Respiratory syncytial virus and parainfluenza virus

Possible respiratory syncytial virus infection presenting as diffuse alveolar hemorrhage in an elderly treated with systemic corticosteroid: A case report

Introduction

Respiratory syncytial virus infection is gaining interest in the elderly due to its growing morbidity and mortality. We present a Case of respiratory syncytial virus infection presenting as diffuse alveolar hemorrhage that was highly responsive to systemic corticosteroid in an elderly patient.

Case presentation

An 82-year old man was admitted to the intensive care unit with worsening hypoxic respiratory failure. Chest radiograph showed non-homogeneous air space opacities. Bronchoalveolar lavage showed a finding of alveolar hemorrhage. The diagnosis of diffuse alveolar hemorrhage was made and high-dose systemic corticosteroid was given. However, concomitant respiratory syncytial virus infection was later confirmed. Therefore, ribavirin and human immunoglobulin were added. During the course of his treatment, the steroid was stopped and restarted. Interestingly, the clinical course was highly responsive to systemic corticosteroid.

Conclusion

It appears that diffuse alveolar hemorrhage in this patient may have been due to an immunological process caused by respiratory syncytial virus. Therefore, corticosteroid therapy was highly effective in improving the patient's hemoptysis and hypoxic respiratory failure. We suggest that further studies are required on the use of steroid in this subset of patients with respiratory syncytial virus lower respiratory tract infection.

Community-Acquired Respiratory Viruses Post-Lung Transplant

Survival in lung transplant recipients (LTRs) lags behind heart, liver, and kidney transplant, in part due to the direct and indirect effects of infection. LTRs have increased susceptibility to infection due to the combination of a graft continually exposed to the outside world, multiple mechanisms for impaired mucus clearance, and immunosuppression. Community-acquired respiratory viral infections (CARVs) are common in LTRs. Picornaviruses have roughly 40% cumulative incidence followed by respiratory syncytial virus and coronaviruses. Although single-center retrospective and prospective series implicate CARV in rejection and mortality, conclusive evidence for and well-defined mechanistic links to long-term outcome are lacking. Treatment of viral infections can be challenging except for influenza. Future studies are needed to develop better treatments and clarify the links between CARV and long-term outcomes.

Seasonality, molecular epidemiology, and virulence of Respiratory Syncytial Virus (RSV): A perspective into the Brazilian Influenza Surveillance Program

Background

Respiratory Syncytial Virus (RSV) is the main cause of pediatric morbidity and mortality. The complex evolution of RSV creates a need for worldwide surveillance, which may assist in the understanding of multiple viral aspects.

Objectives

This study aimed to investigate RSV features under the Brazilian Influenza Surveillance Program, evaluating the role of viral load and genetic diversity in disease severity and the influence of climatic factors in viral seasonality.

Methodology

We have investigated the prevalence of RSV in children up to 3 years of age with severe acute respiratory infection (SARI) in the state of Espirito Santo (ES), Brazil, from 2016 to 2018. RT-qPCR allowed for viral detection and viral load quantification, to evaluate association with clinical features and mapping of local viral seasonality. Gene G sequencing and phylogenetic reconstruction demonstrated local genetic diversity.

Results

Of 632 evaluated cases, 56% were caused by RSV, with both subtypes A and B co-circulating throughout the years. A discrete inverse association between average temperature and viral circulation was observed. No correlation between viral load and disease severity was observed, but children infected with RSV-A presented a higher clinical severity score (CSS), stayed longer in the hospital, and required intensive care, and ventilatory support more frequently than those infected by RSV-B. Regarding RSV diversity, some local genetic groups were observed within the main genotypes circulation RSV-A ON1 and RSV-B BA, with strains showing modifications in the G gene amino acid chain.

Conclusion

Local RSV studies using the Brazilian Influenza Surveillance Program are relevant as they can bring useful information to the global RSV surveillance. Understanding seasonality, virulence, and genetic diversity can aid in the development and suitability of antiviral drugs, vaccines, and assist in the administration of prophylactic strategies.

Update on respiratory syncytial virus hospitalizations among U.S. preterm and term infants before and after the 2014 American Academy of Pediatrics policy on immunoprophylaxis: 2011-2017

Palivizumab is the only licensed respiratory syncytial virus (RSV) immunoprophylaxis (IP) available to prevent severe RSV disease in high-risk pediatric populations, including infants born at 29-34 weeks' gestational age (wGA). In 2014, the American Academy of Pediatrics (AAP) stopped recommending RSV IP use for otherwise healthy 29-34 wGA infants and stated that 29-34 wGA infants and term infants have similar RSV hospitalization (RSVH) rates. This study aimed to compare RSV IP use and RSVH rates in 29-34 wGA infants and term infants during the 3 RSV seasons before and after the 2014 AAP policy change. RSV IP use in otherwise healthy infants 29-30, 31-32, and 33-34 wGA was estimated from pharmacy or outpatient medical claims for palivizumab. RSVH rates in the first 6 months of life were calculated per 100 infant-seasons. RSVH rate ratios were used to compare preterm infants and term infants before and after the policy change. Across infant cohorts (29-34 wGA) and chronologic age groups (<3 months and 3-<6 months), absolute decreases in RSV IP use between the combined 2011-2014 seasons and 2014-2017 seasons ranged from 7% to 38% and from 68% to 97%, respectively. Compared with 2011-2014, the RSVH risk increased 2.09-fold (P< .001) and 1.76-fold (P< .001) in 2014-2017 for infants born at 29-34 wGA and aged <6 months with commercial and Medicaid insurance, respectively. Overall, RSV IP use declined in the RSV seasons following the 2014 RSV IP policy change, and RSVH increased among 29-34 wGA infants aged <6 months.

In silico virtual screening of lead compounds for major antigenic sites in respiratory syncytial virus fusion protein

Human respiratory syncytial virus (RSV) is a leading ubiquitous respiratory pathogen in newborn infants, young children, and the elderly, with no vaccine available to date. The viral fusion glycoprotein (RSV F) plays an essential role in the infection process, and it is a primary target of neutralizing antibodies, making it an attractive site for vaccine development. With this in view, there is a persistent need to identify selective antiviral drugs against RSV, targeting the major antigenic sites on the F protein. We aimed to conduct a robust in silico high-throughput drug screening of one million compounds to explore potential inhibitors that bind the major antigenic site Ø and site II on RSV F protein, which are the main target of neutralizing antibodies (NAb). We utilized the three-dimensional crystallographic structure of both antigenic site Ø on pre-F and antigenic II on post-F to screen for potential anti-RSV inhibitors. A library of one million small compounds was docked to explore lead binders in the major antigenic sites by using virtual lab bench CLC Drug Discovery. We also performed Quantitative Structure-Activity and Relationship (QSAR) for the lead best binders known for their antiviral activity. Among one million tested ligands, seven ligands (PubChem ID: 3714418, 24787350, 49828911, 24802036, 79824892, 49726463, and 3139884) were identified as the best binders to neutralizing epitopes site Ø and four ligands (PubChem ID: 865999, 17505357, 24802036, and 24285058) to neutralizing epitopes site II, respectively. These binders exhibited significant interactions with neutralizing epitopes on RSV F, with an average of six H bonds, docking energy of - 15.43 Kcal·mol^-1, and minimum interaction energy of - 7.45 Kcal·mol^-1. Using in silico virtual screening, we identified potential RSV inhibitors that bind two major antigenic sites on the RSV F protein. Using structure-based design and combination-based drug therapy, identified molecules could be modified to generate the next generation anti-RSV drugs.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42247-021-00213-6.

Repeated Dose Toxicity Study and Developmental and Reproductive Toxicology Studies of a Respiratory Syncytial Virus Candidate Vaccine in Rabbits and Rats

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infections, and vaccines are needed to treat young children and older adults. One of GSK's candidate vaccines for RSV contains recombinant RSVPreF3 protein maintained in the prefusion conformation. The differences in immune function of young children and older adults potentially require different vaccine approaches. For young children, anti-RSV immunity can be afforded during the first months of life by vaccinating the pregnant mother during the third trimester with unadjuvanted RSVPreF3, which results in protection of the infant due to the transplacental passage of anti-RSV maternal antibodies. For older adults with a waning immune response, the approach is to adjuvant the RSVPreF3 vaccine with AS01 to elicit a more robust immune response.The local and systemic effects of biweekly intramuscular injections of the RSVPreF3 vaccine (unadjuvanted, adjuvanted with AS01, or coadministered with a diphtheria-tetanus-acellular pertussis vaccine) was tested in a repeated dose toxicity study in rabbits. After three intramuscular doses, the only changes observed were those commonly related to a vaccine-elicited inflammatory reaction. Subsequently, the effects of unadjuvanted RSVPreF3 vaccine on female fertility, embryo-fetal, and postnatal development of offspring were evaluated in rats and rabbits. There were no effects on pregnancy, delivery, lactation, or the pre- and postnatal development of offspring.In conclusion, the RSVPreF3 vaccine was well-tolerated locally and systemically and was not associated with any adverse effects on female reproductive function or on the pre- and postnatal growth and development of offspring.

Prognostic Implications of CT Feature Analysis in Patients with COVID-19: a Nationwide Cohort Study

BACKGROUND

Few studies have classified chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) and analyzed their correlations with prognosis. The present study aimed to evaluate retrospectively the clinical and chest CT findings of COVID-19 and to analyze CT findings and determine their relationships with clinical severity.

METHODS

Chest CT and clinical features of 271 COVID-19 patients were assessed. The presence of CT findings and distribution of parenchymal abnormalities were evaluated, and CT patterns were classified as bronchopneumonia, organizing pneumonia (OP), or diffuse alveolar damage (DAD). Total extents were assessed using a visual scoring system and artificial intelligence software. Patients were allocated to two groups based on clinical outcomes, that is, to a severe group (requiring O₂ therapy or mechanical ventilation, n = 55) or a mild group (not requiring O₂ therapy or mechanical ventilation, n = 216). Clinical and CT features of these two groups were compared and univariate and multivariate logistic regression analyses were performed to identify independent prognostic factors.

RESULTS

Age, lymphocyte count, levels of C-reactive protein, and procalcitonin were significantly different in the two groups. Forty-five of the 271 patients had normal chest CT findings. The most common CT findings among the remaining 226 patients were ground-glass opacity (98%), followed by consolidation (53%). CT findings were classified as OP (93%), DAD (4%), or bronchopneumonia (3%) and all nine patients with DAD pattern were included in the severe group. Uivariate and multivariate analyses showed an elevated procalcitonin (odds ratio [OR], 2.521; 95% confidence interval [CI], 1.001-6.303, P = 0.048), and higher visual CT scores (OR, 1.137; 95% CI, 1.042-1.236; P = 0.003) or higher total extent by AI measurement (OR, 1.048; 95% CI, 1.020-1.076; P < 0.001) were significantly associated with a severe clinical course.

CONCLUSION

CT findings of COVID-19 pneumonia can be classified into OP, DAD, or bronchopneumonia patterns and all patients with DAD pattern were included in severe group. Elevated inflammatory markers and higher CT scores were found to be significant predictors of poor prognosis in patients with COVID-19 pneumonia.

Epidemiology of Respiratory Syncytial Virus Across Five Influenza Seasons Among Adults and Children One Year of Age and Older-Washington State, 2011/2012-2015/2016

BACKGROUND

Vaccines and novel prophylactics against respiratory syncytial virus (RSV) are in development. To provide a baseline for evaluating these interventions, we characterized the incidence and molecular epidemiology of RSV in persons aged ≥1 year.

METHODS

We identified patients with medically attended acute respiratory illness (MAARI) from the 2011/2012 through 2015/2016 influenza seasons among members of Kaiser Permanente Washington. We estimated the cumulative incidence of MAARI for laboratory-confirmed RSV or influenza infection.

RESULTS

Annual cohorts ranged from 82 266 to 162 633 individuals, 14% of whom were children aged 1 to 17 years. Cumulative incidence of RSV each season ranged from 14 per 1000 population (95% confidence interval [CI], 12-16) to 22 per 1000 (95% CI, 19-25). Incidence of RSV was greater than influenza in children aged 12-23 months and 2-4 years; incidence of influenza was greater in other age groups. Respiratory syncytial virus subtype A dominated in 2011/2012, 2012/2013, and 2015/2016, with ON1 being the most common genotype. Respiratory syncytial virus subtype B dominated in 2013/2014 and 2014/2015, primarily of the BA genotype.

CONCLUSIONS

The burden of RSV is comparable to that of influenza across the life course. These results provide a baseline for evaluating the impact of new RSV interventions on the epidemiology of RSV.

The landscape of extrapulmonary manifestations of human parainfluenza viruses: A systematic narrative review

Human parainfluenza virus (HPIV) infection is associated with every kind of respiratory tract illnesses, including the common cold, laryngotracheobronchitis (i.e. croup), tracheobronchitis, bronchiolitis, and pneumonia, in both children and adults. Although HPIVs are common respiratory pathogens, there are increasing reports about extrapulmonary manifestations of HPIVs infection. Each of the HPIVs could produce infection of other organs (central nervous system, heart, myocardium, etc.) in all age groups who are either immunocompetent or immunocompromised. This review aimed at summarizing the available data on clinical manifestations of HPIV infection outside the respiratory tract from 1961 to 2020. The findings support the possibility of extrapulmonary infections that were thought to be due to rare host genetic or immunologic defects in infected patients. These findings highlight the fact that extrapulmonary dissemination of HPIV can occur, but the association is not clearly demonstrated. Our data support the hypothesis that HPIV infection is one of the possible causes of these alterations and may even be the direct cause in some cases.

Respiratory Syncytial Virus-Associated Hospitalization Rates among US Infants: A Systematic Review and Meta-Analysis

BACKGROUND

Although global reviews of infant RSV burden exist, none have summarized data from the United States or evaluated how RSV burden estimates are influenced by variations in study design.

METHODS

We performed a systematic literature review and meta-analysis of studies describing RSV-associated hospitalization rates among US infants and examined the impact of key study characteristics on these estimates.

RESULTS

We reviewed 3328 articles through August 14, 2020 and identified 25 studies with 31 unique estimates of RSV-associated hospitalization rates. Among US infants <1 year of age, annual rates ranged from 8.4 to 40.8 per 1000 with a pooled rate= 19.4 (95%CI: 17.9-20.9). Study type influenced RSV-associated hospitalization rates (P=.003), with active surveillance studies having pooled rates (11.0; 95%CI: 9.8-12.2) that were half that of studies based on administrative claims (21.4; 95%CI: 19.5-23.3) or modeling approaches (23.2; 95%CI: 20.2-26.2).

CONCLUSIONS

Applying our pooled rates to the 2020 US birth cohort suggests that 79,850 (95%CI: 73,680-86,020) RSV-associated infant hospitalizations occur each year. The full range of RSV-associated hospitalization rates identified in our review can better inform future evaluations of RSV prevention strategies. More research is needed to better understand differences in estimated RSV burden across study design.

Respiratory Syncytial Virus Infection Reduces Kynurenic Acid Production and Reverses Th17/Treg Balance by Modulating Indoleamine 2,3-Dioxygenase (IDO) Molecules in Plasmacytoid Dendritic Cells

Background

Respiratory syncytial virus (RSV) infection causes a world-wide medical and economic burden. This study analyzed the effects of RSV infection on plasmacytoid dendritic cells (pDCs) and evaluated the immunopathogenesis of RSV infection by measuring relative numbers of FoxP3+ Treg cells and Th17 cells.

Material/Methods

pDCs were isolated from human blood samples, purified using magnetic microbeads, and treated with RSV, IFN-γ, or vehicle. These cells were mixed with purified CD4+ T cells to yield preparations of pDCs+T cells+vehicle, pDCs+T cells+RSV, and pDCs+T cells+IFN-γ. Preparations of pDCs+T cells+RSV were also incubated with an inducer or an inhibitor of indoleamine 2,3-dioxygenase (IDO). Kynurenic acid concentration was measured by high-pressure liquid chromatography (HPLC). The differentiation of Foxp3+ Treg and Th17 cells from CD4+ T cells was determined by flow cytometry.

Results

pDCs were successfully isolated and purified using the magnetic microbeads. Compared with preparations of pDCs+T cells+vehicle, RSV infection (pDCs+T cells+RSV) significantly reduced and IFN-γ treatment (pDC+T cells+IFN-γ) increased kynurenic acid concentrations and the proportions of Foxp3⁺ Tregs (p<0.05 each). Conversely, RSV infection increased and IFN-γ treatment decreased the proportions of Th17 cells (p<0.05 each). RSV infection reduced kynurenic acid concentrations and inhibited the transformation from Th17 to Foxp3⁺ Tregs by modulating IDO molecules.

Conclusions

RSV infection reduced the production of kynurenic acid and inhibited transformation from Th17 to Foxp3⁺ Tregs (Th17/Treg balance) by modulating IDO molecules in pDCs.

Evaluation of immuview RSV antigen test (SSI siagnostica) and BinaxNOW RSV card (alere) for rapid detection of respiratory syncytial virus in retrospectively and prospectively collected respiratory samples

Human orthopneumovirus, formerly known as respiratory syncytial virus (RSV), is a frequent cause of hospitalization among infants due to respiratory tract infection. Fast, reliable, and easy to perform tests are needed to optimize treatment and to identify children that should be contact isolated to avoid nosocomial outbreaks. We prospectively tested 200 respiratory samples with a new assay (ImmuView RSV Antigen Test, SSI Diagnostica) and compared the results to the Alere BinaxNOW RSV Card by using our laboratory-developed real-time reverse transcription polymerase chain reaction (PCR) as reference. In addition, 300 retrospectively collected respiratory samples were included in the study. The sensitivities of both antigen kits were very low (<50%). Sensitivities were higher when samples came from children less than 6 years, when samples came from nasopharynx or lower respiratory airways, or when samples were positive for RSV serotype A compared to when samples came from adults, samples were throat swabs, or samples were positive for RSV serotype B. In conclusion, the ImmuView RSV antigen kit did not perform well and may at the most be used as a quick guidance for clinical decision. Thus, it cannot stand alone without reverse transcription PCR confirmation of negative results.

Electrochemical Immunosensors Based on Screen-Printed Gold and Glassy Carbon Electrodes: Comparison of Performance for Respiratory Syncytial Virus Detection

This paper presents the development and comparison of label-free electrochemical immunosensors based on screen-printed gold and glassy carbon (GC) disc electrodes for efficient and rapid detection of respiratory syncytial virus (RSV). Briefly, the antibody specific to the F protein of RSV was successfully immobilized on modified electrodes. Antibody coupling on the Au surface was conducted via 4-aminothiophenol (4-ATP) and glutaraldehyde (GA). The GC surface was modified with poly-L-lysine (PLL) for direct anti-RSV conjugation after EDC/NHS (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-Hydroxysuccinimide) activation. Electrochemical characterizations of the immunosensors were carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). GC-based immunosensors show a dynamic range of antigen detection from 1.0 × 105 PFU/mL to 1.5×107 PFU/mL, more than 1.0 × 105 PFU/mL to 1.0 × 107 PFU/mL for the Au-based sensor. However, the GC platform is less sensitive and shows a higher detection limit (LOD) for RSV. The limit of detection of the Au immunosensor is 1.1 × 103 PFU/mL, three orders of magnitude lower than 2.85 × 106 PFU/mL for GC. Thus, the Au-based immunosensor has better analytical performance for virus detection than a carbon-based platform due to high sensitivity and very low RSV detection, obtained with good reproducibility.

A phase 1, randomized, placebo-controlled study to evaluate the safety and immunogenicity of an mRNA-based RSV prefusion F protein vaccine in healthy younger and older adults

Respiratory Syncytial Virus (RSV) causes lower respiratory tract infections that can be severe and sometimes fatal. The risk for severe RSV infection is highest in infants and older adults. A safe and effective RSV vaccine for older adults represents a serious unmet medical need due to higher morbidity and mortality in this age group. In this randomized, partially double-blind, placebo-controlled, phase 1 dose-escalation study, we evaluated the safety, tolerability and immunogenicity of an investigational messenger ribonucleic acid (mRNA) vaccine encoding the RSV fusion protein (F) stabilized in the prefusion conformation. The study was conducted in healthy younger adults (ages ≥18 and ≤49 years) and healthy older adults (ages ≥60 and ≤79 years). Participants received mRNA-1777 (V171) or placebo as a single intramuscular dose. For each dose level, three sentinel participants were administered open-label mRNA-1777 (V171). Seventy-two younger adults were randomized and administered 25, 100, or 200 µg mRNA-1777 (V171) or placebo, and 107 older adults were randomized and administered 25, 100, 200 or 300 µg mRNA-1777 (V171) or placebo. Primary objectives were safety and tolerability and secondary objectives included humoral and cell-mediated immunogenicity. All dose levels of mRNA-1777 (V171) were generally well tolerated and no serious adverse events related to the vaccine were reported. Immunization with mRNA-1777 (V171) elicited a humoral immune response as measured by increases in RSV neutralizing antibody titers, serum antibody titers to RSV prefusion F protein, D25 competing antibody titers to RSV prefusion F protein, and cell-mediated immune responses to RSV-F peptides.

Advances in the development of entry inhibitors for sialic-acid-targeting viruses

Over the past decades, several antiviral drugs have been developed to treat a range of infections. Yet the number of treatable viral infections is still limited, and resistance to current drug regimens is an ever-growing problem. Therefore, additional strategies are needed to provide a rapid cure for infected individuals. An interesting target for antiviral drugs is the process of viral attachment and entry into the cell. Although most viruses use distinct host receptors for attachment to the target cell, some viruses share receptors, of which sialic acids are a common example. This review aims to give an update on entry inhibitors for a range of sialic-acid-targeting viruses and provides insight into the prospects for those with broad-spectrum potential.

Biochemical Characterization of Respiratory Syncytial Virus RNA-Dependent RNA Polymerase Complex

RNA-dependent RNA polymerases (RdRPs) from nonsegmented negative strand (NNS) RNA viruses perform both mRNA transcription and genome replication, and these activities are regulated by their interactions with RNA and other accessory proteins within the ribonucleoprotein (RNP) complex. Detailed biochemical characterization of these enzymatic activities and their regulation is essential for understanding the life cycles of many pathogenic RNA viruses and for antiviral drug discovery. We developed biochemical and biophysical kinetic methods to study the RNA synthesis and RNA binding activities of respiratory syncytial virus (RSV) L/P RdRP. We determined that the intact L protein is essential for RdRP activity, and in truncated L protein constructs, RdRP activity is abrogated due to their deficiency in RNA template binding. These results are in agreement with the observation of an RNA template-binding tunnel at the interface of RdRP and capping domains in RSV and vesicular stomatitis virus (VSV) L protein cryo-EM structures. We also describe nonradiometric assays for measuring RNA binding and RNA polymerization activity of RSV RdRP, which are amenable to compound screening and profiling.

Peripheral blood T cells response in human parainfluenza virus-associated lower respiratory tract infection in children

Human Parainfluenza virus (HPIV) causes lower respiratory tract infections (LRTI) mostly in young children. Respiratory viral infections may decline T cells in circulation and display enhanced pathogenicity. This study is aimed to analyze T cells alterations due to HPIV in children with LRTIs. Children (N = 152) with bronchitis or pneumonia, admitted in tertiary care hospitals were included in the study. Respiratory samples (throat or nasopharyngeal swabs) were taken and HPIV genotypes (1-4) were analyzed through RT-PCR. Peripheral blood T cells, CD3+, CD4+, CD8+, and CD19+, were analyzed in confirmed HPIV positive and healthy control group children through flow cytometry. The positivity rate of HPIV was 24.34% and the most prevalent genotype was HPIV-3 (20.40%). HPIV-1 and HPIV-2 were detected in 0.66% and 02% children respectively. The T lymphocyte counts were observed significantly reduced in children infected with HPIV-3. CD4+ cell (1580 ± 97.87) counts did not change significantly but the lowest CD8+ T cell counts (518.5 ± 74.00) were recorded. Similarly, CD3+ and CD19 cell ratios were also reduced. The CD4/CD8 ratio was significantly higher (3.12 ± 0.59) in the study population as compared to the control group (2.18 ± 0.654). Changes in the count of CD8+ T cells were more pronounced in patients with bronchiolitis and pneumonia. It is concluded that CD8+ T cells show a reduced response to HPIV-3 in children with severe LRTIs suggesting a strong association of these cells with disease severity.

Identifying Effective Antiviral Drugs Against SARS-CoV-2 by Drug Repositioning Through Virus-Drug Association Prediction

A new coronavirus called SARS-CoV-2 is rapidly spreading around the world. Over 16,558,289 infected cases with 656,093 deaths have been reported by July 29th, 2020, and it is urgent to identify effective antiviral treatment. In this study, potential antiviral drugs against SARS-CoV-2 were identified by drug repositioning through Virus-Drug Association (VDA) prediction. 96 VDAs between 11 types of viruses similar to SARS-CoV-2 and 78 small molecular drugs were extracted and a novel VDA identification model (VDA-RLSBN) was developed to find potential VDAs related to SARS-CoV-2. The model integrated the complete genome sequences of the viruses, the chemical structures of drugs, a regularized least squared classifier (RLS), a bipartite local model, and the neighbor association information. Compared with five state-of-the-art association prediction methods, VDA-RLSBN obtained the best AUC of 0.9085 and AUPR of 0.6630. Ribavirin was predicted to be the best small molecular drug, with a higher molecular binding energy of -6.39 kcal/mol with human angiotensin-converting enzyme 2 (ACE2), followed by remdesivir (-7.4 kcal/mol), mycophenolic acid (-5.35 kcal/mol), and chloroquine (-6.29 kcal/mol). Ribavirin, remdesivir, and chloroquine have been under clinical trials or supported by recent works. In addition, for the first time, our results suggested several antiviral drugs, such as FK506, with molecular binding energies of -11.06 and -10.1 kcal/mol with ACE2 and the spike protein, respectively, could be potentially used to prevent SARS-CoV-2 and remains to further validation. Drug repositioning through virus-drug association prediction can effectively find potential antiviral drugs against SARS-CoV-2.

Respiratory syncytial virus infection-induced mucus secretion by down-regulation of miR-34b/c-5p expression in airway epithelial cells

Severe RSV infection is the main cause of hospitalization to children under the age of five. The regulation of miRNAs on the severity of RSV infection is unclear. The aim of the study was to identify the critical differential expression miRNAs (DE miRNAs) that can regulate the pathological response in RSV‐infected airway epithelial cells. In this study, miRNA and mRNA chips of RSV‐infected airway epithelia from Gene Expression Omnibus (GEO) were screened and analysed, separately. DE miRNAs‐targeted genes were performed for further pathway and process enrichment analysis. DE miRNA‐targeted gene functional network was constructed on the basis of miRNA‐mRNA interaction. The screened critical miRNA was also investigated by bioinformatics analysis. Then, RSV‐infected human bronchial epithelial cells (HBECs) were constructed to verify the expression of the DE miRNAs. Finally, specific synthetic DE miRNAs mimics were used to confirm the effect of DE miRNAs on the RSV‐infected HBECs. 45 DE miRNAs were identified from GEO62306 dataset. Our results showed that hsa‐mir‐34b‐5p and hsa‐mir‐34c‐5p decreased significantly in HBECs after RSV infection. Consistent with the biometric analysis, hsa‐mir‐34b/c‐5p is involved in the regulation of mucin expression gene MUC5AC. In RSV‐infected HBECs, the inducement of MUC5AC production by decreased hsa‐mir‐34b/c‐5p was partly mediated through activation of c‐Jun. These findings provide new insights into the mechanism of mucus obstruction after RSV infection and represent valuable targets for RSV infection and airway obstruction treatment.

Titanium dioxide nanoparticles exaggerate respiratory syncytial virus-induced airway epithelial barrier dysfunction

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in children worldwide. While most develop a mild, self-limiting illness, some develop severe acute lower respiratory infection and persistent airway disease. Exposure to ambient particulate matter has been linked to asthma, bronchitis, and viral infection in multiple epidemiological studies. We hypothesized that coexposure to nanoparticles worsens RSV-induced airway epithelial barrier dysfunction. Bronchial epithelial cells were incubated with titanium dioxide nanoparticles (TiO2-NP) or a combination of TiO2-NP and RSV. Structure and function of epithelial cell barrier were analyzed. Viral titer and the role of reactive oxygen species (ROS) generation were evaluated. In vivo, mice were intranasally incubated with TiO2-NP, RSV, or a combination. Lungs and bronchoalveolar lavage (BAL) fluid were harvested for analysis of airway inflammation and apical junctional complex (AJC) disruption. RSV-induced AJC disruption was amplified by TiO2-NP. Nanoparticle exposure increased viral infection in epithelial cells. TiO2-NP induced generation of ROS, and pretreatment with antioxidant, N-acetylcysteine, reversed said barrier dysfunction. In vivo, RSV-induced injury and AJC disruption were augmented in the lungs of mice given TiO2-NP. Airway inflammation was exacerbated, as evidenced by increased white blood cell infiltration into the BAL, along with exaggeration of peribronchial inflammation and AJC disruption. These data demonstrate that TiO2-NP exposure exacerbates RSV-induced AJC dysfunction and increases inflammation by mechanisms involving generation of ROS. Further studies are required to determine whether NP exposure plays a role in the health disparities of asthma and other lung diseases, and why some children experience more severe airway disease with RSV infection.

Auxiliary role of mesenchymal stem cells as regenerative medicine soldiers to attenuate inflammatory processes of severe acute respiratory infections caused by COVID-19

Acute respiratory infections as one of the most common problems of healthcare systems also can be considered as an important reason for worldwide morbidity and mortality from infectious diseases. Coronaviruses are a group of well-known respiratory viruses that can cause acute respiratory infections. At the current state, the 2019 novel coronavirus is cited as the most worldwide problematic agent for the respiratory system. According to investigations, people with old age and underlying diseases are at higher risk of 2019 novel coronavirus infection. Indeed, they may show a severe form of the disease (with severe acute respiratory infections). Based on the promising role of cell therapy and regenerative medicine approaches in the treatment of several life-threatening diseases, it seems that applying cell-based approaches can also be a hopeful strategy for improving subjects with severe acute respiratory infections caused by the 2019 novel coronavirus. Herein, due to the amazing effects of mesenchymal stem cells in the treatment of various diseases, this review focuses on the auxiliary role of mesenchymal stem cells to reduce inflammatory processes of acute respiratory infections caused by the 2019 novel coronavirus.

Unbiased analysis of peripheral blood mononuclear cells reveals CD4 T cell response to RSV matrix protein

Respiratory syncytial virus (RSV) is the most important cause of respiratory tract illness especially in young infants that develop severe disease requiring hospitalization, and accounting for 74,000-126,000 admissions in the United States (Rezaee et al., 2017; Resch, 2017). Observations of neonatal and infant T cells suggest that they may express different immune markers compared to T-cells from older children. Flow cytometry analysis of cellular responses using "conventional" anti-viral markers (IL2, IFN-γ, TNF, IL10 and IL4) upon RSV-peptide stimulation detected an overall low RSV response in peripheral blood. Therefore we sought an unbiased approach to identify RSV-specific immune markers using RNA-sequencing upon stimulation of infant PBMCs with overlapping peptides representing RSV antigens. To understand the cellular response using transcriptional signatures, transcription factors and cell-type specific signatures were used to investigate breadth of response across peptides. Unexpected from the ICS data, M peptide induced a response equivalent to the F-peptide and was characterized by activation of GATA2, 3, STAT3 and IRF1. This along with upregulation of several unconventional T cell signatures was only observed upon M-peptide stimulation. Moreover, signatures of natural RSV infections were identified from the data available in the public domain to investigate similarities between transcriptional signatures from PBMCs and upon peptide stimulation. This analysis also suggested activation of T cell response upon M-peptide stimulation. Hence, based on transcriptional response, markers were chosen to validate the role of M-peptide in activation of T cells. Indeed, CD4+CXCL9+ cells were identified upon M-peptide stimulation by flow cytometry. Future work using additional markers identified in this study could reveal additional unconventional T cells responding to RSV infections in infants. In conclusion, T cell responses to RSV in infants may not follow the canonical Th1/Th2 patterns of effector responses but include additional functions that may be unique to the neonatal period and correlate with clinical outcomes.

Factors Contributing to Symptom Duration and Viral Reduction in Outpatient Children With Respiratory Syncytial Virus Infection

BACKGROUND

We investigated the association between age, duration of clinical symptoms and viral shedding in outpatient children infected with respiratory syncytial virus (RSV) in Japan.

METHODS

Outpatients younger than 2 years of age, with suspected RSV infection between 2014 and 2018, were enrolled in the study. Following informed consent, nasal samples were collected at first and second clinic visits (with 0-9 days gap). RSV-A or -B infection and viral load were determined by real-time polymerase chain reaction. Clinical symptoms were recorded at first clinic visit, and fever and symptoms were recorded at home for up to 8 days. Association between clinical symptoms and patient characteristics, such as age, sex and birth weight, were analyzed using ordered logistic regression analysis. The association between viral reduction and estimated shedding period was examined using linear regression analysis.

RESULTS

Among the 205 cases enrolled in the study, no difference was found in patient characteristics between RSV-A and -B infection. Duration of fever was prolonged with increased age. Duration of rhinorrhea and cough was shorter in females than in males and in groups with birth weight ≥3 kg than in those with <2.5 kg. Daily viral reduction increased and estimated viral elimination period decreased with age.

CONCLUSIONS

Fever duration was found to increase while viral shedding decreased with patient age.

Single-Dose Nirsevimab for Prevention of RSV in Preterm Infants

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants, and a need exists for prevention of RSV in healthy infants. Nirsevimab is a monoclonal antibody with an extended half-life that is being developed to protect infants for an entire RSV season with a single intramuscular dose.

METHODS

In this trial conducted in both northern and southern hemispheres, we evaluated nirsevimab for the prevention of RSV-associated lower respiratory tract infection in healthy infants who had been born preterm (29 weeks 0 days to 34 weeks 6 days of gestation). We randomly assigned the infants in a 2:1 ratio to receive nirsevimab, at a dose of 50 mg in a single intramuscular injection, or placebo at the start of an RSV season. The primary end point was medically attended RSV-associated lower respiratory tract infection through 150 days after administration of the dose. The secondary efficacy end point was hospitalization for RSV-associated lower respiratory tract infection through 150 days after administration of the dose.

RESULTS

From November 2016 through November 2017, a total of 1453 infants were randomly assigned to receive nirsevimab (969 infants) or placebo (484 infants) at the start of the RSV season. The incidence of medically attended RSV-associated lower respiratory tract infection was 70.1% lower (95% confidence interval [CI], 52.3 to 81.2) with nirsevimab prophylaxis than with placebo (2.6% [25 infants] vs. 9.5% [46 infants]; P<0.001) and the incidence of hospitalization for RSV-associated lower respiratory tract infection was 78.4% lower (95% CI, 51.9 to 90.3) with nirsevimab than with placebo (0.8% [8 infants] vs. 4.1% [20 infants]; P<0.001). These differences were consistent throughout the 150-day period after the dose was administered and across geographic locations and RSV subtypes. Adverse events were similar in the two trial groups, with no notable hypersensitivity reactions.

CONCLUSIONS

A single injection of nirsevimab resulted in fewer medically attended RSV-associated lower respiratory tract infections and hospitalizations than placebo throughout the RSV season in healthy preterm infants. (Funded by AstraZeneca and Sanofi Pasteur; ClinicalTrials.gov number, NCT02878330.).

Severe Morbidity and Mortality Associated With Respiratory Syncytial Virus Versus Influenza Infection in Hospitalized Older Adults

Background

Respiratory syncytial virus (RSV) is an important cause of serious respiratory illness in older adults. Comparison of RSV and influenza infection in hospitalized older adults may increase awareness of adult RSV disease burden.

Methods

Hospitalized adults aged ≥60 years who tested positive for RSV or influenza between 1 January 2011 and 30 June 2015 were identified from Kaiser Permanente Southern California electronic medical records. Baseline characteristics, comorbidities, utilization, and outcomes were compared.

Results

The study included 645 RSV- and 1878 influenza-infected hospitalized adults. Patients with RSV were older than those with influenza (mean, 78.5 vs 77.4 years; P = .035) and more likely to have congestive heart failure (35.3% vs 24.5%; P < .001) and chronic obstructive pulmonary disease (COPD) (29.8% vs 24.3%; P = .006) at baseline. In adjusted analyses, RSV infection was associated with greater odds of length of stay ≥7 days (odds ratio [OR] = 1.5; 95% confidence interval [CI], 1.2–1.8; P < .001); pneumonia (OR = 2.7; 95% CI, 2.2–3.2; P < .001); intensive care unit admission (OR = 1.3; 95% CI, 1.0–1.7; P = .023); exacerbation of COPD (OR = 1.7; 95% CI, 1.3–2.4; P = .001); and greater mortality within 1 year of admission (OR = 1.3; 95% CI, 1.0–1.6; P = .019).

Conclusions

RSV infection may result in greater morbidity and mortality among older hospitalized adults than influenza. Increased recognition of adult RSV disease burden will be important in the evaluation and use of new RSV vaccines and antivirals.

The Contribution of Neutrophils to the Pathogenesis of RSV Bronchiolitis

Acute viral bronchiolitis causes significant mortality in the developing world, is the number one cause of infant hospitalisation in the developed world, and is associated with the later development of chronic lung diseases such as asthma. A vaccine against respiratory syncytial virus (RSV), the leading cause of viral bronchiolitis in infancy, remains elusive, and hence new therapeutic modalities are needed to limit disease severity. However, much remains unknown about the underlying pathogenic mechanisms. Neutrophilic inflammation is the predominant phenotype observed in infants with both mild and severe disease, however, a clear understanding of the beneficial and deleterious effects of neutrophils is lacking. In this review, we describe the multifaceted roles of neutrophils in host defence and antiviral immunity, consider their contribution to bronchiolitis pathogenesis, and discuss whether new approaches that target neutrophil effector functions will be suitable for treating severe RSV bronchiolitis.

Detection of community-acquired respiratory viruses in allogeneic stem-cell transplant recipients and controls-A prospective cohort study

Background

Community‐acquired respiratory viruses (CARV) cause upper and lower respiratory tract infections (URTI/LRTI) and may be life‐threatening for recipients of an allogeneic stem cell transplantation (allo‐SCT).

Methods

In a prospective study encompassing 4 winter‐seasons, we collected throat gargles (TG) at random time points from allo‐SCT recipients (patients) and controls and followed them up for at least 3 weeks including repetitive sampling and documentation of symptoms. A Multiplex‐PCR system to identify 20 CARV and Mycoplasma pneumoniae was used to detect CARV.

Results

One hundred ninety‐four patients with 426 TG and 273 controls with 549 TG were included. There were more patients with a positive test result (25% vs 11% in the controls), and the patients had a higher number of positive TG (70 = 16%) compared to controls (32 = 6%) (P < .001). Altogether, 115 viruses were detected. Multiple viruses in one TG (11/48, 34%) and prolonged shedding were only observed in patients (13/48, 27%). Patients had more RSV (18/83, 26%) and adenovirus (15/83, 21%) than controls (both viruses 2/32, 6%). Independent risk factors for the detection of CARV included age >40 years (OR 3.38, 95% CI 1.8‐6.4, P < .001) and presence of URTI‐symptoms (OR 3.22, 95% CI 1.9‐5.5, P < .001). No controls developed a LRTI or died whereas 4/48 (8%) patients developed a LRTI (coronavirus in 2, RSV in 1 and influenza A H1N1 in 1 patient). One patient died of CARV (influenza A H1N1).

Conclusion

Allo‐SCT‐recipients have more CARV‐infections, exhibit a different epidemiology, have more cases of co‐infection or prolonged shedding and have a higher rate of LRTI and mortality.

Health Care Resource Utilization of Late Premature Versus Term Infants With Bronchiolitis

It is controversial whether it is cost-beneficial for late preterm infants to receive respiratory syncytial virus prophylaxis. This study compares community and hospital health care resource utilization (HCRU) of late premature infants (33-36 weeks gestational age) with term infants (>36 weeks gestational age) hospitalized with bronchiolitis. This was a retrospective, population-based, observational study spanning a 9-year period (2004-2012). HCRU data were obtained from the Health Maintenance Organization "Clalit" and included duration of hospitalization, physician visits, laboratory tests, and treatments. Compared with term infants, late preterm infants had significantly longer duration of hospitalization and higher admission rates to pediatric intensive care unit. They also had higher rates of mean outpatients clinic visits, total outpatient clinic and specialist visits, blood chemistry, and virology testing. HCRU of term infants with bronchiolitis was also substantial, indicating that they also can greatly benefit from respiratory syncytial virus prophylaxis. These findings can guide stakeholders in decisions concerning the prevention of bronchiolitis and will be useful in performing further cost-benefit analysis.

Cumulative incidence of post-infection asthma or wheezing among young children clinically diagnosed with respiratory syncytial virus infection in the United States: A retrospective database analysis

Background

Respiratory syncytial virus (RSV) infection is implicated in subsequent development of asthma/wheezing (AW) among term and pre‐term infants. We describe the cumulative incidence of AW among hospitalized and ambulatory neonates/infants/toddlers following RSV infection diagnosis over three independent follow‐up periods.

Methods

Between January 1, 2007 and March 31, 2016, patients aged 0‐2 years old with first clinical diagnosis of RSV infection were identified using the Optum^® integrated electronic health records and claims database. Patients diagnosed with AW ≤ 30 days post‐RSV diagnosis were excluded. Three cohorts with 1, 3, and 5 years of follow‐up were stratified by presence or absence of specific RSV high‐risk factors, including pre‐term birth and pre‐defined, pre‐existing comorbidities. Descriptive statistics and logistic regression results were reported.

Results

Overall, 9811, 4524, and 1788 RSV‐infected high‐risk factor negative patients were included in 1, 3, and 5‐year independent cohorts, respectively. Of these, 6.5%, 6.9%, and 5.8%, respectively had RSV‐related hospitalization. By the end of follow‐up, 14.9%, 28.2%, and 36.3% had AW events. Overall, 3030, 1378, and 552 RSV‐infected high‐risk factor positive patients were included in the respective cohorts. Of these, 11.4%, 11.1%, and 11.6%, respectively were hospitalized with initial RSV infection and 18.1%, 32.9%, and 37.9% had subsequent AW events within the follow‐up period. Logistic regression confirmed RSV‐related hospitalization significantly increased the likelihood of developing AW (P < .05) in high‐risk factor positive and negative patients.

Conclusions

In infants diagnosed with RSV infection, RSV‐related hospitalization was associated with a significantly increased likelihood of AW development for at least 5 years, compared with non‐hospitalized patients.

Interleukin-22 Inhibits Respiratory Syncytial Virus Production by Blocking Virus-Mediated Subversion of Cellular Autophagy

Respiratory syncytial virus (RSV) infection can cause severe bronchiolitis in infants requiring hospitalization, whereas the elderly and immunocompromised are prone to RSV-induced pneumonia. RSV primarily infects lung epithelial cells. Given that no vaccine against RSV is currently available, we tested the ability of the epithelial-barrier protective cytokine interleukin-22 (IL-22) to control RSV production. When used in a therapeutic modality, IL-22 efficiently blunted RSV production from infected human airway and alveolar epithelial cells and IL-22 administration drastically reduced virus titer in the lungs of infected newborn mice. RSV infection resulted in increased expression of LC3B, a key component of the cellular autophagic machinery, and knockdown of LC3B ablated virus production. RSV subverted LC3B with evidence of co-localization and caused a significant reduction in autophagic flux, both reversed by IL-22 treatment. Our findings inform a previously unrecognized anti-viral effect of IL-22 that can be harnessed to prevent RSV-induced severe respiratory disease.

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RSV infection of lung epithelial cells subverts the cellular autophagic machinery

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RSV infection inhibits autophagic flux in infected cells

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IL-22 inhibits RSV production from human lung epithelial cells and in neonatal mice

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IL-22 blocks RSV-LC3B co-localization and restores cellular autophagic flux

Association of Age at First Severe Respiratory Syncytial Virus Disease With Subsequent Risk of Severe Asthma: A Population-Based Cohort Study

OBJECTIVE

In a population-based cohort study, we determined the association between the age at first severe respiratory syncytial virus (RSV) disease and subsequent asthma.

METHODS

Incidence rates and rate ratios of the first asthma-associated hospitalization after 2 years of age in children hospitalized for RSV disease at <3 months, 3 to <6 months, 6 to <12 months, and 12-24 months of age were calculated.

RESULTS

The incidence of asthma-associated hospitalization per 1000 child-years among children hospitalized for RSV disease at <3 months of age was 0.5 (95% confidence interval [CI], .2-.7); at 3 to <6 months of age, 0.9 (95% CI,.5-1.3); at 6 to <12 months of age, 2.0 (95% CI, 1.4-2.7); and at 12-24 months of age, 1.7 (95% CI, 1.0-2.5). The rate ratio of hospitalization for asthma was 2-7-fold greater among children hospitalized for RSV disease at ages ≥6 months than that among those hospitalized for RSV disease at ages 0 to <6 months.

CONCLUSIONS

Although the burden of RSV disease is highest in children aged <6 months, the burden of subsequent asthma is higher in children who develop RSV disease at ages ≥6 months.

Measles Resurgence and Drug Development

Measles caused an estimated minimum of one million fatalities annually before vaccination. Outstanding progress towards controlling the virus has been made since the measles vaccine was introduced, but reduction of measles case-fatalities has stalled at around 100,000 annually for the last decade and a 2019 resurgence in several geographical regions threatens some of these past accomplishments. Whereas measles eradication through vaccination is feasible, a potentially open-ended endgame of elimination may loom. Other than doubling-down on existing approaches, is it worthwhile to augment vaccination efforts with antiviral therapeutics to solve the conundrum? This question is hypothetical at present, since no drugs have yet been approved specifically for the treatment of measles, or infection by any other pathogen of the paramyxovirus family. This article will consider obstacles that have hampered anti-measles and anti-paramyxovirus drug development, discuss MeV-specific challenges of clinical testing, and define drug properties suitable to address some of these problems.

Insights into Interactions of Flavanones with Target Human Respiratory Syncytial Virus M2-1 Protein from STD-NMR, Fluorescence Spectroscopy, and Computational Simulations

The human Respiratory Syncytial Virus (hRSV) is the most frequent agent of respiratory infections in infants and children with no currently approved vaccine. The M_2-1 protein is an important transcriptional antitermination factor and a potential target for viral replication inhibitor development. Hesperetin (HST) and hesperidin (HSD) are flavonoids from the flavanone group, naturally found in citrus and have, as one of their properties, antiviral activity. The present study reports on the interactions between hRSV M_2-1 and these flavanones using experimental techniques in association with computational tools. STD-NMR results showed that HST and HSD bind to M_2-1 by positioning their aromatic rings into the target protein binding site. Fluorescence quenching measurements revealed that HST had an interaction affinity greater than HSD towards M_2-1. The thermodynamic analysis suggested that hydrogen bonds and van der Waals interactions are important for the molecular stabilization of the complexes. Computational simulations corroborated with the experimental results and indicated that the possible interaction region for the flavonoids is the AMP-binding site in M_2-1. Therefore, these results point that HST and HSD bind stably to a critical region in M_2-1, which is vital for its biological function, and thus might play a possible role antiviral against hRSV.

Structural Insight into Paramyxovirus and Pneumovirus Entry Inhibition

Paramyxoviruses and pneumoviruses infect cells through fusion (F) protein-mediated merger of the viral envelope with target membranes. Members of these families include a range of major human and animal pathogens, such as respiratory syncytial virus (RSV), measles virus (MeV), human parainfluenza viruses (HPIVs), and highly pathogenic Nipah virus (NiV). High-resolution F protein structures in both the metastable pre- and the postfusion conformation have been solved for several members of the families and a number of F-targeting entry inhibitors have progressed to advanced development or clinical testing. However, small-molecule RSV entry inhibitors have overall disappointed in clinical trials and viral resistance developed rapidly in experimental settings and patients, raising the question of whether the available structural information may provide a path to counteract viral escape through proactive inhibitor engineering. This article will summarize current mechanistic insight into F-mediated membrane fusion and examine the contribution of structural information to the development of small-molecule F inhibitors. Implications are outlined for future drug target selection and rational drug engineering strategies.

Primary and Repeated Respiratory Viral Infections Among Infants in Rural Nepal

BACKGROUND

Respiratory viruses cause significant morbidity and death in infants; 99% of such deaths occur in resource-limited settings. Risk factors for initial and repeated respiratory viral infections in young infants in resource-limited settings have not been well described.

METHODS

From 2011 to 2014, a birth cohort of infants in rural Nepal was enrolled and followed with weekly household-based active surveillance for respiratory symptoms until 6 months of age. Respiratory illness was defined as having any of the following: fever, cough, wheeze, difficulty breathing, and/or a draining ear. We tested nasal swabs of infants with respiratory illness for multiple respiratory viruses by using a reverse transcription polymerase chain reaction assay. The risk of primary and repeated infections with the same virus was evaluated using Poisson regression.

RESULTS

Of 3528 infants, 1726 (49%) had a primary infection, and 419 (12%) had a repeated infection. The incidences of respiratory viral infection in infants were 1816 per 1000 person-years for primary infections and 1204 per 1000 person-years for repeated infection with the same virus. Exposure to other children and male sex were each associated with an increased risk for primary infection (risk ratios, 1.13 [95% confidence interval (CI), 1.06-1.20] and 1.14 [95% CI, 1.02-1.27], respectively), whereas higher maternal education was associated with a decreased risk for both primary and repeated infections (risk ratio, 0.96 [95% CI, 0.95-0.98]). The incidence of subsequent infection did not change when previous infection with the same or another respiratory virus occurred. Illness duration and severity were not significantly different in the infants between the first and second episodes for any respiratory virus tested.

CONCLUSIONS

In infants in rural Nepal, repeated respiratory virus infections were frequent, and we found no decrease in illness severity with repeated infections and no evidence of replacement with another virus. Vaccine strategies and public health interventions that provide durable protection in the first 6 months of life could decrease the burden of repeated infections by multiple respiratory viruses, particularly in low-resource countries.

Safety and immunogenicity of novel modified vaccinia Ankara-vectored RSV vaccine: A randomized phase I clinical trial

Respiratory disease caused by RSV infection is recognized as a severe public health issue in infants, young children and elderly with no specific treatment option. Vaccination may be the most effective strategy to combat this highly infectious virus although no vaccine has been approved. The novel vaccine candidate MVA-BN-RSV encodes RSV surface proteins F and G (subtypes A, B) as well as internal proteins N and M2 in the MVA-BN viral vector backbone to provide broad protection against RSV. This was a first in human study to investigate safety, reactogenicity and immunogenicity of MVA-BN-RSV. Sixty-three participants were allocated to 3 groups: adult (18-49 years) low (1 × 10⁷ TCID₅₀) or high (1 × 10⁸ TCID₅₀) dose and older adult (50-65 years) high dose. Participants in each group were randomized in a 6:1 ratio to receive 2 doses of MVA-BN-RSV or placebo 4 weeks apart and were monitored for 30 weeks. All participants completed the study, receiving both doses. No serious AEs or AEs of special interest were reported. The most common AEs were injection site pain (56% in the combined high dose groups, 17% in the low dose group). MVA-BN-RSV induced robust T cell responses covering all 5 inserts with fold increases ranging from 1.8 to 3.8. Higher and broader responses were observed in the high dose groups (83% responders to at least 3 peptide pools in the combined high dose groups compared to 63% in the low dose group). Moderate but consistent humoral responses were observed against A and B RSV subtypes (up to approximately 2-fold increases in the high dose groups). No differences were observed between the adult and the older adult groups in safety, reactogenicity or immunogenicity. The study demonstrated that the well tolerated MVA-BN-RSV vaccine candidate induces broad cellular and humoral immune responses, warranting further development.

Preventing respiratory syncytial virus infections in hospitalized children and adults: should we do better?

Objective

To compare the burden of nosocomial and community-acquired respiratory syncytial virus (RSV)-associated acute lower respiratory tract infections (ALRIs) in adult and pediatric patients concomitantly admitted to a French tertiary hospital, and to evaluate the effectiveness of existing infection control measures.

Patients and methods

We prospectively included all adult and pediatric patients admitted to Necker hospital (Paris) between October 2018 and February 2019 with a diagnosis of RSV-associated ALRI. We compared characteristics of ALRIs between patients with community-acquired versus nosocomial infections and, in each group, between children and adults.

Results

Community-acquired and nosocomial RSV-associated ALRIs were diagnosed in 229 and 11 inpatients, respectively. The burden of community-acquired infections was higher in children than in adults: 2.1% versus 0.2% of the total number of pediatric and adult inpatients, respectively (p < 0.0001); 4.2% versus 0.2% of the total number of hospitalization days in pediatric and adult units, respectively (p < 0.0001). Compared to inpatients with community-acquired ALRIs, those with nosocomial infections were more frequently adults (45.5% versus 2.6%, p = 0.0005) and subjects with at least one chronic complex condition (100.0% versus 41.0%, p < 0.0001). The total number of hospitalization days due to nosocomial ALRIs was higher in adults than in children (0.32% versus 0.11%, p < 0.0001).

Conclusions

Nosocomial RSV-associated ALRIs rarely occurred, suggesting a good effectiveness of our infection control strategy. However, the burden of nosocomial infection was higher in adults than in children, suggesting that education and training of healthcare personnel, patients and visitors about the risk of nosocomial RSV infections should be reinforced in adult wards.

Respiratory syncytial virus infection: why does disease severity vary among individuals?

Introduction: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infections in infancy. While many infants are infected with RSV, the nature and severity of the disease vary among individuals. RSV causes bronchiolitis, pneumonia, and asthma exacerbation. However, most children infected with RSV have only mild upper airways disease and may be asymptomatic.Areas covered: Despite efforts to elucidate mechanisms for the various clinical responses to RSV infection, they remain largely unknown, suggesting that susceptibility and disease are influenced by multiple intrinsic and extrinsic factors. This article reviews the available literature on the field of RSV disease severity and discusses important factors associated to susceptibility and different disease outcome.Expert opinion: The severity of RSV-induced illness is a phenomenon that depends on a variety of graded mechanisms of interaction between the host, virus, and environment. This may lead to differences in the intensity of immune response in the lung and different courses of the disease. By characterizing, classifying, and grading the affecting factors in high-risk patients versus those who do not fall ill by RSV, we may find therapies or point to disease-limiting medications.

Healthcare resource utilization and costs in the 12 months following hospitalization for respiratory syncytial virus or unspecified bronchiolitis among infants

Aims: To examine healthcare resource utilization (HRU) and costs within 12 months after hospitalization for respiratory syncytial virus (RSVH) or unspecified bronchiolitis (UBH) in infants.Materials and methods: Infants born July 1, 2009-June 30, 2015 were identified in the MarketScan Medicaid and Commercial databases and were assigned to one of three cohorts: RSVH (with/without UBH), UBH, or comparator (no RSVH or UBH). Each infant was identified as pre-term (5 groups) or term (2 groups) based on weeks gestational age (wGA). Index dates were the first admission dates for RSVH or UBH infants and were randomly assigned to comparator infants based on time from birth to index in the RSVH cohort. HRU, all-cause costs, and incremental cost differences between hospitalized and comparator infants were assessed over 12 months post-index with and without the index hospitalization. Results were propensity score weighted to balance pre-index characteristics across hospitalization cohorts.Results: This study identified 15,872 RSVH infants, 6,081 UBH infants, and 986,087 comparator infants in the Medicaid population and 5,755 RSVH infants, 1,888 UBH infants, and 696,302 comparator infants in the commercial population. HRU in follow-up was greater for RSVH and UBH infants relative to comparator infants in both populations, including hospitalizations (commercial: 7.4%, 11.0%, 1.7%; Medicaid: 12.3%, 15.3%, 3.2%) and emergency department visits (commercial: 33.0%, 33.3%, 17.2%; Medicaid: 65.8%, 68.5%, 51.4%). HRU was highest among RSVH and UBH infants born at <29 wGA. Hospitalized infants had numerically higher follow-up costs than comparator infants, with incremental differences reaching $19,896 among Medicaid UBH infants and $37,417 among commercial RSVH infants.Limitations: RSV/UB may be miscoded in claims data.Conclusions: Infants hospitalized for RSV or UB largely had greater subsequent HRU and costs in the first year after index hospitalization than comparator infants. Absolute and incremental follow-up costs relative to comparator infants were highest among infants <29 wGA.

Diagnosis of severe respiratory infections in immunocompromised patients

An increasing number of critically ill patients are immunocompromised. Acute hypoxemic respiratory failure (ARF), chiefly due to pulmonary infection, is the leading reason for ICU admission. Identifying the cause of ARF increases the chances of survival, but may be extremely challenging, as the underlying disease, treatments, and infection combine to create complex clinical pictures. In addition, there may be more than one infectious agent, and the pulmonary manifestations may be related to both infectious and non-infectious insults. Clinically or microbiologically documented bacterial pneumonia accounts for one-third of cases of ARF in immunocompromised patients. Early antibiotic therapy is recommended but decreases the chances of identifying the causative organism(s) to about 50%. Viruses are the second most common cause of severe respiratory infections. Positive tests for a virus in respiratory samples do not necessarily indicate a role for the virus in the current acute illness. Invasive fungal infections (Aspergillus, Mucorales, and Pneumocystis jirovecii) account for about 15% of severe respiratory infections, whereas parasites rarely cause severe acute infections in immunocompromised patients. This review focuses on the diagnosis of severe respiratory infections in immunocompromised patients. Special attention is given to newly validated diagnostic tests designed to be used on non-invasive samples or bronchoalveolar lavage fluid and capable of increasing the likelihood of an early etiological diagnosis.

Parainfluenza Virus in Hospitalized Adults: A 7-Year Retrospective Study

Background

Parainfluenza virus (PIV) is a cause of respiratory tract infection in children and the immunocompromised population, but its clinical manifestations, impact, and outcomes in hospitalized adults are not well studied.

Methods

This retrospective study included adults (≥18 years old) admitted to Northwestern Memorial Hospital or Prentice Women's Hospital (both in Chicago, Illinois) between 1 August 2009 and 31 July 2016 with a positive molecular test result for PIV. Epidemiologic, clinical, and outcomes data were collected from the enterprise data warehouse and patient electronic health records after institutional review board approval. Descriptive statistics were used to summarize the data.

Results

A total of 550 adults with a positive molecular test for PIV were identified. Differences in seasonality, clinical presentation, and prevalence between the different PIV serotypes (PIV-1, PIV-2, and PIV-3) were identified. The most common signs/symptoms were cough (88%), productive sputum (55%), fever (63%), and dyspnea (49%). Of the patients administered antibiotics, 349 (79.6%) had no confirmed bacterial infection throughout their hospitalization. The average length of hospitalization was 7.7 days. Presence of bacterial coinfection (P = .01), fungal coinfection (P < .01), decreased body mass index (P = .03), and increased respiratory rate (P < .01) were associated with significant differences in mortality rates.

Conclusions

PIV infection is associated with substantial morbidity in hospitalized adults. Such data will be useful in understanding the impact on epidemiology and outcomes if a PIV-specific vaccine becomes available. Furthermore, this highlights the need for novel preventive and therapeutic approaches to PIV infection.

Hamster neogenin, a host-cell protein contained in a respiratory syncytial virus candidate vaccine, induces antibody responses in rabbits but not in clinical trial participants

A recombinant respiratory syncytial virus (RSV) fusion glycoprotein candidate vaccine (RSV-PreF) manufactured in Chinese hamster ovary cells was developed for immunization of pregnant women, to protect newborns against RSV disease through trans-placental antibody transfer. Traces of a host-cell protein, hamster neogenin (haNEO1), were identified in purified RSV-PreF antigen material. Given the high amino-acid sequence homology between haNEO1 and human neogenin (huNEO1), there was a risk that potential vaccine-induced anti-neogenin immunity could affect huNEO1 function in mother or fetus. Anti-huNEO1 IgGs were measured by enzyme-linked immunosorbent assay in sera from rabbits and trial participants (Phase 1 and 2 trials enrolling 128 men and 500 non-pregnant women, respectively; NCT01905215/NCT02360475) collected after immunization with RSV-PreF formulations containing different antigen doses with/without aluminum-hydroxide adjuvant. In rabbits, four injections administered at 14-day intervals induced huNEO1-specific IgG responses in an antigen-dose- and adjuvant-dependent manner, which plateaued in the highest-dose groups after three injections. In humans, no vaccination-induced anti-huNEO1 IgG responses were detected upon a single immunization, as the values in vaccine and control groups fluctuated around pre-vaccination levels up to 90/360 days post-vaccination. A minority of participants had anti-huNEO1 levels ≥ assay cutoff before vaccination, which did not increase post-vaccination. Thus, despite detecting vaccine-induced huNEO1-specific responses in rabbits, we found no evidence that the candidate vaccine had induced anti-huNEO1 immunity in human adults. The antigen purification process was nevertheless optimized, and haNEO1-reduced vaccines were used in a subsequent Phase 2 trial enrolling 400 non-pregnant women (NCT02956837), in which again no vaccine-induced anti-huNEO1 responses were detected.

Molecular Evolution of the Fusion Protein (F) Gene in Human Respirovirus 3

To elucidate the evolution of human respirovirus 3 (HRV3), we performed detailed genetic analyses of the F gene (full-length) detected from hundreds of HRV3 strains obtained from various geographic regions. First, we performed time-scaled evolutionary analyses using the Bayesian Markov chain Monte Carlo method. Then, we performed analyses of phylodynamics, similarity, phylogenetic distance, selective pressure, and conformational B-cell epitope with the F-protein structural analyses. Time-scaled phylogenetic tree showed that the common ancestor of HRV3 and bovine respirovirus 3 diverged over 300 years ago and subdivided it into three major clusters and four subclusters during the most recent 100 years. The overall evolutionary rate was approximately 10^-3 substitutions/site/year. Indigenous similarity was seen in the present strains, and the mean phylogenetic distance were 0.033. Many negative selection sites were seen in the ectodomain. The conformational epitopes did not correspond to the neutralizing antibody binding sites. These results suggest that the HRV3 F gene is relatively conserved and restricted in this diversity to preserve the protein function, although these strains form many branches on the phylogenetic tree. Furthermore, HRV3 reinfection may be responsible for discordances between the conformational epitopes and the neutralizing antibody binding sites of the F protein. These findings contribute to a better understanding of HRV3 virology.

Epidemiology of Respiratory Syncytial Virus-Related Hospitalization Over a 5-Year Period in Italy: Evaluation of Seasonality and Age Distribution Before Vaccine Introduction

Respiratory Syncytial Virus (RSV) is associated with most of the acute viral respiratory tract infections causing hospitalization with a peak during the first months of life. Many clinical trials of RSV vaccine candidates are being carried out. The aim of this study was to obtain epidemiologic information to give suggestions on target populations and prevention strategies before the introduction of new vaccines or monoclonal antibodies. We retrospectively evaluated, over a 5-year period (September 2014–August 2019), a population of hospitalized Italian children aged 0–6 years with a laboratory confirmed diagnosis of RSV infection. Risk factors, seasonality of RSV infection, distribution according to age, cases of coinfections and reinfections and cases needing Intensive Care Unit were evaluated. Hospitalizations due to RSV were 624 in the period under study. The peak was found between November and April, with 80.4% of cases recorded between December and February. 62.5% of cases were found in children under three months of age and 41% in children under 30 days old. The need for intensive care was associated with younger ages, with 70.9% of cases in children below three months of age. Unless the incoming vaccines demonstrate a strong herd protection effect, preventive strategies should be aimed at newborns or at maternal immunization.

Two Cases of Primary Human Parainfluenza Virus 1 Pneumonia in Which Bronchoalveolar Lavage Fluid Yielded Human Parainfluenza Virus 1

Two patients, a 76-year-old woman and 66-year-old woman, presented to our hospital with symptoms of lower respiratory tract infection. Both patients showed chest imaging findings of bilateral ground-glass opacities and consolidations. We initially suspected these patients of having influenza-associated pneumonia and cryptogenic organizing pneumonia, respectively, and performed bronchoalveolar lavage, but only human parainfluenza virus-1 infection was detected by multiplex polymerase chain reaction testing. These findings suggest that pneumonia due to human parainfluenza virus-1 should be included in the differential diagnosis of such cases.

Systematic review on respiratory syncytial virus epidemiology in adults and the elderly in Latin America

OBJECTIVES

The present study provides a comprehensive review of the recently published data on RSV epidemiology in adults and the elderly in Latin America.

METHODS

A systematic literature search was carried out in Medline, Scielo, Lilacs, and Cochrane Library. The search strategy aimed at retrieving studies focusing on RSV prevalence, burden, risk factors, and the routine clinical practice in the prevention and management of RSV infections in Latin American countries. Only articles published between January 2011 and December 2017 were considered.

RESULTS

Eighteen studies were included. Percentages of RSV detection varied highly across included studies for adult subjects with respiratory infections (0% to 77.9%), influenza-like illness (1.0% to 16.4%) and community-acquired pneumonia (1.3% to 13.5%). Considerable percentages of hospitalization were reported for RSV-infected adults with influenza-like illness (40.9% and 69.9%) and community-acquired pneumonia (91.7%).

CONCLUSIONS

Recent RSV data regarding adult populations in Latin America are scarce. RSV was documented as a cause of illness in adults and the elderly, being identified in patients with acute respiratory infections, influenza-like illness and community-acquired pneumonia. The studies suggest that RSV infections may be a significant cause of hospitalization in adult populations in Latin America, including younger adults.

The non-antibiotic macrolide EM900 attenuates HDM and poly(I:C)-induced airway inflammation with inhibition of macrophages in a mouse model

OBJECTIVE

Macrolides have been reported to reduce the exacerbation of severe asthma. The aim of this study was to clarify the effects and mechanisms of EM900, a non-antibiotic macrolide, on allergic airway inflammation.

METHODS

Mice were sensitized and challenged by house dust mite (HDM), then exposed to polyinosinic-polycytidylic acid (poly(I:C)) as a model of asthma complicated with viral infection. Mice were administered with EM900. Airway inflammation was assessed from inflammatory cells in bronchoalveolar lavage fluid (BALF) and cytokines in lung tissues. Lung interstitial macrophages were counted by flow cytometry. Cytokine production, phosphorylation of NF-κB, and p38 in macrophages were examined by ELISA and western blotting.

RESULTS

Counts of cells in BALF and concentrations of IL-13, IL-5, RANTES, IL-17A, and MIP-2 were significantly decreased by EM900 compared to those without EM900. Percentages of lung interstitial macrophages were significantly decreased with EM900. Concentrations of IL-6, RANTES, and MIP-2 induced by HDM and poly(I:C) were significantly suppressed by EM900 through the suppression of NF-κB and p38 phosphorylation in macrophages.

CONCLUSIONS

HDM and poly(I:C)-induced airway inflammation is attenuated by EM900 with the inhibition of lung interstitial macrophages. Clinical use of EM900 is expected, because EM900 has inhibitory effects against airway inflammation without inducing bacterial drug resistance.

Are Community Acquired Respiratory Viral Infections an Underestimated Burden in Hematology Patients?

Despite a plethora of studies demonstrating significant morbidity and mortality due to community-acquired respiratory viral (CRV) infections in intensively treated hematology patients, and despite the availability of evidence-based guidelines for the diagnosis and management of respiratory viral infections in this setting, there is no uniform inclusion of respiratory viral infection management in the clinical hematology routine. Nevertheless, timely diagnosis and systematic management of CRV infections in intensively treated hematology patients has a demonstrated potential to significantly improve outcome. We have briefly summarized the recently published data on CRV infection epidemiology, as well as guidelines on the diagnosis and management of CRV infections in patients intensively treated for hematological malignancies. We have also assessed available treatment options, as well as mentioned novel agents currently in development.

An Outbreak of Human Parainfluenza Virus 3 (Phylogenetic Subcluster C5) Infection among Adults at a Residential Care Facility for the Disabled in Croatia, 2018

INTRODUCTION

Although highly pertinent for children, outbreaks of human parainfluenza virus (HPIV) may cause up to 15% of all respiratory illnesses in adults and predispose them to serious adverse outcomes, with HPIV serotype 3 (HPIV3) being the most common. This study represents the first report of an HPIV3 outbreak among adults at a long-term health-care facility in Croatia.

METHODS

A retrospective study was conducted to investigate an outbreak of acute respiratory infection (ARI) at a single residential care facility for the disabled in Croatia. Demographic, epidemiological, and clinical data were collected for all residents, while hospitalized patients were appraised in detail by laboratory/radiological methods. Multiplex PCR for respiratory viruses and sequencing was performed. Partial HPIV3 HN 581 nt sequences were aligned with HPIV3 sequences from the GenBank database to conduct a phylogenetic analysis, where different bioinformatic approaches were employed.

RESULTS

In late June 2018, 5 of the 10 units at the facility were affected by the outbreak. Among the 106 residents, 23 (21.7%) developed ARI, and 6 (26.1%) of them were hospitalized. HPIV3 was identified in 18 (73%) of the residents and 5 (83%) of the hospitalized individuals. Isolated HPIV3 strains were classified within the phylogenetic subcluster C5 but grouped on 2 separate branches of the phylogenetic tree. During the entire outbreak period, none of the institution's employees reported symptoms of ARI.

CONCLUSIONS

Our study has shown that this health care-associated outbreak of HPIV3 infection could have been linked to multiple importation events. Preventive measures in curbing such incidents should be enforced vigorously.