Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment

Detailed Evolutionary Analyses of the F Gene in the Respiratory Syncytial Virus Subgroup A

We performed evolution, phylodynamics, and reinfection-related antigenicity analyses of respiratory syncytial virus subgroup A (RSV-A) fusion (F) gene in globally collected strains (1465 strains) using authentic bioinformatics methods. The time-scaled evolutionary tree using the Bayesian Markov chain Monte Carlo method estimated that a common ancestor of the RSV-A, RSV-B, and bovine-RSV diverged at around 450 years ago, and RSV-A and RSV-B diverged around 250 years ago. Finally, the RSV-A F gene formed eight genotypes (GA1-GA7 and NA1) over the last 80 years. Phylodynamics of RSV-A F gene, including all genotype strains, increased twice in the 1990s and 2010s, while patterns of each RSV-A genotype were different. Phylogenetic distance analysis suggested that the genetic distances of the strains were relatively short (less than 0.05). No positive selection sites were estimated, while many negative selection sites were found. Moreover, the F protein 3D structure mapping and conformational epitope analysis implied that the conformational epitopes did not correspond to the neutralizing antibody binding sites of the F protein. These results suggested that the RSV-A F gene is relatively conserved, and mismatches between conformational epitopes and neutralizing antibody binding sites of the F protein are responsible for the virus reinfection.

Immunopathology of RSV: An Updated Review

RSV is a leading cause of respiratory tract disease in infants and the elderly. RSV has limited therapeutic interventions and no FDA-approved vaccine. Gaps in our understanding of virus-host interactions and immunity contribute to the lack of biological countermeasures. This review updates the current understanding of RSV immunity and immunopathology with a focus on interferon responses, animal modeling, and correlates of protection.

Clinical features of respiratory syncytial virus bronchiolitis in an infant: rapid and fatal brain involvement

Background

Respiratory Syncytial Virus (RSV) infection is a significant cause of bronchiolitis and pneumonia, mostly responsible for hospitalization and infant death worldwide. However, in recent years the importance of extrapulmonary RSV manifestations, especially at neurological level, have become evident. Seizures, lethargy, ataxia and status epilepticus are suggestive of brain involvement, but also in their absence a direct neurological damage RSV-related need to be evaluated.

Case presentation

A 40-day old male infant was admitted to the Emergency Department with severe bronchiolitis and dyspnea. The patient was reported to be coughing for a week with a vomiting episode in the previous two days. The nasopharyngeal swab confirmed the diagnosis of RSV infection and blood gas test showed hypoxemia and respiratory acidosis. For these reasons, the patient was provided with oxygen therapy. A few hours later, after an initial improvement in clinical parameters, a worsening of respiratory dynamics occurred and the patient was prepared for endotracheal intubation, but in the meantime death occurred. During all the observation period in the Emergency Room, no signs of neuropathological damage were evident. Post mortem examination showed lungs congestion with alveolar atelectasis and white matter degradation with severe edema at brain level. Microbiological analysis performed on autoptic samples confirmed the presence of RSV genome in tracheobronchial aspirate, meningeal swabs, pericardic and abdominal fluids, lung and brain biopsies.

Conclusions

RSV is usually associated with respiratory diseases, however, as reported by an increasingly number of studies, the systemic dissemination of virus during severe disease can lead to a sudden infant death. The clinical picture herein reported showed a severe bronchiolitis resulting in a fatal and underestimated cerebral involvement due to RSV neurotropic behaviour and underline the need for clinicians to pay more attention to neurological involvement of RSV infection, even in absence of cerebral damage evidence.

Efficient Inactivation of SARS-CoV-2 and Other RNA or DNA Viruses with Blue LED Light

Blue LED light has proven to have a powerful bacteria-killing ability; however, little is known about its mechanism of virucidal activity. Therefore, we analyzed the effect of blue light on different respiratory viruses, such as adenovirus, respiratory syncytial virus and SARS-CoV-2. The exposure of samples to a blue LED light with a wavelength of 420 nm (i.e., in the visible range) at 20 mW/cm² of irradiance for 15 min appeared optimal and resulted in the complete inactivation of the viral load. These results were similar for all the three viruses, demonstrating that both enveloped and naked viruses could be efficiently inactivated with blue LED light, regardless of the presence of envelope and of the viral genome nature (DNA or RNA). Moreover, we provided some explanations to the mechanisms by which the blue LED light could exert its antiviral activity. The development of such safe and low-cost light-based devices appears to be of fundamental utility for limiting viral spread and for sanitizing small environments, objects and surfaces, especially in the pandemic era.

Host Defence RNases as Antiviral Agents against Enveloped Single Stranded RNA Viruses

Owing to the recent outbreak of Coronavirus Disease of 2019 (COVID-19), it is urgent to develop effective and safe drugs to treat the present pandemic and prevent other viral infections that might come in the future. Proteins from our own innate immune system can serve as ideal sources of novel drug candidates thanks to their safety and immune regulation versatility. Some host defense RNases equipped with antiviral activity have been reported over time. Here, we try to summarize the currently available information on human RNases that can target viral pathogens, with special focus on enveloped single-stranded RNA (ssRNA) viruses. Overall, host RNases can fight viruses by a combined multifaceted strategy, including the enzymatic target of the viral genome, recognition of virus unique patterns, immune modulation, control of stress granule formation, and induction of autophagy/apoptosis pathways. The review also includes a detailed description of representative enveloped ssRNA viruses and their strategies to interact with the host and evade immune recognition. For comparative purposes, we also provide an exhaustive revision of the currently approved or experimental antiviral drugs. Finally, we sum up the current perspectives of drug development to achieve successful eradication of viral infections.

Integrated Network Pharmacology and Lipidomics to Reveal the Inhibitory Effect of Qingfei Oral Liquid on Excessive Autophagy in RSV-Induced Lung Inflammation

Background: Respiratory syncytial virus (RSV) can cause varying degrees of lung inflammation in children. Qingfei Oral Liquid (QF) is effective in treating childhood RSV-induced lung inflammation (RSV-LI) in clinics, but its pharmacological profiles and mechanisms remain unclear. Methods: This study combined network Pharmacology, lipidomics, pharmacodynamics, and pathway validation to evaluate the therapeutic mechanisms of QF. Using Cytoscape (v3.8.2) and enrichment analyses from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO), a global view of the putative compound-target-pathway network was created. The corresponding lipidomic profiles were then used to detect differently activated lipids, revealing the metabolic pathway, using ultra-high-performance liquid chromatography linked to hybrid Quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap MS). Meanwhile, the in vivo efficiency of QF, the enrichment pathway, and the excessive autophagy inhibition mechanisms were validated in RSV-infected mice models. Results: The network pharmacology results demonstrated 117 active compounds acted directly upon 101 core targets of QF against RSV-LI. The most significantly enriched pathway was the PI3K/Akt/mTOR signaling pathway (p < 0.05). In addition, untargeted lipidomics were performed, and it was revealed that higher lung levels of DAG 30:0, DAG 30:5, DAG 32:0, DAG 16:0_18:0, DAG 17:0_17:0, DAG 34:1, DAG 36:0, DAG 36:1 in the RSV-LI group were decreased after QF administration (FDR < 0.05, FC > 1.2). Lipin-1, a key enzyme in DAG synthesis, was increased in the RSV-LI mouse model. Animal experiments further validated that QF inhibited the PI3K/Akt/mTOR signaling pathway, with lower lung levels of phosphorylated PI3K, AKT and mTOR, as well as its related proteins of lipin-1 and VPS34 (p < 0.01). Finally, pharmacodynamic investigations indicated that QF reduced airway inflammation caused by excessive autophagy by decreasing lung levels of RSV F and G proteins, Beclin-1, Atg5, and LC3B II, IL-1 and TNF-α (p < 0.05). Conclusion: Lipidomic-based network pharmacology, along with experimental validation, may be effective approaches for illustrating the therapeutic mechanism of QF in the treatment of RSV-LI.

Clinical Epidemiological Characteristics and Risk Factors for Severe Bronchiolitis Caused by Respiratory Syncytial Virus in Vietnamese Children

Introduction

Bronchiolitis is the most prevalent cause of hospitalization in infants under the age of 12 months. The disease is caused by respiratory syncytial virus (RSV) infection, which can cause breathing difficulties and respiratory failure. Therefore, it is necessary to discover the risk factors of severe bronchiolitis to diagnose and treat promptly. This study is aimed at describing the epidemiological characteristics and clinical features of acute bronchiolitis caused by RSV and assessing the related factors to severe acute bronchiolitis in studied patients.

Methods

A descriptive cross-sectional study was carried out in Haiphong Children's Hospital, Haiphong, Vietnam, for one year, from October 1, 2016, to September 30, 2017. All bronchiolitis admissions < 2 years were included.

Results

377 children were evaluated, including 261 boys and 116 girls; children under 6 months accounted for the highest proportion (57%), and 47 (12.5%) of all patients had severe disease. Wheezing was the main reason to be taken to the hospital 261 (69.2%). Clinical symptoms of acute bronchiolitis such as cough, tachypnea, and runny nose were found in all patients. Bronchiolitis cases increased in the winter-spring season, and the highest registered number of patients was 42 in March. Image of bronchiolitis on chest X-ray was found in all patients, and air trapping lung was found in 124 (32.9%) patients. The risk factors included age (≤6 months), low birth weight, preterm birth, nonbreastfeeding for the first six months, early weaning, and exposition to cigarette smoke increased the severe disease (p < 0.05).

Conclusion

The number of hospitalized infants with bronchiolitis caused by RSV has an upward trend during the winter-spring season (from October to March). This study confirms that age, preterm birth, breastfeeding under 6 months, history of exposure to cigarette smoking, low birth weight, having sibling(s) under five years old going to kindergarten, history of undergoing cesarean section, history of mechanical ventilation, poor living condition, and maternal education are 10 risk factors of severe bronchiolitis caused by RSV.

Statin-mediated disruption of Rho GTPase prenylation and activity inhibits respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is a leading cause of severe respiratory tract infections in children. To uncover new antiviral therapies, we developed a live cell-based high content screening approach for rapid identification of RSV inhibitors and characterized five drug classes which inhibit the virus. Among the molecular targets for each hit, there was a strong functional enrichment in lipid metabolic pathways. Modulation of lipid metabolites by statins, a key hit from our screen, decreases the production of infectious virus through a combination of cholesterol and isoprenoid-mediated effects. Notably, RSV infection globally upregulates host protein prenylation, including the prenylation of Rho GTPases. Treatment by statins or perillyl alcohol, a geranylgeranyltransferase inhibitor, reduces infection in vitro. Of the Rho GTPases assayed in our study, a loss in Rac1 activity strongly inhibits the virus through a decrease in F protein surface expression. Our findings provide new insight into the importance of host lipid metabolism to RSV infection and highlight geranylgeranyltransferases as an antiviral target for therapeutic development.

Depletion of TAX1BP1 Amplifies Innate Immune Responses during Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the main cause of acute respiratory infections in young children and also has a major impact on the elderly and immunocompromised people. In the absence of a vaccine or efficient treatment, a better understanding of RSV interactions with the host antiviral response during infection is needed. Previous studies revealed that cytoplasmic inclusion bodies (IBs), where viral replication and transcription occur, could play a major role in the control of innate immunity during infection by recruiting cellular proteins involved in the host antiviral response. We recently showed that the morphogenesis of IBs relies on a liquid-liquid-phase separation mechanism depending on the interaction between viral nucleoprotein (N) and phosphoprotein (P). These scaffold proteins are expected to play a central role in the recruitment of cellular proteins to IBs. Here, we performed a yeast two-hybrid screen using RSV N protein as bait and identified the cellular protein TAX1BP1 as a potential partner of this viral protein. This interaction was validated by pulldown and immunoprecipitation assays. We showed that TAX1BP1 suppression has only a limited impact on RSV infection in cell cultures. However, RSV replication is decreased in TAX1BP1-deficient (TAX1BP1 knockout [TAX1BP1KO]) mice, whereas the production of inflammatory and antiviral cytokines is enhanced. In vitro infection of wild-type or TAX1BP1KO alveolar macrophages confirmed that the innate immune response to RSV infection is enhanced in the absence of TAX1BP1. Altogether, our results suggest that RSV could hijack TAX1BP1 to restrain the host immune response during infection. IMPORTANCE Respiratory syncytial virus (RSV), which is the leading cause of lower respiratory tract illness in infants, remains a medical problem in the absence of a vaccine or efficient treatment. This virus is also recognized as a main pathogen in the elderly and immunocompromised people, and the occurrence of coinfections (with other respiratory viruses and bacteria) amplifies the risks of developing respiratory distress. In this context, a better understanding of the pathogenesis associated with viral respiratory infections, which depends on both viral replication and the host immune response, is needed. The present study reveals that the cellular protein TAX1BP1, which interacts with the RSV nucleoprotein N, participates in the control of the innate immune response during RSV infection, suggesting that the N-TAX1BP1 interaction represents a new target for the development of antivirals.

The effects of the dietary compound L-sulforaphane against respiratory pathogens

L-sulforaphane (LSF) is an isothiocyanate derived from cruciferous vegetables that has long been known for its anticarcinogenic, antioxidant and anti-inflammatory effects. LSF also possesses antimicrobial properties, although the evidence for this is limited. Respiratory pathogens, such as Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes and respiratory syncytial virus (RSV), are leading global causes of illness and death among children aged under five years, particularly in resource-poor countries where access to vaccines are limited or, in the case of S. pyogenes and RSV, vaccines have not been licensed for use in humans. Therefore, alternative strategies to prevent and/or treat these common infectious diseases are urgently needed. This study was conducted to investigate the antimicrobial effects of LSF against common respiratory pathogens, S. pneumoniae (serotypes 1 and 6B), H. influenzae type B (HiB), non-typeable H. influenzae (NTHi), S. pyogenes and RSV in relevant human cell-based models. LSF significantly inhibited the growth of H. influenzae, but not S. pneumoniae or S. pyogenes. LSF did not improve opsonophagocytic capacity or killing by human phagocytic cell lines (HL-60s and THP-1 macrophages) for S. pneumoniae yet showed some improved killing for H. influenzae species in THP-1 macrophages. However, LSF significantly reduced RSV infection in human lung epithelial cells, associated with increased expression of cyclin D1 (CCND1) gene as well as the antioxidant genes, nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX-1). Overall, LSF represents an exciting avenue for further antimicrobial research, particularly as a novel therapy against H. influenzae species and RSV.

During the COVID-19 pandemic where has respiratory syncytial virus gone?

The diffusion of the SARS-CoV-2 virus and the implementation of restrictive measures led to a drastic reduction of respiratory syncytial virus (RSV) diffusion. Few RSV cases have been detected worldwide, even after the removal of the restrictions. We review the current literature and present possible explanations on why there has been a significant reduction of RSV detection during the COVID-19 pandemic. We also hypothesize what may happen when RSV begins to circulate again. The increase of an immunologically naïve population, with infants born from mothers who have not reinforced their immunity to RSV, could lead to greater RSV epidemics in the coming seasons. It is crucial to prepare the scientific community and to keep RSV surveillance active to avoid dramatic consequences.

Reversible disruption of XPO1-mediated nuclear export inhibits respiratory syncytial virus (RSV) replication

Respiratory syncytial virus (RSV) is the primary cause of serious lower respiratory tract disease in infants, young children, the elderly and immunocompromised individuals. Therapy for RSV infections is limited to high risk infants and there are no safe and efficacious vaccines. Matrix (M) protein is a major RSV structural protein with a key role in virus assembly. Interestingly, M is localised to the nucleus early in infection and its export into the cytoplasm by the nuclear exporter, exportin-1 (XPO1) is essential for RSV assembly. We have shown previously that chemical inhibition of XPO1 function results in reduced RSV replication. In this study, we have investigated the anti-RSV efficacy of Selective Inhibitor of Nuclear Export (SINE) compounds, KPT-335 and KPT-185. Our data shows that therapeutic administration of the SINE compounds results in reduced RSV titre in human respiratory epithelial cell culture. Within 24 h of treatment, RSV replication and XPO1 expression was reduced, M protein was partially retained in the nucleus, and cell cycle progression was delayed. Notably, the effect of SINE compounds was reversible within 24 h after their removal. Our data show that reversible inhibition of XPO1 can disrupt RSV replication by affecting downstream pathways regulated by the nuclear exporter.

Evaluation of prognostic scores for respiratory syncytial virus infection in a French multicentre cohort of allogeneic haematopoietic stem cell transplantation recipients

Haematopoietic stem cell transplantation (HSCT) recipients are at risk for severe respiratory syncytial virus (RSV) infection. Two prognostic scores have been proposed to predict the risk of progression from upper respiratory tract infection (URTI) to lower respiratory tract infection (LRTI) and death. This was a multicentre study of allogeneic HSCT recipients diagnosed with an RSV infection between 2010 and 2019 who were retrospectively stratified by the immunodeficiency scoring index (ISI) and the severe immunodeficiency (SID) score. Endpoints were overall survival, RSV-attributable mortality and progression to LRTI after URTI. Prognostic analyses were performed using Cox regression models. We included 147 consecutive patients, including 94 (63.9%) initially diagnosed with URTI and 53 (36.1%) with LRTI. At 90 days, 14 patients had died (survival rate, 90.5%; 95% CI: 85.9-95.3), and nine deaths were attributable to RSV (attributable mortality rate, 5.4%; 95% CI: 2.5-10.0). The cumulative 90-day incidence of LRTI after URTI was 13.8% (95% CI: 7.8-21.6). Neither score showed prognostic value for mortality, while the ISI allowed the prediction of progression to LRTI (p = 0.0008). Our results do not fully replicate the results previously reported in cohorts of HSCT recipients. This may reflect the recent epidemiology of RSV infections in this HSCT cohort.

Monoclonal Antibodies Against Infectious Microbes: So Long and Too Little!

Monoclonal antibodies (mAbs) as alternatives or more often as complementary to the conventional antimicrobials have been developed for the management of infectious conditions for the past two decades. These pharmacotherapeutic strategies are inevitable as the burden of antimicrobial resistance is far-reaching in recent times. MAbs are part of the targeted pharmacotherapy armamentarium with a high degree of specificity - hence, exert comparatively superior efficacy and tolerability than the conventional polyclonal antisera. So far, only five mAbs have been approved for the management of infectious states, since the marketing authorization (1998) given to palivizumab (Synagis®) for the prophylaxis of lower respiratory tract disease caused by a respiratory syncytial virus in pediatric patients. Ibalizumab-uiyk (Trogarzo™) used for the management of multidrug-resistant HIV-1 infection not yielding to at least 10 antiretroviral drugs, was approved recently. Among the three antibacterial mAbs, raxibacumab (ABthrax®/ Anthrin®) and obiltoxaximab (Anthim®) are indicated for the treatment and prophylaxis of inhalation anthrax due to Bacillus anthracis; bezlotoxumab (Zinplava®) is used to reduce the recurrence of Clostridium difficile infection. There are also around 30 and 15 mAbs in different phases of development for viral and bacterial conditions. As alternatives to the traditional antivirals and antibacterials, the antimicrobial mAbs are the need of the hour. These mAbs are more relevant to the management of conditions like emerging viral outbreaks wherein there is a lack of prophylactic vaccines. The current cutting-edge engineering technologies revolutionizing the production of mAbs include phagedisplayed antibody libraries, cloning from single-memory B cells or single-antibody-secreting plasma B cells, proteomics-directed cloning of mAbs from serum clubbed with high-throughput sequencing techniques. Yet, the cost of manufacture continues to be the main limiting factor. In this review, the different therapeutic monoclonal antibodies directed against the microbial pathogens are discussed.

The spatial-temporal dynamics of respiratory syncytial virus infections across the east-west coasts of Australia during 2016-17

Respiratory syncytial virus (RSV) is an important human respiratory pathogen. In temperate regions, a distinct seasonality is observed, where peaks of infections typically occur in early winter, often preceding the annual influenza season. Infections are associated with high rates of morbidity and mortality and in some populations exceed that of influenza. Two subtypes, RSV-A and RSV-B, have been described, and molecular epidemiological studies have shown that both viruses mostly co-circulate. This trend also appears to be the case for Australia; however, previous genomic studies have been limited to cases from one Eastern state—New South Wales. As such, the broader spatial patterns and viral traffic networks across the continent are not known. Here, we conducted a whole-genome study of RSV comparing strains across eastern and Western Australia during the period January 2016 to June 2017. In total, 96 new RSV genomes were sequenced, compiled with previously generated data, and examined using a phylodynamic approach. This analysis revealed that both RSV-A and RSV-B strains were circulating, and each subtype was dominated by a single genotype, RSV-A ON1-like and RSV-B BA10-like viruses. Some geographical clustering was evident in strains from both states with multiple distinct sub-lineages observed and relatively low mixing across jurisdictions, suggesting that endemic transmission was likely seeded from imported, unsampled locations. Overall, the RSV phylogenies reflected a complex pattern of interactions across multiple epidemiological scales from fluid virus traffic across global and regional networks to fine-scale local transmission events.

Polyclonal alpaca antibodies protect against hantavirus pulmonary syndrome in a lethal Syrian hamster model

The use of antibody-based therapies for the treatment of high consequence viral pathogens has gained interest over the last fifteen years. Here, we sought to evaluate the use of unique camelid-based IgG antibodies to prevent lethal hantavirus pulmonary syndrome (HPS) in Syrian hamsters. Using purified, polyclonal IgG antibodies generated in DNA-immunized alpacas, we demonstrate that post-exposure treatments reduced viral burdens and organ-specific pathology associated with lethal HPS. Antibody treated animals did not exhibit signs of disease and were completely protected. The unique structures and properties, particularly the reduced size, distinct paratope formation and increased solubility of camelid antibodies, in combination with this study support further pre-clinical evaluation of heavy-chain only antibodies for treatment of severe respiratory diseases, including HPS.

Viral and Bacterial Co-Infections in the Lungs: Dangerous Liaisons

Respiratory tract infections constitute a significant public health problem, with a therapeutic arsenal that remains relatively limited and that is threatened by the emergence of antiviral and/or antibiotic resistance. Viral–bacterial co-infections are very often associated with the severity of these respiratory infections and have been explored mainly in the context of bacterial superinfections following primary influenza infection. This review summarizes our current knowledge of the mechanisms underlying these co-infections between respiratory viruses (influenza viruses, RSV, and SARS-CoV-2) and bacteria, at both the physiological and immunological levels. This review also explores the importance of the microbiome and the pathological context in the evolution of these respiratory tract co-infections and presents the different in vitro and in vivo experimental models available. A better understanding of the complex functional interactions between viruses/bacteria and host cells will allow the development of new, specific, and more effective diagnostic and therapeutic approaches.

In-hospital and midterm out-hospital complications of adults hospitalised with respiratory syncytial virus infection in France, 2017-2019: an observational study

OBJECTIVES

To describe the clinical characteristics and in/out-hospital outcomes of respiratory syncytial virus (RSV) infection among adults hospitalised with influenza-like illness (ILI) and compared against patients admitted for influenza.

METHODS

Adults hospitalised with ILI were prospectively included from five French university hospitals over two consecutive winter seasons (2017/2018 and 2018/2019). RSV and influenza virus were detected by multiplex RT-PCR on nasopharyngeal swabs. RSV-positive patients were compared to RSV-negative and influenza-positive hospitalised patients. Poisson regression models were used to estimate the adjusted prevalence ratio (aPR) associated with in-hospital and post-discharge outcomes between RSV and influenza infections. The in-hospital outcome was a composite of the occurrence of at least one complication, length of stay ≥7 days, intensive care unit (ICU) admission, use of mechanical ventilation and in-hospital death. Post-discharge outcome included 30/90-day all-cause mortality and 90-day readmission rates.

RESULTS

Overall, 1,428 hospitalised adults with ILI were included. RSV was detected in 8% (114/1428) and influenza virus in 31% (437/1428). Patients hospitalised with RSV were older than those with influenza (mean age, 73.0 versus 68.8 years; p=0.015) with a higher frequency of respiratory (52% versus 39%, p=0.012) or cardiac chronic diseases (52% versus 41%, p=0.039) and longer hospitalisation duration (median stay 8 versus 6 days, p<0.001). Anti-influenza therapies were less prescribed among RSV than influenza patients (20% versus 66%, p<0.001). In-hospital composite outcome was poorer in RSV patients (adjusted prevalence ratio (aPR)=1.5; 95% Confidence Interval (95% CI) 1.1-2.1) than in those hospitalised with influenza. No difference was observed for the post-discharge composite outcome (aPR=1.1; 95% CI 0.8-1.6).

CONCLUSION

RSV infection results in serious respiratory illness with in-hospital outcomes worse than influenza and with similar midterm post-discharge outcomes.

Preventive Strategies for Respiratory Syncytial Virus Infection in Young Infants

Respiratory syncytial virus (RSV) is the leading cause of acute viral lower respiratory tract infections in young children, with the peak of severe disease occurring in infants younger than 6 months of age. Most infants who develop severe RSV infection are born full-term and previously healthy; however, premature infants represent an especially vulnerable population at high risk of developing serious sequelae because of RSV. Despite the high disease burden, the pathogenesis of the disease is not completely understood, treatment options are limited to supportive care, and no licensed vaccines are available.The young age of children affected by severe disease and incomplete understanding of the disease pathogenesis, along with prior vaccine failures, have represented major obstacles to RSV vaccine development. Nevertheless, the increasingly recognized burden associated with RSV in low-middle income countries, where RSV represents the second cause of infant mortality, has made the development of preventive strategies for RSV a global health priority. Increased awareness, together with a better understanding of the viral structure and identification of new viral targets, has led to the development of newer RSV vaccines and monoclonal antibodies to confer protection to both preterm and term infants who represent the most vulnerable population for severe RSV disease.

Surveillance in hospitalized children with infectious diseases in Japan: Pre- and post-coronavirus disease 2019

Introduction

The epidemic of coronavirus disease 2019 (COVID-19) rapidly spread worldwide, and the various infection control measures have a significant influence on the spread of many infectious diseases. However, there have been no multicenter studies on how the number of hospitalized children with various infectious diseases changed before and after the outbreak of COVID-19 in Japan.

Methods

We conducted a multicenter, prospective survey for hospitalized pediatric patients in 18 hospitals in Hokkaido Prefecture, Japan, from July 2019 to February 2021. We defined July 2019 to February 2020 as pre-COVID-19, and July 2020 to February 2021 as post-COVID-19. We surveyed various infectious diseases by sex and age.

Results

In total, 5300 patients were hospitalized during the study period. The number of patients decreased from 4266 in the pre-COVID-19 period to 701 (16.4%) post-COVID-19. Patients with influenza and RSV decreased from 308 to 795 pre-COVID-19 to zero and three (0.4%) post-COVID-19. However, patients with adenovirus (respiratory infection) only decreased to 60.9% (46–28) of pre-COVID levels. Patients with rotavirus, norovirus, and adenovirus gastroenteritis decreased markedly post-COVID-19 to 2.6% (38–1), 27.8% (97–27) and 13.5% (37–5). The number of patients with UTIs was similar across the two periods (109 and 90). KD patients decreased to 31.7% (161–51) post-COVID-19.

Conclusions

We suggest that current infection control measures for COVID-19 such as wearing masks, washing hands, and disinfecting hands with alcohol are effective against various infectious diseases. However, these effects vary by disease.

Impact of public health measures on the post-COVID-19 respiratory syncytial virus epidemics in France

Since the beginning of the COVID-19 pandemic, other respiratory illnesses decreased worldwide. This study described the consequences of public health measures on respiratory syncytial virus (RSV) severe infections in France, where an interseasonal resurgence of RSV occurred recently. All patients admitted to Necker Hospital (Paris) between August 2018 and April 2021 with a diagnosis of RSV-associated acute lung respiratory infection (ALRI) were enrolled. Characteristics of subjects with RSV-associated ALRI in 2020/2021 were compared to those infected during the two previous outbreaks. Overall, 664 inpatients were diagnosed with RSV-associated ALRI: 229, 183, and 252 during the 2018/2019, 2019/2020, and 2020/2021 outbreaks, respectively. During autumn 2020, a national lockdown began in France but schools remained open. A 3-month delayed RSV epidemic occurred at the end of this lockdown. Compared to previous outbreaks, the 2020/2021 epidemics involved more children aged 6 to 11 months (25.8% versus 13.1%, p < 0.0001), but less infants aged < 6 months (41.3% versus 56.6%, p < 0.0001) and less adults (0.0 versus 2.7%, p < 0.0001). Shorter length of stay at hospital, less frequent requirement of admission to intensive care unit, use of non-invasive ventilation, and/or high-flow nasal oxygen were observed in 2020/2021 than during previous epidemics (p < 0.0001). Delayed RSV outbreak was associated with more hospitalizations for ALRI, higher age of pediatric inpatients, but milder median clinical phenotype. Reinforced public health measures (even while keeping nurseries and schools open with mandatory face masks since six years of age) could impact, at least transiently, the burden of RSV-related hospitalizations.

Metal Nanoparticles: a Promising Treatment for Viral and Arboviral Infections

Globally, viral diseases continue to pose a significant threat to public health. Recent outbreaks, such as influenza, coronavirus, Ebola, and dengue, have emphasized the urgent need for new antiviral therapeutics. Considerable efforts have focused on developing metal nanoparticles for the treatment of several pathogenic viruses. As a result of these efforts, metal nanoparticles are demonstrating promising antiviral activity against pathogenic surrogates and clinical isolates. This review summarizes the application of metal nanoparticles for the treatment of viral infections. It provides information on synthesis methods, size-related properties, nano-bio-interaction, and immunological effects of metal nanoparticles. This article also addresses critical criteria and considerations for developing clinically translatable nanosized metal particles to treat viral diseases.

COVID-19 Shuts Doors to Flu but Keeps Them Open to Rhinoviruses

Simple Summary

Ten years have passed since the beginning of the H1N1pdm09 flu pandemic. No sooner had humanity recovered from its consequences than a new attack came—the COVID-19 pandemic. What happens to other respiratory infectious diseases during a global disaster such as the COVID-19 pandemic? The pandemic brought about by the novel SARS-CoV-2 virus has disrupted many well-established epidemiological and pathogenetic relationships, as well as mechanisms affecting infections with other respiratory viruses. The level of circulation of many respiratory pathogens has changed significantly. For instance, global influenza activity is at much lower levels than expected. In many regions, the influenza season has not started. Intriguingly, the COVID-19 pandemic did not substantially affect the spread of human rhinoviruses. In this review, the main properties of epidemiologically significant respiratory viruses such as SARS-CoV-2, influenza virus, and human rhinovirus are described.

Abstract

It is well known that rhinoviruses are distributed across the globe and are the most common cause of the common cold in all age groups. Rhinoviruses are widely considered to be harmless because they are generally perceived as respiratory viruses only capable of causing mild disease. However, they may also infect the lower respiratory tract, inducing chronic obstructive pulmonary disease and exacerbations of asthma, bronchiolitis, etc. The role of rhinoviruses in pathogenesis and the epidemiological process is underestimated, and they need to be intensively studied. In the light of recent data, it is now known that rhinoviruses could be one of the key epidemiological barriers that may influence the spread of influenza and novel coronaviruses. It has been reported that endemic human rhinoviruses delayed the development of the H1N1pdm09 influenza pandemic through viral interference. Moreover, human rhinoviruses have been suggested to block SARS-CoV-2 replication in the airways by triggering an interferon response. In this review, we summarized the main biological characteristics of genetically distinct viruses such as rhinoviruses, influenza viruses, and SARS-CoV-2 in an attempt to illuminate their main discrepancies and similarities. We hope that this comparative analysis will help us to better understand in which direction research in this area should move.

Neutralization of IL-33 modifies the type 2 and type 3 inflammatory signature of viral induced asthma exacerbation

Background

Respiratory viral infections are one of the leading causes of need for emergency care and hospitalizations in asthmatic individuals, and airway-secreted cytokines are released within hours of viral infection to initiate these exacerbations. IL-33, specifically, contributes to these allergic exacerbations by amplifying type 2 inflammation. We hypothesized that blocking IL-33 in RSV-induced exacerbation would significantly reduce allergic inflammation.

Methods

Sensitized BALB/c mice were challenged with aerosolized ovalbumin (OVA) to establish allergic inflammation, followed by RSV-A2 infection to yield four treatment groups: saline only (Saline), RSV-infected alone (RSV), OVA alone (OVA), and OVA-treated with RSV infection (OVA-RSV). Lung outcomes included lung mRNA and protein markers of allergic inflammation, histology for mucus cell metaplasia and lung immune cell influx by cytospin and flow cytometry.

Results

While thymic stromal lymphopoietin (TSLP) and IL-33 were detected 6 h after RSV infection in the OVA-RSV mice, IL-23 protein was uniquely upregulated in RSV-infected mice alone. OVA-RSV animals varied from RSV- or OVA-treated mice as they had increased lung eosinophils, neutrophils, group 2 innate lymphoid cells (ILC2) and group 3 innate lymphoid cells (ILC3) detectable as early as 6 h after RSV infection. Neutralized IL-33 significantly reduced ILC2 and eosinophils, and the prototypical allergic proteins, IL-5, IL-13, CCL17 and CCL22 in OVA-RSV mice. Numbers of neutrophils and ILC3 were also reduced with anti-IL-33 treatment in both RSV and OVA-RSV treated animals as well.

Conclusions

Taken together, our findings indicate a broad reduction in allergic-proinflammatory events mediated by IL-33 neutralization in RSV-induced asthma exacerbation.

Disease Burden Due to Respiratory Syncytial Virus in Indian Pediatric Population: A Literature Review

Respiratory syncytial virus (RSV) is one of the leading causes of lower respiratory tract infections in young children. Globally, there is huge disease burden, high treatment cost, and health impact beyond acute episodes due to RSV which necessitate development and implementation of preventive strategies for the control of RSV infection. The disease burden due to RSV in pediatric population across India is still not clearly understood so this literature review was therefore conducted to gather data on disease burden due to RSV in Indian pediatric population. Systematic literature search was performed using PubMed and Google search with different medical subject headings from 2007 to 2020. Studies performed in Indian pediatric population were selected for review. Literature review revealed that in India, epidemiology of RSV infection is well documented in young children (0-5 years) as compared to children from other age groups. The rates of RSV detection in various studies conducted in younger children (0-5 years) vary from 2.1% to 62.4% in India which is higher as compared to children from other age groups. In India, RSV mainly peaks around rainy to early winter season, that is, during months of June through October while smaller peak was noted during December, January, and February. In 2020, higher RSV-associated disease burden was reported among children (<5 years) in low-income and lower-middle-income countries. Considering significant disease burden due to RSV in young Indian children, availability of RSV vaccine would be crucial to prevent RSV infections in children and its spread in the community.

Promising traditional Indian medicinal plants for the management of novel Coronavirus disease: A systematic review

Traditional Indian medical practices (Ayurveda, Siddha, Unani, and homeopathy) are a vast reservoir of knowledge about medicinal plants. The promising pharmacological properties of these plants have paved the way for developing therapy against novel Coronavirus (CoV) infection. The current review will summarize published works of literature on the effects of traditional Indian medicinal plants against acute respiratory infection (COVID‐19, SARS, Influenza, and Respiratory syncytial virus infection) and registered clinical trials of traditional Indian herbal medicines in COVID‐19. The current study aims to comprehensively evaluate the data of traditional Indian medicinal plants to warrant their use in COVID‐19 management. PubMed, Embase, and Cochrane databases were searched along with different clinical trial databases. A total of 22 relevant traditional Indian medicinal plants (35 relevant studies) were included in the current study having potential antiviral properties against virus‐induced respiratory illness along with promising immunomodulatory and thrombolytic properties. Further, 36 randomized and nonrandomized registered clinical trials were also included that were aimed at evaluating the efficacy of herbal plants or their formulations in COVID‐19 management. The antiviral, immunomodulatory, and thrombolytic activities of the traditional Indian medicinal plants laid down a strong rationale for their use in developing therapies against SARS‐CoV‐2 infection. The study identified some important potential traditional Indian medicinal herbs such as Ocimum tenuiflorum, Tinospora cordifolia, Achyranthes bidentata, Cinnamomum cassia, Cydonia oblonga, Embelin ribes, Justicia adhatoda, Momordica charantia, Withania somnifera, Zingiber officinale, Camphor, and Kabusura kudineer, which could be used in therapeutic strategies against SARS‐CoV‐2 infection.

Effectiveness of palivizumab in preventing respiratory syncytial virus infection in high-risk children

To date, there is no consensus regarding palivizumab prophylaxis for respiratory syncytial virus infection. The purpose of this study is to assess the effectiveness of palivizumab prophylaxis to prevent respiratory syncytial virus-related infection consultations and hospitalizations in high-risk children <2 y. We studied children <2 y of age with risk factors who had indication of palivizumab prophylaxis over eight epidemic seasons (2011-2012 to 2018-2019) in Navarra, Spain. Children positives for respiratory syncytial virus by reverse-transcription polymerase chain reaction were compared to negative testers. Palivizumab was indicated in 1,214 children <2 y of age with risk factors during 2011-2012 to 2018-2019 seasons. A total of 142 high-risk children tested for respiratory syncytial virus were included in the study. From the 35 respiratory syncytial virus-positive confirmed cases, 20 (57%) had received palivizumab versus 82 (77%) from the 107 negative controls. The effectiveness of prophylactic palivizumab was 70% (95% CI, 19%-90%) in preventing confirmed clinical infection and 82% (95% CI, 29%-96%) in preventing hospitalized cases. Our results show that palivizumab is notably effective for preventing laboratory-confirmed cases of respiratory syncytial virus and hospitalization in high-risk children <2 y of age. For children who have received palivizumab, the risk of getting sick remains high; thus, other preventive measures are necessary.

TRIM22 inhibits respiratory syncytial virus replication by targeting JAK-STAT1/2 signaling

Respiratory syncytial virus (RSV) infection is a major cause of lower respiratory tract disease. Although RSV causes major economic losses every year, effective treatments have not been found so far. Recent studies have shown that the tripartite motif-containing (TRIM) superfamily plays an essential role in the immune response. In this study, we found that TRIM22 had an inhibitory effect on RSV infection, and downregulation of TRIM22 moderately enhanced RSV replication. Our data further demonstrated that RSV infection induced TRIM22 expression through the activation of JAK-STAT1/2 signaling. RSV infection also induced TRIM22 expression. Taken together, these data points showed that the TRIM family member, TRIM22, had an essential role in resisting RSV infection, and this effect was closely related to the JAK-STAT1/2 pathway. Our results provide promising evidence for a novel target for the prevention and treatment of RSV.

Sendai Virus-Vectored Vaccines That Express Envelope Glycoproteins of Respiratory Viruses

Human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), and human parainfluenza viruses (HPIVs) are leading causes of respiratory disease in young children, the elderly, and individuals of all ages with immunosuppression. Vaccination strategies against these pneumoviruses and paramyxoviruses are vast in number, yet no licensed vaccines are available. Here, we review development of Sendai virus (SeV), a versatile pediatric vaccine that can (a) serve as a Jennerian vaccine against HPIV1, (b) serve as a recombinant vaccine against HRSV, HPIV2, HPIV3, and HMPV, (c) accommodate foreign genes for viral glycoproteins in multiple intergenic positions, (d) induce durable, mucosal, B-cell, and T-cell immune responses without enhanced immunopathology, (e) protect cotton rats, African green monkeys, and chimpanzees from infection, and (f) be formulated into a vaccine cocktail. Clinical phase I safety trials of SeV have been completed in adults and 3–6-year-old children. Clinical testing of SeVRSV, an HRSV fusion (F) glycoprotein gene recombinant, has also been completed in adults. Positive results from these studies, and collaborative efforts with the National Institutes of Health and the Serum Institute of India assist advanced development of SeV-based vaccines. Prospects are now good for vaccine successes in infants and consequent protection against serious viral disease.

Designing of Potential Polyvalent Vaccine Model for Respiratory Syncytial Virus by System Level Immunoinformatics Approaches

BACKGROUND

Respiratory syncytial virus (RSV) infection is a public health epidemic, leading to around 3 million hospitalization and about 66,000 deaths each year. It is a life-threatening condition exclusive to children with no effective treatment.

METHODS

In this study, we used system-level and vaccinomics approaches to design a polyvalent vaccine for RSV, which could stimulate the immune components of the host to manage this infection. Our framework involves data accession, antigenicity and subcellular localization analysis, T cell epitope prediction, proteasomal and conservancy evaluation, host-pathogen-protein interactions, pathway studies, and in silico binding affinity analysis.

RESULTS

We found glycoprotein (G), fusion protein (F), and small hydrophobic protein (SH) of RSV as potential vaccine candidates. Of these proteins (G, F, and SH), we found 9 epitopes for multiple alleles of MHC classes I and II bear significant binding affinity. These potential epitopes were linked to form a polyvalent construct using AAY, GPGPG linkers, and cholera toxin B adjuvant at N-terminal with a 23.9 kDa molecular weight of 224 amino acid residues. The final construct was a stable, immunogenic, and nonallergenic protein containing cleavage sites, TAP transport efficiency, posttranslation shifts, and CTL epitopes. The molecular docking indicated the optimum binding affinity of RSV polyvalent construct with MHC molecules (-12.49 and -10.48 kcal/mol for MHC classes I and II, respectively). This interaction showed that a polyvalent construct could manage and control this disease.

CONCLUSION

Our vaccinomics and system-level investigation could be appropriate to trigger the host immune system to prevent RSV infection.

Evolutionary analysis of human respiratory syncytial virus collected in Myanmar between 2015 and 2018

We studied genetic variation in the second hypervariable region (HVR) of the G gene of human respiratory syncytial virus (HRSV) from 1701 nasal swab samples collected from outpatients with acute respiratory infections at two general hospitals in the cities Yangon and Pyinmana in Myanmar from 2015 to 2018. HRSV genotypes were characterized using phylogenetic trees constructed using the maximum likelihood method. Time-scale phylogenetic tree analyses were performed using the Bayesian Markov chain Monte Carlo method. In total, 244 (14.3%) samples were HRSV-positive and were classified as HRSV-A (n = 84, 34.4%), HRSV-B (n = 158, 64.8%), and co-detection of HRSV-A/HRSV-B (n = 2, 0.8%). HRSV epidemics occurred seasonally between July (1.9%, 15/785) and August (10.5%, 108/1028), with peak infections in September (35.8%, 149/416) and October (58.2%, 89/153). HRSV infection rate was higher in children ≥1 year of age than in those <1 year of age (70.5% vs. 29.5%). The most common HRSV symptoms in children were cough (80%-90%) and rhinorrhea (70%-100%). The predominant genotypes were ON1for HRSV-A (78%) and BA9 for HRSV-B (64%). Time to the most recent common ancestor was 2014 (95% highest posterior density [HPD], 2012-2015) for HRSV-A ON1 and 2009 (95% HPD, 2004-2012) for HRSV-B BA9. The mean evolutionary rate (substitutions/site/year) for HRSV-B (2.12 × 10^-2, 95% HPD, 8.53 × 10^-3-3.63 × 10^-2) was slightly higher than that for HRSV-A (1.39 × 10^-2, 95% HPD, 6.03 × 10^-3-2.12 × 10^-2). The estimated effective population size (diversity) for HRSV-A increased from 2015 to 2016 and declined in mid-2018, whereas HRSV-B diversity was constant in 2015 and 2016 and increased in mid-2017. In conclusion, the dominant HRSV-A and HRSV-B genotypes in Myanmar were ON1 and BA9, respectively, between 2015 and 2018. HRSV-B evolved slightly faster than HRSV-A and exhibited unique phylogenetic characteristics.

Pediatric Infectious Disease Group (GPIP) position paper on the immune debt of the COVID-19 pandemic in childhood, how can we fill the immunity gap?

Since the beginning of the COVID-19 pandemic, reduced incidence of many viral and bacterial infections has been reported in children: bronchiolitis, varicella, measles, pertussis, pneumococcal and meningococcal invasive diseases. The purpose of this opinion paper is to discuss various situations that could lead to larger epidemics when the non-pharmaceutical interventions (NPI) imposed by the SARS-CoV-2 epidemic will no longer be necessary. While NPIs limited the transmission of SARS-CoV-2, they also reduced the spread of other pathogens during and after lockdown periods, despite the re-opening of schools since June 2020 in France. This positive collateral effect in the short term is welcome as it prevents additional overload of the healthcare system. The lack of immune stimulation due to the reduced circulation of microbial agents and to the related reduced vaccine uptake induced an "immunity debt" which could have negative consequences when the pandemic is under control and NPIs are lifted. The longer these periods of "viral or bacterial low-exposure" are, the greater the likelihood of future epidemics. This is due to a growing proportion of "susceptible" people and a declined herd immunity in the population. The observed delay in vaccination program without effective catch-up and the decrease in viral and bacterial exposures lead to a rebound risk of vaccine-preventable diseases. With a vaccination schedule that does not include vaccines against rotavirus, varicella, and serogroup B and ACYW Neisseria meningitidis, France could become more vulnerable to some of these rebound effects.

CX3CR1 Engagement by Respiratory Syncytial Virus Leads to Induction of Nucleolin and Dysregulation of Cilia-related Genes

Respiratory syncytial virus (RSV) contains a conserved CX3C motif on the ectodomain of the G-protein. The motif has been indicated as facilitating attachment of the virus to the host initiating infection via the human CX3CR1 receptor. The natural CX3CR1 ligand, CX3CL1, has been shown to induce signaling pathways resulting in transcriptional changes in the host cells. We hypothesize that binding of RSV to CX3CR1 via CX3C leads to transcriptional changes in host epithelial cells. Using transcriptomic analysis, the effect of CX3CR1 engagement by RSV was investigated. Normal human bronchial epithelial (NHBE) cells were infected with RSV virus containing either wildtype G-protein, or a mutant virus containing a CX4C mutation in the G-protein. RNA sequencing was performed on mock and 4-days-post-infected cultures. NHBE cultures were also treated with purified recombinant wild-type A2 G-protein. Here we report that RSV infection resulted in significant changes in the levels 766 transcripts. Many nuclear associated proteins were upregulated in the WT group, including nucleolin. Alternatively, cilia-associated genes, including CC2D2A and CFAP221 (PCDP1), were downregulated. The addition of recombinant G-protein to the culture lead to the suppression of cilia-related genes while also inducing nucleolin. Mutation of the CX3C motif (CX4C) reversed these effects on transcription decreasing nucleolin induction and lessening the suppression of cilia-related transcripts in culture. Furthermore, immunohistochemical staining demonstrated decreases in in ciliated cells and altered morphology. Therefore, it appears that engagement of CX3CR1 leads to induction of genes necessary for RSV entry as well as dysregulation of genes associated with cilia function.ImportanceRespiratory Syncytial Virus (RSV) has an enormous impact on infants and the elderly including increased fatality rates and potential for causing lifelong lung problems. Humans become infected with RSV through the inhalation of viral particles exhaled from an infected individual. These virus particles contain specific proteins that the virus uses to attach to human ciliated lung epithelial cells, initiating infection. Two viral proteins, G-protein and F-protein, have been shown to bind to human CX3CR1and nucleolin, respectively. Here we show that the G-protein induces nucleolin and suppresses gene transcripts specific to ciliated cells. Furthermore, we show that mutation of the CX3C-motif on the G-protein, CX4C, reverses these transcriptional changes.

Structural Insights into the Respiratory Syncytial Virus RNA Synthesis Complexes

RNA synthesis in respiratory syncytial virus (RSV), a negative-sense (-) nonsegmented RNA virus, consists of viral gene transcription and genome replication. Gene transcription includes the positive-sense (+) viral mRNA synthesis, 5'-RNA capping and methylation, and 3' end polyadenylation. Genome replication includes (+) RNA antigenome and (-) RNA genome synthesis. RSV executes the viral RNA synthesis using an RNA synthesis ribonucleoprotein (RNP) complex, comprising four proteins, the nucleoprotein (N), the large protein (L), the phosphoprotein (P), and the M2-1 protein. We provide an overview of the RSV RNA synthesis and the structural insights into the RSV gene transcription and genome replication process. We propose a model of how the essential four proteins coordinate their activities in different RNA synthesis processes.

Status of inhalable antimicrobial agents for lung infection: progress and prospects

Introduction: Available parenteral and oral administration of antimicrobial agents (AMAs) in respiratory infections often show less penetration into the lung parenchyma. Due to inappropriate dose availability, the rate of antibiotic resistance is increasing gradually. Inhaled antibiotics intensely improve the availability of drugs at the site of respiratory infections. This targeted delivery minimizes systemic exposure and associated toxicity.Area covers: This review was performed by searching in the scientific database like PubMed and several trusted government sites like fda.gov, cdc.gov, ClinicalTrials.gov, etc. For better understanding, AMAs are classified in different stages of approval. Mechanism and characterization of pulmonary drug deposition section helps to understand the effective delivery of AMAs to the respiratory tract. There is a need for proper adoption of delivery devices for inhalable AMAs. Thus, delivery devices are extensively explained. Inspiratory flow has a remarkable impact on the delivery device that has been explained in detail.Expert opinion: Pulmonary delivery restricts the bulk administration of drugs in comparison with other routes. Therefore, novel AMAs with higher bactericidal activity at lower concentrations need to be synthesized. Extensive research is indeed in developing innovative delivery devices that would able to deliver higher doses of AMAs through the pulmonary route.

Evaluation of Small Molecule Combinations against Respiratory Syncytial Virus In Vitro

Respiratory syncytial virus (RSV) is a major pathogen that causes severe lower respiratory tract infection in infants, the elderly and the immunocompromised worldwide. At present no approved specific drugs or vaccines are available to treat this pathogen. Recently, several promising candidates targeting RSV entry and multiplication steps are under investigation. However, it is possible to lead to drug resistance under the long-term treatment. Therapeutic combinations constitute an alternative to prevent resistance and reduce antiviral doses. Therefore, we tested in vitro two-drug combinations of fusion inhibitors (GS5806, Ziresovir and BMS433771) and RNA-dependent RNA polymerase complex (RdRp) inhibitors (ALS8176, RSV604, and Cyclopamine). The statistical program MacSynergy II was employed to determine synergism, additivity or antagonism between drugs. From the result, we found that combinations of ALS8176 and Ziresovir or GS5806 exhibit additive effects against RSV in vitro, with interaction volume of 50 µM²% and 31 µM²% at 95% confidence interval, respectively. On the other hand, all combinations between fusion inhibitors showed antagonistic effects against RSV in vitro, with volume of antagonism ranging from −50 µM² % to −176 µM² % at 95% confidence interval. Over all, our results suggest the potentially therapeutic combinations in combating RSV in vitro could be considered for further animal and clinical evaluations.

Recommendations for respiratory syncytial virus surveillance at national level

Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory tract infections and hospitalisations among young children and is globally responsible for many deaths in young children, especially in infants aged <6 months. Furthermore, RSV is a common cause of severe respiratory disease and hospitalisation among older adults. The development of new candidate vaccines and monoclonal antibodies highlights the need for reliable surveillance of RSV. In the European Union (EU), no up-to-date general recommendations on RSV surveillance are currently available. Based on outcomes of a workshop with 29 European experts in the field of RSV virology, epidemiology and public health, we provide recommendations for developing a feasible and sustainable national surveillance strategy for RSV that will enable harmonisation and data comparison at the European level. We discuss three surveillance components: active sentinel community surveillance, active sentinel hospital surveillance and passive laboratory surveillance, using the EU acute respiratory infection and World Health Organization (WHO) extended severe acute respiratory infection case definitions. Furthermore, we recommend the use of quantitative reverse transcriptase PCR-based assays as the standard detection method for RSV and virus genetic characterisation, if possible, to monitor genetic evolution. These guidelines provide a basis for good quality, feasible and affordable surveillance of RSV. Harmonisation of surveillance standards at the European and global level will contribute to the wider availability of national level RSV surveillance data for regional and global analysis, and for estimation of RSV burden and the impact of future immunisation programmes.

Recommendations for developing a feasible and sustainable national surveillance strategy for respiratory syncytial virus that will enable harmonisation and data comparison at the European level.https://bit.ly/3rWUOOI

Elucidation of the Host Bronchial Lymph Node miRNA Transcriptome Response to Bovine Respiratory Syncytial Virus

Bovine respiratory disease (BRD) causes substantial morbidity and mortality, affecting cattle of all ages. One of the main causes of BRD is an initial inflammatory response to bovine respiratory syncytial virus (BRSV). MicroRNAs are novel and emerging non-coding small RNAs that regulate many biological processes and are implicated in various inflammatory diseases. The objective of the present study was to elucidate the changes in the bovine bronchial lymph node miRNA transcriptome in response to BRSV following an experimental viral challenge. Holstein-Friesian calves were either administered a challenge dose of BRSV (103.5 TCID50/ml × 15 ml) (n = 12) or were mock inoculated with sterile phosphate buffered saline (n = 6). Daily scoring of clinical signs was performed and calves were euthanized at day 7 post-challenge. Bronchial lymph nodes were collected for subsequent RNA extraction and sequencing (75 bp). Read counts for known miRNAs were generated using the miRDeep2 package using the UMD3.1 reference genome and the bovine mature miRNA sequences from the miRBase database (release 22). EdgeR was used for differential expression analysis and Targetscan was used to identify target genes for the differentially expressed (DE) miRNAs. Target genes were examined for enriched pathways and gene ontologies using Ingenuity Pathway Analysis (Qiagen). Multi-dimensional scaling (MDS) based on miRNA gene expression changes, revealed a clearly defined separation between the BRSV challenged and control calves, although the clinical manifestation of disease was only mild. One hundred and nineteen DE miRNAs (P < 0.05, FDR < 0.1, fold change > 1.5) were detected between the BRSV challenged and control calves. The DE miRNAs were predicted to target 465 genes which were previously found to be DE in bronchial lymph node tissue, between these BRSV challenged and control calves. Of the DE predicted target genes, 455 had fold changes that were inverse to the corresponding DE miRNAs. There were eight enriched pathways among the DE predicted target genes with inverse fold changes to their corresponding DE miRNA including: granulocyte and agranulocyte adhesion and diapedesis, interferon signalling and role of pathogen recognition receptors in recognition of bacteria and viruses. Functions predicted to be increased included: T cell response, apoptosis of leukocytes, immune response of cells and stimulation of cells. Pathogen recognition and proliferation of cytotoxic T cells are vital for the recognition of the virus and its subsequent elimination.

Intervention Strategies for Seasonal and Emerging Respiratory Viruses with Drugs and Vaccines Targeting Viral Surface Glycoproteins

Vaccines and therapeutics targeting viral surface glycoproteins are a major component of disease prevention for respiratory viral diseases. Over the years, vaccines have proven to be the most successful intervention for preventing disease. Technological advances in vaccine platforms that focus on viral surface glycoproteins have provided solutions for current and emerging pathogens like SARS-CoV-2, and our understanding of the structural basis for antibody neutralization is guiding the selection of other vaccine targets for respiratory viruses like RSV. This review discusses the role of viral surface glycoproteins in disease intervention approaches.

Burden of noninfluenza respiratory viral infections in adults admitted to hospital: analysis of a multiyear Canadian surveillance cohort from 2 centres

BACKGROUND:

Data on the outcomes of noninfluenza respiratory virus (NIRV) infections among hospitalized adults are lacking. We aimed to study the burden, severity and outcomes of NIRV infections in this population.

METHODS:

We analyzed pooled patient data from 2 hospital-based respiratory virus surveillance cohorts in 2 regions of Canada during 3 consecutive seasons (2015/16, 2016/17, 2017/18; n = 2119). We included patients aged ≥ 18 years who developed influenza-like illness or pneumonia and were hospitalized for management. We included patients confirmed positive for ≥ 1 virus by multiplex polymerase chain reaction assays (respiratory syncytial virus [RSV], human rhinovirus/enterovirus (hRV), human coronavirus (hCoV), metapneumovirus, parainfluenza virus, adenovirus, influenza viruses). We compared patient characteristics, clinical severity conventional outcomes (e.g., hospital length-of stay, 30-day mortality) and ordinal outcomes (5 levels: discharged, receiving convalescent care, acute ward or intensive care unit [ICU] care and death) for patients with NIRV infections and those with influenza.

RESULTS:

Among 2119 adults who were admitted to hospital, 1156 patients (54.6%) had NIRV infections (hRV 14.9%, RSV 12.9%, hCoV 8.2%) and 963 patients (45.4%) had influenza (n = 963). Patients with NIRVs were younger (mean 66.4 [standard deviation 20.4] yr), and more commonly had immunocompromising conditions (30.3%) and delay in diagnosis (median 4.0 [interquartile range (IQR) 2.0–7.0] days). Overall, 14.6% (12.4%–19.5%) of NIRV infections were acquired in hospital. Admission to ICU (18.2%, median 6.0 [IQR 3.0–13.0] d), hospital length-of-stay (median 5.0 [IQR 2.0–10.0] d) and 30-day mortality (8.4%; RSV 9.5%, hRV 6.6%, hCoV 9.2%) and the ordinal outcomes were similar for patients with NIRV infection and those with influenza. Age > 60 years, immunocompromised state and hospital-acquired viral infection were associated with worse outcomes. The estimated median cost per acute care admission was $6000 (IQR $2000–$16 000).

INTERPRETATION:

The burden of NIRV infection is substantial in adults admitted to hospital and associated outcomes may be as severe as for influenza, suggesting a need to prioritize therapeutics and vaccines for at-risk people.

Molecular Characterization of Multidrug-resistant Bacteria Isolated From Patients With Pneumonia at Two Hospitals in North-West Nigeria

Background and aims: The spread of antimicrobial resistance (AMR) is a serious public health threat complicating treatment and resulting in prolonged hospitalization. The prevalence of AMR threat is not well defined due to the dearth of appropriate surveillance systems. This study sought to assess the prevalence of AMR among bacterial isolates from sputum specimens obtained from patients with pneumonia presenting at two secondary healthcare facilities in Zaria from June 1 to August 31, 2018. Methods: Standard methodology was followed in processing sputum samples that met the acceptance criteria. The antibiotic susceptibility patterns of bacterial pathogens cultured from sputum specimens obtained from June 1 to August 31, 2018) were evaluated using the recommendation of the Clinical and Laboratory Standards Institute. Finally, data were analyzed using descriptive statistics. Results: Acinetobacter spp. were the predominant pathogens accounting for 32% of recovered isolates, followed by Staphylococcus spp. (18%) and Klebsiella spp. (17%), respectively. AMR was found in 91% of the isolates. Most isolates were resistant to erythromycin (ERY) (80%) and amoxicillin (83.3%). Eventually, the multiple antibiotic resistance index ≥0.3 was observed in 76% of the isolates. Conclusion: Based on the findings, AMR rates were observed to be high, and may display a serious therapeutic challenge to the management of community-acquired pneumonia. Concerted efforts are needed to combat the worrisome AMR trends revealed in this study.

Streptococcus pneumoniae serotype 22F infection in respiratory syncytial virus infected neonatal lambs enhances morbidity

Respiratory syncytial virus (RSV) is the primary cause of viral bronchiolitis resulting in hospitalization and a frequent cause of secondary respiratory bacterial infection, especially by Streptococcus pneumoniae (Spn) in infants. While murine studies have demonstrated enhanced morbidity during a viral/bacterial co-infection, human meta-studies have conflicting results. Moreover, little knowledge about the pathogenesis of emerging Spn serotype 22F, especially the co-pathologies between RSV and Spn, is known. Here, colostrum-deprived neonate lambs were divided into four groups. Two of the groups were nebulized with RSV M37, and the other two groups were mock nebulized. At day three post-RSV infection, one RSV group (RSV/Spn) and one mock-nebulized group (Spn only) were inoculated with Spn intratracheally. At day six post-RSV infection, bacterial/viral loads were assessed along with histopathology and correlated with clinical symptoms. Lambs dually infected with RSV/Spn trended with higher RSV titers, but lower Spn. Additionally, lung lesions were observed to be more frequent in the RSV/Spn group characterized by increased interalveolar wall thickness accompanied by neutrophil and lymphocyte infiltration and higher myeloperoxidase. Despite lower Spn in lungs, co-infected lambs had more significant morbidity and histopathology, which correlated with a different cytokine response. Thus, enhanced disease severity during dual infection may be due to lesion development and altered immune responses rather than bacterial counts.

Structural basis for IFN antagonism by human respiratory syncytial virus nonstructural protein 2

Human respiratory syncytial virus (RSV) nonstructural protein 2 (NS2) inhibits host interferon (IFN) responses stimulated by RSV infection by targeting early steps in the IFN-signaling pathway. But the molecular mechanisms related to how NS2 regulates these processes remain incompletely understood. To address this gap, here we solved the X-ray crystal structure of NS2. This structure revealed a unique fold that is distinct from other known viral IFN antagonists, including RSV NS1. We also show that NS2 directly interacts with an inactive conformation of the RIG-I-like receptors (RLRs) RIG-I and MDA5. NS2 binding prevents RLR ubiquitination, a process critical for prolonged activation of downstream signaling. Structural analysis, including by hydrogen-deuterium exchange coupled to mass spectrometry, revealed that the N terminus of NS2 is essential for binding to the RIG-I caspase activation and recruitment domains. N-terminal mutations significantly diminish RIG-I interactions and result in increased IFNβ messenger RNA levels. Collectively, our studies uncover a previously unappreciated regulatory mechanism by which NS2 further modulates host responses and define an approach for targeting host responses.

Qingfei oral liquid inhibited autophagy to alleviate inflammation via mTOR signaling pathway in RSV-infected asthmatic mice

Qingfei oral liquid (QF) is a traditional Chinese medicine that has been used to treat patients with viral pneumonia and asthma for decades. Our previous study revealed that QF prevents airway inflammation and reduces airway hyperresponsiveness (AHR) in respiratory syncytial virus (RSV)-infected asthmatic mice. RSV infection can exacerbate asthma in pediatric patients and induce autophagy, which leads to the promotion of inflammatory cytokine production in the pathology of this disease. The effect of QF on regulating autophagy in RSV-infected asthma patients has not been fully elucidated. In this study, we identified compounds of QF by HPLC-DAD-Q-TOF-MS/MS. The RSV infected OVA challenged mice, we evaluated the RSV-infected asthma model. We found that treatment with QF alleviated airway inflammation and mitigated airway AHR in RSV-infected asthmatic mice. In addition, we found that QF inhibited autophagosome formation and the expression of LC3 protein by using electron and laser confocal microscopy, respectively, to assess RSV-infected asthmatic mice lung tissues. Furthermore, QF was found to reduce the quantity of autophagy and its related proteins LC3B (light chain 3B), Beclin-1, p62 and Atg5 (autophagy-related gene 5) and downstream inflammatory cytokines TNF-α, IL-4, IL-6, and IL-13 via an action in mTOR-dependent signaling in vivo and in vitro. These findings suggest that QF can alleviate the inflammation caused by RSV infection in asthmatic mice, and its mechanism may be involved in the regulation of autophagy via the mTOR signaling pathway.

Comparison of clinical characteristics and outcomes between respiratory syncytial virus and influenza-related pneumonia in China from 2013 to 2019

This study aims to compare clinical characteristics and severity between adults with respiratory syncytial virus (RSV-p) and influenza-related pneumonia (Flu-p). A total of 127 patients with RSV-p, 693 patients with influenza A-related pneumonia (FluA-p), and 386 patients with influenza B-related pneumonia (FluB-p) were retrospectively reviewed from 2013 through 2019 in five teaching hospitals in China. A multivariate logistic regression model indicated that age ≥ 50 years, cerebrovascular disease, chronic kidney disease, solid malignant tumor, nasal congestion, myalgia, sputum production, respiratory rates ≥ 30 beats/min, lymphocytes < 0.8×10⁹/L, and blood albumin < 35 g/L were predictors that differentiated RSV-p from Flu-p. After adjusting for confounders, a multivariate logistic regression analysis confirmed that, relative to RSV-p, FluA-p (OR 2.313, 95% CI 1.377–3.885, p = 0.002) incurred an increased risk for severe outcomes, including invasive ventilation, ICU admission, and 30-day mortality; FluB-p (OR 1.630, 95% CI 0.958–2.741, p = 0.071) was not associated with increased risk. Some clinical variables were useful for discriminating RSV-p from Flu-p. The severity of RSV-p was less than that of FluA-p, but was comparable to FluB-p.

Current State of Respiratory Syncytial Virus Disease and Management

Respiratory syncytial virus (RSV) is a major cause of hospitalizations due to pneumonia and bronchiolitis. Substantial morbidity and socioeconomic burden are associated with RSV infection worldwide. Populations with higher susceptibility to developing severe RSV include premature infants, children with chronic lung disease of prematurity (CLDP) or congenital heart disease (CHD), elderly individuals aged > 65 years, and immunocompromised individuals. In the pediatric population, RSV can lead to long-term sequelae such as wheezing and asthma, which are associated with increased health care costs and reduced quality of life. Treatment for RSV is mainly supportive, and general preventive measures such as good hygiene and isolation are highly recommended. Although vaccine development for RSV has been a global priority, attempts to date have failed to yield a safe and effective product for clinical use. Currently, palivizumab is the only immunoprophylaxis (IP) available to prevent severe RSV in specific high-risk pediatric populations. Well-controlled, randomized clinical trials have established the efficacy of palivizumab in reducing RSV hospitalization (RSVH) in high-risk infants including moderate- to late-preterm infants. However, the American Academy of Pediatrics (AAP), in its 2014 policy, stopped recommending RSV IP use for ≥ 29 weeks' gestational age infants. Revisions to the AAP policy for RSV IP have largely narrowed the proportion of pediatric patients eligible to receive RSV IP and have been associated with an increase in RSVH and morbidity. On the other hand, after reviewing the recent evidence on RSV burden, the National Perinatal Association, in its 2018 clinical practice guidelines, recommended RSV IP use for a wider pediatric population. As the AAP recommendations drive insurance reimbursements for RSV IP, they should be revised to help further mitigate RSV disease burden.

Socioeconomic Impact of RSV Hospitalization

Respiratory syncytial virus (RSV) disease is a significant cause of morbidity and socioeconomic burden worldwide among young children. The majority of RSV-associated lower respiratory tract infections (LRTI) and mortality occurs in developing countries and is associated with various sociodemographic risk factors. Independent risk factors for severe RSV disease include age and premature birth. While RSV mortality in developed countries is lower relative to developing countries, high-risk infants with comorbidities experience higher rates of mortality. RSV LRTI is often severe and is associated with hospitalization, increased need for intensive care unit admission and mechanical ventilation, long-term complications, and caregiver stress and loss of work productivity. Overall, these factors translate to higher health care resource utilization and costs and should be factored into the consideration for RSV prophylaxis. Multiple vaccine candidates and long-acting monoclonal antibodies are in various stages of clinical development. Currently, palivizumab is the only approved RSV immunoprophylaxis available for use in specific high-risk pediatric populations. This review will discuss the socioeconomic impact and health care resource utilization of RSV-related hospitalization (RSVH) as well as various sociodemographic risk factors that can be used to identify children at high risk of developing severe RSV disease.

Thrombocytopenia in Virus Infections

Thrombocytopenia, which signifies a low platelet count usually below 150 × 10⁹/L, is a common finding following or during many viral infections. In clinical medicine, mild thrombocytopenia, combined with lymphopenia in a patient with signs and symptoms of an infectious disease, raises the suspicion of a viral infection. This phenomenon is classically attributed to platelet consumption due to inflammation-induced coagulation, sequestration from the circulation by phagocytosis and hypersplenism, and impaired platelet production due to defective megakaryopoiesis or cytokine-induced myelosuppression. All these mechanisms, while plausible and supported by substantial evidence, regard platelets as passive bystanders during viral infection. However, platelets are increasingly recognized as active players in the (antiviral) immune response and have been shown to interact with cells of the innate and adaptive immune system as well as directly with viruses. These findings can be of interest both for understanding the pathogenesis of viral infectious diseases and predicting outcome. In this review, we will summarize and discuss the literature currently available on various mechanisms within the relationship between thrombocytopenia and virus infections.