New therapies for acute RSV infections: where are we?

Intranasal antivirals against respiratory syncytial virus: the current therapeutic development landscape

INTRODUCTION

Respiratory syncytial virus (RSV) causes bronchiolitis and other respiratory issues in immunocompromised individuals, the elderly, and children. After six decades of research, we have only recently seen the approval of two RSV vaccines, Arexvy and Abrysvo. Direct-acting antivirals against RSV have been more difficult to develop with ribavirin and palivizumab giving very modest reductions in hospitalizations and no differences in mortality. Recently, nirsevimab was licensed and has proven to be much more effective when given prophylactically. These are delivered intravenously (IV) and intramuscularly (IM), but an intranasal (IN) antiviral has several advantages in terms of ease of use, lower resource need, and acting at the site of infection.

AREAS COVERED

In this paper, we review the available literature on the current pre-clinical research landscape of anti-RSV therapeutics tested for IN delivery.

EXPERT OPINION

As RSV is a respiratory virus that infects both the upper and lower respiratory tracts, efforts are focused on developing a therapeutic that can be delivered via the nasal route. The rationale is to directly target the replicating virus with an obvious respiratory tract tropism. This approach will not only pave the way for a nasal delivery approach aimed at reducing respiratory viral illness but also controlling aerosol virus transmission.

The in vitro and in vivo antiviral effects of IGF1R inhibitors against respiratory syncytial virus infection

The insulin-like growth factor 1 receptor (IGF1R) was recognized as a pivotal receptor that facilitated the cellular entry of RSV. Small molecule inhibitors designed to target IGF1R exhibited potential as potent antiviral agents. Through virtual screening, we conducted a screening process involving small molecule compounds derived from natural products, aiming to target the IGF1R protein against respiratory syncytial virus infection. The molecular dynamics simulation analysis showed that tannic acid and daptomycin interacted with the IGF1R. The experimental results in vivo and in vitro showed that tannic acid and daptomycin had anti-RSV infection potential through reducing viral loads, inflammation, airway resistance and protecting alveolar integrity. The CC50 values of tannic acid and daptomycin were 6 nM and 0.45 μM, respectively. Novel small-molecule inhibitors targeting the IGF1R, tannic acid and daptomycin, may be effective anti-RSV therapy agents. This study may in future broaden the arsenal of therapeutics for use against RSV infection and lead to more effective care against the virus.Communicated by Ramaswamy H. Sarma.

Prevention and Potential Treatment Strategies for Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is a significant viral pathogen that causes respiratory infections in infants, the elderly, and immunocompromised individuals. RSV-related illnesses impose a substantial economic burden worldwide annually. The molecular structure, function, and in vivo interaction mechanisms of RSV have received more comprehensive attention in recent times, and significant progress has been made in developing inhibitors targeting various stages of the RSV replication cycle. These include fusion inhibitors, RSV polymerase inhibitors, and nucleoprotein inhibitors, as well as FDA-approved RSV prophylactic drugs palivizumab and nirsevimab. The research community is hopeful that these developments might provide easier access to knowledge and might spark new ideas for research programs.

Current state and challenges in respiratory syncytial virus drug discovery and development

Human respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTI) in young children and elderly people worldwide. Recent significant progress in our understanding of the structure and function of RSV proteins has led to the discovery of several clinical candidates targeting RSV fusion and replication. These include both the development of novel small molecule interventions and the isolation of potent monoclonal antibodies. In this review, we summarize the state-of-the-art of RSV drug discovery, with a focus on the characteristics of the candidates that reached the clinical stage of development. We also discuss the lessons learned from failed and discontinued clinical developments and highlight the challenges that remain for development of RSV therapies.

Andrographolide Attenuates RSV-induced Inflammation by Suppressing Apoptosis and Promoting Pyroptosis after Respiratory Syncytial Virus Infection In Vitro

BACKGROUND

Respiratory syncytial virus (RSV), which is the predominant viral pathogen responsible for causing acute lower respiratory tract infections in children, currently lacks specific therapeutic drugs. Despite andrographolide's demonstrated effectiveness against various viral infections, its effects on RSV infection remain unclear.

METHODS

In this study, RSV infection and andrographolide-intervened A549 cell lines were used. The virus load of RSV and the levels of IL-6 and IL-8 in the cell supernatant were quantified. The potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were analyzed using the Gene Expression Omnibus (GEO) database and the PharmMapper Database, and the changes in mRNA expression of these target genes were measured. To further illustrate the effect of andrographolide on the death pattern of RSV-infected airway epithelial cells, Annexin V-FITC/PI apoptosis assays and Western blotting were conducted.

RESULTS

Andrographolide decreased the viral load and attenuated IL-6 and IL-8 levels in cell supernatant post-RSV infection. A total of 25 potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were discovered, and CASP1, CCL5, JAK2, and STAT1 were identified as significant players. Andrographolide noticeably suppressed the increased mRNA expressions of these genes post-RSV infection as well as IL-1β. The flow cytometry analysis demonstrated that andrographolide alleviated apoptosis in RSV-infected cells. Additionally, RSV infection decreased the protein levels of caspase-1, cleaved caspase-1, cleaved IL-1β, N-terminal of GSDMD, and Bcl-2. Conversely, andrographolide increased their levels.

CONCLUSION

These results suggest that andrographolide may reduce RSV-induced inflammation by suppressing apoptosis and promoting pyroptosis in epithelial cells, leading to effective viral clearance.

RSV Burden and Its Impact on Pediatric Inpatient Bed Occupancy in Belgium: An Analysis of National Hospital Claims Data

BACKGROUND

Respiratory syncytial virus (RSV) infections represent a substantial burden on pediatric services during winter. While the morbidity and financial burden of RSV are well studied, less is known about the organizational impact on hospital services (ie, impact on bed capacity and overcrowding and variation across hospitals).

METHODS

Retrospective analysis of the population-wide Belgian Hospital Discharge Data Set for the years 2017 and 2018 (including all hospital sites with pediatric inpatient services), covering all RSV-associated (RSV-related International Classification of Diseases, 10th Version, Clinical Modification diagnoses) inpatient hospitalization by children under 5 years old as well as all-cause acute hospitalizations in pediatric wards.

RESULTS

RSV hospitalizations amount to 68.3 hospitalizations per 1000 children less than 1 year and 5.0 per 1000 children 1-4 years of age and are responsible for 20%-40% of occupied beds during the peak period (November-December). The mean bed occupancy rate over the entire year (2018) varies across hospitals from 22.8% to 85.1% and from 30.4% to 95.1% during the peak period. Small-scale pediatric services (<25 beds) are more vulnerable to the volatility of occupancy rates. Forty-six hospital sites have daily occupancy rates above 100% (median of 9 days). Only in 1 of 23 geographically defined hospital networks these high occupancy rates are on the same calendar days.

CONCLUSIONS

Pediatric services tend to be over-dimensioned to deal with peak activity mainly attributable to RSV. RSV immunization can substantially reduce pediatric capacity requirements. Enhanced collaboration in regional networks is an alternative strategy to deal with peaks and reduce capacity needs.

A pilot phase 2a, randomized, double-blind, placebo-controlled study to explore the antiviral activity, clinical outcomes, safety, and tolerability of rilematovir at two dose levels in non-hospitalized adults with respiratory syncytial virus infection

OBJECTIVES

To assess the antiviral effect, clinical outcomes, and safety of the respiratory syncytial virus (RSV) fusion inhibitor rilematovir in non-hospitalized RSV-infected adults.

METHODS

This phase 2a, double-blind, multicentre study randomly assigned RSV-positive adult outpatients ≤5 days from symptom onset 1:1:1 to receive rilematovir 500 mg, 80 mg, or placebo once-daily for 7 days. Antiviral effect was assessed by RSV RNA viral load (VL), measured by quantitative RT-PCR, and Kaplan-Meier (KM) estimates of time to undetectable VL. Clinical course was assessed by KM estimates of median time to resolution of key RSV symptoms assessed through patient-reported outcomes.

RESULTS

RSV-positive patients (n = 72) were randomly assigned; 66 had confirmed RSV infection and received rilematovir 500 mg (n = 23), 80 mg (n = 21) or placebo (n = 22). Differences versus placebo in mean RSV RNA VL area under the curve (90% CI) through days 3, 5 and 8, respectively, were 0.09 (-0.837; 1.011), -0.10 (-2.171; 1.963), and -1.03 (-4.746; 2.682) log10 copies.day/mL for rilematovir 500 mg, and 1.25 (0.291; 2.204), 2.53 (0.430; 4.634), and 3.85 (0.097; 7.599) log10 copies.day/mL for rilematovir 80 mg. KM estimates of median (90% CI) time-to-first confirmed undetectable VL were 5.9 (3.85; 6.90), 8.0 (6.86; 12.80) and 7.0 (6.62; 10.88) days and 5.7 (2.93; 7.01), 8.1 (6.74; 12.80) and 7.9 (6.62; 11.74) days in patients with symptom onset ≤3 days, for rilematovir 500 mg, 80 mg, and placebo, respectively. KM estimates of median (90% CI) time to resolution of key RSV symptoms were 7.1 (5.03; 11.43), 7.6 (5.93; 8.32), and 9.6 (5.95; 14.00) days for rilematovir 500 mg, 80 mg, and placebo, respectively; and in patients with symptom onset ≤3 days, median 8.0, 7.6, and 11.8 days, respectively.

DISCUSSION

Rilematovir use, initiated early, suggests a potential clinical benefit in RSV-infected adults, with data supporting development of RSV therapeutic options.

TRIAL REGISTRATION

This study is registered with clinicaltrials.gov (NCT03379675).

Respiratory Syncytial Virus Infections in Polish Pediatric Patients from an Expert Perspective

Respiratory syncytial virus (RSV) is the most common pathogen causing respiratory tract infections in infants, affecting over 90% of children within the first two years of life. It may cause lower respiratory tract infections, which constitute a significant healthcare burden both in the primary and secondary care settings. Meanwhile, the data regarding RSV disease in Poland is scarce, and published data significantly differs from the numbers reported for other countries with longstanding surveillance and reporting systems. A literature review and an expert panel were conducted to (1) understand the healthcare burden of RSV infections in Poland; (2) collect data on infection seasonality, patient pathway, and management patterns; and (3) evaluate RSV infection surveillance in Poland. According to the literature, RSV is the major agent responsible for non-influenza respiratory diseases in Poland. The reported rates of hospitalization for RSV infections are 267.5/100,000 for children under 5 years of age and 1132.1/100,000 for those under 1 year of age. Comparisons with data from other countries suggest that these values may be underestimated, possibly due to insufficient access to microbiological testing and a low awareness of RSV. Infections occur mainly between December and April, however, this pattern has changed following the implementation of preventive measures for coronavirus disease 2019 in the past few years. According to available reports, bronchodilators, antibiotics, corticosteroids, and X-ray imaging have been frequently used. The surveillance system in Poland has limitations, but these may be overcome due to recent changes in healthcare law as well as the availability and reimbursement of diagnostic tests.

The convergent evolution of influenza A virus: Implications, therapeutic strategies and what we need to know

Influenza virus infection, more commonly known as the 'cold flu', is an etiological agent that gives rise to recurrent annual flu and many pandemics. Dated back to the 1918- Spanish Flu, the influenza infection has caused the loss of many human lives and significantly impacted the economy and daily lives. Influenza virus can be classified into four different genera: influenza A-D, with the former two, influenza A and B, relevant to humans. The capacity of antigenic drift and shift in Influenza A has given rise to many novel variants, rendering vaccines and antiviral therapies useless. In light of the emergence of a novel betacoronavirus, the SARS-CoV-2, unravelling the underpinning mechanisms that support the recurrent influenza epidemics and pandemics is essential. Given the symptom similarities between influenza and covid infection, it is crucial to reiterate what we know about the influenza infection. This review aims to describe the origin and evolution of influenza infection. Apart from that, the risk factors entail the implication of co-infections, especially regarding the COVID-19 pandemic is further discussed. In addition, antiviral strategies, including the potential of drug repositioning, are discussed in this context. The diagnostic approach is also critically discussed in an effort to understand better and prepare for upcoming variants and potential influenza pandemics in the future. Lastly, this review encapsulates the challenges in curbing the influenza spread and provides insights for future directions in influenza management.

DTX3L Enhances Type I Interferon Antiviral Response by Promoting the Ubiquitination and Phosphorylation of TBK1

Studies already revealed that some E3 ubiquitin ligases participated in the immune response after viral infection by regulating the type I interferon (IFN) pathway. Here, we demonstrated that type I interferon signaling enhanced the translocation of ETS1 to the nucleus and the promoter activity of E3 ubiquitin ligase DTX3L (deltex E3 ubiquitin ligase 3L) after virus infection and thus increased the expression of DTX3L. Further experiments suggested that DTX3L ubiquitinated TBK1 at K30 and K401 sites on K63-linked ubiquitination pathway. DTX3L was also necessary for mediating the phosphorylation of TBK1 through binding with the tyrosine kinase SRC: both together enhanced the activation of TBK1. Therefore, DTX3L, being an important positive-feedback regulator of type I interferon, exerted a key role in antiviral response. IMPORTANCE Our present study evaluated DTX3L as an antiviral molecule by promoting IFN production and establishing an IFN-β-ETS1-DTX3L-TBK1 positive-feedback loop as a novel immunomodulatory step to enhance interferon signaling and inhibit respiratory syncytial virus (RSV) infection. Our finding enriches and complements the biological function of DTX3L and provides a new strategy to protect against lung diseases such as bronchiolitis and pneumonia that develop with RSV.

Worldwide research trends on bronchiolitis in pediatrics

BACKGROUND

The COVID-19 pandemic has led to a significant increase in cases of bronchiolitis among children. As a result, there has been a corresponding increase in the number of publications on this topic. It is essential to examine the main areas of focus within the scientific literature to understand the current trends in research on pediatric bronchiolitis. This research aims to analyze the types of scientific advances related to pediatric bronchiolitis, the research trends being pursued, and the countries and research institutions leading these efforts. By understanding these aspects of bronchiolitis research, we can better understand the current state of knowledge and identify areas where further research is needed.

METHODS

To conduct a bibliometric analysis of the scientific literature on pediatric bronchiolitis, all relevant publications were retrieved from the Scopus database. The Scopus API and the SW VosViewer software with optimized modularity functions were used. This analysis was intended to provide a comprehensive overview of the current state of research on this topic, including the types of scientific advances being developed, the research trends being pursued, and the countries and research institutions leading these efforts.

RESULTS

A total of 3810 publications were reviewed. We observed an increasing number of publications, particularly in recent years. Of these, 73.7% were articles, 95% were written in English, and 29.4% were from the United States. The main keywords used in these publications included: human, bronchiolitis, child, preschool, preschool child, major clinical study, controlled study, pneumonia, asthma, adolescent, hospitalization, infant, and newborn. These keywords were grouped into six clusters: outpatient management, long-term consequences, etiology, intensive care management, diagnostic methods, and the main cluster, which focused on hospital treatment and clinical studies.

CONCLUSIONS

The bibliometric analysis of bronchiolitis research in pediatrics reveals that there has been a significant increase in the number of publications on this topic, particularly in recent years. Most of these publications are articles written in English and published in the United States. The main keywords used in these studies relate to various aspects of bronchiolitis, including diagnosis, treatment, and long-term consequences. The results of this analysis suggest that bronchiolitis is a topic of significant interest and concern for researchers and practitioners in the field of pediatrics and that further research is needed to improve our understanding and management of this condition.

Respiratory Syncytial Virus Infection: Treatments and Clinical Management

Respiratory syncytial virus (RSV) is a major healthcare concern, especially for immune-compromised individuals and infants below 5 years of age. Worldwide, it is known to be associated with incidences of morbidity and mortality in infants. Despite the seriousness of the issue and continuous rigorous scientific efforts, no approved vaccine or available drug is fully effective against RSV. The purpose of this review article is to provide insights into the past and ongoing efforts for securing effective vaccines and therapeutics against RSV. The readers will be able to confer the mechanism of existing therapies and the loopholes that need to be overcome for future therapeutic development against RSV. A methodological approach was applied to collect the latest data and updated results regarding therapeutics and vaccine development against RSV. We outline the latest throughput vaccination technologies and prophylactic development efforts linked with RSV. A range of vaccination approaches with the already available vaccine (with limited use) and those undergoing trials are included. Moreover, important drug regimens used alone or in conjugation with adjuvants or vaccines are also briefly discussed. After reading this article, the audience will be able to understand the current standing of clinical management in the form of the vaccine, prophylactic, and therapeutic candidates against RSV. An understanding of the biological behavior acting as a reason behind the lack of effective therapeutics against RSV will also be developed. The literature indicates a need to overcome the limitations attached to RSV clinical management, drugs, and vaccine development that could be explained by dealing with the challenges of current study designs with continuous improvement and further work and approval on novel therapeutic applications.

The burden and surveillance of RSV disease in young children in Belgium-expert opinion

Infections with respiratory syncytial virus (RSV) can cause severe disease. In young children, RSV is the most common cause of lower respiratory tract illness and life-threatening infections most commonly occur in the first years of life. In adults, elderly and immunocompromised people are most vulnerable. Recently there has been an acceleration in the development of candidate RSV vaccines, monoclonal antibodies and therapeutics which are expected to become available in Europe within the next 2-10 years. Understanding the true burden of childhood RSV disease will become very important to support public health authorities and policy makers in the assessment of new therapeutic opportunities against RSV disease. A systematic literature search was performed to map local data on the burden of RSV disease and to evaluate available RSV surveillance systems. A group of 9 paediatric infectious diseases specialists participated in an expert panel. The purpose of this meeting was to evaluate and map the burden associated with RSV infection in children, including patient pathways and the epidemiological patterns of virus circulation in Belgium. Sources of information on the burden of RSV disease in Belgium are very limited. For the outpatient setting, it is estimated that 5-10% of young patients seen in primary care are referred to the hospital. Around 3500 children between 0 and 12 months of age are hospitalized for RSV-bronchiolitis every year and represent the majority of all hospitalizations. The current Belgian RSV surveillance system was evaluated and found to be insufficient. Knowledge gaps are highlighted and future perspectives and priorities offered.

CONCLUSION

The Belgian population-based RSV surveillance should be improved, and a hospital-led reporting system should be put in place to enable the evaluation of the true burden of RSV disease in Belgium and to improve disease management in the future.

WHAT IS KNOWN

• RSV bronchiolitis is a very important cause of infant hospitalization. • The burden of disease in the community is poorly studied and underestimated.

WHAT IS NEW

• This expert opinion summarizes knowledge gaps and offers insights that allow improvement of local surveillance systems in order to establish a future-proof RSV surveillance system.

The continuing need for therapeutic agents for respiratory syncytial virus infection

Respiratory syncytial virus infections recur throughout life despite induction of immunity by the first natural infection. An effective vaccine has long been sought but no vaccine is currently licensed, although promising candidates are currently being developed based on greater knowledge of the virus properties. However, there are significant populations that may not be protected adequately by a vaccine or are unable to be vaccinated. Thus, there is a continued need for effective therapeutic agents to treat the infection, especially in higher-risk individuals, a perspective presented in this article.

Immunity Cell Responses to RSV and the Role of Antiviral Inhibitors: A Systematic Review

Antigen-presenting cells recognize respiratory syncytial virus antigens, and produce cytokines and chemokines that act on immune cells. Dendritic cells play the main role in inflammatory cytokine responses. Similarly, alveolar macrophages produce IFN-β, IFN-α, TNF-α, IL-6, CXCL10, and CCL3, while alternatively activated macrophages differentiate at the late phase, and require IL-13 or IL-4 cytokines. Furthermore, activated NKT cells secrete IL-13 and IL-4 that cause lung epithelial, endothelial and fibroblasts to secrete eotaxin that enhances the recruitment of eosinophil to the lung. CD8⁺ and CD4⁺T cells infection by the virus decreases the IFN-γ and IL-2 production. Despite this, both are involved in terminating virus replication. CD8⁺T cells produce a larger amount of IFN-γ than CD4⁺T cells, and CD8⁺T cells activated under type 2 conditions produce IL-4, down regulating CD8 expression, granzyme and IFN-γ production. Antiviral inhibitors inhibit biological functions of viral proteins. Some of them directly target the virus replication machinery and are effective at later stages of infection; while others inhibit F protein dependent fusion and syncytium formation. TMC353121 reduces inflammatory cytokines, TNF-α, IL-6, and IL-1β and chemokines, KC, IP-10, MCP and MIP1-α. EDP-938 inhibits viral nucleoprotein (N), while GRP-156784 blocks the activity of respiratory syncytial virus ribonucleic acid (RNA) polymerase. PC786 inhibits non-structural protein 1 (NS-1) gene, RANTES transcripts, virus-induced CCL5, IL-6, and mucin increase. In general, it is an immune reaction that is blamed for the disease severity and pathogenesis in respiratory syncytial virus infection. Anti-viral inhibitors not only inhibit viral entry and replication, but also may reduce inflammatory cytokines and chemokines. Many respiratory syncytial virus inhibitors are proposed; however, only palivizumab and ribavirin are approved for prophylaxis and treatment, respectively. Hence, this review is focused on immunity cell responses to respiratory syncytial virus and the role of antiviral inhibitors.

Airway Epithelial Cell Junctions as Targets for Pathogens and Antimicrobial Therapy

Intercellular contacts between epithelial cells are established and maintained by the apical junctional complexes (AJCs). AJCs conserve cell polarity and build epithelial barriers to pathogens, inhaled allergens, and environmental particles in the respiratory tract. AJCs consist of tight junctions (TJs) and adherens junctions (AJs), which play a key role in maintaining the integrity of the airway barrier. Emerging evidence has shown that different microorganisms cause airway barrier dysfunction by targeting TJ and AJ proteins. This review discusses the pathophysiologic mechanisms by which several microorganisms (bacteria and viruses) lead to the disruption of AJCs in airway epithelial cells. We present recent progress in understanding signaling pathways involved in the formation and regulation of cell junctions. We also summarize the potential chemical inhibitors and pharmacological approaches to restore the integrity of the airway epithelial barrier. Understanding the AJCs-pathogen interactions and mechanisms by which microorganisms target the AJC and impair barrier function may further help design therapeutic innovations to treat these infections.

Species-specific transcriptomic changes upon respiratory syncytial virus infection in cotton rats

The cotton rat (Sigmodon) is the gold standard pre-clinical small animal model for respiratory viral pathogens, especially for respiratory syncytial virus (RSV). However, without a reference genome or a published transcriptome, studies requiring gene expression analysis in cotton rats are severely limited. The aims of this study were to generate a comprehensive transcriptome from multiple tissues of two species of cotton rats that are commonly used as animal models (Sigmodon fulviventer and Sigmodon hispidus), and to compare and contrast gene expression changes and immune responses to RSV infection between the two species. Transcriptomes were assembled from lung, spleen, kidney, heart, and intestines for each species with a contig N50 > 1600. Annotation of contigs generated nearly 120,000 gene annotations for each species. The transcriptomes of S. fulviventer and S. hispidus were then used to assess immune response to RSV infection. We identified 238 unique genes that are significantly differentially expressed, including several genes implicated in RSV infection (e.g., Mx2, I27L2, LY6E, Viperin, Keratin 6A, ISG15, CXCL10, CXCL11, IRF9) as well as novel genes that have not previously described in RSV research (LG3BP, SYWC, ABEC1, IIGP1, CREB1). This study presents two comprehensive transcriptome references as resources for future gene expression analysis studies in the cotton rat model, as well as provides gene sequences for mechanistic characterization of molecular pathways. Overall, our results provide generalizable insights into the effect of host genetics on host-virus interactions, as well as identify new host therapeutic targets for RSV treatment and prevention.

Epidemiological and clinical characteristics of infections with seasonal human coronavirus and respiratory syncytial virus in hospitalized children immediately before the coronavirus disease 2019 pandemic

INTRODUCTION

Seasonal human coronavirus (HCoV)-229E, -NL63, -OC43, and -HKU1 are seasonal coronaviruses that cause colds in humans. However, the clinical characteristics of pediatric inpatients infected with HCoVs are unclear. This study aimed to compare and clarify the epidemiological and clinical features of HCoVs and respiratory syncytial virus (RSV), which commonly causes severe respiratory infections in children.

METHODS

Nasopharyngeal swabs were collected from all pediatric inpatients with respiratory symptoms at two secondary medical institutions in Fukushima, Japan. Eighteen respiratory viruses, including RSV and four HCoVs, were detected via reverse transcription-polymerase chain reaction.

RESULTS

Of the 1757 specimens tested, viruses were detected in 1272 specimens (72.4%), with 789 single (44.9%) and 483 multiple virus detections (27.5%). RSV was detected in 639 patients (36.4%) with no difference in clinical characteristics between RSV-A and RSV-B. HCoV was detected in 84 patients (4.7%): OC43, NL63, HKU1, and 229E in 25 (1.4%), 26 (1.5%), 23 (1.3%), and 16 patients (0.9%), respectively. Patients with HCoV monoinfection (n = 35) had a significantly shorter period from onset to hospitalization (median [interquartile range] days, 2 [1-4.5] vs. 4 [2-5]), significantly shorter hospitalization stays (4 [3-5] vs. 5 [4-6]), and more cases of upper respiratory infections (37.1% vs. 3.9%) and croup (17.1% vs. 0.3%) but less cases of lower respiratory infection (54.3% vs. 94.8%) than patients with RSV monoinfection (n = 362).

CONCLUSION

Seasonal HCoV-infected patients account for approximately 5% of children hospitalized for respiratory tract infections and have fewer lower respiratory infections and shorter hospital stays than RSV-infected patients.

Inhaled siRNA Formulations for Respiratory Diseases: From Basic Research to Clinical Application

The development of siRNA technology has provided new opportunities for gene-specific inhibition and knockdown, as well as new ideas for the treatment of disease. Four siRNA drugs have already been approved for marketing. However, the instability of siRNA in vivo makes systemic delivery ineffective. Inhaled siRNA formulations can deliver drugs directly to the lung, showing great potential for treating respiratory diseases. The clinical applications of inhaled siRNA formulations still face challenges because effective delivery of siRNA to the lung requires overcoming the pulmonary and cellular barriers. This paper reviews the research progress for siRNA inhalation formulations for the treatment of various respiratory diseases and summarizes the chemical structural modifications and the various delivery systems for siRNA. Finally, we conclude the latest clinical application research for inhaled siRNA formulations and discuss the potential difficulty in efficient clinical application.

Integrated Trinity Test With RPA-CRISPR/Cas12a-Fluorescence for Real-Time Detection of Respiratory Syncytial Virus A or B

Respiratory syncytial virus (RSV) is a common virus that causes respiratory infection, especially severe respiratory infection in infants and young children, the elderly people over 65 years old, and people with weak immunity. Currently, RSV infection has no effective vaccine and antiviral treatment. The number of deaths due to RSV infection increases every year. Moreover, RSV A infection occurs in a large number and has severe clinical symptoms and complications than RSV B infection. Therefore, the development of a simple, rapid, and inexpensive detection method with high amplification efficiency, high sensitivity, and specificity is very important for the diagnosis of RSV A or RSV B infection, which can help in the early clinical medication and prevent the progress of the disease. Therefore, we developed an integrated trinity test with an RPA-CRISPR/Cas12a-fluorescence (termed IT-RAISE) assay system to detect RSV A or RSV B. The characteristic of the IT-RAISE system is that after target recognition, the reporter single-stranded DNA (ssDNA) is cleaved by Cas12a that is activated by different crRNAs to detect the generated fluorescent signal. This method is simple and helps in adding all reagents rapidly. It is a high-sensitive method that can detect 1.38 × 10¹ copies/μl of the target sequences, and it can distinguish RSV A or RSV B infection within 37 min. In addition, clinical specimens were detected for IT-RAISE system. It was found that the sensitivity and specificity of RSV A were 73.08 and 90%, respectively, and those of RSV B were 42.86 and 93.33%, respectively. The cost of ONE specimen for IT-RAISE system was approximately $ 2.6 (excluding rapid RNA extraction and reverse transcription costs). IT-RAISE system has good clinical application prospects for detecting RSV A or RSV B infection; it is a simple, rapid, and inexpensive method with high amplification efficiency, high sensitivity, and high specificity. The IT-RAISE system might also detect other viral or bacterial infections.

Which outcomes should be used in future bronchiolitis trials? Developing a bronchiolitis core outcome set using a systematic review, Delphi survey and a consensus workshop

OBJECTIVES

The objective of this study was to develop a core outcome set (COS) for use in future clinical trials in bronchiolitis. We wanted to find out which outcomes are important to healthcare professionals (HCPs) and to parents and which outcomes should be prioritised for use in future clinical trials.

DESIGN AND SETTING

The study used a systematic review, workshops and interviews, a Delphi survey and a final consensus workshop.

RESULTS

Thirteen parents and 45 HCPs took part in 5 workshops; 15 other parents were also separately interviewed. Fifty-six items were identified from the systematic review, workshops and interviews. Rounds one and two of the Delphi survey involved 299 and 194 participants, respectively. Sixteen outcomes met the criteria for inclusion within the COS. The consensus meeting was attended by 10 participants, with representation from all three stakeholder groups. Nine outcomes were added, totalling 25 outcomes to be included in the COS.

CONCLUSION

We have developed the first parent and HCP consensus on a COS for bronchiolitis in a hospital setting. The use of this COS will ensure outcomes in future bronchiolitis trials are important and relevant, and will enable the trial results to be compared and combined.

TRIAL REGISTRATION NUMBER

ISRCTN75766048.

Favipiravir in the Battle with Respiratory Viruses

Abstract:

Among antiviral drugs, the vast majority targets only one or two related viruses. The conventional model, one virus - one drug, significantly limits therapeutic options. Therefore, in the strategy of controlling viral infections, there is a necessity to develop compounds with pleiotropic effects. Favipiravir (FPV) emerged as a strong candidate to become such a drug. The aim of the study is to present up-to-date information on the role of favipiravir in the treatment of viral respiratory infections. The anti-influenza activity of favipiravir has been confirmed in cell culture experiments, animal models and clinical trials. Thoroughly different - from the previously registered drugs - mechanism of action suggests that FVP can be used as a countermeasure for the novel or re-emerging influenza virus infections. In recent months, favipiravir has been broadly investigated due to its potential efficacy in the treatment of Covid-19. Based on preclinical and clinical studies and a recently published meta-analysis it seems that favipiravir may be a promising antiviral drug in the treatment of patients with Covid-19. FPV is also effective against other RNA respiratory viruses and may be a candidate for the treatment of serious infections caused by human rhinovirus, respiratory syncytial virus, metapneumovirus, parainfluenza viruses and hantavirus pulmonary syndrome.

Machine learning early prediction of respiratory syncytial virus in pediatric hospitalized patients

Respiratory syncytial virus (RSV) causes millions of infections among children in the US each year and can cause severe disease or death. Infections that are not promptly detected can cause outbreaks that put other hospitalized patients at risk. No tools besides diagnostic testing are available to rapidly and reliably predict RSV infections among hospitalized patients. We conducted a retrospective study from pediatric electronic health record (EHR) data and built a machine learning model to predict whether a patient will test positive to RSV by nucleic acid amplification test during their stay. Our model demonstrated excellent discrimination with an area under the receiver-operating curve of 0.919, a sensitivity of 0.802, and specificity of 0.876. Our model can help clinicians identify patients who may have RSV infections rapidly and cost-effectively. Successfully integrating this model into routine pediatric inpatient care may assist efforts in patient care and infection control.

Role of ARP2/3 Complex-Driven Actin Polymerization in RSV Infection

Respiratory syncytial virus (RSV) is the leading viral agent causing bronchiolitis and pneumonia in children under five years old worldwide. The RSV infection cycle starts with macropinocytosis-based entry into the host airway epithelial cell membrane, followed by virus transcription, replication, assembly, budding, and spread. It is not surprising that the host actin cytoskeleton contributes to different stages of the RSV replication cycle. RSV modulates actin-related protein 2/3 (ARP2/3) complex-driven actin polymerization for a robust filopodia induction on the infected lung epithelial A549 cells, which contributes to the virus’s budding, and cell-to-cell spread. Thus, a comprehensive understanding of RSV-induced cytoskeletal modulation and its role in lung pathobiology may identify novel intervention strategies. This review will focus on the role of the ARP2/3 complex in RSV’s pathogenesis and possible therapeutic targets to the ARP2/3 complex for RSV.

mTOR kinase is a therapeutic target for respiratory syncytial virus and coronaviruses

Therapeutic interventions targeting viral infections remain a significant challenge for both the medical and scientific communities. While specific antiviral agents have shown success as therapeutics, viral resistance inevitably develops, making many of these approaches ineffective. This inescapable obstacle warrants alternative approaches, such as the targeting of host cellular factors. Respiratory syncytial virus (RSV), the major respiratory pathogen of infants and children worldwide, causes respiratory tract infection ranging from mild upper respiratory tract symptoms to severe life-threatening lower respiratory tract disease. Despite the fact that the molecular biology of the virus, which was originally discovered in 1956, is well described, there is no vaccine or effective antiviral treatment against RSV infection. Here, we demonstrate that targeting host factors, specifically, mTOR signaling, reduces RSV protein production and generation of infectious progeny virus. Further, we show that this approach can be generalizable as inhibition of mTOR kinases reduces coronavirus gene expression, mRNA transcription and protein production. Overall, defining virus replication-dependent host functions may be an effective means to combat viral infections, particularly in the absence of antiviral drugs.

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.

Impact of multiplexed respiratory viral panels on infection control measures and antimicrobial stewardship: a review of the literature

Multiplexed respiratory viral panels (MRVP) have recently been added to the diagnostic work-up of respiratory infections. This review provides a summary of the main literature of MRVP for patients with regard to 3 different topics. Can the results of MRVP reduce the inappropriate use of antibiotics, can they guide the use of appropriate antiviral therapy and do they have an added value with respect to infection control measures? Literature was searched for based on a defined search string using both the PubMed and Embase database. Twenty-five articles report on the impact of MRVP on antibiotic therapy. In all the articles where active antimicrobial stewardship was performed (e.g., education/advice on interpreting results of MRVP) (N = 9), a reduction in antibiotic therapy was shown (with exception of 2 studies). Three studies evaluating the effect of MRVP on antimicrobial use in a population that is not suspected of having bacterial pneumonia (e.g., absence of radiology suggestive for bacterial infection or low PCT) found a positive impact on antibiotic therapy. Eight studies with a short TAT (< 7 h) had a positive impact on use of antibiotic therapy. Eleven studies focused on the impact of MRVP on antiviral use. In contrast to antibiotic reduction, all studies systematically objectified improved antiviral use as a consequence of MRVP results. With regard to the impact of MRVP on infection control, eleven articles were withheld. All these studies led to a more accurate use of infection control measures by detecting unidentified pathogens or stopping isolation precautions in case of a negative MRVP result. MRVP don’t reduce antibiotic therapy in all populations. Reduction seems more likely if the following factors are present: active antimicrobial stewardship, low likelihood of a bacterial infection, and a short turnaround time to result. With respect to antiviral therapy, all studies have an impact but the targeted use of antivirals is so far not that evidence based for all viral respiratory pathogens. Regarding infection control measures, the potential impact of MRVP is high because of the need of additional isolation precautions for many respiratory viruses, although logistical problems can occur.

The impact of childhood RSV infection on children's and parents' quality of life: a prospective multicenter study in Spain

Background

 Several immunisation candidates against RSV are in late-stage clinical trials. To evaluate the benefits of a potential vaccination programme, both economic and health benefits will be needed. Health benefits are usually measured in Health-related Quality of Life (HRQoL) loss using standardised questionnaires. However, there are no RSV-specific questionnaires validated for children under 2 years, in whom most RSV episodes occur. Therefore, HRQoL estimates are taken from literature or inadequate tools. We determined HRQoL loss and direct costs due to an RSV episode in children younger than 2 years and their caregivers during a month of follow up, using a new questionnaire administered online.

Methods

 An observational prospective multicentre surveillance study was conducted in children aged younger than two years. Children were recruited from 8 primary care centres and 1 hospital in the Valencia region and Catalonia (Spain). RSV-positive cases were obtained by immunochromatographic test. HRQoL was assessed using a new ad-hoc 38 item-questionnaire developed. Parents of infected children completed 4 questionnaires at four timepoints (day 0, 7, 14 and 30) after diagnosis.

Results

 117 children were enrolled in the study and 86 (73.5%) were RSV + . Median (interquartile range; IQR) scores were 0.52 (0.42–0.68), 0.65 (0.49–0.79), 0.82 (0.68–0.97) and 0.94 (0.81–1), for days 0, 7, 14 and 30, respectively. Compared to total recovery (Q30), HRQoL loss was 37.5%, 31.5% and 8.9% on days 0, 7 and 14 since diagnosis of the disease. The total median cost per patient (including treatments) was €598.8 (IQR: 359.63–2425.85).

Conclusions

 RSV had almost 40% impact on HRQoL during the first week since onset of symptoms and the median cost per episode and patient was about €600. These results represent a substantial input for health-economic evaluations of future RSV-related interventions such as vaccination.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06629-z.

Pharmacological Efficacy of Ginseng against Respiratory Tract Infections

Respiratory tract infections are underestimated, as they are mild and generally not incapacitating. In clinical medicine, however, these infections are considered a prevalent problem. By 2030, the third most comprehensive reason for death worldwide will be chronic obstructive pulmonary disease (COPD), according to the World Health Organization. The current arsenal of anti-inflammatory drugs shows little or no benefits against COPD. For thousands of years, herbal drugs have been used to cure numerous illnesses; they exhibit promising results and enhance physical performance. Ginseng is one such herbal medicine, known to alleviate pro-inflammatory chemokines and cytokines (IL-2, IL-4, IFN-γ, TNF-α, IL-5, IL-6, IL-8) formed by macrophages and epithelial cells. Furthermore, the mechanisms of action of ginsenoside are still not fully understood. Various clinical trials of ginseng have exhibited a reduction of repeated colds and the flu. In this review, ginseng’s structural features, the pathogenicity of microbial infections, and the immunomodulatory, antiviral, and anti-bacterial effects of ginseng were discussed. The focus was on the latest animal studies and human clinical trials that corroborate ginseng’s role as a therapy for treating respiratory tract infections. The article concluded with future directions and significant challenges. This review would be a valuable addition to the knowledge base for researchers in understanding the promising role of ginseng in treating respiratory tract infections. Further analysis needs to be re-focused on clinical trials to study ginseng’s efficacy and safety in treating pathogenic infections and in determining ginseng-drug interactions.

Adjustable Algorithmic Tool for Assessing the Effectiveness of Maternal Respiratory Syncytial Virus (RSV) Vaccination on Infant Mortality in Developing Countries

Acute lower respiratory infection (ALRI) due to RSV is a common cause of global infant mortality, with most cases occurring in developing countries. Using data aggregated from priority countries as designated by the United States Agency for International Development's (USAID) Maternal Child Health and Nutrition (MCHN) program, we created an adjustable algorithmic tool for visualizing the effectiveness of candidate maternal RSV vaccination on infant mortality. Country-specific estimates for disease burden and case fatality rates were computed based on established data. Country-specific RSV-ALRI incidence rates for infants 0-5 months were scaled based on the reported incidence rates for children 0-59 months. Using in-hospital mortality rates and predetermined “inflation factor,” we estimated the mortality of infants aged 0-5 months. Given implementation of a candidate maternal vaccination program, estimated reduction in infant RSV-ALRI incidence and mortality rates were calculated. User input is used to determine the coverage of the program and the efficacy of the vaccine. Using the generated algorithm, the overall reduction in infant mortality varied considerably depending on vaccine efficacy and distribution. Given a potential efficacy of 70% and a maternal distribution rate of 50% in every USAID MCHN priority country, annual RSV-ALRI-related infant mortality is estimated to be reduced by 14,862 cases. The absolute country-specific reduction is dependent on the number of live births; countries with the highest birth rates had the greatest impact on annual mortality reduction. The adjustable algorithm provides a standardized analytical tool in the evaluation of candidate maternal RSV vaccines. Ultimately, it can be used to guide public health initiatives, research funding, and policy implementation concerning the effectiveness of potential maternal RSV vaccination on reducing infant mortality.

A potent neutralizing nanobody against SARS-CoV-2 with inhaled delivery potential

The coronavirus disease 2019 (COVID‐19) pandemic has become a serious burden on global public health. Although therapeutic drugs against COVID‐19 have been used in many countries, their efficacy is still limited. We here reported nanobody (Nb) phage display libraries derived from four camels immunized with the SARS‐CoV‐2 spike receptor‐binding domain (RBD), from which 381 Nbs were identified to recognize SARS‐CoV‐2‐RBD. Furthermore, seven Nbs were shown to block interaction of human angiotensin‐converting enzyme 2 (ACE2) with SARS‐CoV‐2‐RBD variants and two Nbs blocked the interaction of human ACE2 with bat‐SL‐CoV‐WIV1‐RBD and SARS‐CoV‐1‐RBD. Among these candidates, Nb11‐59 exhibited the highest activity against authentic SARS‐CoV‐2 with 50% neutralizing dose (ND₅₀) of 0.55 μg/ml. Nb11‐59 can be produced on large scale in Pichia pastoris, with 20 g/L titer and 99.36% purity. It also showed good stability profile, and nebulization did not impact its stability. Overall, Nb11‐59 might be a promising prophylactic and therapeutic molecule against COVID‐19, especially through inhalation delivery.

The Future of Respiratory Syncytial Virus Disease Prevention and Treatment

Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, young children, and older or immunocompromised adults. Although aerosolized ribavirin was licensed for RSV treatment on the basis of data demonstrating a reduced need for supplemental oxygen, ribavirin use is limited because of issues with efficacy, safety, and cost. Currently, the treatment of RSV is primarily supportive. New antiviral treatments for RSV are in the early stages of development, but it will be years until any of these may be licensed by the US Food and Drug Administration (FDA). Palivizumab, an RSV monoclonal antibody [immunoprophylaxis (IP)], has demonstrated effectiveness in disease prevention and is the only licensed IP for RSV disease in specific high-risk pediatric populations. Although its efficacy is well established, some challenges that may interfere with its clinical use include cost, need for monthly injections, and changing policy for use by the American Academy of Pediatrics (AAP). Preventing RSV disease would be possible through RSV vaccine development (e.g., live-attenuated, vector-based subunit, or particle-based). Alternatively, new long-acting monoclonal antibodies have demonstrated promising results in early clinical trials. Despite scientific advances, until new agents become available, palivizumab should continue to be used to reduce RSV disease burden in high-risk patients for whom it is indicated.

Transient Neutropenia in Immunocompetent Infants with Respiratory Syncytial Virus Infection

The incidence of neutropenia and the association between neutropenia and severity of respiratory symptoms among infants with respiratory syncytial virus (RSV) infections remain to be elucidated. This single-center, retrospective study included immunocompetent infants (<10 months old) with laboratory-confirmed RSV infection admitted to our center between January 2012 and December 2019. Incidence of neutropenia (<1.0 × 10⁹/L) within 10 days of onset and risk factors associated with subsequent neutropenia were evaluated. Among the 292 infants with RSV infection, including 232 (79%) with mild infection, neutropenia was observed in 31 (11%), with severe neutropenia (<0.5 × 10⁹/L) in 3 (1.0%). No neutropenic infants developed serious infection or hematological disorder. Infants without neutropenia showed age <3 months at onset in 34%, C-reactive protein level <1.0 mg/L in 27%, and nasopharyngeal microbiota composition with any of Moraxella catarrhalis, Streptococcus pneumoniae, or Haemophilus influenzae in 63%. In comparison, infants with neutropenia showed age <3 months at onset in 74% (relative risk [RR] 2.15; 95% confidence interval [CI] 1.65-2.81), C-reactive protein level <1.0 mg/L in 55% (RR 2.02; 95% CI 1.38-2.94), and microbiota including Moraxella catarrhalis, Streptococcus pneumoniae, or Haemophilus influenzae in 15% (RR 0.24; 95% CI 0.10-0.61). Multiple logistic regression analyses showed that younger age at onset and absence of that nasopharyngeal microbiota profile were associated with development of neutropenia. In conclusion, age and airway microbiota are considered as risk factors for the development of transient neutropenia among infants with RSV infection. However, the neutropenia seems not to develop serious infection or hematological disorder.

Antiviral Drug Targets of Single-Stranded RNA Viruses Causing Chronic Human Diseases

Ribonucleic acid (RNA) viruses associated with chronic diseases in humans are major threats to public health causing high mortality globally. The high mutation rate of RNA viruses helps them to escape the immune response and also is responsible for the development of drug resistance. Chronic infections caused by human immunodeficiency virus (HIV) and hepatitis viruses (HBV and HCV) lead to acquired immunodeficiency syndrome (AIDS) and hepatocellular carcinoma respectively, which are one of the major causes of human deaths. Effective preventative measures to limit chronic and re-emerging viral infections are absolutely necessary. Each class of antiviral agents targets a specific stage in the viral life cycle and inhibits them from its development and proliferation. Most often, antiviral drugs target a specific viral protein, therefore only a few broad-spectrum drugs are available. This review will be focused on the selected viral target proteins of pathogenic viruses containing single-stranded (ss) RNA genome that causes chronic infections in humans (e.g. HIV, HCV, Flaviviruses). In the recent past, an exponential increase in the number of available three-dimensional protein structures (>150000 in Protein Data Bank), allowed us to better understand the molecular mechanism of action of protein targets and antivirals. Advancements in the in silico approaches paved the way to design and develop several novels, highly specific small-molecule inhibitors targeting the viral proteins.

Respiratory viral infections in the elderly

With the global over 60-year-old population predicted to more than double over the next 35 years, caring for this aging population has become a major global healthcare challenge. In 2016 there were over 1 million deaths in >70 year olds due to lower respiratory tract infections; 13-31% of these have been reported to be caused by viruses. Since then, there has been a global COVID-19 pandemic, which has caused over 2.3 million deaths so far; increased age has been shown to be the biggest risk factor for morbidity and mortality. Thus, the burden of respiratory viral infections in the elderly is becoming an increasing unmet clinical need. Particular challenges are faced due to the interplay of a variety of factors including complex multimorbidities, decreased physiological reserve and an aging immune system. Moreover, their atypical presentation of symptoms may lead to delayed necessary care, prescription of additional drugs and prolonged hospital stay. This leads to morbidity and mortality and further nosocomial spread. Clinicians currently have limited access to sensitive detection methods. Furthermore, a lack of effective antiviral treatments means there is little incentive to diagnose and record specific non-COVID-19 viral infections. To meet this unmet clinical need, it is first essential to fully understand the burden of respiratory viruses in the elderly. Doing this through prospective screening research studies for all respiratory viruses will help guide preventative policies and clinical trials for emerging therapeutics. The implementation of multiplex point-of-care diagnostics as a mainstay in all healthcare settings will be essential to understand the burden of respiratory viruses, diagnose patients and monitor outbreaks. The further development of novel targeted vaccinations as well as anti-viral therapeutics and new ways to augment the aging immune system is now also essential.The reviews of this paper are available via the supplemental material section.

Role of Respiratory Syncytial Virus in Pediatric Pneumonia

Respiratory viral infections represent the leading cause of hospitalization in infants and young children worldwide and the second leading cause of infant mortality. Among these, Respiratory Syncytial Virus (RSV) represents the main cause of lower respiratory tract infections (LRTIs) in young children worldwide. RSV manifestation can range widely from mild upper respiratory infections to severe respiratory infections, mainly bronchiolitis and pneumonia, leading to hospitalization, serious complications (such as respiratory failure), and relevant sequalae in childhood and adulthood (wheezing, asthma, and hyperreactive airways). There are no specific clinical signs or symptoms that can distinguish RSV infection from other respiratory pathogens. New multiplex platforms offer the possibility to simultaneously identify different pathogens, including RSV, with an accuracy similar to that of single polymerase chain reaction (PCR) in the majority of cases. At present, the treatment of RSV infection relies on supportive therapy, mainly consisting of oxygen and hydration. Palivizumab is the only prophylactic method available for RSV infection. Advances in technology and scientific knowledge have led to the creation of different kinds of vaccines and drugs to treat RSV infection. Despite the good level of these studies, there are currently few registered strategies to prevent or treat RSV due to difficulties related to the unpredictable nature of the disease and to the specific target population.

Challenges in the prevention or treatment of RSV with emerging new agents in children from low- and middle-income countries

INTRODUCTION

Respiratory syncytial virus (RSV) causes approximately 120,000 deaths annually in children <5 years, with 99% of fatalities occurring in low- and middle-income countries (LMICs).

AREAS COVERED

There are numerous RSV interventions in development, including long-acting monoclonal antibodies, vaccines (maternal and child) and treatments which are expected to become available soon. We reviewed the key challenges and issues that need to be addressed to maximize the impact of these interventions in LMICs. The epidemiology of RSV in LMICs was reviewed (PubMed search to 30 June 2020 inclusive) and the need for more and better-quality data, encompassing hospital admissions, community contacts, and longer-term respiratory morbidity, emphasized. The requirement for an agreed clinical definition of RSV lower respiratory tract infection was proposed. The pros and cons of the new RSV interventions are reviewed from the perspective of LMICs.

EXPERT OPINION

We believe that a vaccine (or combination of vaccines, if practicable) is the only viable solution to the burden of RSV in LMICs. A coordinated program, analogous to that with polio, involving governments, non-governmental organizations, the World Health Organization, the manufacturers and the healthcare community is required to realize the full potential of vaccine(s) and end the devastation of RSV in LMICs.

Efficacy and safety of interferon on neonates with respiratory syncytial virus pneumonia

Respiratory syncytial virus (RSV) pneumonia is a leading cause of hospitalization and mortality among neonates worldwide, and there are currently no specific clinical treatments for RSV infection. Interferons (IFNs) possess broad-spectrum antiviral properties, and the present study aimed to evaluate the efficacy and safety of IFN-α1b for the treatment of neonatal RSV pneumonia. Neonates with RSV pneumonia were divided into the treatment (126 neonates) and control (160 neonates) groups, the former of which were treated with IFN. Aside from IFN administration, both groups received the same routine treatments. There were no significant differences in patient characteristics between the two groups. All neonates in the two groups displayed symptoms such as a cough (93.0%), tachypnea (90.1%), perilabial cyanosis (67.8%), choking on milk (62.9%) and moist rales (58.4%), and no significant differences in the occurrence of these symptoms were observed between the groups (P>0.05). The percentage of cases with bacterial co-infection was 66.8% (191/286), and the bacterial species in the spectrum primarily included Escherichia coli (21.5%), Klebsiella pneumonia (20.4%), Staphylococcus aureus (17.2%), Acihetobacter baumanii (13.1%) and Pseudomonas aeruginosa (9.9%). There were no significant differences in the co-infection rate or bacterial spectrum between the two groups. The remission time of cough, tachypnea, choking on milk, perilabial cyanosis, moist rales and oxygen inhalation in the treatment group was significantly lower compared with the control group (P<0.05). Although the hospitalization time in the treatment group was shorter compared with the control group, the difference was not significant. There were two patients in the treatment group that developed fever within 2-6 h after receiving IFN-α1b, though no other adverse effects were observed. In conclusion, IFN-α1b treatment improved the symptoms associated with neonatal RSV pneumonia with minimal adverse effects.

Structural Basis of SARS-CoV-2 and SARS-CoV Antibody Interactions

The 2019 coronavirus pandemic remains a major public health concern. Neutralizing antibodies (nAbs) represent a cutting-edge antiviral strategy. We focus here on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-CoV, and discuss current progress in antibody research against rampant SARS-CoV-2 infections. We provide a perspective on the mechanisms of SARS-CoV-2-derived nAbs, comparing these with existing SARS-CoV-derived antibodies. We offer insight into how these antibodies cross-react and cross-neutralize by analyzing available structures of spike (S) glycoprotein-antibody complexes. We also propose ways of adopting antibody-based strategies - such as cocktail antibody therapeutics against SARS-CoV-2 - to overcome the possible resistance of currently identified mutants and mitigate possible antibody-dependent enhancement (ADE) pathologies. This review provides a platform for the progression of antibody and vaccine design against SARS-CoV-2, and possibly against future coronavirus pandemics.

Inhaled RNA Therapy: From Promise to Reality

RNA-based medicine is receiving growing attention for its diverse roles and potential therapeutic capacity. The largest obstacle in its clinical translation remains identifying a safe and effective delivery system. Studies investigating RNA therapeutics in pulmonary diseases have rapidly expanded and drug administration by inhalation allows the direct delivery of RNA therapeutics to the target site of action while minimizing systemic exposure. In this review, we highlight recent developments in pulmonary RNA delivery systems with the use of nonviral vectors. We also discuss the major knowledge gaps that require thorough investigation and provide insights that will help advance this exciting field towards the bedside.

Risk factors of severe hospitalized respiratory syncytial virus infection in tertiary care center in Thailand

AIM

To determine factors associated with severe hospitalized Respiratory syncytial virus (RSV)-associated LRTI and to describe management in tertiary care center.

METHODS

Retrospective medical record review was conducted among children under 5 years old hospitalized with RSV-associated LRTI at King Chulalongkorn Memorial Hospital. Severe RSV-associated LRTI was defined as death, mechanical ventilator, or positive pressure ventilation use, prolonged hospitalization >7 days. Factors associated with severe RSV were analyzed using univariate and multivariate logistic regression.

RESULTS

From January 2011 to December 2016, 427 children were hospitalized. Median age was 10 months (IQR 4.2-23.0). One hundred seventy-four (41%) patients had severe RSV (11 deaths, 56 mechanical ventilators, 19 positive pressure ventilation, and 88 prolonged hospitalization). Factors associated with severe RSV were chronic lung disease (aOR 15.16 [4.26-53.91]), cirrhosis/biliary atresia (aOR 15.01 [3.21-70.32]), congenital heart disease (aOR 5.11 [1.97-13.23]), chemotherapy (aOR 4.7 [1.34-16.56]), and pre-term (aOR 2.03 [1.13-3.67]). Oxygen therapy was mainly low flow oxygen delivery. 88% of cases received bronchodilator. Parenteral antibiotics were prescribed in 37.9% of cases.

CONCLUSIONS

Children with co-morbidities have higher risk of severe RSV-associated LRTI. More than two-third of patients received bronchodilator, of which was not recommended by American Academy of Pediatrics. The specific treatment and prevention for RSV are urgently needed.

How does one choose the appropriate pharmacotherapy for children with lower respiratory tract infections?

INTRODUCTION

The definition of acute lower respiratory tract infection (LRTI) includes any infection involving the respiratory tract below the level of the larynx. In children, the most common acute LRTIs, and those with the greatest clinical relevance, are community-acquired pneumonia (CAP), bronchiolitis, bronchitis and tuberculosis (TB). The clinical relevance of LRTIs implies that they must be addressed with the most effective therapy. Antibiotics and antivirals play an essential role in this regard.

AREAS COVERED

In this paper, the most recent advances in the drug treatment of LRTIs in children are discussed.

EXPERT OPINION

Although LRTIs are extremely common and one of the most important causes of hospitalization and death in children, anti-infective therapy for these diseases remains unsatisfactory. For CAP and BR, the most important problem is the overuse and misuse of antibiotics; for BCL, the lack of drugs with demonstrated efficacy, safety and tolerability; for TB, the poor knowledge on the true efficacy and safety of the new drugs specifically planned to overcome the problem of MDR M. tuberculosis strains. There is still a long way to go for the therapy of pediatric LRTIs to be considered satisfactory.

Update on current views and advances on RSV infection (Review)

Respiratory syncytial virus (RSV) infection represents an excellent paradigm of precision medicine in modern paediatrics and several clinical trials are currently performed in the prevention and management of RSV infection. A new taxonomic terminology for RSV was recently adopted, while the diagnostic and omics techniques have revealed new modalities in the early identification of RSV infections and for better understanding of the disease pathogenesis. Coordinated clinical and research efforts constitute an important step in limiting RSV global predominance, improving epidemiological surveillance, and advancing neonatal and paediatric care. This review article presents the key messages of the plenary lectures, oral presentations and posters of the '5th workshop on paediatric virology' (Sparta, Greece, 12th October 2019) organized by the Paediatric Virology Study Group, focusing on recent advances in the epidemiology, pathogenesis, diagnosis, prognosis, clinical management and prevention of RSV infection in childhood.

Antiviraux chez l’enfant en pratique de ville : infections herpétiques, varicelle, grippe

Les infections liées à l’herpès virus humain (HSV), au virus de la varicelle et du zona (VZV) et au virus de la grippe (Influenza A et B) sont très fréquentes en pédiatrie et sont le plus souvent bénignes avec une guérison spontanée. L’utilisation des antiviraux antigrippaux (inhibiteurs de neuraminidase) a été étudiée dans de larges essais randomisés et fait l’objet de recommandations nationales et internationales. Celle des anti-HSV et anti-VZV n’a pas fait l’objet d’études de la même ampleur et de ce fait, leur prescription est plus discutée avec des bénéfices moins bien définis et variables (à l’exception des infections néonatales et/ou neuro-méningées). L’objectif de cette mise au point est donc de proposer une synthèse des données disponibles dans la littérature concernant les indications des antiviraux en pratique de ville pour les infections liées à l’HSV (gingivostomatite, herpès récurrent, faux panaris herpétique), au VZV (varicelle, zona) et à la grippe.

Innate Type 2 Responses to Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is a common and contagious virus that results in acute respiratory tract infections in infants. In many cases, the symptoms of RSV remain mild, however, a subset of individuals develop severe RSV-associated bronchiolitis. As such, RSV is the chief cause of infant hospitalization within the United States. Typically, the immune response to RSV is a type 1 response that involves both the innate and adaptive immune systems. However, type 2 cytokines may also be produced as a result of infection of RSV and there is increasing evidence that children who develop severe RSV-associated bronchiolitis are at a greater risk of developing asthma later in life. This review summarizes the contribution of a newly described cell type, group 2 innate lymphoid cells (ILC2), and epithelial-derived alarmin proteins that activate ILC2, including IL-33, IL-25, thymic stromal lymphopoietin (TSLP), and high mobility group box 1 (HMGB1). ILC2 activation leads to the production of type 2 cytokines and the induction of a type 2 response during RSV infection. Intervening in this innate type 2 inflammatory pathway may have therapeutic implications for severe RSV-induced disease.

Comparison of health care resource utilization among preterm and term infants hospitalized with Human Respiratory Syncytial Virus infections: A systematic review and meta-analysis of retrospective cohort studies

INTRODUCTION

Data on the variation in the medical resource utilization rate of Human Respiratory Syncytial Virus (HRSV) infected children by gestational age have recently been made available. This review aimed to determine whether prematurity is independently associated with the use of medical resources in hospitalized children for HRSV infections.

METHODS

We conducted this systematic review on cohort studies published on the medical resources use in preterm and full-term patients hospitalized for confirmed HRSV infections. We searched PubMed, Embase, and Global Index medicus for eligible studies. The standardized mean difference (SMD) and Risk Ratio (RR) with their 95% confidence intervals (95% CI) were estimated as summary statistics with random effects meta-analysis. The overall results were adjusted to the common confounders by stratified analyses.

RESULTS

A total of 14 articles (20 studies) were included. Compared to full-term, preterm hospitalized with HRSV infections had more frequent intensive care unit admission (RR = 2.6, 95% CI = 1.9-3.5), increased length of stay in hospital (SMD = 0.6, 95% CI = 0.5-0.8) and intensive care unit (SMD = 0.6, 95% CI = 0.4-0.8) and increased case fatality rate (RR = 6.9, 95% CI = 2.0-23.8). Mechanical ventilation utilization was more frequent in preterm children ≤ 2 years (RR = 15.5, 95% CI = 8.9-26.4) and those who did not receive prophylaxis against HRSV (RR = 15.9, 95% CI = 9.1-27.9)] than in full-term children. No differences were identified in the frequency of emergency department visits, oxygen utilization, and the age at the first HRSV episode between preterm and full-term infants.

CONCLUSIONS

Regardless of gestational age, preterm infants hospitalized for HRSV infections, especially those ≤ 2 years, have an increased frequency of use of health resources and poor outcomes compared to full-term infants. HRSV vaccine development programs for pregnant women should be accelerated.

CLINICAL TRIALS REGISTRATION

Review registration PROSPERO, CRD42019124375.

Overtesting and overtreatment-statement from the European Academy of Paediatrics (EAP)

Child health has improved considerably, partly due to increased availability of appropriate disease surveillance and treatment. Inappropriate testing and treatment may impose a risk. There is a large and unexplained variation in the use of tests and treatments for children between and within countries. This suggests that non-scientific factors determine their use. In an era of increasing availability of health services, pediatricians have an important role in balancing risks and benefits of available tests and treatments. Examples from the medical literature of overtesting and overtreatment challenge us to reconsider current practices. Antibiotic overuse, overtreatment of bronchiolitis, and non-indicated radiological procedures are found in common practice across Europe. Choosing Wisely is an initiative to improve the quality of care by reducing unnecessary testing and treatment.Conclusion: Clinicians have the challenge to find the optimal balance between too much and too little medicine-just appropriate.