The Future of Respiratory Syncytial Virus Disease Prevention and Treatment

Randomized, Open-Label Phase 3 Study Evaluating Immunogenicity, Safety, and Reactogenicity of RSVPreF3 OA Coadministered with FLU-QIV-HD in Adults Aged ≥ 65

INTRODUCTION

Respiratory syncytial virus (RSV) and influenza pose major disease burdens in older adults due to an aging immune system and comorbidities; seasonal overlap exists between these infections. In 2023, the RSV prefusion protein F3 older adult (RSVPreF3 OA) vaccine was first approved in the USA as a single dose for prevention of lower respiratory tract disease due to RSV in adults aged ≥ 60 years. The vaccine has since been approved in the European Union and elsewhere. RSVPreF3 OA and FLU-QIV-HD could be coadministered if immunogenicity, safety, and reactogenicity are not affected.

METHODS

This open-label, randomized (1:1), controlled, phase 3 study in 1029 adults aged ≥ 65 years in the USA evaluated the immunogenicity (up to 1 month after last vaccine dose) and safety (up to 6 months after last vaccine dose) of RSVPreF3 OA coadministered with FLU-QIV-HD (co-ad group) versus FLU-QIV-HD alone followed by RSVPreF3 OA at a separate visit 1 month later (control group). Non-inferiority criterion was defined as an upper limit of the two-sided 95% confidence interval of the geometric mean titer (GMT) group ratio (control/co-ad) ≤ 1.5. Secondary endpoints included safety and reactogenicity.

RESULTS

Proportions of participants across age categories between groups and proportions of male (50.4%) and female (49.6%) participants were well balanced; most participants were white (68.7%). Group GMT ratios for RSV-A neutralizing titers, hemagglutination inhibition titers for four influenza vaccine strains, and RSV-B neutralizing titers were non-inferior in the co-ad group versus the control group. No clinically meaningful differences in local or systemic solicited and unsolicited adverse events (AEs), serious AEs, and potential immune-mediated diseases were identified. The most common solicited AEs in both groups were injection-site pain and myalgia.

CONCLUSION

In adults aged ≥ 65 years, coadministration of RSVPreF3 OA and FLU-QIV-HD was immunogenically non-inferior to the sequential administration of both vaccines 1 month apart, and had clinically acceptable safety and reactogenicity profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT05559476.

A Review of Respiratory Syncytial Virus Epidemiology Among Children: Linking Effective Prevention to Vulnerable Populations

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

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.

CROCuS, a Phase II Study Evaluating the Antiviral Activity, Clinical Outcomes, and Safety of Rilematovir in Children Aged ≥ 28 Days and ≤ 3 Years with Acute Respiratory Tract Infection Due to Respiratory Syncytial Virus

BACKGROUND

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in children aged ≤ 5 years and adults aged ≥ 60 years worldwide. Despite this, RSV-specific therapeutic options are limited. Rilematovir is an investigational, orally administered inhibitor of RSV fusion protein-mediated viral entry.

OBJECTIVE

To establish the antiviral activity, clinical outcomes, safety, and tolerability of rilematovir (low or high dose) in children aged ≥ 28 days and ≤ 3 years with RSV disease.

METHODS

CROCuS was a multicenter, international, double-blind, placebo-controlled, randomized, adaptive phase II study, wherein children aged ≥ 28 days and ≤ 3 years with confirmed RSV infection who were either hospitalized (Cohort 1) or treated as outpatients (Cohort 2) were randomized (1:1:1) to receive rilematovir (low or high dose) or placebo. Study treatment was administered daily as an oral suspension from days 1 to 7, with dosing based on weight and age groups. The primary objective was to establish antiviral activity of rilematovir by evaluating the area under the plasma concentration-time curve of RSV viral load in nasal secretions from baseline through day 5. Severity and duration of RSV signs and symptoms and the safety and tolerability of rilematovir were also assessed through day 28 (± 3).

RESULTS

In total, 246 patients were randomized, treated, and included in the safety analysis population (Cohort 1: 147; Cohort 2: 99). Of these, 231 were included in the intent-to-treat-infected analysis population (Cohort 1: 138; Cohort 2: 93). In both cohorts, demographics were generally similar across treatment groups. In both cohorts combined, the difference (95% confidence interval) in the mean area under the plasma concentration-time curve of RSV RNA viral load through day 5 was - 1.25 (- 2.672, 0.164) and - 1.23 (- 2.679, 0.227) log10 copies∙days/mL for the rilematovir low-dose group and the rilematovir high-dose group, respectively, when compared with placebo. The estimated Kaplan-Meier median (95% confidence interval) time to resolution of key RSV symptoms in the rilematovir low-dose, rilematovir high-dose, and placebo groups of Cohort 1 was 6.01 (4.24, 7.25), 5.82 (4.03, 8.18), and 7.05 (5.34, 8.97) days, respectively; in Cohort 2, estimates were 6.45 (4.81, 9.70), 6.26 (5.41, 7.84), and 5.85 (3.90, 8.27) days, respectively. A similar incidence of adverse events was reported in patients treated with rilematovir and placebo in Cohort 1 (rilematovir: 61.9%; placebo: 58.0%) and Cohort 2 (rilematovir: 50.8%; placebo: 47.1%), with most reported as grade 1 or 2 and none leading to study discontinuation. The study was terminated prematurely, as the sponsor made a non-safety-related strategic decision to discontinue rilematovir development prior to full recruitment of Cohort 2.

CONCLUSIONS

Data from the combined cohort suggest that rilematovir has a small but favorable antiviral effect of indeterminate clinical relevance compared with placebo, as well as a favorable safety profile. Safe and effective therapeutic options for RSV in infants and young children remain an unmet need.

CLINICAL TRIAL REGISTRATION

EudraCT Number: 2016-003642-93; ClinicalTrials.gov Identifier: NCT03656510. First posted date: 4 September, 2018.

Farnesyltransferase inhibitor lonafarnib suppresses respiratory syncytial virus infection by blocking conformational change of fusion glycoprotein

Respiratory syncytial virus (RSV) is the major cause of bronchiolitis and pneumonia in young children and the elderly. There are currently no approved RSV-specific therapeutic small molecules available. Using high-throughput antiviral screening, we identified an oral drug, the prenylation inhibitor lonafarnib, which showed potent inhibition of the RSV fusion process. Lonafarnib exhibited antiviral activity against both the RSV A and B genotypes and showed low cytotoxicity in HEp-2 and human primary bronchial epithelial cells (HBEC). Time-of-addition and pseudovirus assays demonstrated that lonafarnib inhibits RSV entry, but has farnesyltransferase-independent antiviral efficacy. Cryo-electron microscopy revealed that lonafarnib binds to a triple-symmetric pocket within the central cavity of the RSV F metastable pre-fusion conformation. Mutants at the RSV F sites interacting with lonafarnib showed resistance to lonafarnib but remained fully sensitive to the neutralizing monoclonal antibody palivizumab. Furthermore, lonafarnib dose-dependently reduced the replication of RSV in BALB/c mice. Collectively, lonafarnib could be a potential fusion inhibitor for RSV infection.

The respiratory syncytial virus vaccines are here: Implications for solid organ transplantation

In 2023, the Food and Drug Administration approved 2 recombinant subunit respiratory syncytial virus (RSV) vaccines based on prefusion RSV F glycoproteins for the prevention of RSV-associated lower respiratory tract disease. These vaccines were subsequently recommended for individuals ≥60 years of age using shared clinical decision-making by the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices. The development, deployment, and uptake of respiratory virus vaccines are of particular importance for solid organ recipients who are at higher risk of infectious complications and poor clinical outcomes, including from RSV-associated lower respiratory tract disease, compared to patients without immunocompromise. This review aims to summarize what is currently known about the burden of RSV disease in solid organ transplantation, to describe the currently available tools to mitigate the risk, and to highlight considerations regarding the implementation of these vaccines before and after transplantation. We also explore areas of unmet need for organ transplant recipients including questions of RSV vaccine effectiveness and safety, inequities in disease and vaccine access based on race and socioeconomic status, and expansion of coverage to immunocompromised individuals below the age of 60 years.

Respiratory Syncytial Virus Infections in Recipients of Bone Marrow Transplants: A Systematic Review and Meta-Analysis

Human Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infections. Usually associated with infants and children, an increasing amount of evidence suggests that RSV can cause substantial morbidity and mortality in immunocompromised individuals, including recipients of bone marrow transplantation (BMT). The present systematic review was therefore designed in accordance with the PRISMA guidelines to collect available evidence about RSV infections in BMT recipients. Three medical databases (PubMed, Embase, and MedRxiv) were therefore searched for eligible observational studies published up to 30 September 2023 and collected cases were pooled in a random-effects model. Heterogeneity was assessed using I2 statistics. Reporting bias was assessed by means of funnel plots and regression analysis. Overall, 30 studies were retrieved, including 20,067 BMT cases and 821 RSV infection episodes. Of them, 351 were lower respiratory tract infections, and a total of 78 RSV-related deaths were collected. A pooled attack rate of 5.40% (95% confidence interval [95%CI] 3.81 to 7.60) was identified, with a corresponding incidence rate of 14.77 cases per 1000 person-years (95%CI 9.43 to 20.11), and a case fatality ratio (CFR) of 7.28% (95%CI 4.94 to 10.60). Attack rates were higher in adults (8.49%, 95%CI 5.16 to 13.67) than in children (4.79%, 95%CI 3.05 to 7.45), with similar CFR (5.99%, 95%CI 2.31 to 14.63 vs. 5.85%, 95%CI 3.35 to 10.02). By assuming RSV attack rates as a reference group, influenza (RR 0.518; 95%CI 0.446 to 0.601), adenovirus (RR 0.679, 95%CI 0.553 to 0.830), and human metapneumovirus (RR 0.536, 95%CI 0.438 to 0.655) were associated with a substantially reduced risk for developing corresponding respiratory infection. Despite the heterogeneous settings and the uneven proportion of adult and pediatric cases, our study has identified high attack rates and a substantial CFR of RSV in recipients of BMT, stressing the importance of specifically tailored preventive strategies and the need for effective treatment options.

Comparison of mortality and outcomes of four respiratory viruses in the intensive care unit: a multicenter retrospective study

This retrospective study aimed to compare the mortality and burden of respiratory syncytial virus (RSV group), SARS-CoV-2 (COVID-19 group), non-H1N1 (Seasonal influenza group) and H1N1 influenza (H1N1 group) in adult patients admitted to intensive care unit (ICU) with respiratory failure. A total of 807 patients were included. Mortality was compared between the four following groups: RSV, COVID-19, seasonal influenza, and H1N1 groups. Patients in the RSV group had significantly more comorbidities than the other patients. At admission, patients in the COVID-19 group were significantly less severe than the others according to the simplified acute physiology score-2 (SAPS-II) and sepsis-related organ failure assessment (SOFA) scores. Using competing risk regression, COVID-19 (sHR = 1.61; 95% CI 1.10; 2.36) and H1N1 (sHR = 1.87; 95% CI 1.20; 2.93) were associated with a statistically significant higher mortality while seasonal influenza was not (sHR = 0.93; 95% CI 0.65; 1.31), when compared to RSV. Despite occurring in more severe patients, RSV and seasonal influenza group appear to be associated with a more favorable outcome than COVID-19 and H1N1 groups.

Drug repurposing screen identifies lonafarnib as respiratory syncytial virus fusion protein inhibitor

Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory tract infection in infants, older adults and the immunocompromised. Effective directly acting antivirals are not yet available for clinical use. To address this, we screen the ReFRAME drug-repurposing library consisting of 12,000 small molecules against RSV. We identify 21 primary candidates including RSV F and N protein inhibitors, five HSP90 and four IMPDH inhibitors. We select lonafarnib, a licensed farnesyltransferase inhibitor, and phase III candidate for hepatitis delta virus (HDV) therapy, for further follow-up. Dose-response analyses and plaque assays confirm the antiviral activity (IC50: 10-118 nM). Passaging of RSV with lonafarnib selects for phenotypic resistance and fixation of mutations in the RSV fusion protein (T335I and T400A). Lentiviral pseudotypes programmed with variant RSV fusion proteins confirm that lonafarnib inhibits RSV cell entry and that these mutations confer lonafarnib resistance. Surface plasmon resonance reveals RSV fusion protein binding of lonafarnib and co-crystallography identifies the lonafarnib binding site within RSV F. Oral administration of lonafarnib dose-dependently reduces RSV virus load in a murine infection model using female mice. Collectively, this work provides an overview of RSV drug repurposing candidates and establishes lonafarnib as a bona fide fusion protein inhibitor.

Favipiravir induces HuNoV viral mutagenesis and infectivity loss with clinical improvement in immunocompromised patients

Chronic human norovirus (HuNoV) infections in immunocompromised patients result in severe disease, yet approved antivirals are lacking. RNA-dependent RNA polymerase (RdRp) inhibitors inducing viral mutagenesis display broad-spectrum in vitro antiviral activity, but clinical efficacy in HuNoV infections is anecdotal and the potential emergence of drug-resistant variants is concerning. Upon favipiravir (and nitazoxanide) treatment of four immunocompromised patients with life-threatening HuNoV infections, viral whole-genome sequencing showed accumulation of favipiravir-induced mutations which coincided with clinical improvement although treatment failed to clear HuNoV. Infection of zebrafish larvae demonstrated drug-associated loss of viral infectivity and favipiravir treatment showed efficacy despite occurrence of RdRp variants potentially causing favipiravir resistance. This indicates that within-host resistance evolution did not reverse loss of viral fitness caused by genome-wide accumulation of sequence changes. This off-label approach supports the use of mutagenic antivirals for treating prolonged RNA viral infections and further informs the debate surrounding their impact on virus evolution.

Respiratory syncytial virus in adults with comorbidities: an update on epidemiology, vaccines, and treatments

BACKGROUND

Respiratory syncytial virus (RSV) is widely known as a frequent cause of respiratory distress among adults, particularly in older people. Recent years have witnessed several improvements in respiratory virus detection, leading to more questions about therapeutic management strategies.

OBJECTIVES

This narrative review focuses on the RSV burden in older people and adults with risk factors and provides an update on the main recent developments regarding managing this infection.

SOURCES

A comprehensive PubMed search was conducted till August 2023 to identify studies on RSV among the adult population. We included observational studies, RCTs on vaccines, and different therapies.

CONTENT

This review should give clinicians an overview of RSV epidemiology and burden among older people and adults with pre-existing risk factors, the most recent randomized clinical trials on RSV vaccines, and the existing data on the different therapeutics existing and under development.

IMPLICATIONS

There is a growing body of evidence on RSV burden in adults. The landscape of preventive and curative treatments is quickly evolving.

Respiratory Syncytial Virus Vaccines: A Review of the Candidates and the Approved Vaccines

Respiratory syncytial virus (RSV) is responsible for a significant proportion of global morbidity and mortality affecting young children and older adults. In the aftermath of formalin-inactivated RSV vaccine development, the effort to develop an immunizing agent was carefully guided by epidemiologic and pathophysiological evidence of the virus, including various vaccine technologies. The pipeline of RSV vaccine development includes messenger ribonucleic acid (mRNA), live-attenuated (LAV), subunit, and recombinant vector-based vaccine candidates targeting different virus proteins. The availability of vaccine candidates of various technologies enables adjustment to the individualized needs of each vulnerable age group. Arexvy® (GSK), followed by Abrysvo® (Pfizer), is the first vaccine available for market use as an immunizing agent to prevent lower respiratory tract disease in older adults. Abrysvo is additionally indicated for the passive immunization of infants by maternal administration during pregnancy. This review presents the RSV vaccine pipeline, analyzing the results of clinical trials. The key features of each vaccine technology are also mentioned. Currently, 24 vaccines are in the clinical stage of development, including the 2 licensed vaccines. Research in the field of RSV vaccination, including the pharmacovigilance methods of already approved vaccines, promotes the achievement of successful prevention.

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).

Two synthetic steroid analogs reduce human respiratory syncytial virus replication and the immune response to infection both in vitro and in vivo

HRSV is responsible for many acute lower airway infections and hospitalizations in infants, the elderly and those with weakened immune systems around the world. The strong inflammatory response that mediates viral clearance contributes to pathogenesis, and is positively correlated with disease severity. There is no specific effective therapy on hand. Antiviral synthetic stigmastanes (22S, 23S)-22,23-dihydroxystigmast-4-en-3-one (Compound 1) and 22,23-dihydroxystigmasta-1,4-dien-3-one (Compound 2) have shown to be active inhibiting unrelated virus like Herpes Simplex type 1 virus (HSV-1) and Adenovirus, without cytotoxicity. We have also shown that Compound 1 modulates the activation of cell signaling pathways and cytokine secretion in infected epithelial cells as well as in inflammatory cells activated by nonviral stimuli. In the present work, we investigated the inhibitory effect of both compounds on HRSV replication and their modulatory effect on infected epithelial and inflammatory cells. We show that compounds 1 and 2 inhibit in vitro HRSV replication and propagation and reduce cytokine secretion triggered by HRSV infection in epithelial and inflammatory cells. The compounds reduce viral loads and inflammatory infiltration in the lungs of mice infected with HRSV.

The role of vaccination in COPD: influenza, SARS-CoV-2, pneumococcus, pertussis, RSV and varicella zoster virus

Exacerbations of COPD are associated with worsening of the airflow obstruction, hospitalisation, reduced quality of life, disease progression and death. At least 70% of COPD exacerbations are infectious in origin, with respiratory viruses identified in approximately 30% of cases. Despite long-standing recommendations to vaccinate patients with COPD, vaccination rates remain suboptimal in this population.Streptococcus pneumoniae is one of the leading morbidity and mortality causes of lower respiratory tract infections. The Food and Drug Administration recently approved pneumococcal conjugate vaccines that showed strong immunogenicity against all 20 included serotypes. Influenza is the second most common virus linked to severe acute exacerbations of COPD. The variable vaccine efficacy across virus subtypes and the impaired immune response are significant drawbacks in the influenza vaccination strategy. High-dose and adjuvant vaccines are new approaches to tackle these problems. Respiratory syncytial virus is another virus known to cause acute exacerbations of COPD. The vaccine candidate RSVPreF3 is the first authorised for the prevention of RSV in adults ≥60 years and might help to reduce acute exacerbations of COPD. The 2023 Global Initiative for Chronic Lung Disease report recommends zoster vaccination to protect against shingles for people with COPD over 50 years.

Broad-Spectrum Antiviral Activity of Influenza A Defective Interfering Particles against Respiratory Syncytial, Yellow Fever, and Zika Virus Replication In Vitro

New broadly acting and readily available antiviral agents are needed to combat existing and emerging viruses. Defective interfering particles (DIPs) of influenza A virus (IAV) are regarded as promising options for the prevention and treatment of IAV infections. Interestingly, IAV DIPs also inhibit unrelated viral infections by stimulating antiviral innate immunity. Here, we tested the ability of IAV DIPs to suppress respiratory syncytial, yellow fever and Zika virus infections in vitro. In human lung (A549) cells, IAV DIP co-infection inhibited the replication and spread of all three viruses. In contrast, we observed no antiviral activity in Vero cells, which are deficient in the production of interferon (IFN), demonstrating its importance for the antiviral effect. Further, in A549 cells, we observed an enhanced type-I and type-III IFN response upon co-infection that appears to explain the antiviral potential of IAV DIPs. Finally, a lack of antiviral activity in the presence of the Janus kinase 1/2 (JAK1/2) inhibitor ruxolitinib was detected. This revealed a dependency of the antiviral activity on the JAK/signal transducers and activators of transcription (STAT) signaling pathway. Overall, this study supports the notion that IAV DIPs may be used as broad-spectrum antivirals to treat infections with a variety of IFN-sensitive viruses, particularly respiratory viruses.

Establishment of a new reverse genetics system for respiratory syncytial virus under the control of RNA polymerase II

A reverse genetics system for the respiratory syncytial virus (RSV), which causes acute respiratory illness, is an effective tool for understanding the pathogenicity of RSV. To date, a method dependent on T7 RNA polymerase is commonly used for RSV. Although this method is well established and recombinant RSV is well rescued from transfected cells, the requirement for artificial supply of T7 RNA polymerase limits its application. To overcome this, we established a reverse genetics system dependent on RNA polymerase II, which is more convenient for the recovery of recombinant viruses from various cell lines. First, we identified human cell lines with high transfection efficiency in which RSV can replicate effectively. Two human cell lines, Huh-7 and 293T, permitted the propagation of recombinant green fluorescent protein-expressing RSV. Our minigenome system revealed that efficient transcription and replication of RSV occurred in both Huh-7 and 293T cells. We then confirmed that recombinant green fluorescent protein-expressing RSV was rescued in both Huh-7 and 293T cells. Furthermore, the growth capability of viruses rescued from Huh-7 and 293T cells was similar to that of recombinant RSV rescued using the conventional method. Thus, we succeeded in establishing a new reverse genetics system for RSV that is dependent on RNA polymerase II.

The antitumor effect of oncolytic respiratory syncytial virus via the tumor necrosis factor-alpha induction and ROS-bax-mediated mechanisms

BACKGROUND

Cervical cancer represents one of the most prevalent cancers among women worldwide, particularly in low- and middle-income nations. Oncolytic viruses (OVs) can infect cancer cells selectively and lethally without harming normal cells. Respiratory syncytial virus (RSV) is an oncolytic virus for anticancer therapy because of its propensity to multiply within tumor cells. This research aimed to assess the in vitro antitumor activities and molecular basis processes of the oncolytic RSV-A2 on the TC-1 cancer cells as a model for HPV‑related cervical cancers.

METHODS

Cellular proliferation (MTT) and lactate dehydrogenase (LDH) release assays were used to investigate the catalytic impacts of RSV-A2 by the ELISA method. Real-time PCR and flow cytometry assays were utilized to assess apoptosis, autophagy, intracellular concentrations of reactive oxygen species (ROS), and cell cycle inhibition.

RESULTS

Our MTT and LDH results demonstrated that TC-1 cell viability after oncolytic RSV-A2 treatment was MOI-dependently and altered significantly with increasing RSV-A2 virus multiplicity of infection (MOI). Other findings showed that the RSV-A2 potentially resulted in apoptosis and autophagy induction, caspase-3 activation, ROS generation, and cell cycle inhibition in the TC-1 cell line. Real-time PCR assay revealed that RSV-A2 infection significantly elevated the Bax and decreased the Bcl2 expression.

CONCLUSIONS

The results indicated that oncolytic RSV-A2 has cytotoxic and inhibiting effects on HPV-associated cervical cancer cells. Our findings revealed that RSV-A2 is a promising treatment candidate for cervical cancer.

Multiplex Quantitative Analysis of 9 Compounds of Scutellaria baicalensis Georgi in the Plasma of Respiratory Syncytial Virus-Infected Mice Based on HPLC-MS/MS and Pharmacodynamic Effect Correlation Analysis

According to traditional Chinese medicine, Scutellaria baicalensis Georgi possesses the therapeutic properties of heat-clearing, dampness-drying, diarrhea alleviation, and detoxification, making it a clinically used remedy for respiratory infections. The objective of this study was to investigate the changes in constituent content, pharmacodynamic effects, and material basis of Scutellaria baicalensis Georgi in the plasma of mice infected with respiratory syncytial virus (RSV). The results showed that a sensitive and efficient high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) method was established in this study. Multiple quantitative analyses of Baicalein, Apigenin-7-glucuronide, Baicalin, Oroxylin A 7-O-beta-d-glucuronide, Wogonoside, Norwogonin, Wogonin, Chrysin, and Oroxylin A in mouse plasma revealed a bimodal absorption phenomenon within the time frame of 0.167 h to 6 h post-administration, with the exception of chrysin. Following 6 h of administration, the concentrations of 9 components continued to decrease until they became undetectable. In comparison to the model group, all administered groups exhibited significant reductions in lung index and viral load, with their lung index repair rate and viral suppression rate aligning with the blood concentration-time curve. Finally, through the application of the gray correlation analysis method, we identified Baicalein, Baicalin, Oroxylin A 7-O-beta-d-glucuronide, Wogonoside, Norwogonin, and Wogonin as potential pharmacodynamic material bases of Scutellaria baicalensis Georgi against RSV infection.

T cell immune profiling of respiratory syncytial virus for the development of a targeted immunotherapy

Respiratory syncytial virus (RSV)-associated viral infections are a major public health problem affecting the immunologically naïve/compromised populations. Given the RSV-associated morbidity and the limited treatment options, we sought to characterize the cellular immune response to RSV to develop a targeted T cell therapy for off-the-shelf administration to immunocompromised individuals. Here we report on the immunological profiling, as well as manufacturing, characterization and antiviral properties of these RSV-targeted T cells. A randomized, phase 1/2 clinical trial evaluating their safety and activity in haematopoietic stem cell transplant recipients as an off-the-shelf multi-respiratory virus-directed product is currently underway (NCT04933968, https://clinicaltrials.gov).

Development of an Antiviral Ion-Activated In Situ Gel Containing 18β-Glycyrrhetinic Acid: A Promising Alternative against Respiratory Syncytial Virus

The human respiratory syncytial virus (hRSV) is a major cause of serious lower respiratory infections and poses a considerable risk to public health globally. Only a few treatments are currently used to treat RSV infections, and there is no RSV vaccination. Therefore, the need for clinically applicable, affordable, and safe RSV prevention and treatment solutions is urgent. In this study, an ion-activated in situ gelling formulation containing the broad-spectrum antiviral 18β-glycyrrhetinic acid (GA) was developed for its antiviral effect on RSV. In this context, pH, mechanical characteristics, ex vivo mucoadhesive strength, in vitro drug release pattern, sprayability, drug content, and stability were all examined. Rheological characteristics were also tested using in vitro gelation capacity and rheological synergism tests. Finally, the cytotoxic and antiviral activities of the optimized in situ gelling formulation on RSV cultured in the human laryngeal epidermoid carcinoma (HEp-2) cell line were evaluated. In conclusion, the optimized formulation prepared with a combination of 0.5% w/w gellan gum and 0.5% w/w sodium carboxymethylcellulose demonstrated good gelation capacity and sprayability (weight deviation between the first day of the experiment (T0) and the last day of the experiment (T14) was 0.34%), desired rheological synergism (mucoadhesive force (Fb): 9.53 Pa), mechanical characteristics (adhesiveness: 0.300 ± 0.05 mJ), ex vivo bioadhesion force (19.67 ± 1.90 g), drug content uniformity (RSD%: 0.494), and sustained drug release over a period of 6 h (24.56% ± 0.49). The optimized formulation demonstrated strong anti-hRSV activity (simultaneous half maximal effective concentration (EC50) = 0.05 µg/mL; selectivity index (SI) = 306; pre-infection EC50 = 0.154 µg/mL; SI = 100), which was significantly higher than that of ribavirin (EC50 = 4.189 µg/mL; SI = 28) used as a positive control against hRSV, according to the results of the antiviral activity test. In conclusion, this study showed that nasal in situ gelling spray can prevent viral infection and replication by directly inhibiting viral entry or modulating viral replication.

Impact of RSV test positivity, patient characteristics, and treatment characteristics on the cost of hospitalization for acute bronchiolitis in a French university medical center (2010-2015)

Background

In young children, respiratory syncytial virus (RSV)-related bronchiolitis is typically more severe than other respiratory tract infections, with a greater need for oxygen therapy and respiratory support. Few studies have compared the cost of hospitalization with regard to virological status. The objective of this study was to compare the costs of hospitalization for RSV-positive vs. RSV-negative bronchiolitis in a French university medical center between 2010 and 2015.

Methods

The cost models were compared using conventional goodness-of-fit criteria. Covariates included the characteristics of the patients, pre-existing respiratory and non-respiratory comorbidities, superinfections, medical care provided, and the length of stay.

Results

RSV was detected in 679 (58.3%) of the 1,164 hospital stays by children under 2 years with virological data. Oxygen therapy and respiratory support were twice as frequent for the RSV-positive cases. The median hospitalization cost was estimated at €3,248.4 (interquartile range: €2,572.1). The cost distribution was positively skewed with a variation coefficient (CV = standard deviation/mean) greater than one (mean = €4,212.9, standard deviation = €5,047, CV = 1.2). In univariate analyses, there was no significant cost difference between the RSV-positive and RSV-negative cases. In the best multivariate model, the significant positive effect of RSV positivity on cost waned after the introduction of medical care variables and the length of stay. The results were sensitive to the specification of the model.

Conclusions

It was impossible to firmly conclude that hospitalization costs were higher for the RSV-positive cases.

Respiratory Syncytial Virus: A Systematic Review and Meta-Analysis of Tomographic Findings (2000-2022)

Human respiratory syncytial virus (RSV) is a main cause of medical referrals and hospitalizations in all infants, particularly among newborns. Nevertheless, relatively limited evidence on chest tomography (CT) findings has been collected. According to the PRISMA statement, Pubmed, Embase, and medRxiv were searched for eligible observational studies published up to 31 December 2022. Cases were categorized in children and adolescents (age < 18 years), adults and elderly (age ≥ 18 years), and immunocompromised patients, and then pooled in a random-effects model. Heterogeneity was assessed using the I2 statistics, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 10 studies (217 RSV cases) were retrieved (children, 37.3%; immunocompromised, 41.0%; adults, 21.7%). The most common features were signs of organizing pneumonia (33.65%, 95% confidence interval [95% CI] 22.39-47.27), followed by septal thickening (33.19%, 95% CI 21.76-47.03), ground glass opacities (GGOs; 28.03%, 95% CI 14.69-46.82), and tree-in-bud (TIB, 27.44%, 95% CI 15.04-44.68). Interestingly, up to 16.23% (95% CI 8.17-29.69) showed normal findings, while the large majority (76.06%, 95% CI 64.81-84.56) were characterized by bilateral involvement. Studies were highly heterogeneous without substantial reporting bias. Assuming children and adolescents as reference groups, healthy adults were characterized by a higher risk ratio [RR] for septal thickening (RR 3.878, 95% CI 1.253-12.000), nodular lesions (RR 20.197, 95% CI 1.286-317.082), and GGOs (RR 2.121, 95% CI 1.121-4.013). RSV cases are rarely assessed in terms of CT characteristics. Our study identified some specificities, suggesting that RSV infections evolve heterogeneous CT features in children/adolescents and adults, but the paucity of studies recommends a cautious appraisal.

Respiratory Syncytial Virus-An Update for Prenatal and Primary Health Providers

Respiratory syncytial virus (RSV) infection is a significant cause of morbidity and mortality among infants aged younger than 1 year, adults aged 65 years or older, and immunocompromised persons. Limited data exist on RSV infection in pregnancy and further research is needed. Strides are being made to develop vaccines, including vaccines for maternal immunization, as well as monoclonal antibodies for disease prevention.

New perspectives on respiratory syncytial virus surveillance at the national level: lessons from the COVID-19 pandemic

The emergence of SARS-CoV-2 and the resulting coronavirus disease 2019 (COVID-19) pandemic has led to the reconsideration of surveillance strategies for respiratory syncytial virus (RSV) and other respiratory viruses. The COVID-19 pandemic and the non-pharmaceutical interventions for COVID-19 had a substantial impact on RSV transmission in many countries, with close to no transmission detected during parts of the usual season of 2020–2021. Subsequent relaxation of social restrictions has resulted in unusual out-of-season resurgences of RSV in several countries, causing a higher healthcare burden and often a higher proportion of hospitalisations than usual among children older than 1 year in age [1]. In case of an emerging infectious disease with pandemic potential, preparedness to scale up surveillance for the emerging disease while continuing the maintenance of surveillance activities of pre-existing seasonal diseases is necessary.

Learning from the COVID-19 pandemic and considering the effects of this pandemic, we provide recommendations that can guide towards sustainable RSV surveillance with the potential to be integrated into the broader perspective of respiratory surveillance. https://bit.ly/40TsO0G

Summarizing Study Characteristics and Diagnostic Performance of Commercially Available Tests for Respiratory Syncytial Virus: A Scoping Literature Review in the COVID-19 Era

BACKGROUND

Nonpharmaceutical interventions to prevent the spread of coronavirus disease 2019 also decreased the spread of respiratory syncytial virus (RSV) and influenza. Viral diagnostic testing in patients with respiratory tract infections (RTI) is a necessary tool for patient management; therefore, sensitive and specific tests are required. This scoping literature review aimed to summarize the study characteristics of commercially available sample-to-answer RSV tests.

CONTENT

PubMed and Embase were queried for studies reporting on the diagnostic performance of tests for RSV in patients with RTI (published January 2005-January 2021). Information on study design, patient and setting characteristics, and published diagnostic performance of RSV tests were extracted from 77 studies that met predefined inclusion criteria. A literature gap was identified for studies of RSV tests conducted in adult-only populations (5.3% of total subrecords) and in outpatient (7.5%) or household (0.8%) settings. Overall, RSV tests with analytical time >30 min had higher published sensitivity (62.5%-100%) vs RSV tests with analytical time ≤30 min (25.7%-100%); this sensitivity range could be partially attributed to the different modalities (antigen vs molecular) used. Molecular-based rapid RSV tests had higher published sensitivity (66.7%-100%) and specificity (94.3%-100%) than antigen-based RSV tests (sensitivity: 25.7%-100%; specificity:80.3%-100%).

SUMMARY

This scoping review reveals a paucity of literature on studies of RSV tests in specific populations and settings, highlighting the need for further assessments. Considering the implications of these results in the current pandemic landscape, the authors preliminarily suggest adopting molecular-based RSV tests for first-line use in these settings.

RSV through the COVID-19 pandemic: Burden, shifting epidemiology, and implications for the future

Respiratory syncytial virus (RSV) represents a major global healthcare burden, particularly in those under 5 years of age. There is no available vaccine, with treatment limited to supportive care or palivizumab for high-risk children. Additionally, although a causal relationship has not been established, RSV has been associated with the development of asthma or wheezing in some children. The COVID-19 pandemic and the introduction of nonpharmaceutical interventions (NPIs) have caused substantial changes to RSV seasonality and epidemiology. Many countries have experienced an absence of RSV during the time of a typical season, followed by an out-of-season surge upon relaxation of NPI use. These dynamics have disrupted traditional RSV disease patterns and assumptions, but also provide a unique opportunity to learn more about the transmission of RSV and other respiratory viruses, as well as inform future approaches to RSV preventive strategies. Here, we review the RSV burden and epidemiology through the COVID-19 pandemic and discuss how new data may affect future decisions regarding RSV prevention.

Respiratory Syncytial Virus Prevention through Monoclonal Antibodies: A Cross-Sectional Study on Knowledge, Attitudes, and Practices of Italian Pediatricians

Respiratory Syncytial Virus (RSV) is a leading cause of morbidity and hospitalization in all infants. Many RSV vaccines and monoclonal antibodies (mAb) are currently under development to protect all infants, but to date preventive options are available only for preterms. In this study, we assessed the knowledge, attitudes, and practices towards RSV and the preventive use of mAb in a sample of Italian Pediatricians. An internet survey was administered through an internet discussion group, with a response rate of 4.4% over the potential respondents (No. 389 out of 8842, mean age 40.1 ± 9.1 years). The association of individual factors, knowledge, and risk perception status with the attitude towards mAb was initially inquired by means of a chi squared test, and all variables associated with mAb with p < 0.05 were included in a multivariable model calculating correspondent adjusted Odds Ratio (aOR) with 95% confidence intervals (95%CI). Of the participants, 41.9% had managed RSV cases in the previous 5 years, 34.4% had diagnosed RSV cases, and 32.6% required a subsequent hospitalization. However, only 14.4% had previously required mAb as immunoprophylaxis for RSV. Knowledge status was substantially inappropriate (actual estimate 54.0% ± 14.2, potential range 0-100), while the majority of participants acknowledged RSV as a substantial health threat for all infants (84.8%). In multivariable analysis, all these factors were characterized as positive effectors for having prescribed mAb (aOR 6.560, 95%CI 2.904-14.822 for higher knowledge score; aOR 6.579, 95%CI 2.919-14.827 for having a hospital background, and a OR 13.440, 95%CI 3.989; 45.287 for living in Italian Major Islands). In other words, reporting less knowledge gaps, having worked in settings with a higher risk of interaction with more severe cases, and being from Italian Major Islands, were identified as positive effectors for a higher reliance on mAb. However, the significant extent of knowledge gaps highlights the importance of appropriate medical education on RSV, its potential health consequences, and the investigational preventive interventions.

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.

Quinones as Promising Compounds against Respiratory Viruses: A Review

Respiratory viruses represent a world public health problem, giving rise to annual seasonal epidemics and several pandemics caused by some of these viruses, including the COVID-19 pandemic caused by the novel SARS-CoV-2, which continues to date. Some antiviral drugs have been licensed for the treatment of influenza, but they cause side effects and lead to resistant viral strains. Likewise, aerosolized ribavirin is the only drug approved for the therapy of infections by the respiratory syncytial virus, but it possesses various limitations. On the other hand, no specific drugs are licensed to treat other viral respiratory diseases. In this sense, natural products and their derivatives have appeared as promising alternatives in searching for new compounds with antiviral activity. Besides their chemical properties, quinones have demonstrated interesting biological activities, including activity against respiratory viruses. This review summarizes the activity against respiratory viruses and their molecular targets by the different types of quinones (both natural and synthetic). Thus, the present work offers a general overview of the importance of quinones as an option for the future pharmacological treatment of viral respiratory infections, subject to additional studies that support their effectiveness and safety.

Respiratory Syncytial Virus Prefusion F Protein Vaccine in Older Adults

BACKGROUND

Respiratory syncytial virus (RSV) is an important cause of acute respiratory infection, lower respiratory tract disease, clinical complications, and death in older adults. There is currently no licensed vaccine against RSV infection.

METHODS

In an ongoing, international, placebo-controlled, phase 3 trial, we randomly assigned, in a 1:1 ratio, adults 60 years of age or older to receive a single dose of an AS01_E-adjuvanted RSV prefusion F protein-based candidate vaccine (RSVPreF3 OA) or placebo before the RSV season. The primary objective was to show vaccine efficacy of one dose of the RSVPreF3 OA vaccine against RSV-related lower respiratory tract disease, confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR), during one RSV season. The criterion for meeting the primary objective was a lower limit of the confidence interval around the efficacy estimate of more than 20%. Efficacy against severe RSV-related lower respiratory tract disease and RSV-related acute respiratory infection was assessed, and analyses according to RSV subtype (A and B) were performed. Safety was evaluated.

RESULTS

A total of 24,966 participants received one dose of the RSVPreF3 OA vaccine (12,467 participants) or placebo (12,499). Over a median follow-up of 6.7 months, vaccine efficacy against RT-PCR-confirmed RSV-related lower respiratory tract disease was 82.6% (96.95% confidence interval [CI], 57.9 to 94.1), with 7 cases (1.0 per 1000 participant-years) in the vaccine group and 40 cases (5.8 per 1000 participant-years) in the placebo group. Vaccine efficacy was 94.1% (95% CI, 62.4 to 99.9) against severe RSV-related lower respiratory tract disease (assessed on the basis of clinical signs or by the investigator) and 71.7% (95% CI, 56.2 to 82.3) against RSV-related acute respiratory infection. Vaccine efficacy was similar against the RSV A and B subtypes (for RSV-related lower respiratory tract disease: 84.6% and 80.9%, respectively; for RSV-related acute respiratory infection: 71.9% and 70.6%, respectively). High vaccine efficacy was observed in various age groups and in participants with coexisting conditions. The RSVPreF3 OA vaccine was more reactogenic than placebo, but most adverse events for which reports were solicited were transient, with mild-to-moderate severity. The incidences of serious adverse events and potential immune-mediated diseases were similar in the two groups.

CONCLUSIONS

A single dose of the RSVPreF3 OA vaccine had an acceptable safety profile and prevented RSV-related acute respiratory infection and lower respiratory tract disease and severe RSV-related lower respiratory tract disease in adults 60 years of age or older, regardless of RSV subtype and the presence of underlying coexisting conditions. (Funded by GlaxoSmithKline Biologicals; AReSVi-006 ClinicalTrials.gov number, NCT04886596.).

Neosuberitenone, a New Sesterterpenoid Carbon Skeleton; New Suberitenones; and Bioactivity against Respiratory Syncytial Virus, from the Antarctic Sponge Suberites sp

Respiratory syncytial virus (RSV) is a highly contagious human pathogen that poses a significant threat to children under the age of two, and there is a current need for new small molecule treatments. The Antarctic sponge Suberites sp. is a known source of sesterterpenes, and following an NMR-guided fractionation procedure, it was found to produce several previously unreported metabolites. Neosuberitenone (1), with a new carbon scaffold herein termed the 'neosuberitane' backbone, six suberitenone derivatives (2-7), an ansellane-type terpenoid (8), and a highly degraded sesterterpene (9), as well as previously reported suberitenones A (10) and B (11), were characterized. The structures of all of the isolated metabolites including absolute configurations are proposed on the basis of NMR, HRESIMS, optical rotation, and XRD data. The biological activities of the metabolites were evaluated in a range of infectious disease assays. Suberitenones A, B, and F (3) were found to be active against RSV, though, along with other Suberites sp. metabolites, they were inactive in bacterial and fungal screens. None of the metabolites were cytotoxic for J774 macrophages or A549 adenocarcinoma cells. The selectivity of suberitenones A, B, and F for RSV among other infectious agents is noteworthy.

Prevention and Treatment Strategies for Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus (RSV) is a leading cause of severe lower respiratory tract disease, especially in young children. Despite its global impact on healthcare, related to its high prevalence and its association with significant morbidity, the current therapy is still mostly supportive. Moreover, while more than 50 years have passed since the first trial of an RSV vaccine (which unfortunately caused enhanced RSV disease), no vaccine has been approved for RSV prevention. In the last two decades, our understanding of the pathogenesis and immunopathology of RSV have continued to evolve, leading to significant advancements in RSV prevention strategies. These include both the development of new potential vaccines and the successful implementation of passive immunization, which, together, will provide coverage from infancy to old age. In this review, we provide an update of the current treatment options for acute disease (RSV-specific and -non-specific) and different therapeutic approaches focusing on RSV prevention.

Temporal dynamics of RSV shedding and genetic diversity in adults during the COVID-19 pandemic in a French hospital, early 2021

Human respiratory syncytial virus (RSV) is responsible of lower respiratory tract infections which may be severe in infants, elderly and immunocompromised adults. Europe and North-American countries have observed a massive reduction of RSV incidence during the 2020-2021 winter season. Using a systematic RSV detection coupled to SARS-CoV-2 for all adult patients admitted at the Foch hospital (Suresnes, France) between January and March 2021 (n = 11,324), only eight RSV infections in patients with prolonged RNA shedding were diagnosed. RSV whole-genome sequencing revealed that six and two patients were infected by RSV groups A and B, respectively. RSV carriage lasted from 7 to at least 30 days disregarding of RSV lineage. The most prolonged RSV shedding was observed in an asymptomatic patient. We detected novel patient-specific non-synonymous mutations in the G glycoprotein gene, including a double identical mutation in the repeated region for one patient. No additional mutation occurred in the RSV genome over the course of infection in the four patients tested for. In conclusion, our results suggest that the temporal shift in the RSV epidemic is not likely to be explained by the emergence of a high frequency, unreported variant. Moreover, prolonged RSV carriages in asymptomatic patients could play a role in virus spread.

[Postviral rhinosinusitis, focus on pathogenetic therapy]

Currently, the problem of acute rhinosinusitis continues to be relevant due to the frequent occurrence of this pathology. A certain difficulty is caused by the differential diagnosis of viral, post-viral and bacterial forms of rhinosinusitis, which carries the risks of irrational therapy. The authors of the article discuss the role of a viral infection in the etiology and pathogenesis of acute rhinosinusitis, the stages in the development of an inflammatory reaction on the mucous membrane of the nose and paranasal sinuses, and the disruption of mucociliary clearance. The authors consider options for the pathogenetic therapy of postviral sinusitis, concluding that the use of local combined preparations containing the mucolytic acetylcysteine and the vasoconstrictor component of tuaminoheptane sulfate is effective.

Parent tRNA Modification Status Determines the Induction of Functional tRNA-Derived RNA by Respiratory Syncytial Virus Infection

tRNA-derived RNA fragments (tRFs) are a recently discovered family of small noncoding RNAs (sncRNAs). We previously reported that respiratory syncytial virus (RSV) infection induces functional tRFs, which are derived from a limited subset of parent tRNAs, in airway epithelial cells. Such induction is also observed in nasopharyngeal wash samples from RSV patients and correlates to RSV genome copies, suggesting a clinical significance of tRFs in RSV infection. This work also investigates whether the modification of parent tRNAs is changed by RSV to induce tRFs, using one of the most inducible tRFs as a model. We discovered that RSV infection changed the methylation modification of adenine at position 57 in tRNA glutamic acid, with a codon of CTC (tRNA-GluCTC), and the change is essential for its cleavage. AlkB homolog 1, a previously reported tRNA demethylase, appears to remove methyladenine from tRNA-GluCTC, prompting the subsequent production of tRFs from the 5'-end of tRNA-GluCTC, a regulator of RSV replication. This study demonstrates for the first time the importance of post-transcriptional modification of tRNAs in tRF biogenesis following RSV infection, providing critical insights for antiviral strategy development.

Analysis of Template Variations on RNA Synthesis by Respiratory Syncytial Virus Polymerase

Respiratory syncytial virus (RSV) is a significant threat to infants and elderly individuals globally. Currently, there are no effective therapies or treatments for RSV infection because of an insufficient understanding of the RSV viral machinery. In this study, we investigated the effects of the template variations on RNA synthesis by the RSV polymerase through in vitro RNA synthesis assays. We confirmed the previously reported back-priming activity of the RSV polymerase, which is likely due to the secondary structure of the RNA template. We found that the expansion of the hairpin loop size of the RNA template abolishes the RSV polymerase back-priming activity. At the same time, it seemingly does not affect the de novo RNA synthesis activities of the RSV polymerase. Interestingly, our results show that the RSV polymerase also has a new primer-based terminal extension activity that adds nucleotides to the template and primer in a nonspecific manner. We also mapped the impact of the RNA 5' chemical group on its mobility in a urea-denaturing RNA gel shift assay. Overall, these results enhance our knowledge about the RNA synthesis processes of the RSV polymerase and may guide future therapeutic efforts to develop effective antiviral drugs for RSV treatment.

Respiratory Syncytial Virus Two-Step Infection Screen Reveals Inhibitors of Early and Late Life Cycle Stages

Human respiratory syncytial virus (hRSV) infection is a leading cause of severe respiratory tract infections. Effective, directly acting antivirals against hRSV are not available. We aimed to discover new and chemically diverse candidates to enrich the hRSV drug development pipeline. We used a two-step screen that interrogates compound efficacy after primary infection and a consecutive virus passaging. We resynthesized selected hit molecules and profiled their activities with hRSV lentiviral pseudotype cell entry, replicon, and time-of-addition assays. The breadth of antiviral activity was tested against recent RSV clinical strains and human coronavirus (hCoV-229E), and in pseudotype-based entry assays with non-RSV viruses. Screening 6,048 molecules, we identified 23 primary candidates, of which 13 preferentially scored in the first and 10 in the second rounds of infection, respectively. Two of these molecules inhibited hRSV cell entry and selected for F protein resistance within the fusion peptide. One molecule inhibited transcription/replication in hRSV replicon assays, did not select for phenotypic hRSV resistance and was active against non-hRSV viruses, including hCoV-229E. One compound, identified in the second round of infection, did not measurably inhibit hRSV cell entry or replication/transcription. It selected for two coding mutations in the G protein and was highly active in differentiated BCi-NS1.1 lung cells. In conclusion, we identified four new hRSV inhibitor candidates with different modes of action. Our findings build an interesting platform for medicinal chemistry-guided derivatization approaches followed by deeper phenotypical characterization in vitro and in vivo with the aim of developing highly potent hRSV drugs.

Preventing Respiratory Syncytial Virus in Children in France: A Narrative Review of the Importance of a Reinforced Partnership Between Parents, Healthcare Professionals, and Public Health Authorities

The highly contagious respiratory syncytial virus (RSV) is responsible for up to approximately 50,000 hospitalisations during each RSV season in children aged under 5 years in France, with the burden greatest in infants younger than 1 year who were born at term. There is a need for a strategy to universally protect young children from RSV infection, and thereby reduce the pressure that RSV places every year on RSV-infected children, their parents, and French healthcare systems. Potential strategies currently undergoing clinical investigation include passive immunisation via maternal vaccination or administration of long-acting monoclonal antibodies at or soon after birth, followed by vaccination later in infancy or childhood. An ongoing partnership and collaboration between parents, public health authorities, and frontline primary healthcare will need to be reinforced once these new RSV prevention strategies are available, to facilitate their use and ensure that all children receive adequate protection from the start of their first RSV season.

Impact of Respiratory Syncytial Virus and Influenza Virus Infection in the Adult Population in Spain between 2012 and 2020

Respiratory syncytial virus (RSV) infection is increasingly recognized as a cause of significant morbidity and mortality in adults. We aimed to estimate the rates of age-specific hospitalization and in-hospital mortality caused by acute lower respiratory tract infections (ALRTIs) in Spain between 2012 and 2020 and to compare the relative impact of RSV and influenza virus infection in adults. We used the discharge reports from the Minimum Basic Data Set to retrospectively analyze hospital discharge data on the basis of the ICD-9-CM and ICD-10-CM diagnosis codes. A total of 1,518,244 patients were hospitalized for ALRTIs, of whom 137,794 (9.1%) were admitted for RSV-related infections and 46,288 (3.0%) for influenza-related infections. In patients aged 60 years or older, the hospitalization rates (per 100,000 population) were estimated at 1.69 (95% CI 1.68-1.70) and 2.72 (95% CI 2.71-2.73) for RSV and influenza patients, respectively. However, in-hospital mortality rates were significantly higher among RSV patients than among influenza patients, 7.91% (95% CI 7.89-7.93) (83.0% of all RSV-related deaths) versus 6.91% (95% CI 6.89-6.93) (85.6% of all influenza-related deaths), respectively (p = 0.007). RSV-associated in-hospital mortality increases exponentially with age, posing a greater risk for older adults, particularly frail and high-risk patients.

Impact of COVID-19 Pandemic and Lockdown on the Epidemiology of RSV-Mediated Bronchiolitis: Experience from Our Centre

Background: The COVID-19 pandemic has dramatically affected the global epidemiology of other infectious respiratory diseases, leading to a significant decrease in their incidence. Hence, we aimed to characterize the epidemiology of RSV-bronchiolitis in children. Methods: children aged ≤2 years diagnosed with RSV-mediated bronchiolitis admitted to our Unit from October 2018 to December 2021, were retrospectively enrolled. Results: We included 95 patients (M/F = 46/49; mean age 7.56 ± 6.6 months). Specifically, 17 infants in 2018, 34 in 2019, 0 during 2020 lockdown, 1 during 2020 post-lockdown, and 43 in 2021. Incidence was significantly lower in 2020 compared with 2018, 2019 and 2021 (p < 0.05). No differences were found concerning need for respiratory support. Discussion: Several factors related to SARS-CoV-2 pandemic, especially restrictive measures, may have contributed to a significant reduction in hospitalizations due to RSV. The new outbreak in RSV infection-related hospitalizations reported between October and December 2021 has been suggested it may be due to an increased number of susceptible individuals to RSV infection. Conclusion: The experience of the SARS-CoV-2 outbreak has led to a marked decrease in other viral respiratory infections, such as RSV. This may pave the way for new approaches in preventing respiratory infections, highlighting the role of preventive measures.

The clinical impact of multiple prevention strategies for respiratory syncytial virus infections in infants and high-risk toddlers in the United States

BACKGROUND

Respiratory syncytial virus (RSV) remains a leading cause of medically-attended acute respiratory infection in infants and children. With multiple preventative interventions under development, accurate estimates of health care resource utilization are essential for policy decision making.

METHODS

We developed a literature-based decision-tree model that estimated annual medically-attended RSV (MA-RSV) lower respiratory tract infection (LRTI) and non-LRTI episodes in the US for all infants and for high-risk toddlers. The model accounted for the gestational age and birth-month of infants, and the seasonal variation in RSV incidence. The impact of no prophylaxis, palivizumab, maternal vaccine, and long-acting monoclonal antibody (mAb) interventions was estimated.

RESULTS

We estimated 1.23 million (range: 0.96 million-1.40 million) annual MA-RSV LRTI/non-LRTI episodes comprised of 1.19 million (range: 0.93 million-1.36 million) emergency department (ED) and outpatient visits, and 39,040 (range: 32,726-45,851) hospitalizations. Outpatient and ED visits were comprised of 586,034 (range: 430,595-718,868) LRTIs and 608,733 (range: 495,705-644,658) non-LRTIs. The long-acting mAb intervention resulted in the greatest number of averted outpatient and ED episodes (310,997 [53%] LRTIs; 284,305 [47%] non-LRTIs) and hospitalizations (21,845 [56%]). Full-term infants constitute the highest proportion of episodes across all interventions.

CONCLUSIONS

MA-RSV disease is substantial in infants and high-risk toddlers. Long-acting mAbs are most effective at reducing the number of MA-RSV LRTI/non-LRTI episodes, and the only intervention that prevents disease in older infants (≥6 months old).

Respiratory syncytial virus infection changes the piwi-interacting RNA content of airway epithelial cells

Piwi-interacting RNAs (piRNAs) are small non-coding RNAs (sncRNAs) of about 26–32 nucleotides in length and represent the largest class of sncRNA molecules expressed in animal cells. piRNAs have been shown to play a crucial role to safeguard the genome, maintaining genome complexity and integrity, as they suppress the insertional mutations caused by transposable elements. However, there is growing evidence for the role of piRNAs in controlling gene expression in somatic cells as well. Little is known about changes in piRNA expression and possible function occurring in response to viral infections. In this study, we investigated the piRNA expression profile, using a human piRNA microarray, in human small airway epithelial (SAE) cells infected with respiratory syncytial virus (RSV), a leading cause of acute respiratory tract infections in children. We found a time-dependent increase in piRNAs differentially expressed in RSV-infected SAE cells. We validated the top piRNAs upregulated and downregulated at 24 h post-infection by RT-qPCR and identified potential targets. We then used Gene Ontology (GO) tool to predict the biological processes of the predicted targets of the most represented piRNAs in infected cells over the time course of RSV infection. We found that the most significant groups of targets of regulated piRNAs are related to cytoskeletal or Golgi organization and nucleic acid/nucleotide binding at 15 and 24 h p.i. To identify common patterns of time-dependent responses to infection, we clustered the significantly regulated expression profiles. Each of the clusters of temporal profiles have a distinct set of potential targets of the piRNAs in the cluster Understanding changes in piRNA expression in RSV-infected airway epithelial cells will increase our knowledge of the piRNA role in viral infection and might identify novel therapeutic targets for viral lung-mediated diseases.

Acteoside attenuates RSV-induced lung injury by suppressing necroptosis and regulating metabolism

Background: Necroptosis and inflammation are closely related to the pathogenesis of respiratory syncytial virus (RSV). Acteoside (AC), a natural phenylpropanoid glycoside from Kuding Tea, has significant anti-RSV effect. However, the roles of AC on RSV-induced lung necroptosis and inflammation are yet to be elucidated.

Methods: The effects of AC were investigated in BALB/c mice and A549 cells. Lung histopathology was observed through H&amp;E staining. The viral titer was assessed via plaque assay. The RSV-F expression was determined by RT-qPCR and immunohistochemistry assay. The levels of cytokines were detected by ELISA and RT-qPCR. The necroptosis rate and mitochondrial membrane potential were evaluated via flow cytometry. The expressions of HMGB1/NF-κB and RIP1/RIP3/MLKL/PGAM5/DRP1 were detected by western blot. Additionally, untargeted metabolomics was conducted to investigate the metabolic profiles and related metabolic pathways via Gas Chromatography-Mass Spectrometry.

Results: The results showed that compared with the RSV-infected group, AC treatment significantly attenuated lung pathological damage, virus replication, and cytokines levels. AC also alleviated RSV-induced necroptosis and mitochondrial dysfunction in vitro and in vivo. Moreover, AC treatment down-regulated the expression of HMGB1, p-Iκbα/Iκbα, p-p65/p65, RIP1, RIP3, MLKL, PGAM5, and DRP1. Furthermore, metabolomic analyses suggested that the perturbations in major metabolites of AC therapy were related to variations in amino acid and energy metabolism.

Conclusion: Our findings validated the beneficial effects of AC in suppressing necroptosis and regulating metabolism, suggesting AC may be a new drug candidate for RSV infection.

NRF2 Regulates Cystathionine Gamma-Lyase Expression and Activity in Primary Airway Epithelial Cells Infected with Respiratory Syncytial Virus

Cystathionine-y-lyase (CSE) is a critical enzyme for hydrogen sulfide (H2S) biosynthesis and plays a key role in respiratory syncytial virus (RSV) pathogenesis. The transcription factor NRF2 is the master regulator of cytoprotective and antioxidant gene expression, and is degraded during RSV infection. While some evidence supports the role of NRF2 in CSE gene transcription, its role in CSE expression in airway epithelial cells is not known. Here, we show that RSV infection decreased CSE expression and activity in primary small airway epithelial (SAE) cells, while treatment with tert-butylhydroquinone (tBHQ), an NRF2 inducer, led to an increase of both. Using reporter gene assays, we identified an NRF2 response element required for the NRF2 inducible expression of the CSE promoter. Electrophoretic mobility shift assays demonstrated inducible specific NRF2 binding to the DNA probe corresponding to the putative CSE promoter NRF2 binding sequence. Using chromatin immunoprecipitation assays, we found a 50% reduction in NRF2 binding to the endogenous CSE proximal promoter in SAE cells infected with RSV, and increased binding in cells stimulated with tBHQ. Our results support the hypothesis that NRF2 regulates CSE gene transcription in airway epithelial cells, and that RSV-induced NRF2 degradation likely accounts for the observed reduced CSE expression and activity.

Antiviral activity of extracellular vesicles derived from respiratory syncytial virus-infected airway epithelial cells

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infections in children and elderly. No vaccine or effective treatment is currently available for RSV. Extracellular vesicles (EVs) are microvesicles known to carry biologically active molecules, including RNA, DNA and proteins (i.e. cargo). Viral infections can induce profound changes in EV cargo, and the cargo can modulate cellular responses of recipient cells. We have recently shown that EVs isolated from RSV-infected cells were able to activate innate immune response by inducing cytokine and chemokine release from human monocytes and airway epithelial cells, however, we did not investigate the potential antiviral contribution of EVs to a subsequent infection. The objective of this study was to assess the presence of innate immune mediators, including type I and III interferons (IFNs) in EVs released from airway epithelial cells infected with RSV, and their potential role in modulating viral replication in recipient cells. EV-derived from cells infected with RSV were associated with significant amounts of cytokine and chemokines, as well as IFN-β and -λ, compared to EVs isolated from mock-infected cells. Cells treated with RSV-EVs showed significantly lower levels of viral replication compared to untreated or mock-EV-treated RSV infected cells. Cellular pretreatment with Cerdulatinib, an IFN receptor signaling inhibitor, inhibited the antiviral activity of RSV-EVs in recipient airway epithelial cells. Furthermore, treatment of A549 cells with RSV-EVs induced the expression of IFN-dependent antiviral genes, supporting the idea that RSV-EVs exerts their antiviral activity through an interferon-dependent mechanism. Finally, we determined the concentrations of soluble and EV-associated IFN-β and IFN-λ in five nasopharyngeal secretions (NPS) of children with viral infections. There were significant levels of IFN-λ in NPS and NPS-derived EVs, while IFN-β was not detected in either of the two types of samples. EVs released from RSV-infected cells could represent a potential therapeutic approach for modulating RSV replication in the airways.

Recent Progress in the Discovery and Development of Monoclonal Antibodies against Viral Infections

Monoclonal antibodies (mAbs), the new revolutionary class of medications, are fast becoming tools against various diseases thanks to a unique structure and function that allow them to bind highly specific targets or receptors. These specialized proteins can be produced in large quantities via the hybridoma technique introduced in 1975 or by means of modern technologies. Additional methods have been developed to generate mAbs with new biological properties such as humanized, chimeric, or murine. The inclusion of mAbs in therapeutic regimens is a major medical advance and will hopefully lead to significant improvements in infectious disease management. Since the first therapeutic mAb, muromonab-CD3, was approved by the U.S. Food and Drug Administration (FDA) in 1986, the list of approved mAbs and their clinical indications and applications have been proliferating. New technologies have been developed to modify the structure of mAbs, thereby increasing efficacy and improving delivery routes. Gene delivery technologies, such as non-viral synthetic plasmid DNA and messenger RNA vectors (DMabs or mRNA-encoded mAbs), built to express tailored mAb genes, might help overcome some of the challenges of mAb therapy, including production restrictions, cold-chain storage, transportation requirements, and expensive manufacturing and distribution processes. This paper reviews some of the recent developments in mAb discovery against viral infections and illustrates how mAbs can help to combat viral diseases and outbreaks.

Hydrogen Sulfide Donor GYY4137 Rescues NRF2 Activation in Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) can cause severe respiratory illness in infants, immunocompromised, and older adults. Despite its burden, no vaccine or specific treatment is available. RSV infection is associated with increased reactive oxygen species (ROS) production, degradation of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), and decreased antioxidant enzymes (AOEs), leading to oxidative damage and lung injury. Hydrogen sulfide (H2S) is an endogenous gaseous molecule that plays a physiological role in numerous cellular processes and a protective role in multiple pathological conditions, displaying vasoactive, cytoprotective, anti-inflammatory, and antioxidant activities. H2S can promote NRF2 activation through the sulfhydration of Kelch-like ECH-associated protein 1, the cytoplasmic repressor of NRF2. Here we investigated whether increasing cellular H2S levels could rescue NRF2 and NRF2-dependent gene expression in RSV-infected primary airway epithelial cells. We found that treatment with the H2S donor GYY4137 significantly increased NRF2 levels and AOEs gene expression by decreasing KEAP1 levels, and by modulating pathways involved in RSV-induced NRF2 degradation, such as NRF2 ubiquitination, and promyelocytic leukemia (PML) protein levels. These results suggest that the administration of exogenous H2S can positively impact the altered redox balance associated with RSV infection, which represents an important determinant of RSV-induced lung disease.

Nasal-spraying Bacillus spores as an effective symptomatic treatment for children with acute respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is a leading cause of Acute Respiratory Tract Infections (ARTIs) in young children. However, there is currently no vaccine or treatment available for children. Here, we demonstrated that nasal-spraying probiotics containing 5 billion of Bacillus spores (LiveSpo Navax) is an effective symptomatic treatment in a 6-day randomized controlled clinical study for RSV-infected children (n = 40–46/group). Navax treatment resulted in 1-day faster recovery-time and 10–50% better efficacy in relieving ARTI symptoms. At day 3, RSV load and level of pro-inflammatory cytokines in nasopharyngeal samples was reduced by 630 folds and 2.7–12.7 folds respectively. This showed 53-fold and 1.8–3.6-fold more effective than those in the control-standard of care-group. In summary, nasal-spraying Bacillus spores can rapidly and effectively relieve symptoms of RSV-induced ARTIs while exhibit strong impacts in reducing viral load and inflammation. Our nasal-spraying probiotics may provide a basis for simple-to-use, low-cost, and effective treatment against viral infection in general.