables covering demographic, clinical, and laboratory characteristics were collected. Primary screening and dimension reduction of data were performed using Least Absolute Shrinkage and Selection Operator (LASSO) regression, followed by identification of independent risk factors for RSV-associated SALRTI using Logistic regression, thus finally establishing a predictive nomogram model. Performance of the nomogram was internally evaluated by receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) based on the development dataset. External validation of our model was conducted using same methods based on two independent RSV cohorts comprising pediatric RSV inpatients from another two participating hospitals between January– March 2024. Results: The development dataset included 1102 patients, 239 (21.7%) of whom developed SALRTI; while the external validation dataset included 249 patients (142 in Lincang subset and 107 in Dali subset), 58 (23.3%) of whom were diagnosed as SALRTI. Nine variables, including age, preterm birth, underlying condition, seizures, neutrophil-lymphocyte ratio (NLR), interleukin-6 (IL-6), lactate dehydrogenase (LDH), D-dimer, and co-infection, were eventually confirmed as the independent risk factors of RSV-associated SALRTI. A predictive nomogram was established via integrating these nine predictors. In both internal and external validations, ROC curves indicated that the nomogram had satisfactory discrimination ability, calibration curves demonstrated good agreement between the nomogram-predicted and observed probabilities of outcome, and DCA showed that the nomogram possessed favorable clinical application potential. Conclusion: A novel nomogram combining several common clinical and inflammatory indicators was successfully developed to predict RSV-associated SALRTI. Good performance and clinical effectiveness of this model were confirmed by internal and external validations. [ABSTRACT FROM AUTHOR]

We developed a model of inflammation and airway remodeling in C57 mice provoked by exosomes derived from bone marrow mesenchymal stem cells infected by respiratory syncytial virus (RSV). The mean size of control and infected exosomes in vitro were 167.9 and 118.5 nm, respectively. After induction of modeled pathology, the severity of airway inflammation and its remodeling were analyzed by histopathological methods. In addition, the blood levels of inflammatory factors IL-10, IL-17, transforming growth factor-β (TGF-β), and TNFα were assayed; in the lung tissues, the expression levels of MMP-2, MMP-9, α-smooth muscle actin (α-SMA), and TGF-β were measured. In the developed model, the effects of RSV-induced and non-induced exosomes were compared with those of inactivated and non-inactivated RSV. Intranasal administration of RSV-induced exosomes decreased the levels of serum inflammatory factors IL-10 and IL-17 and increased the expression of serum proinflammatory cytokine TNFα. Increased levels of MMP-2, MMP-9, and α-SMA, enhanced expression of TGF-β in the lung tissue, and pathological staining of the lung tissues indicated infiltration with inflammatory cells and luminal constriction. Thus, RSV-induced exosomes can provoke airway inflammation and remodeling in mice similar to RSV, while non-induced exosomes cannot produce such alterations. [ABSTRACT FROM AUTHOR]

In the post-pandemic period, an endemic circulation of respiratory viruses has been re-established. Respiratory viruses are co-circulating with SARS-CoV-2. We performed a retrospective analysis of co-infections in primary care patients with medically attended acute respiratory infections (MAARI) who consulted from week 40/2022 to week 39/2023 and were tested for a panel of respiratory viruses. Out of 2099 samples tested, 1260 (60.0%) were positive for one virus. In 340 samples, co-infection was detected: two viruses in 281 (13.4%), three viruses in 51 (2.4%), and four viruses in eight (0.4%) samples. Respiratory viruses co-infected the patients with MAARI at very different rates. The lowest rates of co-infections were confirmed for influenza B (13.8%) and influenza A (22.9%) and the highest for human bocaviruses (84.0%) and human parechoviruses (82.1%). Co-infections were detected in 28.2% of SARS-CoV-2 positive samples. SARS-CoV-2 has never been co-infected with influenza B virus, enterovirus or adenovirus, although the latter was found as a co-infecting virus with all other respiratory viruses tested. The rate of co-infections decreased significantly with increasing age (p-value 0.000), and no difference was found regarding gender (p-value 0.672). It is important to understand the epidemiology of respiratory co-infections for prevention and management decisions in patients with MAARI. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to describe the prevalence and the fluctuations of respiratory viral infections among the pediatric population in a tertiary care center during 2019–2023, parallel with the COVID-19 pandemic, and the specific preventative measures applied in the region during this time. Methods: In this observational study, we extracted all respiratory virus PCR tests collected from pediatric patients (< 15 years old) between January 2019 and March 2023. Data on the positivity rate and prevalence of 18 respiratory viruses were presented over the study period. Results: The lowest rate for the studied respiratory viruses was observed in 2020/2021 (during the COVID-19 pandemic), followed by a gradual increase in positive cases in the 2021/2022 season. Timing (seasonality) was altered during 2022/2023 with an early circulation of respiratory viruses in May-June followed by an early start of the usual respiratory viruses' season in September, leading to prolonged respiratory virus activity. Most respiratory viruses were circulating at unprecedented levels during the 2022/2023 season, with rhinovirus/enterovirus being the most commonly detected virus in all seasons. Other viruses that had atypical activity after the COVID-19 pandemic were influenza A(H3) virus, adenovirus, and parainfluenza 3 virus. Conclusion: Our study demonstrates the extended influence of the COVID-19 pandemic and its associated community restriction measures on the timing and distribution of other respiratory viruses. Continuous monitoring of changes in the circulation of respiratory viruses is crucial for the success of related public health measures such as vaccination distributions and epidemic preparedness. [ABSTRACT FROM AUTHOR]

Background: Respiratory infections pose a major public health threat. The predominant viruses causing viral respiratory infections are influenza A and B (Flu-A, Flu-B), coronaviruses, respiratory syncytial virus (RSV), and adenovirus. This study aims to investigate the proportion of these cases via rapid antigen tests and assess seasonal patterns. Methods: Clinical samples were collected from symptomatic adults presenting to the Emergency and Respiratory Medicine Departments of the University Hospital of Larissa (UHL), Greece from 16 October 2023 to 31 March 2024. Nasal specimens were antigen-tested for Flu-A/B, SARS-CoV-2, RSV, and adenovirus. Results: The total sample of specimens collected was 1434, of which 739 (51.5%) were female and 695 were male (48.5%). The mean age of participants was 57 ± 5.5 years. Among the positive results, we recorded a proportion of 40.18% and 11.40% for influenza A and B, respectively, followed by 35.79% for SARS-CoV-2, 10.70% for RSV, and 1.93% for adenovirus. Conclusions: In Greece, surveillance systems in infection control are underutilized. Rapid tests via multiple antigens can quickly identify viral infections, making them a valuable tool with financial benefits for health systems. Early detection of respiratory infections helps allocate resources efficiently, ensures adequate staff and facilities are available, and improves patient care through refined clinical management. [ABSTRACT FROM AUTHOR]

Background: Respiratory syncytial virus (RSV) infection in infants is a major cause of viral bronchiolitis and hospitalisation. We have previously shown in a murine model that ongoing infection with the gut helminth Heligmosomoides polygyrus protects against RSV infection through type I interferon (IFN‐I) dependent reduction of viral load. Yet, the cellular basis for this protection has remained elusive. Given that recruitment of mononuclear phagocytes to the lung is critical for early RSV infection control, we assessed their role in this coinfection model. Methods: Mice were infected by oral gavage with H. polygyrus. Myeloid immune cell populations were assessed by flow cytometry in lung, blood and bone marrow throughout infection and after secondary infection with RSV. Monocyte numbers were depleted by anti‐CCR2 antibody or increased by intravenous transfer of enriched monocytes. Results: H. polygyrus infection induces bone marrow monopoiesis, increasing circulatory monocytes and lung mononuclear phagocytes in a IFN‐I signalling dependent manner. This expansion causes enhanced lung mononuclear phagocyte counts early in RSV infection that may contribute to the reduction of RSV load. Depletion or supplementation of circulatory monocytes prior to RSV infection confirms that these are both necessary and sufficient for helminth induced antiviral protection. Conclusions: H. polygyrus infection induces systemic monocytosis contributing to elevated mononuclear phagocyte numbers in the lung. These cells are central to an anti‐viral effect that reduces the peak viral load in RSV infection. Treatments to promote or modulate these cells may provide novel paths to control RSV infection in high risk individuals. [ABSTRACT FROM AUTHOR]

Newborns and young infants are at risk for severe respiratory syncytial virus (RSV) lower respiratory tract infection. Passive immunity is the mainstay of infection prevention in this cohort. Transplacental transfer of maternal antibodies provides the newborn with immediate protection from life-threatening infections, however, is dependent upon gestational age, birth weight, mother's age, recent maternal vaccination, maternal nutritional status, maternal immunocompetence and medical conditions, and placental integrity. Efficient transplacental transfer of RSV-neutralizing antibodies have led to the development and approval of maternal RSV immunization for the protection of the newborn. Additionally, administration of RSV-specific antibodies to infants leads to high serum titers of RSV-neutralizing antibodies and further protection from severe disease. [ABSTRACT FROM AUTHOR]

This review article will summarize the vaccines and monoclonal antibodies currently under evaluation for the prevention of RSV disease in older infants, toddlers and young children. We will review the rationale for passive protection during the first months of life, and the role of active immunization afterwards, either with live attenuated, protein-based or mRNA vaccines. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) is the greatest contributor to lower respiratory tract infections (LRTI) in children less than 5 years of age and the leading cause for infant hospitalizations in the United States (US). The burden of severe disease disproportionately impacts racial and ethnic minority groups, highlighting the need for interventions that promote health equity. Recent advancements in effective prophylactic agents have the potential to drastically alter the landscape of RSV disease among all young children. The effectiveness of prophylaxis, however, will rely on a clear understanding of RSV epidemiology. The purpose of this review is to discuss key aspects of RSV epidemiology while focusing on efforts to support equitable distribution of prophylactic agents to mitigate existing health disparities. [ABSTRACT FROM AUTHOR]

Introduction: In Germany, the estimation of the disease burden of respiratory syncytial virus (RSV) in older adults is limited. This makes it challenging for public health decision-makers to develop evidence-based recommendations for newly available vaccines against RSV for individuals aged 60 years and older (60+). This study investigates publicly available data sources in Germany to address the current gaps in evidence regarding the burden of RSV. Methods: Hospitalisation databases from the German Federal Statistical Office and national mortality statistic between 2000 and 2023, as well as regular surveillance reports from the national public health institute since 2014, were utilised to extract, combine and analyse data on RSV-related morbidity and mortality. These data were used to triangulate the age-specific burden of RSV. Results: The data indicate that the number of RSV-related outpatient consultations ranges between 1,313,100 and 3,911,800 cases per season from 2014/2015 to 2022/2023 for all age groups, with approximately 13.0% of outpatient consultations occurring in adults 60+. The significant increase in hospitalisations over time suggests that heightened testing due to the coronavirus disease 2019 (COVID-19) pandemic revealed the underdetection of inpatient RSV cases in pre-pandemic seasons. In the most recent season recorded, 2022/2023, the data show 12,800 RSV-related hospitalisations in adults 60+ (24% of all RSV-related hospitalisations) and 1340 in-hospital deaths in adults 60+ (93% of all RSV-related deaths). Conclusion: The comparison of pre- to post-pandemic seasons strongly suggest up to a sevenfold underdetection of RSV in individuals 60+, and the analysis of in-hospital mortality reveals higher mortality rates compared with the general German mortality statistics. These findings highlight the urgent need to improve surveillance and implement targeted prevention strategies to mitigate the impact of RSV in older adults. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) is a common viral pathogen that accounts about 33 million cases of acute lower respiratory tract infection (LRTI) worldwide in children under the age of 5 years each year. High-risk populations, particularly preterm infants, those with underlying chronic lung disease, congenital heart disease, or compromised immune systems, are afflicted most significantly. RSV infection is characterized by significant amount of mucus and submucosal edema in the respiratory tract, leading to congestion and, oftentimes, significant respiratory distress. Antigen- and PCR-based testing are used to diagnose RSV infection. [ABSTRACT FROM AUTHOR]

(1) Background: The literature reports a low risk of serious bacterial infections (SBIs) in febrile infants presenting with bronchiolitis or respiratory syncytial virus infection, but current microbiological techniques have a higher accuracy. (2) Methods: We assessed the risk of SBIs in neonates and infants with bronchiolitis from 2021 to 2023. We also evaluated C-reactive protein, procalcitonin, and leukocyte values. (3) Results: We included 242 infants. Blood cultures (BCs) were performed in 66/242 patients, with a positivity rate of 9.1% (including one BC with Staphylococcus hominis, considered as a contaminant). The cerebrospinal fluid culture was performed in 6/242 patients, and the results were all negative. Infection markers did not discriminate infants with positive BCs from those with negative ones. (4) Conclusions: Blood cultures should be performed in neonates and young infants with bronchiolitis fever, as the sepsis risk is not negligible. Conversely, our proposed algorithm is to wait for the respiratory panel results before decision-making for a lumbar puncture. Further studies are needed to understand lumbar puncture requirements. [ABSTRACT FROM AUTHOR]

Introduction: Several respiratory viruses have been shown to have seasonal patterns. The aim of our study was to evaluate and compare these patterns in immunocompetent and immunosuppressed patients for five different respiratory viruses. Methods: We performed a retrospective analysis of results for 13,591 respiratory tract samples for human metapneumovirus (HMPV), influenza virus, parainfluenza virus (PIV) and respiratory syncytial virus (RSV) in immunocompetent and immunosuppressed patients. A seasonal pattern was aligned to the data of immunocompetent patients through a logistic regression model of positive and negative test results. Results: A narrow seasonal pattern (January to March) was documented for HMPV. Most RSV infections were detected in the winter and early spring months, from December to March, but occasional cases of RSV could be found throughout the year. The peak season for PIV-3 was during the summer months, and that for PIV-4 was mostly in autumn. A narrow seasonal pattern emerged for influenza virus as most infections were detected in the winter, in January and February. The seasonal patterns of HMPV, RSV, PIV, and influenza virus were similar for both immunocompetent and immunocompromised patients. Conclusions: We found no difference in the seasonality of HMPV, RSV, PIV, and influenza virus infections between immunosuppressed and immunocompetent hosts. [ABSTRACT FROM AUTHOR]

Acute respiratory tract infections are one of the leading causes of morbidity and mortality worldwide. More data are needed on circulating respiratory microorganisms in different geographical areas and ecosystems. We analyzed nasopharyngeal swabs from 500 febrile patients living in the Niakhar area (Senegal), using FTDTM multiplex qPCR and simplex qPCR to target a panel of 25 microorganisms. We detected at least one microorganism for 366/500 patients (73.2%), at least one virus for 193/500 (38.6%), and at least one bacterium for 324/500 (64.8%). The most frequently detected microorganisms were Streptococcus pneumoniae (36.8%), Haemophilus influenzae (35.8%), adenovirus (11.8%), influenza viruses (6.4%), rhinovirus (5.0%), SARS-CoV-2 (4.0%), and RSV (4.0%). The main microorganisms significantly associated with respiratory symptoms, with a p-value ≤ 0.05, were influenza virus (11.9% in patients with respiratory symptoms versus 2.9% in patients without), RSV (6.5% versus 2.6%), metapneumovirus (5.4% versus 1.3%), HPIVs (7.6% versus 1.0%), S. pneumoniae (51.9% versus 28.0%), and H. influenzae (54.6% versus 24.5%). Co-infections were significantly associated with respiratory symptoms (65.4% versus 32.9%). All the epidemiological data show a high level of circulation of respiratory pathogens among febrile patients, including those preventable by vaccination such as S. pneumoniae, raising the question of the serotypes currently circulating. Furthermore, the availability of affordable real-time etiological diagnostic tools would enable management to be adapted as effectively as possible. [ABSTRACT FROM AUTHOR]

The introduction of a new vaccine into immunization programs represents a significant advancement in the global effort to combat vaccine-preventable diseases. Data from the World Health Organization support that immunization prevents between 2 and 3 million deaths each year across various diseases, underscoring its pivotal role in global health. The present study aims to assess the knowledge, attitudes, and anticipated vaccination practices among health professionals in Central Greece in response to the potential introduction of new Respiratory Syncytial Virus (RSV) vaccination guidelines by the National Vaccines Committee. Among the 450 health professionals solicited for the study, 219 provided responses, yielding a response rate of approximately 55%. A substantial majority (70.3%) accurately identified the vaccine's current availability, and 62.1% were aware of the current recommendation for RSV vaccination in pregnant women. In response to whether health professionals support the inclusion of an RSV vaccine in the national vaccination program if it becomes commercially available and is recommended by the Greek National Immunization Program, general practitioners showed the most support, with an average score of 4.86 (95% CI, 4.69–5.00), followed by pediatricians at 4.76 (95% CI, 4.63–4.89), pulmonologists at 4.68 (95% CI, 4.36–5.00), and obstetricians at 4.33 (95% CI, 3.95–4.71). Concerning general opinions on vaccinations, a high level of agreement was noted among the majority of health professionals, excluding nurses. Pharmacists recorded the highest agreement, with a perfect score of 5 (CI, 5.00–5.00), followed closely by pediatricians at 4.99 (CI, 4.97–5.00), GPs at 4.95 (CI, 4.85–5.00), pulmonologists at 4.93 (CI, 4.83–5.00), obstetricians at 4.74 (CI, 4.42–5.00), and nurses at 3.80 (CI, 3.06–4.54). A tailored approach to education is needed to ensure that healthcare professionals can communicate more effectively about RSV risks and vaccination benefits, fostering a proactive stance towards disease prevention and patient care. In essence, our study underscores the importance of knowledge in shaping a compassionate and responsive healthcare environment, ready to meet the challenges of RSV head-on. [ABSTRACT FROM AUTHOR]