Respiratory syncytial virus genomic load and disease severity among children hospitalized with bronchiolitis: multicenter cohort studies in the United States and Finland

The role of M2-2 PDZ-binding motifs in pulmonary innate immune responses to human metapneumovirus

Human metapneumovirus (HMPV) is a leading cause of lower respiratory tract infection (LRTI) in pediatric and geriatric populations. We recently found that two PDZ-binding motifs of the M2-2 protein, 29-DEMI-32 and 39-KEALSDGI-46, play a significant role in mediating HMPV immune evasion in airway epithelial cells (AECs). However, their role in the overall pulmonary responses to HMPV infection has not been investigated. In this study, we found that two recombinant HMPVs (rHMPV) lacking the individual M2-2 PDZ-binding motif are attenuated in mouse lungs. Mice infected with mutants produce more cytokines/chemokines in bronchoalveolar lavage (BAL) fluid compared to mice infected with wild-type rHMPV. In addition, both mutants are able to enhance the pulmonary recruitment of dendritic cells (DCs) and T cells and induce effective protections against the HMPV challenge. The DC maturation is also significantly improved by the motif mutation. Taken together, our data provide proof-of-principle for two live-attenuated M2-2 mutants to be promising HMPV vaccine candidates that are effective in inducing higher pulmonary innate immunity and generating protection against HMPV infection.

Integrated-omics endotyping of infants with rhinovirus bronchiolitis and risk of childhood asthma

BACKGROUND

Young children with rhinovirus (RV) infection-particularly bronchiolitis-are at high risk for developing childhood asthma. Emerging evidence suggests clinical heterogeneity within RV bronchiolitis. However, little is known about these biologically distinct subgroups (endotypes) and their relations with asthma risk.

OBJECTIVE

We aimed to identify RV bronchiolitis endotypes and examine their longitudinal relations with asthma risk.

METHODS

As part of a multicenter prospective cohort study of infants (age <12 months) hospitalized for bronchiolitis, we integrated clinical, RV species (RV-A, RV-B, and RV-C), nasopharyngeal microbiome (16S rRNA gene sequencing), cytokine, and metabolome (liquid chromatography tandem mass spectrometry) data collected at hospitalization. We then applied network and clustering approaches to identify bronchiolitis endotypes. We also examined their longitudinal association with risks of developing recurrent wheeze by age 3 years and asthma by age 5 years.

RESULTS

Of 122 infants hospitalized for RV bronchiolitis (median age, 4 months), we identified 4 distinct endotypes-mainly characterized by RV species, microbiome, and type 2 cytokine (T2) response: endotype A, virus^RV-Cmicrobiome^mixedT2^low; endotype B, virus^RV-Amicrobiome^HaemophilusT2^low; endotype C, virus^RSV/RVmicrobiome^{Streptococcus}T2^low; and endotype D, virus^RV-Cmicrobiome^MoraxellaT2^high. Compared with endotype A infants, endotype D infants had a significantly higher rate of recurrent wheeze (33% vs 64%; hazard ratio, 2.23; 95% CI, 1.00-4.96; P = .049) and a higher risk for developing asthma (28% vs 59%; odds ratio, 3.74: 95% CI, 1.21-12.6; P = .03).

CONCLUSIONS

Integrated-omics analysis identified biologically meaningful RV bronchiolitis endotypes in infants, such as one characterized by RV-C infection, Moraxella-dominant microbiota, and high T2 cytokine response, at higher risk for developing recurrent wheeze and asthma. This study should facilitate further research toward validating our inferences.

Nebulised ALX-0171 for respiratory syncytial virus lower respiratory tract infection in hospitalised children: a double-blind, randomised, placebo-controlled, phase 2b trial

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of severe lower respiratory tract infection, with a high global health burden. There are no effective treatments available. ALX-0171 is a novel trivalent Nanobody with antiviral properties against RSV. We aimed to assess the safety and antiviral activity of nebulised ALX-0171 in children admitted to hospital with RSV lower respiratory tract infection.

METHODS

This double-blind, randomised, placebo-controlled, phase 2b trial was done in 50 hospital paediatric departments across 16 countries. Previously healthy children aged between 28 days to younger than 24 months who were admitted to hospital with RSV acute severe lower respiratory tract infection were randomly assigned in three sequential safety cohorts (3:1) to receive nebulised ALX-0171 (cohort 1 received 3 mg/kg, cohort 2 received 6 mg/kg, and cohort 3 received 9 mg/kg) or placebo once daily for 3 days using web-based randomisation in the sequential safety part (first block size 12, subsequently four). In a parallel part of the study, participants (cohort 4) were randomly assigned (parallel 1:1:1:1) to receive nebulised ALX-0171 3 mg/kg, 6 mg/kg, 9 mg/kg, or placebo (blocks of eight by restricted randomisation). Study drug masking was by two consecutive nebulisations (each either ALX-0171 or placebo) depending on assigned treatment group. The primary outcome was to evaluate time for the RSV viral load to drop to below quantifiable limit, measured by plaque assay on mid-turbinate nasal swabs. Safety, clinical efficacy, pharmacokinetics, viral load by RT-qPCR, and immunogenicity were secondary outcomes. Analysis, including of the primary outcome, was by modified intention to treat (participants receiving at least one dose of study drug as assigned), and safety was assessed in all children who received at least one administration of study drug, as treated. This trial is registered with EudraCT, 2016-001651-49.

FINDINGS

Between Jan 10, 2017, and April 26, 2018, 175 children (median age 4·8 months [IQR 2·0-10·8]), received at least one dose of study drug (45 received 3 mg/kg of ALX-0171, 43 received 6 mg/kg of ALX-0171, 45 received 9 mg/kg of ALX-0171, and 42 received placebo; the modified intention-to-treat population) commencing at a mean 3·3 days (SD 1·1) from symptom onset. Median time for the viral load to drop to below quantifiable limit on plaque assay was significantly faster for the 3 mg/kg group (median 14·2 h [IQR 5·0-28·0]), 6 mg/kg group (5·1 h [4·7-28·5]), and 9 mg/kg group (5·1 h [4·6-5·9]) than the placebo group (46·1 h [25·2-116·7]; hazard ratio [HR] all ALX-0171 groups vs placebo 2·6 [1·7-3·9]; p<0·0001). Median time for the viral load to drop below quantification limit with RT-qPCR was 95·9 h (IQR 26·7 to not estimable) for the placebo group (n=35) versus 49·4 h (25·1 to 351·4) for all ALX-0171 groups (n=118). Clinical outcomes were not improved by ALX-0171 compared with placebo, with no difference in time to clinical response (oxygen saturation >92% for 4 h in room air and adequate oral feeding) in ALX-0171 groups and the placebo group (median 43·8 h [IQR 21·7-68·5] vs 47·9 h [22·5-76·4]; HR 1·1 [95% CI 0·8-1·6]) or change in the global severity score from baseline to 5 h post-dose on day 2 (-4 [IQR -6 to -2] vs -4 [-6 to -1]; difference in least-squares mean -0·45 [95% CI -1·39 to 0·49]). Serum concentrations of ALX-0171 on day 2 exceeded the concentration estimated to give full RSV neutralisation in the lung at 6 mg/kg and 9 mg/kg doses. Treatment-emergent antidrug antibodies were detected at day 14 in 46 (34%) of 135 patients who received ALX-0171 and ten (26%) of 39 patients who received placebo. Serious adverse events were reported in five (13%) of 40 children in the placebo group and ten (7%) of 135 children in all ALX-0171 groups, leading to study drug discontinuation in three children (two in the 3 mg/kg group and one in the 6 mg/kg group). 13 of 15 serious adverse events (three of four in the 3 mg/kg group, two of three in the 6 mg/kg group, three of three in the 9 mg/kg group, and five of five in the placebo group) were related to worsening respiratory status, and none were considered to be related to the study drug.

INTERPRETATION

Antivirals against RSV might be unable to improve clinical course once RSV lower respiratory tract infection is established. Future studies of RSV antivirals should focus on earlier intervention and more precise measurement of objective outcomes before the onset of significant lower respiratory tract inflammation.

FUNDING

Ablynx, a Sanofi Company.

The Relationship Between Chest Imaging Findings and the Viral Load of COVID-19

Purpose: We aimed to investigate the relationship between clinical characteristics, radiographic features, and the viral load of patients with coronavirus disease 2019 (COVID-19). Methods and Materials: We retrospectively collected 56 COVID-19 cases from two institutions in Hunan province, China. The basal clinical characteristics, detail imaging features and follow-up CT changes were evaluated and the relationship with the viral load was analyzed. Results: GGO (48, 85.7%) and vascular enlargement (44, 78.6%) were the most frequent signs in COVID-19 patients. Of the lesions, 64.3% of the margins were uneasily differentiated. However, no significant correlations were found in terms of leucocytes, neutrophils, lymphocytes, platelets, and C-reactive protein (all P > 0.05). In contrast, the uneasily differentiated margin was negatively correlated with the Ct value (r = -0.283, P = 0.042), that is, an uneasily differentiated margin indicated a lower Ct value (P = 0.043). Patients with a lower Ct value were likely to present a progress follow-up change (P = 0.022). The Ct value at baseline could predict a progress follow-up change with an AUC of 0.685 (Cut-off value = 29.48). All four patients with normal CT findings presented new lesion(s) on follow-up CT scans. Conclusion: The viral load of COVID-19 is negatively correlated with an uneasily differentiated lesion margin on initial CT scan images and the Ct value should noted when making a diagnosis. In addition, following-up CT scans are necessary for patients who presented a normal CT at the initial diagnosis, especially for those with a low Ct value.

Impact of respiratory viral polymerase chain reaction testing on de-escalation of antibiotic therapy in children who require chronic positive pressure ventilation

BACKGROUND

Children who require chronic positive pressure ventilation (CPPV) are frequently hospitalized with acute respiratory infections. Although respiratory viral testing is often performed, it is unclear how positive results impact antibiotic use. We sought to assess the impact of respiratory viral testing on antibiotic use in hospitalized children on CPPV.

METHODS

This retrospective cohort study included hospitalized children on CPPV who had respiratory viral polymerase chain reaction (RVP) testing on admission. Primary exposure was a positive RVP result; primary outcome was antibiotic de-escalation, defined as discontinuation of antibiotics or narrowing of antimicrobial spectra. To determine the independent association of positive RVP and antibiotic de-escalation, a generalized linear mixed effect model was used to account for within patient clustering and confounders defined a priori (blood and respiratory cultures, leukocytosis, bandemia, chest radiograph findings, aspiration risk, and recent admission).

RESULTS

A total of 200 admissions representing 118 patients were included. A viral pathogen was identified in 46.5% (93/200) of admissions; rhinovirus was most frequently identified (61.5% of positive RVPs). Antibiotic de-escalation occurred in 33% of admissions (35.5% of RVP-positive admissions vs 30.8% of RVP-negative admissions; P = .49). In adjusted analysis, there was no association between positive RVP and antibiotics de-escalation (adjusted OR: 0.86; 95% confidence interval: 0.32-2.26).

CONCLUSION

This single center cohort study suggests that respiratory viral testing may not impact antibiotic prescribing for hospitalized children on CPPV. There is need for improved stewardship of both diagnostic testing and antimicrobial use in this population.

Performance of Abbott ID Now COVID-19 Rapid Nucleic Acid Amplification Test Using Nasopharyngeal Swabs Transported in Viral Transport Media and Dry Nasal Swabs in a New York City Academic Institution

The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2. The two platforms demonstrate comparable performances; however, the run times for each assay are 3.5 h and 45 min, respectively. In search for a platform with a shorter turnaround time, we sought to evaluate the recently released Abbott ID Now COVID-19 assay, which is capable of producing positive results in as little as 5 min. We present here the results of comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media and comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media for Cepheid and dry nasal swabs for Abbott ID Now. Regardless of method of collection and sample type, Abbott ID Now COVID-19 had negative results in a third of the samples that tested positive by Cepheid Xpert Xpress when using nasopharyngeal swabs in viral transport media and 45% when using dry nasal swabs.

Performance of Abbott ID Now COVID-19 Rapid Nucleic Acid Amplification Test Using Nasopharyngeal Swabs Transported in Viral Transport Media and Dry Nasal Swabs in a New York City Academic Institution

The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2.

The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2. The two platforms demonstrate comparable performances; however, the run times for each assay are 3.5 h and 45 min, respectively. In search for a platform with a shorter turnaround time, we sought to evaluate the recently released Abbott ID Now COVID-19 assay, which is capable of producing positive results in as little as 5 min. We present here the results of comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media and comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media for Cepheid and dry nasal swabs for Abbott ID Now. Regardless of method of collection and sample type, Abbott ID Now COVID-19 had negative results in a third of the samples that tested positive by Cepheid Xpert Xpress when using nasopharyngeal swabs in viral transport media and 45% when using dry nasal swabs.

Viral Respiratory Infection, a Risk in Pediatric Cardiac Surgery: A Propensity-Matched Analysis

OBJECTIVES

1) To describe the postoperative course and outcomes of cardiac surgery in children with perioperative viral respiratory infection, 2) to evaluate optimal surgical timing for preoperative viral respiratory infection patients, and 3) to define risk stratification.

DESIGN

Retrospective study of children undergoing cardiac surgery. Children were tested using a multiplex polymerase chain reaction (respiratory virus polymerase chain reaction) panel capturing seven respiratory viruses. Respiratory virus polymerase chain reaction testing was routinely performed in patients under 2 years old. Those with negative results yet highly suspected of viral respiratory infection after surgeries would be tested again.

SETTING

A pediatric cardiac surgical ICU of pediatric cardiac surgery department at Fuwai Hospital.

PATIENTS

Children admitted between January 1, 2014, and December 31, 2016, to perform respiratory virus polymerase chain reaction testing and cardiac surgery were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 2,831 patients had respiratory virus polymerase chain reaction testing, and viruses were detected in 91 patients (3.2%), including 35 preoperative and 56 postoperative. Of the 35 preoperative viral respiratory infection patients, there were 29 viral respiratory infection-resolved (patients for whom surgery was postponed until resolution of viral respiratory infection symptoms and negative respiratory virus polymerase chain reaction) and six viral respiratory infection-unresolved (who underwent cardiac surgery before resolution of symptoms and clearance of carriage) patients. Furthermore, there were seven deaths, including one in the preoperative viral respiratory infection-unresolved group and six in the postoperative viral respiratory infection group. A propensity score matching was performed to correct the selection bias and identify the comparable patient groups. Compared to their matched nonviral respiratory infection patients, viral respiratory infection-resolved patients had similar duration of mechanical ventilation and length of stay, while viral respiratory infection-unresolved patients had longer durations of postoperative mechanical ventilation (p = 0.033), PICU (p = 0.028) and hospital length of stay (p = 0.010), and postoperative viral respiratory infection patients had significantly greater duration of postoperative recovery (p < 0.001) and higher mortality (p < 0.001). Earlier diagnosis of postoperative viral respiratory infection was associated with longer mechanical ventilation duration (r = 0.422; p < 0.001). Palliative cardiac surgery was the only variable significantly associated with mortality in multivariate analysis (odds ratio, 12.0; 95% CI, 1.6-87.5; p = 0.014).

CONCLUSIONS

The preoperative-unresolved and postoperative viral respiratory infection were associated with prolonged postoperative recovery, increased severity, and mortality in children with cardiac surgeries. Our results suggested the optimal surgical timing may be after the resolution of viral respiratory infection symptoms and carriage unless the perceived benefits of early surgery outweigh the risk of death, prolonged ventilation, and PICU length of stay. Palliative surgeries were associated with increasing mortality.

Outcomes of patients with Severe Acute Respiratory Infections (SARI) admitted to the intensive care unit: results from the Egyptian Surveillance Study 2010-2014

Background

Few data exist about respiratory viral infections in Egyptian patients. Hereby we describe the outcomes of hospitalized Egyptian patients with severe acute respiratory infections (SARI) admitted to the ICU.

Methods

A prospective study in which all hospitalized patients meeting the WHO case definition for SARI and admitted to the ICU, during the period 2010–2014, were enrolled. Samples were tested using RT-PCR for influenza A, B, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), parainfluenza virus, adenovirus, bocavirus, enterovirus, and rhinovirus. Data were analyzed to study the clinical features of SARI-ICU patients and which pathogens are related to severe outcomes. Associated comorbidities were evaluated using Charlson Age-Comorbidity Index (CACI).

Results

Out of 1,075 patients with SARI, 219 (20.3%) were admitted to the ICU. The highest rates were reported for RSV (37%). SARI-ICU patients had higher rates of hospital stay, pneumonia, respiratory failure, ARDS, and mortality. Multivariate logistic regression analysis identified associated respiratory disorders (p=0.001), radiological abnormalities (p=0.023), and longer hospital stay (p=0.005) as risk factors for severe outcomes.

Conclusions

This surveillance study showed that 20% of hospitalized Egyptian patients with viral SARI needed ICU admission. SARI-ICU patients had higher rates of hospital stay, pneumonia, respiratory failure, ARDS, and mortality. Higher comorbidity index scores, radiological abnormalities, and longer hospital stay are risk factors for severe outcomes in SARI-ICU patients in our locality.

Testing for Common Respiratory Viruses in Children Admitted to Pediatric Intensive Care: Epidemiology and Outcomes

OBJECTIVES

Viral infections are common in children, but there is a lack of data on severe viral infections in critically ill children. We investigated testing for viral infections in children requiring PICU admission and describe the epidemiology and outcomes.

DESIGN

Multicenter retrospective study. Results of viral testing for nine respiratory viruses using polymerase chain reaction were collected.

PARTICIPANTS

Children less than 16 years old nonelectively admitted to PICU over a 6-year period.

SETTING

Two tertiary PICUs in Queensland, Australia.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Primary outcome was PICU length of stay. Secondary outcomes included need for and duration of intubation and mortality in PICU. Univariate and multivariate regression analyses were performed, adjusting for age, indigenous status, comorbidities, and severity of illness.

RESULTS

Of 6,426 nonelective admissions, 2,956 (46%) were polymerase chain reaction tested for a virus of which 1,353 (46%) were virus positive. Respiratory syncytial virus was the most common pathogen identified (n = 518, 33%), followed by rhinovirus/enterovirus and adenovirus. Across all patients who underwent polymerase chain reaction testing, identification of a respiratory virus was not significantly associated with longer overall length of stay (multivariate odds ratio, 1.08; 95% CI, 0.99-1.17; p = 0.068) or longer intubation (p = 0.181), whereas the adjusted odds for intubation and mortality were significantly lower (p < 0.01). Subgroup analyses restricted to patients with acute respiratory infections (n = 1,241), bronchiolitis (n = 761), pneumonia (n = 311), confirmed bacterial infection (n = 345), and malignancy (n = 95) showed that patients positive for a virus on testing had significantly longer PICU length of stay (multivariate p < 0.05). In children with pneumonia, identification of a respiratory virus was associated with significantly increased duration of ventilation (p = 0.003). No association between positive test results for multiple viruses and outcomes was observed.

CONCLUSION

Viral infections are common in critically ill children. Viral infections were associated with lower intubation and mortality rates compared with all children testing negative for viral infections. In several subgroups studied, identification of viral pathogens was associated with longer PICU length of stay while mortality was comparable. Prospective studies are required to determine the benefit of routine testing for respiratory viruses at the time of PICU admission.

Time to Say Goodbye to Bronchiolitis, Viral Wheeze, Reactive Airways Disease, Wheeze Bronchitis and All That

The diagnosis and management of infants and children with a significant viral lower respiratory tract illness remains the subject of much debate and little progress. Over the decades various terms for such illnesses have been in and fallen out of fashion or have evolved to mean different things to different clinicians. Terms such as "bronchiolitis," "reactive airways disease," "viral wheeze," and many more are used to describe the same condition and the same term is frequently used to describe illnesses caused by completely different dominant pathologies. This lack of clarity is due, in large part, to a failure to understand the basic underlying inflammatory and associated processes and, in part, due to the lack of a simple test to identify a condition such as asthma. Moreover, there is a lack of insight into the fact that the same pathology can produce different clinical signs at different ages. The consequence is that terminology and fashions in treatment have tended to go around in circles. As was noted almost 60 years ago, amongst pre-school children with a viral LRTI and airways obstruction there are those with a "viral bronchitis" and those with asthma. In the former group, a neutrophil dominated inflammation response is responsible for the airways' obstruction whilst amongst asthmatics much of the obstruction is attributable to bronchoconstriction. The airways obstruction in the former group is predominantly caused by airways secretions and to some extent mucosal oedema (a "snotty lung"). These patients benefit from good supportive care including supplemental oxygen if required (though those with a pre-existing bacterial bronchitis will also benefit from antibiotics). For those with a viral exacerbation of asthma, characterized by bronchoconstriction combined with impaired b-agonist responsiveness, standard management of an exacerbation of asthma (including the use of steroids to re-establish bronchodilator responsiveness) represents optimal treatment. The difficulty is identifying which group a particular patient falls into. A proposed simplified approach to the nomenclature used to categorize virus associated LRTIs is presented based on an understanding of the underlying pathological processes and how these contribute to the physical signs.

A randomized controlled trial of a combination of antiviral and nonsteroidal anti-inflammatory treatment in a bovine model of respiratory syncytial virus infection

INTRODUCTION

Bovine respiratory syncytial virus (RSV) is a valid model for human RSV and an important bovine pathogen. Very early administration of ibuprofen and GS-561937, a fusion protein inhibitor (FPI), have separately been shown to decrease the severity of bovine RSV. Our aims were to determine how long after RSV inoculation ibuprofen and GS-561937 can be administered with clinical benefit and whether using both was better than monotherapy.

MATERIALS AND METHODS

We conducted a blinded randomized placebo controlled trial of ibuprofen, GS-561937 (FPI), or combinations of the two initiated at 3 or 5 days after artificial infection with bovine RSV in 36 five to six-week-old Holstein calves (Bos taurus). We measured clinical scores, respiratory rate, and viral shedding daily for 10 days following inoculation. We estimated the average effect for each drug and compared treatment arms using mixed effects models.

RESULTS

We found a significant decrease in clinical scores only in the combined treatment arms. This benefit was greater when treatment was initiated at 3 days rather than 5 days post infection with decreased clinical scores and lower respiratory rates at both time points. Ibuprofen alone started on day 3 increased, and FPI with ibuprofen started on day 3 decreased, viral shedding.

CONCLUSION

Dual therapy with Ibuprofen and FPI, on average, decrease clinical severity of illness in a bovine model of RSV when started at 3 and 5 days after infection.

Serum Metabolome Is Associated With the Nasopharyngeal Microbiota and Disease Severity Among Infants With Bronchiolitis

BACKGROUND

Emerging evidence suggests relationships between the nasopharyngeal metabolome and both the microbiota and severity of bronchiolitis. However, the influence of host systemic metabolism on disease pathobiology remains unclear. We aimed to examine metabolome profiles and their association with more-severe disease, defined by use of positive pressure ventilation (PPV), in infants hospitalized for bronchiolitis.

METHODS

In 140 infants with bronchiolitis, metabolomic profiling was performed on serum; samples from 70 were in a training data set, and samples from 70 were in an independent test data set. We also profiled the nasopharyngeal airway microbiota and examined its association with the serum metabolites.

RESULTS

Serum metabolome profiles differed by bronchiolitis severity (P < .001). In total, 20 metabolites in the training data set were significantly associated with the risk of PPV, of which 18 remained significant following adjustment for confounders (false-discovery rate [FDR], < 0.10). Phosphatidylcholine metabolites were associated with higher risks of PPV use, while metabolites from the plasmalogen subpathway were associated with lower risks. The test data set validated these findings (FDR < 0.05). Streptococcus abundance was positively associated with metabolites that are associated with higher risks of PPV.

CONCLUSIONS

Serum metabolomic signatures were associated with both the nasopharyngeal microbiota and the severity of bronchiolitis. Our findings advance research into the complex interrelations between the airway microbiome, host systemic response, and pathobiology of bronchiolitis.

Respiratory Syncytial Virus Disease Severity Is Associated with Distinct CD8+ T-Cell Profiles

Rationale: Respiratory syncytial virus (RSV) causes significant morbidity and mortality in infants worldwide. Although T-helper type 2 (Th2) cell pathology is implicated in severe disease, the mechanisms underlying the development of immunopathology are incompletely understood.Objectives: We aimed to identify local immune responses associated with severe RSV in infants. Our hypothesis was that disease severity would correlate with enhanced Th2 cellular responses.Methods: Nasal aspirates were collected from infants hospitalized with severe (admitted to the pediatric ICU) or moderate (maintained in the general ward) RSV disease at 5 to 9 days after enrollment. The immune response was investigated by evaluating T-lymphocyte cellularity, cytokine concentration, and viral load.Measurements and Main Results: Patients with severe disease had increased proportions of CD8 (cluster of differentiation 8)-positive T cells expressing IL-4 (Tc2) and reduced proportions of CD8+ T cells expressing IFNγ (Tc1). Nasal aspirates from patients with severe disease had reduced concentrations of IL-17. Patients with greater frequencies of Tc1, CD8+ T cells expressing IL-17 (Tc17), and CD4+ T cells expressing IL-17 (Th17) had shorter durations of hospitalization.Conclusions: Severe RSV disease was associated with distinct T-cell profiles. Tc1, Tc17, and Th17 were associated with shorter hospital stay and may play a protective role, whereas Tc2 cells may play a previously underappreciated role in pathology.

Viral Load Dynamics and Clinical Disease Severity in Infants With Respiratory Syncytial Virus Infection

Background

The association between respiratory syncytial virus (RSV) loads and clinical outcomes in children remains to be defined. In most studies, viral loads (VL) were evaluated in hospitalized children and at a single time-point. We investigated the relationship between VLs and disease severity in both outpatients and inpatients with RSV infection.

Methods

We enrolled previously healthy children with RSV infection. Disease severity was defined by level of care (outpatients vs ward vs pediatric intensive care unit [PICU]), and a clinical disease severity score (CDSS). Nasopharyngeal VLs by polymerase chain reaction and CDSS were measured at enrollment and daily in inpatients. VL decay according to disease severity was analyzed using linear mixed modeling.

Results

From February 2015 to March 2017, we enrolled 150 infants: 39 outpatients and 111 inpatients. VLs were higher in outpatients than in age-matched inpatients. Among inpatients, initial VLs were comparable in ward and PICU patients, and preceded the peak CDSS. However, after excluding infants treated with steroids, those hospitalized in the ward had higher VLs than infants requiring PICU care (P < .001). Dynamic analyses showed that VL decay was delayed in PICU patients, especially in those treated with steroids.

Conclusions

Higher VLs at presentation and a faster and consistent VL decline were both associated with less severe RSV disease in children.

Summary

Infants with less severe respiratory syncytial virus (RSV) disease had higher viral loads (VL) at presentation, and faster and consistent VL decline. Conversely, VL decay and overall viral exposure were prolonged and higher in infants severe RSV disease receiving steroids.

Overnutrition in Infants Is Associated With High Level of Leptin, Viral Coinfection and Increased Severity of Respiratory Infections: A Cross-Sectional Study

Objective: To investigate the relationship of overnutrition (obese and overweight) with severity of illness in children hospitalized with acute lower respiratory infections (ALRIs), frequency of viral coinfections and leptin levels. Methods: We studied 124 children <2 years old that were hospitalized for ALRI. Nutritional status was calculated by z-scores according to weight-for-age z-scores, length or height-for-age z-scores, and weight-for-height z-scores. Nasopharyngeal aspirates (NPAs) were obtained and viral respiratory pathogens were identified using reverse transcription polymerase chain reactions (RT-PCR). Respiratory syncytial virus (RSV) load was assessed using quantitative RT-PCR. NPA and plasma leptin level were measured. Clinical data and nutritional status were recorded, and patients were followed up until hospital discharge. Viral coinfection was defined as the presence of two or more viruses detected in the same respiratory sample. Severity of illness was determined by length of hospitalization and duration of oxygen therapy. Results: Children with overnutrition showed a greater frequency of viral coinfection than those with normal weight (71% obese vs. 37% normal weight p = 0.013; 68% overweight vs. 37% normal weight p = 0.004). A lower RSV load was found in obese (5.91 log₁₀ copies/mL) and overweight children (6.49 log₁₀ copies/mL) compared to normal weight children (8.06 log₁₀ copies/mL; p = 0.021 in both cases). In multivariate analysis, obese, and overweight infants <6 months old were associated with longer hospital stays (RR = 1.68; CI: 1.30-2.15 and obese: RR = 1.68; CI: 1.01-2.71, respectively) as well as a greater duration of oxygen therapy (RR = 1.80; IC: 1.41-2.29 and obese: RR = 1.91; CI: 1.15-3.15, respectively). Obese children <6 months showed higher plasma leptin level than normal weight children (7.58 vs. 5.12 ng/μl; p <0.046). Conclusions: In infants younger than 6 months, overnutrition condition was related to increased severity of infections and high plasma leptin level. Also, children with overnutrition showed a greater frequency of viral coinfection and low RSV viral load compared to normal weights children. These findings further contribute to the already existent evidence supporting the importance of overnutrition prevention in pediatric populations.

Elevated Levels of Type 2 Respiratory Innate Lymphoid Cells in Human Infants with Severe Respiratory Syncytial Virus Bronchiolitis

Rationale: Studies of the immune responses at the site of respiratory syncytial virus (RSV) infection are sparse despite nearly five decades of research into understanding RSV disease.Objectives: To investigate the role of mucosal innate immune responses to RSV and respiratory viral load in infants hospitalized with the natural disease.Methods: Cytokines, viral load, and type 2 innate lymphoid cell (ILC2) levels in nasal aspirates, collected within 24 hours of enrollment, from infants hospitalized with RSV infection were quantified.Measurements and Main Results: RSV severity in infants was categorized based on admission to the general ward (moderate) or the pediatric ICU (severe). Evaluable subjects included 30 patients with severe and 63 patients with moderate disease (median age, 74 d; range, 9-297 d). ILC2s were found in the nasal aspirates of patients with severe disease (0.051% of total respiratory CD45+ cells) to a significantly greater extent than in patients with moderate disease (0.018%, P = 0.004). Levels of IL-4, IL-13, IL-33, and IL-1β were significantly higher in nasal aspirates of patients with severe disease compared with those of patients with moderate disease. Factors associated with disease severity were gestational age (odds ratio, 0.49; 95% confidence interval, 0.29-0.82; P = 0.007) and IL-4 (odds ratio, 9.67; 95% confidence interval, 2.45-38.15; P = 0.001).Conclusions: This study shows, for the first time, that elevated levels of ILC2s is associated with infant RSV severity. The findings highlight the dominance of type-2 responses to RSV infection in infants and suggest an important role of ILC2 in shaping the immune response early during RSV infection.

Viral etiologies of acute respiratory tract infections among hospitalized children - A comparison between single and multiple viral infections

Background

Acute respiratory tract infections are commonly caused by viruses in children. The differences in clinical data and outcome between single and multiple viral infections in hospitalized children were analyzed.

Methods

We retrospectively reviewed the medical records of hospitalized children who had fever and a xTAG Respiratory Virus Panel (RVP) test over a 2-year period. The clinical data were analyzed and compared between single and multiple viral infections. Viral etiologies in upper and lower respiratory infections were analyzed and compared.

Results

A total of 442 patients were enrolled. Patients with positive viral detection (N = 311) had a significantly lower rate of leukocytosis (p = 0.03), less evidence of bacterial infection (p = 0.004), and shorter duration of hospitalization (p = 0.019) than those with negative viral detection. The age of patients with multiple viral infections was younger than those with single viral infection; however, there were no significant differences in duration of fever, antibiotics treatment and hospitalization between these two groups.

The most commonly identified virus was human rhinovirus. About 27% (n = 83) of patients had multiple viral infections. Overall, the highest percentage of human bocavirus infection was detected in multiple viral infections (79%). Lower respiratory tract infection (LRTI) was independently associated with multiple viral infections (p = 0.022), respiratory syncytial virus (RSV) infection (p = 0.001) and longer hospitalization duration (p = 0.011).

Conclusion

Multiple viral infections were associated with younger age and a higher risk of developing LRTI. However, multiple viral infections did not predict a worse disease outcome. More studies are needed to unveil the interplay between the hosts and different viruses in multiple viral infections.

Reduced Nasal Viral Load and IFN Responses in Infants with Respiratory Syncytial Virus Bronchiolitis and Respiratory Failure

RATIONALE

Respiratory syncytial virus (RSV) bronchiolitis is a major cause of morbidity and mortality in infancy. Severe disease is believed to result from uncontrolled viral replication, an excessive immune response, or both.

OBJECTIVES

To determine RSV load and immune mediator levels in nasal mucosal lining fluid by serial sampling of nasal fluids from cases of moderate and severe bronchiolitis over the course of infection.

METHODS

Infants with viral bronchiolitis necessitating admission (n = 55) were recruited from a pediatric center during 2016 and 2017. Of these, 30 were RSV infected (18 "moderate" and 12 mechanically ventilated "severe"). Nasal fluids were sampled frequently over time using nasosorption devices and nasopharyngeal aspiration. Hierarchical clustering of time-weighted averages was performed to investigate cytokine and chemokine levels, and gene expression profiling was conducted.

MEASUREMENTS AND MAIN RESULTS

Unexpectedly, cases with severe RSV bronchiolitis had lower nasal viral loads and reduced IFN-γ and C-C chemokine ligand 5/RANTES (regulated upon activation, normal T cell expressed and secreted) levels than those with moderate disease, especially when allowance was made for disease duration (all P < 0.05). Reduced cytokine/chemokine levels in severe disease were also seen in children with other viral infections. Gene expression analysis of nasopharyngeal aspiration samples (n = 43) confirmed reduced type-I IFN gene expression in severe bronchiolitis accompanied by enhanced expression of MUC5AC and IL17A.

CONCLUSIONS

Infants with severe RSV bronchiolitis have lower nasal viral load, CXCL10 (C-X-C motif chemokine ligand 10)/IP-10, and type-I IFN levels than moderately ill children, but enhanced MUC5AC (mucin-5AC) and IL17A gene expression in nasal cells.

Virus-Specific Antibody, Viral Load, and Disease Severity in Respiratory Syncytial Virus Infection

Background

Maternally derived serum antibody and viral load are thought to influence disease severity in primary respiratory syncytial virus (RSV) infection. As part of the AsPIRES study of RSV pathogenesis, we correlated various serum antibody concentrations and viral load with disease severity.

Methods

Serum neutralizing antibody titers and levels of immunoglobulin G (IgG) to RSV fusion protein (F), attachment proteins of RSV group A and B, the CX3C region of G, and nasal viral load were measured in 139 full-term previously healthy infants with primary RSV infection and correlated with illness severity.

Results

Univariate analysis showed no relationship between measures of serum antibody and severity. However, a multivariate model adjusting for age at the time of infection found a significant 0.56 decrease in severity score for each 2-fold increase in antibody concentration to RSV F. The benefit of antibody was greatest in infants ≤ 2 months of age. Additionally, estimated antibody titer at birth was correlated with age at infection, suggesting that higher antibody titers delay infection. Viral load did not differ by illness severity.

Conclusion

Our data support the concept of maternal immunization with an RSV vaccine during pregnancy as a strategy for reducing the burden of RSV infection in full-term healthy infants exposed to RSV during their first winter.

Pathogenic difference of respiratory syncytial virus infection in cotton rats of different ages

Human respiratory syncytial virus (RSV) is the most common viral pathogen of lower respiratory tract infection worldwide. The virus selectively infects the respiratory epithelium, and causes diseases of variable severity in infants and the elderly. However, the differences in pathogenesis in the age groups remain poorly studied. Age is a major determinant of RSV disease, and the most severe morbidity and mortality occur in the infants and the elderly, because of the immature immunity in infants and declining immunity in old age. The cotton rat is a good model of RSV infection as it is naturally susceptible to RSV. In this study, we established an infant/adult/elderly RSV infection model in 3-week, 8-week and 30-week-old cotton rats and infected them with equal dose of RSV. This model exhibited airway neutrophils infiltration. In the 3-week-old group, higher viral load was observed in the lungs and noses, may due to low IFN-α/Mx2 levels. In contrast, the 8-week-old group had adequate IFN-α/Mx2 but exhibited the most obvious pulmonary inflammation and peribronchiolitis. Interestingly, the most severe pathology and delayed viral clearance in the lungs were observed in the 30-week-old group, may related to the increase of mucus induced by TNF-α and the lower antiviral effect of IFN-α. These results clearly revealed that an age-dependent severity of RSV disease and antiviral defense in the cotton rats, which may provide an effective model for personalized vaccine research and specific treatment strategies for different RSV age groups.

Rhinovirus Type in Severe Bronchiolitis and the Development of Asthma

Background

Respiratory syncytial virus (RSV)- and rhinovirus (RV)-induced bronchiolitis are associated with an increased risk of asthma, but more detailed information is needed on virus types.

Objective

To study whether RSV or RV types are differentially associated with the future use of asthma control medication.

Methods

Over 2 consecutive winter seasons (2008-2010), we enrolled 408 children hospitalized for bronchiolitis at age less than 24 months into a prospective, 3-center, 4-year follow-up study in Finland. Virus detection was performed by real-time reverse transcription PCR from nasal wash samples. Four years later, we examined current use of asthma control medication.

Results

A total of 349 (86%) children completed the 4-year follow-up. At study entry, the median age was 7.5 months, and 42% had RSV, 29% RV, 2% both RSV and RV, and 27% non-RSV/-RV etiology. The children with RV-A (adjusted hazard ratio, 2.3; P = .01), RV-C (adjusted hazard ratio, 3.5; P < .001), and non-RSV/-RV (adjusted hazard ratio, 2.0; P = .004) bronchiolitis started the asthma control medication earlier than did children with RSV bronchiolitis. Four years later, 27% of patients used asthma control medication; both RV-A (adjusted odds ratio, 3.0; P = .03) and RV-C (adjusted odds ratio, 3.7; P < .001) etiology were associated with the current use of asthma medication. The highest risk was found among patients with RV-C, atopic dermatitis, and fever (adjusted odds ratio, 5.0; P = .03).

Conclusions

Severe bronchiolitis caused by RV-A and RV-C was associated with earlier initiation and prolonged use of asthma control medication. The risk was especially high when bronchiolitis was associated with RV-C, atopic dermatitis, and fever.

Respiratory Virus Epidemiology Among US Infants With Severe Bronchiolitis: Analysis of 2 Multicenter, Multiyear Cohort Studies

In 2 multicenter cohort studies of 2912 infants hospitalized for bronchiolitis during 2007-2014, the 5 most common pathogens were RSV (76.5%), rhinovirus (23.8%), coronavirus (6.9%), adenovirus (6.4%) and human metapneumovirus (6.0%). Hospitalization months significantly differed for these common pathogens (P ≤ 0.01), except for coronavirus (P = 0.30). There was a significant heterogeneity in temporal patterns by region in RSV-A and -B (both P < 0.001).

Association of Rhinovirus C Bronchiolitis and Immunoglobulin E Sensitization During Infancy With Development of Recurrent Wheeze

IMPORTANCE

Rhinovirus infection in early life, particularly with allergic sensitization, is associated with higher risks of developing recurrent wheeze and asthma. While emerging evidence links different rhinovirus species (eg, rhinovirus C) to a higher severity of infection and asthma exacerbation, to our knowledge, little is known about longitudinal associations of rhinovirus C infection during infancy with subsequent morbidities.

OBJECTIVE

To examine the association of different viruses (respiratory syncytial virus [RSV], rhinovirus species) in bronchiolitis with risks of developing recurrent wheeze.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective cohort study of infants younger than 1 year who were hospitalized for bronchiolitis was conducted at 17 hospitals across 14 US states during 3 consecutive fall to winter seasons (2011-2014).

EXPOSURES

Major causative viruses of bronchiolitis, including RSV (reference group) and 3 rhinovirus species (rhinovirus A, B, and C).

MAIN OUTCOMES AND MEASURES

Development of recurrent wheeze (as defined in national asthma guidelines) by age 3 years.

RESULTS

This analytic cohort comprised 716 infants who were hospitalized for RSV-only or rhinovirus bronchiolitis. The median age was 2.9 months (interquartile range, 1.6-3.8 months), 541 (76%) had bronchiolitis with RSV only, 85 (12%) had rhinovirus A, 12 (2%) had rhinovirus B, and 78 (11%) had rhinovirus C infection. Overall, 231 (32%) developed recurrent wheeze by age 3 years. In the multivariable Cox model, compared with infants with RSV-only infection, the risk of recurrent wheeze was not significantly different in those with rhinovirus A or B (rhinovirus A: hazard ratio [HR], 1.27; 95% CI, 0.86-1.88; rhinovirus B: HR, 1.39; 95% CI, 0.51-3.77; both P > .10). By contrast, infants with rhinovirus C had a significantly higher risk (HR, 1.58; 95% CI, 1.08-2.32). There was a significant interaction between virus groups and IgE sensitization on the risk of recurrent wheeze (P for interaction < .01). Only infants with both rhinovirus C infection and IgE sensitization (to food or aeroallergens) during infancy had significantly higher risks of recurrent wheeze (HR, 3.03; 95% CI, 1.20-7.61). Furthermore, compared with RSV-only, rhinovirus C infection with IgE sensitization was associated with significantly higher risks of recurrent wheeze with subsequent development of asthma at age 4 years (HR, 4.06; 95% CI, 1.17-14.1).

CONCLUSIONS AND RELEVANCE

This multicenter cohort study of infants hospitalized for bronchiolitis demonstrated between-virus differences in the risk of developing recurrent wheeze. Infants with rhinovirus C infection, along with IgE sensitization, had the highest risk. This finding was driven by the association with a subtype of recurrent wheeze: children with subsequent development of asthma.

Epidemiology of Infections and Development of Asthma

Asthma and allergic diseases have become more prevalent, although the reasons for this increase in disease burden are not known. Understanding why these diseases have become more common requires knowledge of the disease pathogenesis. Multiple studies have identified respiratory viral infections and atypical bacteria as potential etiologic agents underlying the development of asthma (and possibly allergies). This review discusses the epidemiology and potential mechanistic studies that provide links between these infectious agents and the development (and exacerbation) of asthma. These studies provide insight into the increase in disease prevalence and have identified potential targets for future therapeutic intervention.

Clinical characteristics and outcomes of patients with severe acute respiratory infections (SARI): results from the Egyptian surveillance study 2010-2014

Background

Respiratory viral and atypical bacterial infections data in Egyptian patients are sparse. This study describes the clinical features and outcomes of patients with severe acute respiratory infections (SARI) in hospitalized patients in Egypt.

Methods

SARI surveillance was implemented at Cairo University Hospital (CUH) during the period 2010–2014. All hospitalized patients meeting the WHO case definition for SARI were enrolled. Nasopharyngeal/oropharyngeal (NP/OP) swabs were collected and samples were tested using RT-PCR for influenza A, B, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), parainfluenza virus (PIV 1,2,3,4), adenovirus, bocavirus, coronavirus, enterovirus, rhinovirus, and atypical bacteria. Data were analyzed to calculate positivity rates for viral pathogens and determine which pathogens related to severe outcomes or resulted in death.

Results

Overall, 1,075/3,207 (33.5%) cases had a viral etiology, with a mean age of 5.74 (±13.87) years. The highest rates were reported for RSV (485 cases, 45.2%), PIV (125, 11.6%), and adenovirus (105, 9.8%). Children had a higher viral rate (981, 91.2%) compared to 94 (8.8%) cases in adults. Patients with identified viruses had significantly lower rates for ICU admission, hospital stay, mechanical ventilation, and overall mortality than those without identified viruses. No infections were independently associated with severe outcomes.

Conclusions

Viral pathogens were encountered in one-third of hospitalized adult and pediatric Egyptian patients with SARI, while atypical bacteria had a minor role. Highest rates of viral infections were reported for RSV, PIV, and adenovirus. Viral infections had neither negative impacts on clinical features nor outcomes of patients with SARI in our locality.

Antibiotic Prescription in Young Children With Respiratory Syncytial Virus-Associated Respiratory Failure and Associated Outcomes

OBJECTIVES

To describe antibiotic prescribing practices during the first 2 days of mechanical ventilation among previously healthy young children with respiratory syncytial virus-associated lower respiratory tract infection and evaluate associations between the prescription of antibiotics at onset of mechanical ventilation with clinical outcomes.

DESIGN

Retrospective cohort study.

SETTING

Forty-six children's hospitals in the United States.

PATIENTS

Children less than 2 years old discharged between 2012 and 2016 with an International Classification of Diseases diagnosis of respiratory syncytial virus-associated lower respiratory tract infection, no identified comorbid conditions, and receipt of mechanical ventilation.

INTERVENTIONS

Antibiotic prescription during the first 2 days of mechanical ventilation.

MEASUREMENTS AND MAIN RESULTS

We compared duration of mechanical ventilation and hospital length of stay between children prescribed antibiotics on both of the first 2 days of mechanical ventilation and children not prescribed antibiotics during the first 2 days of mechanical ventilation. We included 2,107 PICU children with respiratory syncytial virus-associated lower respiratory tract infection (60% male, median age of 1 mo [interquartile range, 1-4 mo]). The overall proportion of antibiotic prescription on both of the first 2 days of mechanical ventilation was 82%, decreasing over the study period (p = 0.004) and varying from 36% to 100% across centers. In the bivariate analysis, antibiotic prescription was associated with a shorter duration of mechanical ventilation (6 d [4-9 d] vs 8 d [6-11 d]; p < 0.001) and a shorter hospital length of stay (11 d [8-16 d] vs 13 d [10-18 d]; p < 0.001). After adjustment for center, demographics, and vasoactive medication prescription, antibiotic prescription was associated with a 1.21-day shorter duration of mechanical ventilation and a 2.07-day shorter length of stay. Ultimately, 95% of children were prescribed antibiotics sometime during hospitalization, but timing, duration, and antibiotic choice varied markedly.

CONCLUSIONS

Although highly variable across centers and decreasing over time, the practice of instituting antibiotics after intubation in young children with respiratory syncytial virus-associated lower respiratory tract infection was associated with a shortened clinical course after adjustment for the limited available covariates. A prudent approach to identify and optimally treat bacterial coinfection is needed.

Epidemiology of human respiratory viruses in children with acute respiratory tract infection in a 3-year hospital-based survey in Northern Italy

Acute respiratory tract infections (ARTIs) are among the leading causes of morbidity and mortality in children. The viral etiology of ARTIs was investigated over 3 years (October 2012–September 2015) in 2575 children in Parma, Italy, using indirect immunofluorescent staining of respiratory samples for viral antigens, cell culture, and molecular assays. Respiratory viruses were detected in 1299 cases (50.44%); 1037 (79.83%) were single infections and 262 (20.17%) mixed infections. The highest infection incidence was in children aged >6 months to ≤3 years (57.36%). Human respiratory syncytial virus (27.12%) and human adenovirus (23.58%) were the most common viruses identified. The virus detection rate decreased significantly between the first and third epidemic season (53.9% vs. 43.05%, P < 0.0001). The simultaneous use of different diagnostic tools allowed us to identify a putative viral etiology in half the children examined and to provide an estimate of the epidemiology and seasonality of respiratory viruses associated with ARTIs.

•

Respiratory viruses were assessed in children from October 2012 to September 2015.

•

Viruses were detected using antigen and molecular assays, and cell culture.

•

Respiratory syncytial virus and adenovirus were the most common viruses detected.

•

Influenza virus and respiratory syncytial virus detection showed seasonal variation.

•

Respiratory virus detection was highest in children aged >6 months to ≤3 years.

Exchange Proteins Directly Activated by cAMP and Their Roles in Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the leading cause of respiratory infection in young children and high-risk adults. However, a specific treatment for this viral infection is not currently available. In this study, we discovered that an exchange protein directly activated by cyclic AMP (EPAC) can serve as a potential therapeutic target for RSV. In both lower and upper epithelial cells, treatment with EPAC inhibitor (ESI-09), but not protein kinase A inhibitor (H89), significantly inhibits RSV replication and proinflammatory cytokine/chemokine induction. In addition, RSV-activated transcriptional factors belonging to the NF-κB and IRF families are also suppressed by ESI-09. Through isoform-specific gene knockdown, we found that EPAC2, but not EPAC1, plays a dominant role in controlling RSV replication and virus-induced host responses. Experiments using both EPAC2 knockout and EPAC2-specific inhibitor support such roles of EPAC2. Therefore, EPAC2 is a promising therapeutic target to regulate RSV replication and associated inflammation.IMPORTANCE RSV is a serious public health problem, as it is associated with bronchiolitis, pneumonia, and asthma exacerbations. Currently no effective treatment or vaccine is available, and many molecular mechanisms regarding RSV-induced lung disease are still significantly unknown. This project aims to elucidate an important and novel function of a protein, called EPAC2, in RSV replication and innate inflammatory responses. Our results should provide an important insight into the development of new pharmacologic strategies against RSV infection, thereby reducing RSV-associated morbidity and mortality.

Impact of RSV Coinfection on Human Bocavirus in Children with Acute Respiratory Infections

OBJECTIVE

The objective of this study was to assess epidemiological and clinical features of human bocavirus (HBoV) coinfection with other viruses.

METHOD

Children coinfected with HBoV between January 2012 and December 2014 were enrolled and retrospectively reviewed.

RESULT

A total of 984 patients were stratified into five groups: HBoV infection alone (n = 249), respiratory syncytial virus (RSV) infection alone (n = 649), HBoV coinfection with RSV (n = 28), with human rhinovirus (HRV) (n = 39) and with other virus (n = 19). Length of hospitalization was longer in HBoV coinfection with RSV group than HBoV (9.0 days vs. 7.0 days, p = 0.001), RSV (9.0 days vs. 8.0 days, p = 0.016) infection alone group. Pneumonia was more common in the HBoV coinfection with RSV group compared with the HBoV, RSV infection alone group, respectively (75.0% vs. 44.2%, 31.3%, p < 0.001). HBoV DNA copy numbers (383 000 copies/ml) were positively correlated with the length of hospitalization (r = 0.334, p < 0.001).

CONCLUSION

HBoV coinfection with RSV increases HBoV infection severity.

Thiol-Activated Hydrogen Sulfide Donors Antiviral and Anti-Inflammatory Activity in Respiratory Syncytial Virus Infection

We have recently shown that endogenous hydrogen sulfide (H₂S), an important cellular gaseous mediator, exerts an antiviral and anti-inflammatory activity in vitro and in vivo, and that exogenous H₂S delivered via the synthetic H₂S-releasing compound GYY4137 also has similar properties. In this study, we sought to extend our findings to a novel class of H₂S donors, thiol-activated gem-dithiol-based (TAGDDs). In an in vitro model of human respiratory syncytial virus (RSV) infection, TAGDD-1 treatment significantly reduced viral replication, even when added up to six hours after infection. Using a mouse model of RSV infection, intranasal delivery of TAGDD-1 to infected mice significantly reduced viral replication and lung inflammation, markedly improving clinical disease parameters and pulmonary dysfunction, compared to vehicle treated controls. Overall our results indicate that this novel synthetic class of H₂S-releasing compounds exerts antiviral and anti-inflammatory activity in the context of RSV infection and represents a potential novel pharmacological approach to ameliorate viral-induced lung disease.

Predictors of prolonged length of hospital stay for infants with bronchiolitis

Among inpatients suffering from bronchiolitis, approximately a quarter may undergo a prolonged length of stay (LOS) for the treatment of their respiratory condition. However, there have been few research studies that have evaluated variables that may be associated with a prolonged LOS in these patients, especially in low-income and middle-income countries, where the clinical and economic burden of the disease is the greatest. In an analytical single-center cross-sectional study, we included a population of patients with acute bronchiolitis hospitalized between March and June 2016. We collected demographic and clinical information and the LOS of each patient. Prolonged LOS for bronchiolitis was defined as at least one hospital stay of 5 or more days. A total of 303 patients were included, with 176 (58.1%) male and a median (IQR) age of 3.0 (1.0-7.0) months. After controlling for gender, history of bronchopulmonary dysplasia, number of days with respiratory symptoms, the presence of apnea as an initial manifestation of bronchiolitis, and other underlying disease conditions, we found that the independent predictors of prolonged LOS for bronchiolitis in our study population included age (OR 0.92; 95% CI 0.84 to 0.99; p=0.049), history of prematurity (OR 6.34; 95% CI 1.10 to 36.46; p=0.038), respiratory syncytial virus isolation (OR 1.92; 95% CI 1.02 to 3.73; p=0.048), and initial oxygen saturation (OR 0.94; 95% CI 0.88 to 0.98; p=0.048). The factors identified should be taken into account when planning policies to reduce the duration of hospital stay in infants with bronchiolitis.

Respiratory Syncytial Virus and Rhinovirus Bronchiolitis Are Associated With Distinct Metabolic Pathways

Background

Bronchiolitis, the leading cause of hospitalization among infants in the United States, is most commonly caused by respiratory syncytial virus (RSV), followed by rhinovirus (RV). Conventional perception is that bronchiolitis is a single entity, albeit with different viral etiologies and degrees of severity.

Methods

We conducted a cross-sectional study of nasopharyngeal aspirates from 106 infants hospitalized with bronchiolitis due to either RSV only (80 patients) or RV only (26 patients). We performed metabolomics analysis and 16S ribosomal RNA gene sequencing on all samples and metagenomic sequencing on 58 of 106 samples.

Results

Infants with RSV-only and RV-only infections had significantly different nasopharyngeal metabolome profiles (P < .001) and bacterial metagenome profiles (P < .05). RSV-only infection was associated with metabolites from a range of pathways and with a microbiome dominated by Streptococcus pneumoniae. By contrast, RV-only infection was associated with increased levels of essential and nonessential N-acetyl amino acids and with a high relative abundance of Haemophilus influenzae. These co-occurring species were associated with driving the bacterially derived metabolic pathways. Multi-omic analysis showed that both the virus and the microbiome were significantly associated with metabolic function in infants hospitalized with bronchiolitis.

Conclusion

Although replication of these findings is necessary, they highlight that bronchiolitis is not a uniform disease between RSV and RV infections, a result with future implications for prevention and treatment.

Viral Aetiology of Bronchiolitis in Hospitalised Children in a Tertiary Center in Tehran

One of the causes of infants' hospitalizations is bronchiolitis, while different viral agents could be causative agents. As there is little information regarding the common agents of bronchiolitis in Iranian infants, we designed this study to determine which agents were responsible for hospitalization due to bronchiolitis among infants in an Iranian tertiary center. Two hundred and three infants with bronchiolitis who were hospitalized in Bahrami hospital were enrolled. Data regarding age, sex, duration of hospitalization, exposure to smoking, previous antibiotic usage and fever were collected for all enrolled cases. Throat sample by means of soap was collected and rapid test with immunochromatography (IC) test was performed. Rapid test was positive in 59 (29%) cases and three cases had concomitant infection with two viruses. The most common viral agent was RSV (Respiratory Syncytial Virus). Mean age was significantly lower in cases with RSV or RSV+ adenovirus infectious in comparison with other two groups (adenovirus or influenza only), while mean duration of hospitalization was significantly longer in RSV/RSV+ adenovirus group. RSV is the most common viral etiology of bronchiolitis in Iranian infants less than one year old, which is related with younger age and longer duration of hospitalization.

Serum LL-37 Levels Associated With Severity of Bronchiolitis and Viral Etiology

Background

LL-37 is a host defense peptide with antimicrobial and immunomodulatory properties. We examined the relation of serum LL-37 levels to the severity of bronchiolitis and viral etiology.

Methods

We performed a 17-center prospective cohort study in infants hospitalized with bronchiolitis over 3 winters (2011-2014). Site teams collected clinical data, nasopharyngeal aspirates and serum. We used real-time polymerase chain reaction to test nasopharyngeal aspirates for 16 viruses. We tested serum for LL-37. Severity of bronchiolitis was defined by intensive care use and hospital length of stay. Viral etiology was defined as respiratory syncytial virus (RSV) or rhinovirus (RV), including coinfections with other viruses.

Results

The median age of the 1005 enrolled infants was 3 months (interquartile range, 2-6 months). After adjustment for 12 variables, LL-37 levels in the lowest quartile, compared with the highest, were associated both with intensive care use (adjusted odds ratio [aOR], 1.97; P = .01) and longer hospital stay (1.34; P < .001). In separate multivariable models, infants with LL-37 levels in the lowest 3 quartiles, compared with the highest, were more likely to have RSV (eg, aOR, 2.6 [lowest quartile]; P < .001 [all quartiles]). By contrast, infants with the lowest 3 LL-37 quartiles were less likely to have RV (eg, aOR, 0.5 [lowest quartile]; Pall quartiles ≤ .03 [all quartiles]).

Conclusions

In a large multicenter study of infants hospitalized with bronchiolitis, lower levels of serum LL-37 were associated with increased severity of illness. There was also an inverse relationship between LL-37 levels and the most common virus causing bronchiolitis, RSV. These findings highlight the role of LL-37 in the pathogenesis of bronchiolitis.

Haemophilus is overrepresented in the nasopharynx of infants hospitalized with RSV infection and associated with increased viral load and enhanced mucosal CXCL8 responses

BACKGROUND

While almost all infants are infected with respiratory syncytial virus (RSV) before the age of 2 years, only a small percentage develops severe disease. Previous studies suggest that the nasopharyngeal microbiome affects disease development. We therefore studied the effect of the nasopharyngeal microbiome on viral load and mucosal cytokine responses, two important factors influencing the pathophysiology of RSV disease. To determine the relation between (i) the microbiome of the upper respiratory tract, (ii) viral load, and (iii) host mucosal inflammation during an RSV infection, nasopharyngeal microbiota profiles of RSV infected infants (< 6 months) with different levels of disease severity and age-matched healthy controls were determined by 16S rRNA marker gene sequencing. The viral load was measured using qPCR. Nasopharyngeal CCL5, CXCL10, MMP9, IL6, and CXCL8 levels were determined with ELISA.

RESULTS

Viral load in nasopharyngeal aspirates of patients associates significantly to total nasopharyngeal microbiota composition. Healthy infants (n = 21) and RSV patients (n = 54) display very distinct microbial patterns, primarily characterized by a loss in commensals like Veillonella and overrepresentation of opportunistic organisms like Haemophilus and Achromobacter in RSV-infected individuals. Furthermore, nasopharyngeal microbiota profiles are significantly different based on CXCL8 levels. CXCL8 is a chemokine that was previously found to be indicative for disease severity and for which we find Haemophilus abundance as the strongest predictor for CXCL8 levels.

CONCLUSIONS

The nasopharyngeal microbiota in young infants with RSV infection is marked by an overrepresentation of the genus Haemophilus. We present that this bacterium is associated with viral load and mucosal CXCL8 responses, both which are involved in RSV disease pathogenesis.

The association between anterior nares and nasopharyngeal microbiota in infants hospitalized for bronchiolitis

BACKGROUND

The airway microbiome is a subject of great interest for the study of respiratory disease. Anterior nare samples are more accessible than samples from deeper within the nasopharynx. However, the correlation between the microbiota found in the anterior nares and the microbiota found within the nasopharynx is unknown. We assessed the anterior nares and nasopharyngeal microbiota to determine (1) the relation of the microbiota from these two upper airway sites and (2) if associations were maintained between the microbiota from these two sites and two bronchiolitis severity outcomes.

RESULTS

Among 815 infants hospitalized at 17 US centers for bronchiolitis with optimal 16S rRNA gene sequence reads from both nasal swab and nasopharyngeal aspirate samples, there were strong intra-individual correlations in the microbial communities between the two sample types, especially relating to Haemophilus and Moraxella genera. By contrast, we found a high abundance of Staphylococcus genus in the nasal swabs-a pattern not found in the nasopharyngeal samples and not informative when predicting the dominant nasopharyngeal genera. While these disparities may have been due to sample processing differences (i.e., nasal swabs were mailed at ambient temperature to emulate processing of future parent collected swabs while nasopharyngeal aspirates were mailed on dry ice), a previously reported association between Haemophilus-dominant nasopharyngeal microbiota and the increased severity of bronchiolitis was replicated utilizing the nasal swab microbiota and the same outcome measures: intensive care use (adjusted OR 6.43; 95% CI 2.25-20.51; P < 0.001) and hospital length-of-stay (adjusted OR 4.31; 95% CI, 1.73-11.11; P = 0.002). Additionally, Moraxella-dominant nasopharyngeal microbiota was previously identified as protective against intensive care use, a result that was replicated when analyzing the nasal swab microbiota (adjusted OR 0.30; 95% CI, 0.11-0.64; P = 0.01).

CONCLUSIONS

While the microbiota of the anterior nares and the nasopharynx are distinct, there is considerable overlap between the bacterial community compositions from these two anatomic sites. Despite processing differences between the samples, these results indicate that microbiota severity associations from the nasopharynx are recapitulated in the anterior nares, suggesting that nasal swab samples not only are effective sample types, but also can be used to detect microbial risk markers.

Respiratory Syncytial Virus Genotypes, Host Immune Profiles, and Disease Severity in Young Children Hospitalized With Bronchiolitis

Background

Data on how respiratory syncytial virus (RSV) genotypes influence disease severity and host immune responses is limited. Here, we characterized the genetic variability of RSV during 5 seasons, and evaluated the role of RSV subtypes, genotypes, and viral loads in disease severity and host transcriptional profiles.

Methods

A prospective, observational study was carried out, including a convenience sample of healthy infants hospitalized with RSV bronchiolitis. Nasopharyngeal samples for viral load quantitation, typing, and genotyping, and blood samples for transcriptome analyses were obtained within 24 hours of hospitalization. Multivariate models were constructed to identify virologic and clinical variables predictive of clinical outcomes.

Results

We enrolled 253 infants (median age 2.1 [25%-75% interquartile range] months). RSV A infections predominated over RSV B and showed greater genotype variability. RSV A/GA2, A/GA5, and RSV B/BA were the most common genotypes identified. Compared to GA2 or BA, infants with GA5 infections had higher viral loads. GA5 infections were associated with longer hospital stay, and with less activation of interferon and increased overexpression of neutrophil genes.

Conclusions

RSV A infections were more frequent than RSV B, and displayed greater variability. GA5 infections were associated with enhanced disease severity and distinct host immune responses.

Clinical Potential of Prefusion RSV F-specific Antibodies

Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in the very young. The RSV fusion protein (F) is essential for virus entry because it mediates viral and host membrane fusion. During this fusion process F is converted from a metastable prefusion conformation into an energetically favored postfusion state. Antibodies that target F can prevent viral entry and reduce disease caused by RSV. During recent years, many prefusion F-specific antibodies have been described. These antibodies typically have stronger RSV-neutralizing activity compared to those that also bind F in the postfusion conformation. Here, we describe how F-specific antibodies protect against RSV and why specifically targeting prefusion F could have great clinical potential.

Associations of Nasopharyngeal Metabolome and Microbiome with Severity among Infants with Bronchiolitis. A Multiomic Analysis

RATIONALE

Bronchiolitis is the most common lower respiratory infection in infants; however, it remains unclear which infants with bronchiolitis will develop severe illness. In addition, although emerging evidence indicates associations of the upper-airway microbiome with bronchiolitis severity, little is known about the mechanisms linking airway microbes and host response to disease severity.

OBJECTIVES

To determine the relations among the nasopharyngeal airway metabolome profiles, microbiome profiles, and severity in infants with bronchiolitis.

METHODS

We conducted a multicenter prospective cohort study of infants (age <1 yr) hospitalized with bronchiolitis. By applying metabolomic and metagenomic (16S ribosomal RNA gene and whole-genome shotgun sequencing) approaches to 144 nasopharyngeal airway samples collected within 24 hours of hospitalization, we determined metabolome and microbiome profiles and their association with higher severity, defined by the use of positive pressure ventilation (i.e., continuous positive airway pressure and/or intubation).

MEASUREMENTS AND MAIN RESULTS

Nasopharyngeal airway metabolome profiles significantly differed by bronchiolitis severity (P < 0.001). Among 254 metabolites identified, a panel of 25 metabolites showed high sensitivity (84%) and specificity (86%) in predicting the use of positive pressure ventilation. The intensity of these metabolites was correlated with relative abundance of Streptococcus pneumoniae. In the pathway analysis, sphingolipid metabolism was the most significantly enriched subpathway in infants with positive pressure ventilation use compared with those without (P < 0.001). Enrichment of sphingolipid metabolites was positively correlated with the relative abundance of S. pneumoniae.

CONCLUSIONS

Although further validation is needed, our multiomic analyses demonstrate the potential of metabolomics to predict bronchiolitis severity and better understand microbe-host interaction.

Nasosorption as a Minimally Invasive Sampling Procedure: Mucosal Viral Load and Inflammation in Primary RSV Bronchiolitis

Background

Existing respiratory mucosal sampling methods are flawed, particularly in a pediatric bronchiolitis setting.

Methods

Twenty-four infants with bronchiolitis were recruited: 12 were respiratory syncytial virus (RSV)-positive, 12 were RSV-negative. Infants were sampled by nasosorption and nasopharyngeal aspiration (NPA).

Results

Nasosorption was well tolerated and identified all RSV+ samples. RSV load measured by nasosorption (but not NPA) correlated with length of hospital stay (P = .04) and requirement for mechanical ventilation (P = .03). Nasosorption (but not NPA) levels of interferon γ, interleukin 1β, CCL5/RANTES, and interleukin 10 (IL-10) were elevated in RSV+ bronchiolitis (all P < .05), furthermore CCL5 and IL-10 correlated with RSV load (P < .05).

Conclusions

Nasosorption allowed measurement of RSV load and the mucosal inflammatory response in infants.

Hydrogen Sulfide Is an Antiviral and Antiinflammatory Endogenous Gasotransmitter in the Airways. Role in Respiratory Syncytial Virus Infection

Hydrogen sulfide (H₂S) is an endogenous gaseous transmitter whose role in the pathophysiology of several lung diseases has been increasingly appreciated. Our recent studies in vitro have shown, we believe for the first time, that H₂S has an important antiviral and antiinflammatory activity in respiratory syncytial virus (RSV) infection, the leading cause of bronchiolitis and viral pneumonia in children. Our objective was to evaluate the therapeutic potential of GYY4137, a novel slow-releasing H₂S donor, for the prevention and treatment of RSV-induced lung disease, as well as to investigate the role of endogenous H₂S in a mouse model of RSV infection. Ten- to 12-week-old BALB/c mice treated with GYY4137, or C57BL/6J mice genetically deficient in the cystathionine γ-lyase enzyme, the major H₂S-generating enzyme in the lung, were infected with RSV and assessed for viral replication, clinical disease, airway hyperresponsiveness, and inflammatory responses. Our results show that intranasal delivery of GYY4137 to RSV-infected mice significantly reduced viral replication and markedly improved clinical disease parameters and pulmonary dysfunction compared with the results in vehicle-treated control mice. The protective effect of the H₂S donor was associated with a significant reduction of viral-induced proinflammatory mediators and lung cellular infiltrates. Furthermore, cystathionine γ-lyase-deficient mice showed significantly enhanced RSV-induced lung disease and viral replication compared with wild-type animals. Overall, our results indicate that H₂S exerts a novel antiviral and antiinflammatory activity in the context of RSV infection and represent a potential novel pharmacological approach for ameliorating virus-induced lung disease.

Lack of association between viral load and severity of acute bronchiolitis in infants

Objective:

To investigate the correlation between respiratory syncytial viral load and length of hospitalization in infants with acute wheezing episodes.

Methods:

This was a two-year, cross-sectional study of infants ≤ 12 months of age with bronchiolitis at the time of admission to a tertiary hospital. For the identification of respiratory viruses, nasopharyngeal secretions were collected. Samples were analyzed (throughout the study period) by direct immunofluorescence and (in the second year of the study) by quantitative real-time PCR. We screened for three human viruses: rhinovirus, respiratory syncytial virus, and metapneumovirus.

Results:

Of 110 samples evaluated by direct immunofluorescence, 56 (50.9%) were positive for a single virus, and 16 (14.5%) were positive for two or more viruses. Among those 72 samples, the most prevalent virus was respiratory syncytial virus, followed by influenza. Of 56 samples evaluated by quantitative real-time PCR, 24 (42.8%) were positive for a single virus, and 1 (1.7%) was positive for two viruses. Among those 25 samples, the most prevalent virus was again respiratory syncytial virus, followed by human rhinovirus. Coinfection did not influence the length of the hospital stay or other outcome s. In addition, there was no association between respiratory syncytial virus load and the length of hospitalization.

Conclusions:

Neither coinfection nor respiratory syncytial viral load appears to influence the outcomes of acute bronchiolitis in infants.

SOFIA®RSV: prospective laboratory evaluation and implementation of a rapid diagnostic test in a pediatric emergency ward

Background

Respiratory syncytial virus (RSV) is responsible for severe respiratory infections and higher costs in medical care. The two aims of this work were to assess the performances of SOFIA^®RSV tests in “real-life-laboratory” conditions (study 1) and implemented at point-of-care testing in a pediatric emergency department (ED, study 2), during two consecutive winter seasons.

Methods

In study 1, fresh nasopharyngeal swabs from patients of all ages were sampled in 1.5 ml of Universal virological Transport Medium (UTM) and prospectively tested using SOFIA^®RSV tests. In study 2, conducted in a pediatric ED, nasopharyngeal swabs were placed in 3 ml of UTM. All SOFIA^®RSV tests were confirmed by molecular testing, considered as reference method. The epidemiological and clinical features of tested patients, as well as the care of these patients after obtaining quick results were evaluated.

Results

The sensitivities of SOFIA^®RSV in infants (aged under 24 months) performed in the laboratory and in the pediatric ED were respectively 95% (95% CI: 86.8–98.1) and 74.8% (95% CI: 68.0–80.9) compared to PCR. In study 1, the sensitivity among children (from 2 to 15 years old) and adults (above 15 years old) dropped to 45% (95% CI: 23.1–68.5) and 59% (95% CI: 32.9–81.6), respectively. In study 2, there were some differences in bed-management of SOFIA^®RSV positive compared to SOFIA^®RSV negative infants.

Conclusions

SOFIA^®RSV tests performed in the laboratory and in the pediatric ED show high and satisfactory sensitivities among young children under 24 months, which supports its robustness and reliability. However, the impact of these tests on patient care at point-of-care cannot be clearly assessed when considering the limits of the study 2 design.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2557-8) contains supplementary material, which is available to authorized users.

Burden of disease and change in practice in critically ill infants with bronchiolitis

Bronchiolitis represents the most common cause of non-elective admission to paediatric intensive care units (ICUs).

We assessed changes in admission rate, respiratory support, and outcomes of infants <24 months with bronchiolitis admitted to ICU between 2002 and 2014 in Australia and New Zealand.

During the study period, bronchiolitis was responsible for 9628 (27.6%) of 34 829 non-elective ICU admissions. The estimated population-based ICU admission rate due to bronchiolitis increased by 11.76 per 100 000 each year (95% CI 8.11–15.41). The proportion of bronchiolitis patients requiring intubation decreased from 36.8% in 2002, to 10.8% in 2014 (adjusted OR 0.35, 95% CI 0.27–0.46), whilst a dramatic increase in high-flow nasal cannula therapy use to 72.6% was observed (p<0.001). We observed considerable variability in practice between units, with six-fold differences in risk-adjusted intubation rates that were not explained by ICU type, size, or major patient factors. Annual direct hospitalisation costs due to severe bronchiolitis increased to over USD30 million in 2014.

We observed an increasing healthcare burden due to severe bronchiolitis, with a major change in practice in the management from invasive to non-invasive support that suggests thresholds to admittance of bronchiolitis patients to ICU have changed. Future studies should assess strategies for management of bronchiolitis outside ICUs.

[Expression of interferon-λ1 in respiratory epithelial cells of children with RSV infection and its relationship with RSV load]

OBJECTIVE

To investigate the expression of IFN-λ1 in respiratory epithelial cells of children with respiratory syncytial virus (RSV) infection and its relationship with RSV load.

METHODS

The nasopharyngeal swabs were collected from the children who were hospitalized with respiratory tract infection from June 2015 to June 2016. A direct immunofluorescence assay was used to detect the antigens of seven common respiratory viruses (including RSV) in the nasopharyngeal swabs. A total of 120 children who were only RSV positive were selected as the RSV infection group. A total of 50 children who had negative results in the detection of all viral antigens were selected as the healthy control group. Fluorescence quantitative real-time PCR was used to determine the RSV load and the expression of IFN-λ1 mRNA in the nasopharyngeal swabs of children in the two groups.

RESULTS

The expression of IFN-λ1 in the RSV infection group was significantly higher than that in the healthy control group (P<0.05). The expression of IFN-λ1 was positively correlated with RSV load (r=0.56, P<0.05).

CONCLUSIONS

RSV can induce the expression of IFN-λ1 in respiratory epithelial cells, suggesting that IFN-λ1 may play an important role in anti-RSV infection.

[Expression of interferon-λ1 in respiratory epithelial cells of children with RSV infection and its relationship with RSV load]

OBJECTIVE

To investigate the expression of IFN-λ1 in respiratory epithelial cells of children with respiratory syncytial virus (RSV) infection and its relationship with RSV load.

METHODS

The nasopharyngeal swabs were collected from the children who were hospitalized with respiratory tract infection from June 2015 to June 2016. A direct immunofluorescence assay was used to detect the antigens of seven common respiratory viruses (including RSV) in the nasopharyngeal swabs. A total of 120 children who were only RSV positive were selected as the RSV infection group. A total of 50 children who had negative results in the detection of all viral antigens were selected as the healthy control group. Fluorescence quantitative real-time PCR was used to determine the RSV load and the expression of IFN-λ1 mRNA in the nasopharyngeal swabs of children in the two groups.

RESULTS

The expression of IFN-λ1 in the RSV infection group was significantly higher than that in the healthy control group (P<0.05). The expression of IFN-λ1 was positively correlated with RSV load (r=0.56, P<0.05).

CONCLUSIONS

RSV can induce the expression of IFN-λ1 in respiratory epithelial cells, suggesting that IFN-λ1 may play an important role in anti-RSV infection.