Impact of Human Rhinovirus Types and Viral Load on the Severity of Illness in Hospitalized Children With Lower Respiratory Tract Infections

Genotypic Diversity of Childhood Rhinovirus Infections

Our objective was to describe the distribution of rhinovirus (RV) by species and type in both symptomatic and asymptomatic children in a prospective study over multiple years. A large and diverse distribution of RV types was seen among children with and without symptoms. RV-A and RV-C were predominant at all visits.

Association of viral load with TRAIL, IP-10, CRP biomarker signature and disease severity in children with respiratory tract infection or fever without source: A prospective, multicentre cohort study

BACKGROUND

To investigate the association of viral load (VL) with (i) tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein-10, C-reactive protein, and a combinatorial score (BV score), and (ii) clinical severity.

STUDY DESIGN

In this prospective, multicentre cohort substudy, children with respiratory tract infection or fever without source were enrolled. VL for influenza virus, rhinovirus, respiratory syncytial virus, and adenovirus was measured from nasopharyngeal swabs. The reference standard diagnosis was established based on expert panel adjudication.

RESULTS

Of 1140 recruited patients, 333 had a virus monodetection. VL for the aggregated data set correlated with TRAIL and IP-10 levels, with the length of oxygen therapy, and inversely with the BV score. At a single viral level, only the influenza VL yielded a correlation with TRAIL, IP-10 levels, and the BV score. Children with a viral reference standard diagnosis had significantly higher VL than those with bacterial infection (p = 0.0005). Low TRAIL (incidence rate ratio [IRR] 0.6, 95% confidence interval [CI] 0.39-0.91) and young age (IRR 0.62, 95% CI 0.49-0.79) were associated with a longer hospital stay, while young age (IRR 0.33, 95% CI 0.18-0.61), low TRAIL (IRR 0.25, 95% CI 0.08-0.76), and high VL (IRR 1.16, 95% CI 1.00-1.33) were predictive of longer oxygen therapy.

CONCLUSION

These findings indicate that VL correlates with biomarkers and may serve as a complementary tool pertaining to disease severity.

Respiratory viruses among pediatric inpatients with acute lower respiratory tract infections in Jinan, China, 2016-2019

The viral etiologies responsible for acute lower respiratory tract infections (ALRI) are a major cause of pediatric hospitalization, and some develop severe diseases requiring pediatric intensive care unit (PICU) admission. The aim of this study was to determine the prevalence of viruses and risk factors associated with PICU admission among patients hospitalized for ALRI. Nasopharyngeal swabs were collected to detect human rhinovirus (HRV), influenza A and B viruses (IAV, IBV), parainfluenza viruses (PIV), and respiratory syncytial virus (RSV) by reverse transcription-polymerase chain reaction (RT-PCR) and adenovirus (ADV) by PCR. Of the 5590 pediatric inpatients enrolled, respiratory viral infection occurred in 2102 (37.60%) patients, including 1846 (33.02%) single and 256 (4.58%) mixed viral infections. Among the nasopharyngeal swabs from pediatric inpatients, HRV accounted for the highest detection rate (16.48%), followed by PIV (8.35%), RSV (7.41%), ADV (4.63%), IAV (3.51%), and IBV (2.08%). The positive rate of viral tests decreased with increasing age and was higher in males (39.29%) than females (34.67%). The prevalence of viral infection was the highest in winter (41.57%) and lowest in autumn (31.78%). Each virus had a seasonal pattern, with peaks occurring in months of their epidemic seasons. RSV infection and the presence of comorbidities including congenital tracheal stenosis, congenital heart disease, metabolic disorder, immunodeficiency, renal disease, gastrointestinal disease and neurological disorder might be associated with the need for PICU admission. Therefore, this study provides useful information for the prevention and control of virus-related respiratory diseases and the early identification of and the intervention in severe cases. This article is protected by copyright. All rights reserved.

Understanding Rhinovirus Circulation and Impact on Illness

Rhinoviruses (RVs) have been reported as one of the main viral causes for severe respiratory illnesses that may require hospitalization, competing with the burden of other respiratory viruses such as influenza and RSV in terms of severity, economic cost, and resource utilization. With three species and 169 subtypes, RV presents the greatest diversity within the Enterovirus genus, and despite the efforts of the research community to identify clinically relevant subtypes to target therapeutic strategies, the role of species and subtype in the clinical outcomes of RV infection remains unclear. This review aims to collect and organize data relevant to RV illness in order to find patterns and links with species and/or subtype, with a specific focus on species and subtype diversity in clinical studies typing of respiratory samples.

Viral Induced Effects on a Vulnerable Epithelium; Lessons Learned From Paediatric Asthma and Eosinophilic Oesophagitis

The epithelium is integral to the protection of many different biological systems and for the maintenance of biochemical homeostasis. Emerging evidence suggests that particular children have epithelial vulnerabilities leading to dysregulated barrier function and integrity, that resultantly contributes to disease pathogenesis. These epithelial vulnerabilities likely develop in utero or in early life due to various genetic, epigenetic and environmental factors. Although various epithelia are uniquely structured with specific function, prevalent allergic-type epithelial diseases in children potentially have common or parallel disease processes. These include inflammation and immune response dysregulation stemming from atypical epithelial barrier function and integrity. Two diseases where aetiology and pathogenesis are potentially linked to epithelial vulnerabilities include Paediatric Asthma and Eosinophilic Oesophagitis (EoE). For example, rhinovirus C (RV-C) is a known risk factor for paediatric asthma development and is known to disrupt respiratory epithelial barrier function causing acute inflammation. In addition, EoE, a prevalent atopic condition of the oesophageal epithelium, is characterised by similar innate immune and epithelial responses to viral injury. This review examines the current literature and identifies the gaps in the field defining viral-induced effects on a vulnerable respiratory epithelium and resulting chronic inflammation, drawing from knowledge generated in acute wheezing illness, paediatric asthma and EoE. Besides highlighting the importance of epithelial structure and barrier function in allergic disease pathogenesis regardless of specific epithelial sub-types, this review focuses on the importance of examining other parallel allergic-type disease processes that may uncover commonalities driving disease pathogenesis. This in turn may be beneficial in the development of common therapeutics for current clinical management and disease prevention in the future.

Personal Network Inference Unveils Heterogeneous Immune Response Patterns to Viral Infection in Children with Acute Wheezing

Human rhinovirus (RV)-induced exacerbations of asthma and wheeze are a major cause of emergency room presentations and hospital admissions among children. Previous studies have shown that immune response patterns during these exacerbations are heterogeneous and are characterized by the presence or absence of robust interferon responses. Molecular phenotypes of asthma are usually identified by cluster analysis of gene expression levels. This approach however is limited, since genes do not exist in isolation, but rather work together in networks. Here, we employed personal network inference to characterize exacerbation response patterns and unveil molecular phenotypes based on variations in network structure. We found that personal gene network patterns were dominated by two major network structures, consisting of interferon-response versus FCER1G-associated networks. Cluster analysis of these structures divided children into subgroups, differing in the prevalence of atopy but not RV species. These network structures were also observed in an independent cohort of children with virus-induced asthma exacerbations sampled over a time course, where we showed that the FCER1G-associated networks were mainly observed at late time points (days four-six) during the acute illness. The ratio of interferon- and FCER1G-associated gene network responses was able to predict recurrence, with low interferon being associated with increased risk of readmission. These findings demonstrate the applicability of personal network inference for biomarker discovery and therapeutic target identification in the context of acute asthma which focuses on variations in network structure.

Viral Loads and Disease Severity in Children with Rhinovirus-Associated Illnesses

The role of rhinoviruses (RVs) in children with clinical syndromes not classically associated with RV infections is not well understood. We analyzed a cohort of children ≤21 years old who were PCR+ for RV at a large Pediatric Hospital from 2011 to 2013. Using univariate and multivariable logistic regression, we analyzed the associations between demographic, clinical characteristics, microbiology data, and clinical outcomes in children with compatible symptoms and incidental RV detection. Of the 2473 children (inpatients and outpatients) with an RV+ PCR, 2382 (96%) had compatible symptoms, and 91 (4%) did not. The overall median age was 14 months and 78% had underlying comorbidities. No differences in RV viral loads were found according to the presence of compatible symptoms, while in children with classic RV symptoms, RV viral loads were higher in single RV infections versus RV viral co-infections. Bacterial co-infections were more common in RV incidental detection (7.6%) than in children with compatible symptoms (1.9%, p < 0.001). The presence of compatible symptoms independently increased the odds ratio (OR, 95% CI) of hospitalization 4.8 (3.1-7.4), prolonged hospital stays 1.9 (1.1-3.1), need for oxygen 12 (5.8-25.0) and pediatric intensive care unit (PICU) admission 4.13 (2.0-8.2). Thus, despite comparable RV loads, disease severity was significantly worse in children with compatible symptoms.

The importance of viral load in the severity of acute bronchiolitis in hospitalized infants

OBJECTIVE

The relationship between viral load and the clinical evolution of bronchiolitis is controversial. Therefore, we aimed to analyze viral loads in infants hospitalized for bronchiolitis.

METHODS

We tested for the presence of human respiratory syncytial virus (HRSV) or human rhinovirus (HRV) using quantitative molecular tests of nasopharyngeal secretions and recorded severity outcomes.

RESULTS

We included 70 infants [49 (70%) HRSV, 9 (13%) HRV and 12 (17%) HRSV+HRV]. There were no differences among the groups according to the outcomes analyzed individually. Clinical scores showed greater severity in the isolated HRSV infection group. A higher isolated HRSV viral load was associated with more prolonged ventilatory support, oxygen therapy, and hospitalization days, even after adjustment for the age and period of nasopharyngeal secretion collection. In the co-infection groups, there was a longer duration of oxygen therapy when the HRSV viral load was predominant. Isolated HRV infection and co-infection with a predominance of HRV were not associated with severity.

CONCLUSION

Higher HRSV viral load in isolated infections and the predominance of HRSV in co-infections, independent of viral load, were associated with greater severity. These results contribute to the development of therapeutic and prophylactic approaches and a greater understanding of the pathophysiology of bronchiolitis.

Rhinovirus C15 Induces Airway Hyperresponsiveness via Calcium Mobilization in Airway Smooth Muscle

Rhinovirus (RV) exposure evokes exacerbations of asthma that markedly impact morbidity and mortality worldwide. The mechanisms by which RV induces airway hyperresponsiveness (AHR) or by which specific RV serotypes differentially evoke AHR remain unknown. We posit that RV infection evokes AHR and inflammatory mediator release, which correlate with degrees of RV infection. Furthermore, we posit that rhinovirus C-induced AHR requires paracrine or autocrine mediator release from epithelium that modulates agonist-induced calcium mobilization in human airway smooth muscle. In these studies, we used an ex vivo model to measure bronchoconstriction and mediator release from infected airways in human precision cut lung slices to understand how RV exposure alters airway constriction. We found that rhinovirus C15 (RV-C15) infection augmented carbachol-induced airway narrowing and significantly increased release of IP-10 (IFN-γ-induced protein 10) and MIP-1β (macrophage inflammatory protein-1β) but not IL-6. RV-C15 infection of human airway epithelial cells augmented agonist-induced intracellular calcium flux and phosphorylation of myosin light chain in co-cultured human airway smooth muscle to carbachol, but not after histamine stimulation. Our data suggest that RV-C15-induced structural cell inflammatory responses are associated with viral load but that inflammatory responses and alterations in agonist-mediated constriction of human small airways are uncoupled from viral load of the tissue.

Epidemiological characteristics and clinical outcomes of human rhinovirus infections in a hospitalized population. Severity is independently linked to RSV coinfection and comorbidities

Human rhinovirus (hRV) is a predominant respiratory viral pathogen. The determinants that lead to adverse clinical outcomes in hospitalized patients are unclear. Our objective was to analyze the epidemiological and clinical characteristics of hRV infections in a hospitalized population and to compare non-severe and severe infections. The study was based on data from all patients with a respiratory episode admitted to Hospital from October 2015 to September 2016. During the study period, out of 2465 respiratory episodes, 434 were detected positive for hRV. Most of the coinfections involved the respiratory syncytial virus (RSV) and very few influenza viruses. A possible interference between rhinovirus and influenza virus is suggested. Airway involvement was present in a large part of hRV infections with 28.4 % (n = 48/169) of bronchiolitis and 3.6 % (n = 6/169) of bronchitis. One third of patients had at least one of the following severity criteria: need for oxygen therapy, hospitalization ≥ 5 days, and admission to the ICU. On multivariate analysis, a respiratory co-infection with RSV and the presence of a chronic respiratory disease (including a history of asthma) were shown to be independent risk factors for the onset of a severe infection in patients ≤ 2 years old. In a case control study based on 70 patients, hRV-A was the predominant lineage, followed closely by hRV-C. High viral load or viral genotypes were not associated with severe infection.

Rhinovirus infections in infants suggest that early detection can prevent unnecessary treatment

BACKGROUND

Human rhinoviruses (hRV) are small, RNA viruses of the Picornaviridae family, which are divided into three subtypes (A, B, C). hRVs are among the most common causes for acute respiratory illnesses (ARI) involving both the upper and lower respiratory tract.

OBJECTIVES

This study aimed to assess the magnitude and characteristics of hRV infections in hospitalized children, aged less than 5 years, hospitalized in Israel during 2011-2012.

STUDY DESIGN

The 2503 respiratory samples were subjected to real-time PCR, to detect hRV and other respiratory viruses. Rhinovirus-positive samples were further tested by sequencing to identify the infecting species.

RESULTS

Of these 2503 respiratory samples, 422 tested positive for hRV, of them, 243 were from children under 5 years of age (58% of all rhinoviral-positive samples). We also found that among the ARI-associated hospital admissions, 16% were positive for rhinovirus. hRV type A was the most common species. Laboratory data showed monocytosis in 51%, hypercalcemia in 61% and lower respiratory tract involvement in 75% of patients.

CONCLUSIONS

We thus recommend including rhinovirus testing as part of the routine testing performed in young children presenting with ARI.

High correlation between human rhinovirus type C and children with asthma exacerbations in Taiwan

BACKGROUND/PURPOSES

Human rhinovirus type C (HRV-C) has been associated with asthma exacerbation (AE) in children in several countries. However, in Taiwan the association between HRV, especially HRV-C, and AE in children has yet to be elucidated. We sought to investigate the prevalence of respiratory viruses in children with acute lower respiratory tract infection (ALRTI) in Taiwan and the association between different types of HRV and AE in children.

METHODS

This prospective study was conducted from 2011 to 2013, and enrolled children with ALRTI, including an asthma exacerbation group (AE; n = 28) and a Non-asthma group (n = 66). Viruses were detected by culture, reverse transcription-polymerase chain reaction, and molecular sequencing of nasopharyngeal swabs.

RESULTS

The prevalence of identified respiratory viruses was 78.6% in the AE group and 65.2% in the Non-asthma group. The prevalence rates of HRV and HRV-C were significantly higher in the AE group than in the Non-asthma group (67.9% vs. 33.3% in HRV, p = 0.002; and 50% vs. 15.2% in HRV-C, p < 0.001). Among the children with HRV, the prevalence of HRV-C (68.4%) was higher than that of the other types of HRV (31.6%, including HRV-A 26.3%, and HRV-B 5.3%) in the AE group but not in the Non-asthma group (40.9% vs. 59.1%).

CONCLUSIONS

HRV is the most predominant viral infection responsible for pediatric AE in Taiwan, and HRV-C is responsible for more of these exacerbations than HRV-A or HRV-B.

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.

Outcome of children with rhinovirus detection prior to allogeneic hematopoietic cell transplant

Rhinoviruses are commonly detected in symptomatic and asymptomatic children prior to HCT. Unlike pre-HCT detection of other respiratory viruses, it is not known whether RV detection, with or without clinical symptoms, is associated with worse outcomes in children post-HCT. In a retrospective study of children undergoing allogeneic HCT from January 2009 to February 2015, 91 children underwent allogeneic HCT, and 62 children had RPP testing within 30 days pre-HCT. Fifty-six (90%) children had either no pathogen (n = 34, 55%) or single RV detection (n = 22, 35%), which was the most common pathogen identified. Compared with virus negative children, children with pre-HCT RV detection were not more likely to require ventilated support and did not have longer length of stay, higher mortality, or less days alive and out of the hospital within the first 100 days post-HCT. In a secondary analysis of all 56 patients with RPP testing and no pathogen or RV alone detected, the seven children with LRTI had less days alive and out of the hospital within the first 100 days post-HCT compared with the 49 children who were either asymptomatic or had URTI (10 vs 60 days, P = 0.002). In a bootstrapped regression model, presence of LRTI, not RV detection, was significantly associated with decreased days alive and out of the hospital within the first 100 days post-HCT. Thus, pre-HCT detection of RV, without associated LRTI, does not always warrant HCT delay.

Molecular epidemiology and clinical features of rhinovirus infections among hospitalized patients in a medical center in Taiwan

BACKGROUND

Human rhinovirus (HRV) can cause severe illnesses in hospitalized patients. However, there are no studies regarding the prevalence of HRV infection, particularly the recently identified HRV-C, in hospitalized patients reported from Taiwan.

METHODS

Respiratory specimens collected from 487 hospitalized patients in designated wards between 2013 and 2014 in a medical center in northern Taiwan were retrospectively detected for HRV. Positive specimens were further determined for genotyping. Medical charts of the HRV-positive patients were reviewed retrospectively.

RESULTS

Totally, 76 patients (15.6%) were HRV positive, of which 60 were pediatric patients. HRV-A was identified in 41 (54%) patients, HRV-B in 6 patients (7.9%) and HRV-C in 29 patients (38%). A total of 47 different genotypes were identified. HRV infections were predominant during fall and winter seasons. 21.1% were affected by HRV alone and 78.9% were found to be co-infected with other microorganisms. The detection rate of HRV in children (18.6%) was significantly higher than in adults (9.6%). Compared with pediatric patients, adult patients were significantly associated with underlying disease, Pneumocystis jirovesii pneumonia co-infection, a diagnosis of pneumonia, fatal outcome, hospital acquisition of HRV, antibiotics administration and requiring intensive care, while pediatric patients were significantly associated with viral co-infection.

CONCLUSIONS

HRV was a common cause of respiratory tract infection in Taiwan, particularly in pediatric patients. Eighty percent of HRV-infected inpatients had other microorganisms co-infection. Adult patients were more likely to be associated with a severe respiratory disease entity.

An Interaction of LPS and RSV Infection in Augmenting the AHR and Airway Inflammation in Mice

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection (LRTI) in children under 5 years of age, especially infants with severe bronchiolitis. Our preliminary clinical experiments showed that bacterial colonization was commonly observed in children with virus-induced wheezing, particularly in those with recurrent wheezing, suggesting that bacterial colonization with an accompanying viral infection may contribute to disease severity. In most cases, RSV-infected infants were colonized with pathogenic bacteria (mainly Gram-negative bacteria). LPS is the main component of Gram-negative bacteria and acts as a ligand for Toll-like receptor 4 (TLR4). Relevant studies have reported that the TLR family is crucial in mediating the link between viral components and immunologic responses to infection. Of note, TLR4 activation has been associated with disease severity during RSV infection. In the present study, we identified that LPS aggravated RSV-induced AHR and airway inflammation in BALB/c mice using an RSV coinfection model. We found that the airway inflammatory cells and cytokines present in BALF and TRIF in lung tissue play a role in inducing AHR and airway inflammation upon RSV and bacteria coinfection, which might occur through the TRIF-MMP-9-neutrophil-MMP-9 signalling pathway. These results may aid in the development of novel treatments and improve vaccine design.

Risk factors for bronchiolitis severity: A retrospective review of patients admitted to the university hospital from central region of Slovenia

Aim

Study's objective was to identify risk factors associated with bronchiolitis severity.

Methods

A retrospective chart review of all children <2 years old diagnosed with bronchiolitis at the University Medical Centre Ljubljana between May 2014 and April 2015, who were treated as outpatients (paediatric emergency department, PED group) or as inpatients in the standard hospital setting (WARD group) or in the paediatric intensive care unit (PICU group). Detection of respiratory viruses in nasopharyngeal swab was accomplished by RT‐PCR. Severity was assessed by Wang Respiratory Score and hospitalization longer than 24 hours.

Results

The study included 761 children. The three most frequently detected viruses were respiratory syncytial virus (RSV), human rhinovirus (hRV) and human bocavirus (hBoV) (57.5%, 272/473; 25.6%, 121/473; 18.4%, 87/473). Patient groups differed in Wang Respiratory Score for the severity of bronchiolitis (P < 0.001). No differences regarding the causative viruses were found. There was a lower proportion of children with the presence of more than one virus in PICU group compared to other two groups (P = 0.017). The three groups significantly differed in age, birthweight, comorbidities, bronchodilator treatment and antibiotic usage. However, multiple regression analysis revealed that younger age and the use of antibiotics were associated with bronchiolitis severity defined as hospitalization for >24 hours.

Conclusions

Respiratory syncytial virus, hRV and hBoV were the most frequently detected viruses. The majority of patients admitted to the PICU had only one virus detected. Younger age and the use of antibiotics were associated with bronchiolitis severity.

Genotypic Diversity and Epidemiology of Human Rhinovirus Among Children With Severe Acute Respiratory Tract Infection in Shanghai, 2013-2015

Human rhinovirus (HRV), and particularly HRV-C, is increasingly recognized as a cause of severe acute respiratory infections (SARIs). However, little is known about the genotypic diversity and epidemiology of HRV among children with SARI. Thus, we investigated the genotypic diversity and epidemiology of HRV in children with SARI in China over a 2-year period. In total 1,003, nasopharyngeal aspirates were collected from children hospitalized with SARI in Shanghai from 2013 to 2015. HRV was screened for by a PCR method targeting the viral 5' UTR and was genotyped by sequencing of the VP4-VP2 region of the HRV genome. We also screened for 15 other common respiratory viruses to assess the prevalence of co-infection with HRV. The patient demographic and clinical data were reviewed. HRV was detected in 280 (27.9%) of the 1,003 specimens: HRV-A in 140 (14.0%), HRV-B in 21 (2.1%), HRV-C in 56 (5.6%), and HRV-untyped in 63 (6.3%). A phylogenetic analysis identified 77 genotypes (43 HRV-A, 10 HRV-B, and 24 HRV-C), among which A78, A12, A89, B70, C2, C6, and C24 predominated. HRV-A was detected mainly in winter 2013 and autumn 2014, while HRV-C detection peaked in autumn 2013 and 2014. The detection frequency of HRV-A was highest in patients <5 years old. Most HRV co-infections involved adenovirus, human bocavirus, and/or human respiratory syncytial virus. In conclusion, HRV-A and -C predominate in children with SARI in Shanghai. Among the 77 genotypes detected, A78, A12, A89, B70, C2, C6, and C24 were the most frequent. The HRV species responsible for SARIs differs according to season and age.

RSV-hRV co-infection is a risk factor for recurrent bronchial obstruction and early sensitization 3 years after bronchiolitis

To assess risk factors of recurrent bronchial obstruction and allergic sensitization 3 years after an episode of acute bronchiolitis, whether after ambulatory care treatment or hospitalization. A monocentric prospective longitudinal study including infants aged under 1 year with acute bronchiolitis was performed, with clinical (severity score), biological (serum Krebs von den Lungen 6 antigen), and viral (14 virus by naso-pharyngeal suction detection) assessments. Follow-up included a quaterly telephone interview, and a final clinical examination at 3 years. Biological markers of atopy were also measured in peripheral blood, including specific IgEs towards aero- and food allergens. Complete data were available for 154 children. 46.8% of them had recurrent wheezing (RW). No difference was found according to initial severity, care at home or in the hospital, respiratory virus involved, or existence of co-infection. A familial history of atopy was identified as a risk factor for recurrent bronchial obstruction (60% for RW infants versus 39%, P = 0.02), as living in an apartment (35% versus 15%, P = 0.002). 18.6% of the infants were sensitized, with 48.1% of them sensitized to aeroallergens and 81.5% to food allergens. Multivariate analysis confirmed that a familial history of atopy (P = 0.02) and initial co-infection RSV-hRV (P = 0.02) were correlated with the risk of sensitization to aeroallergens at 3 years. Familial history of atopy and RSV-hRV co-infection are risk factors for recurrent bronchial obstruction and sensitization.

Rhinovirus - not just the common cold

Rhinoviruses (RV) are ubiquitous respiratory tract pathogens. They affect both the upper and lower respiratory tract and cause colds but have also been associated with wheezing, asthma exacerbations and pneumonia. New blood transcription profiling techniques of the host immune response are becoming available to characterise the pathogenesis of RV in humans. This review will outline the clinical impact of RVs in children.

Epidemiological analysis and follow-up of human rhinovirus infection in children with asthma exacerbation

To determine the prevalence of human rhinovirus (HRV) infection in children with acute asthma exacerbations, investigation of HRV viral load and severity of asthma exacerbations is also required. Nasopharyngeal aspirates and swabs were collected and assessed for respiratory viruses. HRV-positive samples were sequenced to identify types and determine viral load. Outpatients with asthma exacerbations underwent follow-up evaluations, their swabs were collected and clinical outcomes were recorded at their next clinic visit 4 weeks later. One hundred forty-three inpatients and 131 outpatients, including 88 patients with asthma exacerbations and 43 controls with stable asthma were recruited. HRV-A was mainly detected in September and February (45.5% and 33.3%, respectively), while HRV-C was mainly detected in November and April (70.0% and 55.6%, respectively). HRV-C was the primary type and was primarily found in inpatients with severe asthma exacerbations. HRV-A viral load in the group of inpatients with severe exacerbations was higher than in the mild and moderate groups (P < 0.001 and P = 0.022). The HRV-A viral load of both inpatients and outpatients was higher than that of HRV-C (P < 0.001 and P = 0.036). The main genotypes were HRV-C53 and HRV-A20 among inpatients, and this genotype caused more severe clinical manifestations. HRV persisted for no more than 4 weeks, and their symptoms or signs of disease were well-controlled well. HRV-C was most frequently detected in asthma exacerbations. HRV-A with high viral load led to severe asthma exacerbations.

Prednisolone for the first rhinovirus-induced wheezing and 4-year asthma risk: A randomized trial

BACKGROUND

Previous findings show that corticosteroid treatment during the first acute wheezing episode may reduce recurrent wheezing in children with high rhinovirus genome load at 12-month follow-up. Longer-term effects have not been investigated prospectively.

METHODS

After PCR confirmation of rhinovirus from nasopharyngeal aspirate, 79 children with the first acute wheezing episode were randomized to receive orally prednisolone or placebo for 3 days. The initiation of asthma control medication before the age of 5 years was confirmed from medical record and/or from parental interview. The outcome was the time to initiation of regular asthma control medication. Interaction analysis examined rhinovirus genome load.

RESULTS

Fifty-nine (75%) children completed the follow-up. Asthma control medication was initiated in 40 (68%) children at the median age of 20 months. Overall, prednisolone did not affect the time to initiation of asthma control medication when compared to placebo (P=.99). Rhinovirus load modified the effect of prednisolone regarding the time to initiation of asthma control medication (P-value for interaction=.04). In children with high rhinovirus load (>7000 copies/mL; n=23), the risk for initiation of medication was lower in the prednisolone group compared to the placebo group (P=.05). In the placebo group, asthma medication was initiated to all children with high rhinovirus load (n=9) during the 14 months after the first wheezing episode.

CONCLUSIONS

Overall, prednisolone did not affect the time to initiation of asthma control medication when compared to placebo. However, prednisolone may be beneficial in first-time wheezing children whose episode was severe and associated with high rhinovirus load. (ClinicalTrials.gov, NCT00731575).

Influenza and other respiratory viruses: standardizing disease severity in surveillance and clinical trials

INTRODUCTION

Influenza-Like Illness is a leading cause of hospitalization in children. Disease burden due to influenza and other respiratory viral infections is reported on a population level, but clinical scores measuring individual changes in disease severity are urgently needed. Areas covered: We present a composite clinical score allowing individual patient data analyses of disease severity based on systematic literature review and WHO-criteria for uncomplicated and complicated disease. The 22-item ViVI Disease Severity Score showed a normal distribution in a pediatric cohort of 6073 children aged 0-18 years (mean age 3.13; S.D. 3.89; range: 0 to 18.79). Expert commentary: The ViVI Score was correlated with risk of antibiotic use as well as need for hospitalization and intensive care. The ViVI Score was used to track children with influenza, respiratory syncytial virus, human metapneumovirus, human rhinovirus, and adenovirus infections and is fully compliant with regulatory data standards. The ViVI Disease Severity Score mobile application allows physicians to measure disease severity at the point-of care thereby taking clinical trials to the next level.

Rhinovirus - From bench to bedside

Rhinovirus has been neglected in the past because it was generally perceived as a respiratory virus only capable of causing mild common cold. Contemporary epidemiological studies using molecular assays have shown that rhinovirus is frequently detected in adult and pediatric patients with upper or lower respiratory tract infections. Severe pulmonary and extrapulmonary complications are increasingly recognized. Contrary to popular belief, some rhinoviruses can actually replicate well at 37 °C and infect the lower airway in humans. The increasing availability of multiplex PCR panels allows rapid detection of rhinovirus and provides the opportunity for timely treatment and early recognition of outbreaks. Recent advances in the understanding of host factors for viral attachment and replication, and the host immunological response in both asthmatic and non-asthmatic individuals, have provided important insights into rhinovirus infection which are crucial in the development of antiviral treatment. The identification of novel drugs has been accelerated by repurposing clinically-approved drugs. As humoral antibodies induced by past exposure and vaccine antigen of a particular serotype cannot provide full coverage for all rhinovirus serotypes, novel vaccination strategies are required for inducing protective response against all rhinoviruses.

Single- and multiple viral respiratory infections in children: disease and management cannot be related to a specific pathogen

Background

The number of viral pathogens associated with pediatric acute respiratory tract infection (ARI) has grown since the introduction of reverse transcription real-time polymerase chain reaction (RT-PCR) assays. Multiple viruses are detected during a single ARI episode in approximately a quarter of all cases. The clinical relevance of these multiple detections is unclear, as is the role of the individual virus. We therefore investigated the correlation between clinical data and RT-PCR results in children with single- and multiple viral ARI.

Methods

Data from children with ARI were prospectively collected during two winter seasons. RT-PCR testing for 15 viruses was performed in 560 ARI episodes. In the patients with a single-viral etiology, clinical data, laboratory findings, patient management- and outcome data were compared between the different viruses. With this information, we compared data from children of whom RT-PCR data were negative, with children with single- and multiple viral positive results.

Results

The viral detection rate was 457/560 (81.6%) of which 331/560 (59.1%) were single infections and 126/560 (22.5%) were multiple infections. In single viral infections, some statistically significant differences in demographics, clinical findings, disease severity and outcome were found between children with different viral etiologies. However, no clinically recognizable pattern was established to be virus-specific. In a multivariate analysis, the only variables that were correlated with longer hospital stay were the use of oxygen and nebulizer therapy, irrespective of the viral pathogen. Children with RT-PCR positive test results had a significant higher disease severity, fever, length of hospital stay, days of extra oxygen supply, and days of antibiotic treatment than children with a negative RT-PCR test result. For children with single- versus children with multiple positive RT-PCR test results, these differences were not significant.

Conclusions

Disease (severity), management and outcome in pediatric ARI are not associated with a specific virus. Single- and multiple viral ARI do not significantly differ with regard to clinical outcome and patient management. For general pediatrics, RT-PCR assays should be restricted to pathogens for which therapy is available or otherwise may have clinical consequences. Further research with an extended panel of RT-PCR assays and a larger number of inclusions is necessary to further validate our findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-2118-6) contains supplementary material, which is available to authorized users.

Superiority of Digital Reverse Transcription-PCR (RT-PCR) over Real-Time RT-PCR for Quantitation of Highly Divergent Human Rhinoviruses

Human rhinoviruses (HRV) comprise 3 species representing more than 150 genotypes. As an important human respiratory pathogen, molecular detection is an indispensable tool for diagnosis and surveillance. However, the sequence diversity of HRV genotypes poses challenges for developing robust molecular methods that detect all genotypes with equal efficiencies. This study compares the accuracies of reverse transcription-quantitative PCR (RT-qPCR) and reverse transcription-digital PCR (RT-dPCR) for quantifying HRV RNA using genotype-specific primers and probes and a consensus primer/probe set targeting the 5' noncoding region of HRV. When using consensus primers and probes for the quantification of HRV, RT-dPCR outperformed RT-qPCR by consistently and accurately quantifying HRV RNAs across more genotype groups, despite the presence of up to 2 target-sequence mismatches within the primer or probe binding region. Because it does not rely on amplification efficiency, which can be affected by sequence mismatches in primer/probe binding regions, RT-dPCR may be the optimal molecular method for future HRV quantification studies and for quantitating other viruses with high sequence diversity.

Performance of a Taqman Assay for Improved Detection and Quantification of Human Rhinovirus Viral Load

Human rhinovirus (HRV) is the major aetiology of respiratory tract infections. HRV viral load assays are available but limitations that affect accurate quantification exist. We developed a one-step Taqman assay using oligonucleotides designed based on a comprehensive list of global HRV sequences. The new oligonucleotides targeting the 5′-UTR region showed high PCR efficiency (E = 99.6%, R² = 0.996), with quantifiable viral load as low as 2 viral copies/μl. Assay evaluation using an External Quality Assessment (EQA) panel yielded a detection rate of 90%. When tested on 315 human enterovirus-positive specimens comprising at least 84 genetically distinct HRV types/serotypes (determined by the VP4/VP2 gene phylogenetic analysis), the assay detected all HRV species and types, as well as other non-polio enteroviruses. A commercial quantification kit, which failed to detect any of the EQA specimens, produced a detection rate of 13.3% (42/315) among the clinical specimens. Using the improved assay, we showed that HRV sheds in the upper respiratory tract for more than a week following acute infection. We also showed that HRV-C had a significantly higher viral load at 2–7 days after the onset of symptoms (p = 0.001). The availability of such assay is important to facilitate disease management, antiviral development, and infection control.

Molecular Epidemiology of Rhinovirus Detections in Young Children

Background.  Human rhinoviruses (HRVs) are frequently detected in children with acute respiratory illnesses (ARIs) but also in asymptomatic children. We compared features of ARI with HRV species (A, B, C) and determined genotypes associated with repeated HRV detections within individuals. Methods.  We used clinical data and respiratory samples obtained from children <3 years old during weekly active household-based surveillance. A random subset of samples in which HRV was detected from individuals during both ARI and an asymptomatic period within 120 days of the ARI were genotyped. Features of ARI were compared among HRV species. Concordance of genotype among repeated HRV detections within individuals was assessed. Results.  Among 207 ARI samples sequenced, HRV-A, HRV-B, and HRV-C were detected in 104 (50%), 20 (10%), and 83 (40%), respectively. Presence of fever, decreased appetite, and malaise were significantly higher in children with HRV-B. When codetections with other viruses were excluded (n = 155), these trends persisted, but some did not reach statistical significance. When 58 paired sequential HRV detections during asymptomatic and ARI episodes were sequenced, only 9 (16%) were identical genotypes of HRV. Conclusions.  Clinical features may differ among HRV species. Repeated HRV detections in young children frequently represented acquisition of new HRV strains.