Search Results (239)

Background: Obesity is associated with hypothalamic dysfunction characterized by neuroinflammation and altered transcriptional programs. While resveratrol (RSV) has shown beneficial metabolic effects in peripheral tissues, its central effects on hypothalamic gene expression in obesity remain poorly understood. This study provides the first predictive transcriptomic analysis of the hypothalamic response to RSV in a mouse model of diet-induced obesity. C57BL/6 male mice were fed a high-fat diet (HFD) to induce obesity and then subsequently treated with RSV. Methods: Hypothalamic RNA was extracted and analyzed using RNA sequencing. Differentially expressed genes (DEGs) were identified and functionally analyzed through KEGG pathway analysis. Results: Although RSV did not significantly alter body weight, it reversed the expression of several HFD-induced DEGs. Key genes modulated by RSV included Aqp7, Ccl27a, Lta, Rilp, M6pr-ps, C1ra, Snail1, Gbgt1, and Ppargc1b, which are involved in inflammation, lipid metabolism, mitochondrial function, and immune signaling. Pathway enrichment analysis revealed significant modulation of TNF and NF-κB signaling, cytokine–cytokine receptor interactions, glycosphingolipid biosynthesis, and phagosome-related activity. Remarkably, 45% of RSV-responsive transcripts were non-coding RNAs, suggesting epigenetic regulation. Conclusions: RSV reprograms the hypothalamic transcriptome in obesity, targeting both coding and non-coding RNAs associated with inflammation and metabolic regulation, independently of weight loss. These findings identify RSV as a potential central modulator of metabolic dysfunction and highlight the hypothalamus as a promising therapeutic target in obesity-related disease. Full article

Background: In 2019, pneumonia caused 740,180 deaths in children under five years of age, representing 22% of global mortality in this age group. During the COVID-19 pandemic, public health interventions markedly reduced the circulation of most respiratory viruses other than SARS-CoV-2, leading to significant post-pandemic shifts in respiratory pathogen epidemiology. This study aimed to characterize the epidemiology, clinical features, and risk factors associated with respiratory viruses and bacteria causing pneumonia in Mexican children during the late pandemic and post pandemic periods. Methods: Children younger than 14 years with pneumonia were recruited from seven hospitals in Mexico. Demographic and clinical data were collected, and nasopharyngeal swabs were analyzed using a multiplex PCR panel detecting 19 viruses and 7 bacteria. Univariate, bivariate, and logistic regression analyses were performed (SPSS v25). Results: A total of 1715 children were included: 704 during the pandemic (2021–2023) and 1011 post-pandemic (2023–2025). Co-infections (72% vs. 65%, p < 0.001), virus–virus co-infections (25% vs. 11%, p < 0.001), and single viral infections (20% vs. 15%, p = 0.007) were more frequent during the pandemic. Pathogen detection was high in both periods, though negative samples increased post-pandemic (5.4% vs. 15%, p < 0.001). During the pandemic, the 5 most frequently detected pathogens were rhinovirus (66%), RSV A and B (38%), Streptococcus pneumoniae (30%), Haemophilus influenzae (28%), human metapneumovirus (13%). In the post-pandemic period, the 5 most frequently detected pathogens were rhinovirus (52%), Haemophilus influenzae (36%), Streptococcus pneumoniae (35%), RSV A and B (28%), metapneumovirus (11%). Rhinovirus and RSV predominated during the pandemic, whereas Haemophilus influenzae, Streptococcus pneumoniae, parainfluenza viruses, Bordetella pertussis, and Mycoplasma pneumoniae significantly increased post-pandemic. Conclusions: Pediatric pneumonia epidemiology shifted from a predominantly viral profile during the pandemic to increased bacterial detections and virus–bacteria co-infections post-pandemic, alongside re-emergence of typical RSV and influenza seasonality. Higher mean age and rhinovirus as the most frequent pathogen persist after the pandemic. Sustained molecular surveillance and reinforced vaccination programs remain essential in the post-pandemic era. Full article

Respiratory syncytial virus (RSV) resurged in many regions after the relaxation of stringent non-pharmaceutical interventions (NPIs) implemented during the COVID-19 pandemic. Here, we characterized the epidemiological patterns and molecular evolution of RSV among pediatric inpatients with acute respiratory tract infections (ARTIs) on tropical Hainan Island, China. We retrospectively analyzed 32,329 children (≤18 years) hospitalized at Hainan Women and Children’s Medical Center from January 2021 to December 2024. RSV positivity was determined using targeted next-generation sequencing. In total, 4483/32,329 (13.86%) patients were RSV-positive, with a high positivity in 2021 (20.27%, 957/4721), marked suppression in 2022 (2.03%, 106/5227) during intensive NPIs, and a rebound in 2023–2024 (15.31%, 1490/9732; 15.26%, 1930/12,649). RSV positivity was higher in boys than girls (14.42% vs. 13.00%). Seasonality shifted from a summer–autumn peak in 2021 to a spring–summer predominance in 2023–2024. Among 56 sequenced RSV-positive specimens (29 RSV-A; 27 RSV-B), all RSV-A strains belonged to genotype ON1 (lineages A.D.3 and A.D.5.2), and all RSV-B strains belonged to genotype BA9 (lineages B.D.4.1.1, B.D.E.1, and B.D.E.2). Subtype dominance transitioned from RSV-A (2021–2023; mainly A.D.3) to RSV-B in 2024 (all B.D.E.1). Lineage-specific amino-acid and predicted N-glycosylation changes were observed, including loss of the N179 site in A.D.5.2 and acquisition of N258 in B.D.E.1. These findings indicate that RSV circulation on tropical Hainan was strongly suppressed during intensive NPIs and re-established after policy relaxation, accompanied by earlier seasonal activity and clear lineage replacement, underscoring the need for sustained genomic surveillance to inform locally tailored clinical preparedness and immunization strategies. Full article

Background/Objectives: We aimed to determine safe and immunogenic RSVpreF vaccine dose levels for further clinical development in 2–<18 year olds. Methods: The phase 1, age-descending, open-label Picasso trial evaluated different RSVpreF dose levels in respiratory syncytial virus (RSV)-seropositive 2–<5 year olds and 5–<18 year olds who were either healthy or had chronic medical conditions with increased RSV illness risk. Participants received a single dose of RSVpreF (60 µg or 120 µg dose level). The primary objective was to describe safety and tolerability at each dose level and age group, including frequencies of reactogenicity and adverse events (AEs). The secondary objective was to describe RSV neutralizing antibody responses at each dose level and age group 1 month after vaccination. Results: Overall, 127 participants received RSVpreF 60 µg (2–<5 year olds, n = 20; 5–<18 year olds, n = 35) or 120 µg (n = 24 and n = 48, respectively); 54% were male and 69% were White. Local reactions and systemic events were reported in 17–20% and 33–45% of 2–<5 year olds, respectively, and 49–56% and 52–60% of 5–<18 year olds; most were mild or moderate in severity. AEs were reported in 13–15% of 2–<5 year olds and 8–14% of 5–<18 year olds. No AEs leading to withdrawal or vaccine-related serious AEs were reported. RSV-A and RSV-B neutralizing titer geometric mean fold rises from before to 1 month after vaccination with RSVpreF 60 and 120 µg, which were 17.7–20.6 and 42.8–39.8, respectively, in 2–<5 year olds, and 19.0–23.5 and 20.3–20.3, respectively, in 5–<18 year olds. Conclusions: RSVpreF was safe, well tolerated, and elicited immune responses in RSV-seropositive 2–<18-year-old participants, supporting further clinical development in this pediatric population, including those with chronic conditions. Full article

Respiratory syncytial virus (RSV) remains a leading cause of severe lower respiratory tract disease in infants worldwide. Despite extensive study in animal models and humans, fundamental age-dependent differences in mucosal immunity continue to limit the development of durable protective strategies in early life. Compared to adults, infants mount weaker humoral responses to RSV, underscoring the urgent need for effective vaccines in this age group. Immunoglobulin A (IgA), the dominant antibody isotype at respiratory mucosal surfaces, plays a central role in limiting viral replication and disease severity during RSV infection. While IgA limits RSV severity in adults, infants fail to generate robust IgA responses. Impaired IgA responses in infancy reflect unique immune regulatory pathways that shape early-life antiviral immunity. Emerging evidence highlights a critical role for regulatory B cells (Bregs), particularly neonatal Bregs (nBregs), in suppressing antiviral responses, limiting class switch recombination, and contributing to severe RSV disease. This review summarizes current evidence on IgA regulation during RSV infection, with particular emphasis on age-specific B-cell responses and the emerging role of Bregs. Improved understanding of these mechanisms has direct implications for the rational design of vaccines and immunomodulatory strategies tailored to infants. Full article

Background: Acute viral respiratory infections are a major cause of morbidity among young children, with respiratory syncytial virus (RSV) being the leading pathogen. In Jordan and globally, most RSV research has focused on hospitalized patients, while data from emergency departments (EDs) and outpatient settings remain limited. Methods: This cross-sectional study was conducted at two major Jordanian hospitals between November 2022 and March 2023. Children under five years of age presenting to EDs or outpatient clinics with symptoms of acute respiratory infection were enrolled. Nasopharyngeal specimens were tested for RSV, and subtypes (RSV-A and RSV-B) were identified using multiplex RT-PCR. Results: Of 229 enrolled children, 92 (40.2%) tested positive for RSV, with RSV-B accounting for 81.5% of positive cases. RSV positivity was higher in ED presentations than in outpatient clinics (46% vs. 35%). Wheezing (72.8% vs. 39.4%, p < 0.001) and dyspnea (33.7% vs. 14.6%, p = 0.001) were significantly more frequent among RSV-positive patients. Independent predictors of RSV positivity included non-referred outpatient visits (OR = 15.26), non-referred ED visits (OR = 42.93), younger age, and prior systemic steroid use. Conclusions: RSV poses a substantial burden in outpatient and ED settings. Identified demographic and clinical predictors may help target high-risk groups for future preventive interventions. Full article

Background/Objectives: Respiratory Syncytial Virus (RSV) causes severe disease in infants, the elderly, and immunocompromised individuals, with reinfections linked to poor induction of durable mucosal immunoglobulin A (IgA). We investigated the role of IgA in immunity and protection induced by a RSV subunit vaccine candidate, tFrsc/TriAdj, which consists of a truncated RSV fusion protein (tFrsc) with a tri-component adjuvant (TriAdj). Methods: Wild-type (IgA⁺/⁺) and IgA-deficient (IgA⁻/⁻) BALB/c mice were immunized intranasally and subsequently challenged with RSV. Results: Vaccination with tFrsc/TriAdj induced robust systemic and mucosal IgG, and high lung and serum neutralizing antibodies, in both IgA⁺/⁺ and IgA⁻/⁻ mice. As expected, IgA⁻/⁻ mice lacked IgA and exhibited modest reductions in nasal IgG compared to IgA^+/+ mice following challenge, correlating to failure to clear RSV from the upper respiratory tract. In contrast, viral replication in the lungs was fully suppressed in both genotypes, indicating that IgG alone was sufficient for lower respiratory tract protection. Isotype analysis revealed diminished Th1-associated IgG2a and elevated IgG1 across mucosal and systemic compartments in IgA⁻/⁻ mice, suggesting a Th2 bias. Flow cytometric analysis confirmed reduced recruitment of IFN-γ⁺ CD4⁺ T cells in the lungs of immunized IgA⁻/⁻ mice. Interestingly, IL-17 production and numbers of IL-17⁺ CD4⁺ T cells in the lungs were increased, suggesting an enhanced Th17 response. Furthermore, IgA-deficient mice displayed reduced splenic IgG⁺ B cell populations, which is also a novel observation. Conclusions: Collectively, these findings demonstrate that although tFrsc/TriAdj confers lower airway protection in the absence of IgA, vaccine-induced IgA is critical for upper airway protection, Th1/balanced immune responses, and optimal B cell responses. Full article

Respiratory syncytial virus (RSV) is among leading global causes of lower respiratory tract infections, yet data from Russia and other states of the Former Soviet Union (FSU) remain fragmented and structurally inconsistent. This systematic review aims to map and synthesize existing evidence on RSV epidemiology and genotypic distribution across the FSU. Published studies from eLIBRARY and PubMed databases queried for RSV prevalence data, together with public health surveillance datasets, were used to summarize RSV prevalence research across eight FSU countries. Random-effects meta-analysis across age strata showed high prevalence in children before 6 (21%) and a progressive decline with age, which is in agreement with global data. Prevalence estimates showed a high degree of variability partially explained by study scope and clinical presentation. We observed COVID-19-related seasonal disruptions of RSV seasonality, followed by gradual post-pandemic stabilization. Genotypic data reflects global trends with two cosmopolitan clades, A.D and B.D, and their descendants, dominating in the region. The review is limited by uneven geographical and temporal coverage, and scarce data on adults. The review provides the first integrated summary of RSV epidemiology across the FSU and underscores the need for expanded regional surveillance and genomic reporting. Full article

Background/objectives: RSV is a major cause of mortality in infants, and despite recent progress to prevent RSV in the very young, an RSV vaccine for this population is still highly warranted. Clinical studies in infants in the 1960s using formalin-inactivated RSV (FI-RSV) led to life-threatening enhanced respiratory disease (ERD). Therefore, a thorough safety assessment of RSV vaccine candidates intended for RSV seronegative infants is crucial. Methods: Prior to clinical pediatric development of Ad26.RSV.preF, an adenovirus type 26 vector-encoding RSV F protein stabilized in its prefusion conformation, predisposition to ERD was extensively assessed in cotton rat and mouse models. Results: Cotton rats intramuscularly immunized with a wide dose range of Ad26.RSV.preF, including low and sub-protective vaccine doses, and challenged with vaccine homologous RSV A2 or heterologous RSV B Wash 18537, did not show signs of predisposition to ERD. Histopathology scores for alveolitis, peribronchiolitis, interstitial pneumonia, and perivasculitis after challenge were significantly lower for Ad26.RSV.preF-immunized cotton rats compared to FI-RSV-immunized cotton rats and comparable to or lower than scores in cotton rats intranasally pre-exposed to RSV prior to challenge to mimic natural repeated infection. These results were observed in animals with or without viral replication in the lung after RSV challenge, in the presence or absence of vaccine-induced antibodies. Similar results were observed in mice, where more extensive assessment of mono- and polymorphonuclear cell alveolitis, mucus cell hyperplasia, and mucus accumulation was performed. Conclusions: Based on these extensive analyses, we conclude that there are no indications of ERD predisposition after Ad26.RSV.preF vaccination in rodent models, irrespective of the vaccine dose, challenge virus strain, or presence of viral replication in the lung. These results are crucial for the pediatric development of this vaccine. Full article

The overlapping circulation of influenza (Flu), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; SC2), and respiratory syncytial virus (RSV) continues to challenge clinical laboratories, particularly in settings with limited automation and fragmented healthcare coverage. This study expanded the CDC Flu-SC2 assay by incorporating a laboratory-developed test (LDT) for RSV A/B detection into a fully automated quadruplex RT-qPCR (LDRA) on the Panther Fusion^® Open Access™ system. The design, based on more than 8000 RSV genomic sequences targeting the conserved M gene, achieved optimal amplification efficiencies (97–105%) and full multiplex compatibility. Analytical assessment established limits of detection between 9.6 and 37.8 copies per reaction, absence of cross-reactivity with 30 respiratory pathogens, and inclusivity for 32 viral variants. Commutability and diagnostic performance among the LDRA, CE IVD-marked Allplex™ SARS-CoV-2/FluA/FluB/RSV, and US IVD-marked Panther Fusion^® SARS-CoV-2/Flu A/B/RSV Assays were evaluated using 405 nasopharyngeal UTM-preserved swabs. The LDRA demonstrated excellent concordance (overall agreement ≥ 98%, κ > 0.95), strong diagnostic accuracy, and reliable detection of mixed infections. This quadruplex provides a fully automated, rapid, and accurate solution for the simultaneous detection of influenza A, influenza B, SARS-CoV-2, and RSV viruses, enhancing molecular diagnostic capacity and supporting equitable, timely clinical decision-making in middle-income healthcare systems such as that of the Dominican Republic. Full article

Respiratory viruses such as SARS-CoV-2, influenzas A and B, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), human parainfluenza virus type 3 (HPIV-3), and rhinoviruses remain major causes of global morbidity. Their rapid evolution, high transmissibility, and limited therapeutic options, together with the absence of approved vaccines for several pathogens, highlight the need for broad-acting and pathogen-independent antiviral strategies. Nitric oxide exhibits antiviral activity through redox-dependent mechanisms, including S-nitrosylation of cysteine-containing viral proteins and disruption of redox-sensitive structural domains. Clinical studies conducted during the SARS-CoV-2 pandemic demonstrated that a nitric oxide nasal spray (NONS) rapidly reduced nasal viral load and transmission. In this study, we evaluated the in vitro virucidal activity of the NONS against a panel of clinically relevant respiratory viruses representing four major virus families. Virus suspensions of approximately 10⁴ CCID₅₀ were exposed to a full-strength NONS for contact times ranging from 5 s to 2 min at room temperature, followed by neutralization and quantification of residual infectivity using endpoint dilution assays. The NONS rapidly reduced viral infectivity across all viruses tested, achieving >3 log₁₀ reductions within 2 min. SARS-CoV-2 variants including Alpha, Beta, Gamma, Delta, Omicron BA.1, and XBB 2.0 were reduced to levels at or below the assay detection limit within 30 s to 2 min. Influenza A and B viruses showed the fastest loss of infectivity, reaching detection limits within 10–15 s. RSV, hMPV, HPIV-3, and human rhinovirus 14 were similarly inactivated within 1–2 min. These findings demonstrate that the NONS exhibits rapid and broad-spectrum virucidal activity against diverse respiratory viruses and supports its potential role in pandemic preparedness but also seasonal use. Full article

Respiratory infections are a major public health threat. Significant global mortality is caused by influenza viruses, the new SARS-CoV-2 virus, and the Respiratory Syncytial Viruses (RSVs). Wastewater-based epidemiology (WBE) has recently emerged as a valuable tool for monitoring these pathogens, providing insights into their evolution, transmission patterns, and co-circulation within populations. This study aimed to track influenza viruses (A and B), the new SARS-CoV-2 virus, and the Respiratory Syncytial Viruses (RSVs) (type A and B) during the pandemic period (from October 2020 to October 2021) in a middle-size Spanish city (Valladolid) and its surrounding areas. Viral concentration was performed using an aluminum-based precipitation method, followed by RNA extraction and RT-qPCR quantification targeting the N1 and N2 regions of the SARS-CoV-2 nucleocapsid gene, the N gene for both RSV-A and RSV-B, and the M and non-structural protein genes for influenza A and B, respectively. The results demonstrated the utility of WBE in predicting increases in clinical cases of SARS-CoV-2, as evidenced by a high correlation (r > 0.5). For RSV-A, the findings aligned with previous studies. Interestingly, particularly considering the length and period of analysis, influenza A, influenza B, and RSV-B viruses were not observed during the study period. In addition, the prevalence of RSV-A decreased during the SARS-CoV-2 pandemic, likely due to the implementation of non-pharmaceutical interventions. In conclusion, this study reaffirms that WBE provides critical epidemiological insights, complements clinical surveillance, and supports public health authorities in making informed and timely decisions. Full article

It has been demonstrated that infants and young children exhibit immune tolerance as a consequence of immature immune systems, which are characterized by a natural Th2 bias. RSV infection has been reported to result in acute lower respiratory infection (ALRI), while formalin-inactivated vaccination has been observed to exacerbate Th2 responses, consequently leading to enhanced respiratory disease (ERD). Transcriptomic data from three independent cohorts of RSV-infected infants were analyzed (GSE246622 served as the discovery and train set; GSE105450 and GSE188427 were used as validation sets). Immune infiltration analysis revealed immunological characteristics, which were then used to perform unsupervised clustering using feature-related genes. WGCNA was used to identify co-expressed gene modules, while Mfuzz and TCseq were employed to analyze temporal expression patterns. Machine learning models were developed using a refined panel of candidate genes. Severe symptoms of RSV infection exhibited a strong correlation with age, with younger infants demonstrating more intense inflammatory responses from neutrophils, macrophages, mast cells and dendritic cells. A predictive model was constructed using ten co-expressed genes: The following genes were identified: MCEMP1, FCGR1B, ANXA3, FAM20A, CYSTM1, GYG1, ARG1, SLPI, BMX and SMPDL3A. It was observed that infants of a younger demographic demonstrated a heightened degree of immunosuppression and pronounced innate immune activation in patients of severe symptoms with RSV infection. However, eosinophils exhibited minimal involvement in these processes. These gene models pertaining to the neutrophil, macrophage or mast cell was found to be a relatively effective predictor in patients of severe symptoms. Full article

Influenza and other respiratory viruses pose significant public health threats among SARI patients, yet comprehensive surveillance data remain limited in Pakistan. This prospective, multi-center study characterized the burden, distribution, and molecular evolution of respiratory viruses among hospitalized SARI patients across seven tertiary hospitals from November 2022 to June 2025. Specimens were tested using RT-PCR for influenza, SARS-CoV-2, and RSV, with 375 samples sequenced via Oxford Nanopore Technology. Among 11,451 specimens, 2818 (24.6%) tested positive: RSV (1648, 14.4%), influenza (855, 7.5%; 45% H1N1pdm09, 35% H3N2, 20% influenza B), and SARS-CoV-2 (315, 2.8%). RSV predominantly affected children under 2 years (63%), while influenza and SARS-CoV-2 primarily impacted adults aged 15–40 years. Male predominance (65–79%) reflected healthcare access barriers. Strong winter seasonality (December–February) was observed for influenza and RSV. ICU admission rates were 17% for influenza, 16% for RSV, and 4% for SARS-CoV-2. Shortness of breath was associated with influenza (OR = 1.62) and RSV (OR = 1.27), while malaise (OR = 2.24) and myalgia (OR = 3.87) was associated with SARS-CoV-2. Phylogenetic analysis revealed vaccine-matched influenza clades and rapid SARS-CoV-2 variant succession (3–4 months). RSV is the primary SARI pathogen in young children, necessitating maternal vaccines and nirsevimab implementation. Sustained genomic surveillance remains essential for pandemic preparedness. Full article

Background: Children with congenital heart disease (CHD) are at substantially increased risk for respiratory infections, which occur more frequently and with greater severity than in healthy peers. This heightened vulnerability stems from multifactorial immune impairment, including defects in innate and adaptive immunity, chronic inflammation related to abnormal hemodynamics and hypoxia, reduced thymic function, and genetic syndromes affecting both cardiac and immune development. Viral pathogens—particularly respiratory syncytial virus (RSV), influenza viruses, and SARS-CoV-2—account for most infections, although bacterial pathogens remain relevant, especially in postoperative settings. Methods: This narrative review summarizes current evidence on infection susceptibility in children with CHD, the epidemiology and clinical relevance of major respiratory pathogens, and the effectiveness of available preventive measures. Literature evaluating immunological mechanisms, infection burden, vaccine effectiveness, and passive immunization strategies was examined, along with existing national and international immunization guidelines. Results: Children with CHD consistently exhibit higher rates of hospitalization, intensive care unit admission, mechanical ventilation, and mortality following respiratory infections. RSV, influenza, and SARS-CoV-2 infections are particularly severe in this population, while bacterial infections, though less common, contribute substantially to postoperative morbidity. Preventive options—including routine childhood vaccines, pneumococcal and Haemophilus influenzae type b vaccines, influenza vaccines, COVID-19 mRNA vaccines, and RSV monoclonal antibodies—demonstrate strong protective effects. New long-acting RSV monoclonal antibodies and maternal vaccination markedly enhance prevention in early infancy. However, vaccine coverage remains insufficient due to parental hesitancy, provider uncertainty, delayed immunization, and limited CHD-specific evidence. Conclusions: Respiratory infections pose a significant and preventable health burden in children with CHD. Enhancing the use of both active and passive immunization is essential to reduce morbidity and mortality. Strengthening evidence-based guidelines, improving coordination between specialists and primary care providers, integrating immunization checks into routine CHD management, and providing clear, condition-specific counseling to families can substantially improve vaccine uptake and clinical outcomes in this vulnerable population. Full article