Detecting respiratory viruses in asymptomatic children

Systematic Literature Review of Respiratory Syncytial Virus Laboratory Testing Practices and Incidence in United States Infants and Children <5 Years of Age

Background

Respiratory syncytial virus (RSV) can cause serious illness in those aged <5 years in the United States, but uncertainty remains around which populations receive RSV testing. We conducted a systematic literature review of RSV testing patterns in studies published from 2000 to 2021.

Methods

Studies of RSV, medically attended RSV lower respiratory tract infections (LRTIs), and bronchiolitis were identified using standard methodology. Outcomes were clinical decisions to test for RSV, testing frequency, and testing incidence proportions in inpatient (IP), emergency department (ED), outpatient (OP), and urgent care settings.

Results

Eighty good-/fair-quality studies, which reported data from the period 1988–2020, were identified. Twenty-seven described the clinical decision to test, which varied across and within settings. Two studies reported RSV testing frequency for multiple settings, with higher testing proportions in IP (n = 2, range: 83%–85%, 1996–2009) compared with ED (n = 1, 25%, 2006–2009) and OP (n = 2, 15%–25%, 1996–2009). Higher RSV testing incidence proportions were observed among LRTI infant populations in the ED (n = 1, 74%, 2007–2008) and OP (n = 2, 54%–69%, 1995–2008). Incidence proportions in LRTI populations were not consistently higher in the IP setting (n = 13). Across studies and time, there was heterogeneity in RSV testing patterns, which may reflect varying detection methods, populations, locations, time periods, and healthcare settings.

Conclusions

Not all infants and children with LRTI are tested for RSV, highlighting underestimation of RSV burden across all settings.

Comparison of Severe Viral Pneumonia Caused by SARS-CoV-2 and Other Respiratory Viruses Among Malaysian Children During the COVID-19 Pandemic

OBJECTIVES

We described the etiology of severe pneumonia in children during the height of the COVID-19 pandemic in Malaysia and compared the clinical features of severe SARS-CoV-2 to other respiratory viruses.

METHODS

This retrospective study included all children aged 12 years and below hospitalized with severe pneumonia in Negeri Sembilan, Malaysia, between 1 April 2021 and 31 October 2021. We extracted demographic and clinical data and used logistic regression to examine risk factors associated with severe SARS-CoV-2 or other viral pneumonia.

RESULTS

A total of 111 children were included. The median age was 15 months. Human rhinovirus/enterovirus, SARS-CoV-2 and respiratory syncytial virus were the most common etiology of severe pneumonia. Codetection of >1 viral pathogen was present in 14 (12.6%) patients. Children with severe COVID-19 presented early in the course of illness and had lower rates of pediatric intensive care admission. The presence of sick contact with an adult was a predictor for SARS-CoV-2, whereas adventitious breath sounds were predictive of other respiratory viruses.

CONCLUSIONS

The etiology of severe pneumonia in children evolved with the epidemic curve of COVID-19 and school closures. Children with severe pneumonia due to SARS-CoV-2 experienced a milder clinical course when compared to other respiratory viruses.

Experimental rhinovirus infection induces an antiviral response in circulating B cells which is dysregulated in patients with asthma

BACKGROUND

Rhinoviruses are the predominant cause of respiratory viral infections and are strongly associated with asthma exacerbations. While humoral immunity plays an important role during virus infections, cellular aspects of this response are less well understood. Here, we investigated the antiviral response of circulating B cells upon experimental rhinovirus infection in healthy individuals and asthma patients.

METHODS

We purified B cells from experimentally infected healthy individuals and patients with asthma and subjected them to total RNA-sequencing. Rhinovirus-derived RNA was measured in isolated B cells using a highly sensitive PCR. B cells were stimulated with rhinovirus in vitro to further study gene expression, expression of antiviral proteins and B-cell differentiation in response rhinovirus stimulation. Protein expression of pro-inflammatory cytokines in response to rhinovirus was assessed using a proximity extension assay.

RESULTS

B cells isolated from experimentally infected subjects exhibited an antiviral gene profile linked to IFN-alpha, carried viral RNA in vivo and were transiently infected by rhinovirus in vitro. B cells rapidly differentiated into plasmablasts upon rhinovirus stimulation. While B cells lacked expression of interferons in response to rhinovirus exposure, co-stimulation with rhinovirus and IFN-alpha upregulated pro-inflammatory cytokine expression suggesting a potential new function of B cells during virus infections. Asthma patients showed extensive upregulation and dysregulation of antiviral gene expression.

CONCLUSION

These findings add to the understanding of systemic effects of rhinovirus infections on B-cell responses in the periphery, show potential dysregulation in patients with asthma and might also have implications during infection with other respiratory viruses.

Detection of Respiratory Pathogens Does Not Predict Risks After Outpatient Adenotonsillectomy

OBJECTIVES/HYPOTHESIS

To determine whether the presence of detectable upper respiratory infections (URIs) at the time of adenoidectomy/adenotonsillectomy is associated with increased morbidity, complications, and unexpected admissions.

STUDY DESIGN

Prospective double-blinded cohort.

METHODS

In this prospective cohort study, nasopharyngeal swabs were obtained intraoperatively from 164 pediatric patients undergoing outpatient adenoidectomy/tonsillectomy with or without pressure equalization tubes (PETs) and were analyzed with PCR for the presence of 22 known URIs, including SARS-CoV-2. Surgeons and families were blinded to the results. At the conclusion of the study, rates of detectable infection were determined and intraoperative and postoperative events (unexpected admissions, length of PACU stay, rates of laryngospasm/bronchospasm, oxygen desaturation, bradycardia, and postoperative presentation to an emergency department) were compared between infected and uninfected patients.

RESULTS

Of the 164 patients (50% male, 50% female, ages 8 mo-18 y), 136 patients (82.9%) tested positive for one or more URI at the time of surgery. Forty one patients (25.0%) tested positive for three or more URIs concurrently, and 11 (6.7%) tested positive for five or more URIs concurrently. There were no significant differences in admission rates, length of PACU stay, rates of laryngospasm/bronchospasm, oxygen desaturation, bradycardia, or postoperative presentation to an emergency department between positive and negative patients. No patients tested positive for SARS-CoV-2.

CONCLUSIONS

A recent positive URI test does not confer any additional intraoperative or postoperative risk in the setting of outpatient adenoidectomy/tonsillectomy in healthy patients. There is no utility in preoperative URI testing, and delaying surgery due to a recent positive URI test is not warranted in this population.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E2074-E2079, 2021.

Microarray Technology May Reveal the Contribution of Allergen Exposure and Rhinovirus Infections as Possible Triggers for Acute Wheezing Attacks in Preschool Children

Allergen exposure and rhinovirus (RV) infections are common triggers of acute wheezing exacerbations in early childhood. The identification of such trigger factors is difficult but may have therapeutic implications. Increases of IgE and IgG in sera, were shown against allergens and the N-terminal portion of the VP1 proteins of RV species, respectively, several weeks after allergen exposure or RV infection. Hence, increases in VP1-specific IgG and in allergen-specific IgE may serve as biomarkers for RV infections or allergen exposure. The MeDALL-allergen chip containing comprehensive panels of allergens and the PreDicta RV chip equipped with VP1-derived peptides, representative of three genetic RV species, were used to measure allergen-specific IgE levels and RV-species-specific IgG levels in sera obtained from 120 preschool children at the time of an acute wheezing attack and convalescence. Nearly 20% of the children (22/120) showed specific IgE sensitizations to at least one of the allergen molecules on the MeDALL chip. For 87% of the children, increases in RV-specific IgG could be detected in the follow-up sera. This percentage of RV-specific IgG increases was equal in IgE-positive and -negative children. In 10% of the children, increases or de novo appearances of IgE sensitizations indicative of allergen exposure could be detected. Our results suggest that, in the majority of preschool children, RV infections trigger wheezing attacks, but, in addition, allergen exposure seems to play a role as a trigger factor. RV-induced wheezing attacks occur in IgE-sensitized and non-IgE-sensitized children, indicating that allergic sensitization is not a prerequisite for RV-induced wheeze.

Type 2 and interferon inflammation regulate SARS-CoV-2 entry factor expression in the airway epithelium

Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2, an emerging virus that utilizes host proteins ACE2 and TMPRSS2 as entry factors. Understanding the factors affecting the pattern and levels of expression of these genes is important for deeper understanding of SARS-CoV-2 tropism and pathogenesis. Here we explore the role of genetics and co-expression networks in regulating these genes in the airway, through the analysis of nasal airway transcriptome data from 695 children. We identify expression quantitative trait loci for both ACE2 and TMPRSS2, that vary in frequency across world populations. We find TMPRSS2 is part of a mucus secretory network, highly upregulated by type 2 (T2) inflammation through the action of interleukin-13, and that the interferon response to respiratory viruses highly upregulates ACE2 expression. IL-13 and virus infection mediated effects on ACE2 expression were also observed at the protein level in the airway epithelium. Finally, we define airway responses to common coronavirus infections in children, finding that these infections generate host responses similar to other viral species, including upregulation of IL6 and ACE2. Our results reveal possible mechanisms influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes.

The Epidemiology of Admission-Requiring Pediatric Respiratory Infections in a Japanese Community Hospital Using Multiplex PCR

Respiratory tract infections (RTIs) are the most common diseases globally among children. This study aimed to assess the epidemiology of admission-requiring pediatric RTI cases and evaluate the effect of the pathogen type on the length of hospital stay (LOS) using the FilmArray^® respiratory panel, a multiplex PCR test. The age-specific distribution and seasonality of viruses were investigated between March 26, 2018 and April 12, 2019. Multivariable linear regression analyses were performed to evaluate the effect of pathogen type and coinfection on LOS. Among 153 hospitalized RTI patients, respiratory syncytial virus was the leading cause of hospitalization in infants < 12 months of age (27.7%). Human metapneumovirus and parainfluenza virus were also major causes of hospitalization in patients aged 2-3 years (22.6% and 22.6%, respectively). In the multivariable linear regression model excluding rhinovirus/enterovirus, there was a significant association between viral coinfection and longer LOS (p = 0.012), while single viral infection of any type was not positively correlated with LOS. This study revealed the epidemiology of admission-requiring pediatric RTIs.

Type 2 and interferon inflammation strongly regulate SARS-CoV-2 related gene expression in the airway epithelium

Coronavirus disease 2019 (COVID-19) outcomes vary from asymptomatic infection to death. This disparity may reflect different airway levels of the SARS-CoV-2 receptor, ACE2, and the spike protein activator, TMPRSS2. Here we explore the role of genetics and co-expression networks in regulating these genes in the airway, through the analysis of nasal airway transcriptome data from 695 children. We identify expression quantitative trait loci (eQTL) for both ACE2 and TMPRSS2, that vary in frequency across world populations. Importantly, we find TMPRSS2 is part of a mucus secretory network, highly upregulated by T2 inflammation through the action of interleukin-13, and that interferon response to respiratory viruses highly upregulates ACE2 expression. Finally, we define airway responses to coronavirus infections in children, finding that these infections upregulate IL6 while also stimulating a more pronounced cytotoxic immune response relative to other respiratory viruses. Our results reveal mechanisms likely influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes.

Target-independent high-throughput sequencing methods provide evidence that already known human viral pathogens play a main role in respiratory infections with unexplained etiology

Despite the advanced PCR-based assays available, a fraction of the pediatric respiratory infections remain unexplained every epidemic season, and there is a perception that novel viruses might be present in these specimens. We systematically collected samples from a prospective cohort of pediatric patients with respiratory infections, that returned negative results by validated molecular RT–PCR assays, and studied them with a target-independent, high-throughput sequencing-based approach. We also included a matched cohort of children with no symptoms of respiratory infection, as a contrast study population. More than fifty percent of the specimens from the group of patients with unexplained respiratory infections were resolved. However, the higher rate of detection was not due to the presence of novel viruses, but to the identification of well-known viral respiratory pathogens. Our results show that already known viral pathogens are responsible for the majority of cases that remain unexplained after the epidemic season. High-throughput sequencing approaches that use pathogen-specific probes are easier to standardize because they ensure reproducible library enrichment and sequencing. In consequence, these techniques might be desirable from a regulatory standpoint for diagnostic laboratories seeking to benefit from the many advantages of these sequencing technologies.

Dynamics of Bacterial Colonization With Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis During Symptomatic and Asymptomatic Viral Upper Respiratory Tract Infection

Background

Virus is detected in about 80% of upper respiratory tract infections (URTIs) in children and is also detectable in the nasopharynx of 30% of asymptomatic children. The effect of asymptomatic viral infection on the dynamics of bacterial density and colonization of the nasopharynx has not been reported. The current study was performed

to assess the presence and density of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in the nasopharynx of 4–7-year-old children during URTI and when well.

Methods

Nasal samples were obtained during 4 surveillance periods when children were asymptomatic and whenever they had symptoms of URTI. Respiratory viruses and bacterial pathogens were identified and quantified using polymerase chain reaction.

Results

The proportion of children colonized with all 3 bacteria was higher during visits for acute URTI than during asymptomatic surveillance visits. Mean bacterial densities were significantly higher at all visits for all 3 pathogens when a virus was detected. The differences between the means were 1.0, 0.4, and 0.7 log₁₀ colony-forming unit equivalents per milliliter for S. pneumoniae, H. influenzae, and M. catarrhalis, respectively, compared with visits in which virus was not detected. The percentage of children colonized and density were also higher at asymptomatic visits in which virus was detected than at visits in which virus was not detected.

Conclusion

The density and frequency of colonization with S. pneumoniae, H. influenzae, and M. catarrhalis in nasal wash samples increase during periods of both symptomatic and asymptomatic viral infection. Increases in bacterial colonization observed during asymptomatic viral infection were nearly the same magnitude as when children were symptomatic.

Respiratory virus associated with surgery in children patients

Background

Viral respiratory infection (VRI) is a common contraindication to elective surgery. Asymptomatic shedding among pediatric surgery patients (PSPs) could potentially lead to progression of symptomatic diseases and cause outbreaks of respiratory diseases. The aim of this study is to investigate the incidence of infection among mild symptomatic PSP group and asymptomatic PSP group after surgical procedure.

Methods

We collected the induced sputum from enrolled 1629 children (under 18 years of age) with no respiratory symptom prior to pediatric surgery between March 2017 and February 2019. We tested 16 different respiratory virus infections in post-surgery mild symptomatic PSP group and asymptomatic PSP group using a quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assay panel. We analyzed symptom data and quantitative viral load to investigate the association between viruses, symptoms and viral quantity in qRT-PCR-positive PSPs.

Results

Out of 1629 children enrolled, a total of 204 respiratory viruses were present in 171 (10.50%) PSPs including 47 patients with mild symptoms and 124 with no symptoms after surgery. Commonly detected viruses were human rhino/enterovirus (HRV/EV, 42.19%), parainfluenza virus 3 (PIV3, 24.48%), coronavirus (CoV NL63, OC43, HKU1, 11.46%), and respiratory syncytial virus (RSV, 9.9%). PIV3 infection with a higher viral load was frequently found in PSPs presenting with mild symptoms, progressing to pneumonia with radiographic evidence after surgery. HRV/EV were the most commonly detected pathogens in both asymptomatic and mild symptomatic PSPs. CoV (OC43, HKU1) infections with a higher viral load were mostly observed in asymptomatic PSPs progressing to alveolar or interstitial infiltration.

Conclusions

Our study suggested that PIV3 is a new risk factor for VRI in PSPs. Employing a more comprehensive, sensitive and quantitative method should be considered for preoperative testing of respiratory viruses in order to guide optimal surgical timing.

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.

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

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

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

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Influenza virus and respiratory syncytial virus detection showed seasonal variation.

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

Respiratory Testing and Hospital Outcomes in Asymptomatic Infants Undergoing Heart Surgery

Respiratory viral infections in infants undergoing congenital heart surgery lead to prolonged intubation time, hospital (HLOS) and cardiac intensive care unit length of stay (CICU LOS). The objective of this study was to evaluate the prevalence of respiratory viruses using molecular testing in otherwise healthy infants presenting for low complexity heart surgery, and to evaluate the impact of a positive viral screen and study questionnaire on post-surgical HLOS, CICU LOS, intubation time, respiratory complications, and oxygen therapy at home discharge. Sixty-nine infants (1 month to 1 year) undergoing cardiac surgery from November to May of the years 2012 to 2014 were prospectively enrolled, surveyed and tested. We compared the outcomes of positive molecular testing and positive study questionnaire to test negative subjects. We also evaluated the predictive value of study questionnaire in identification of viruses by molecular testing. Of the 69 enrolled infants, 58 had complete information available for analysis. 17 (30%) infants tested positive by molecular testing for respiratory pathogens. 38 (65%) had a "positive" questionnaire. Among the 20 viruses detected, Human Rhinovirus was the most common 12 (60%). Seven (12%) of the 58 patients developed respiratory symptoms following surgery prompting molecular testing. Four of these tested positive for a respiratory virus post-surgically. Neither positive molecular testing nor a positive questionnaire prior to surgery was associated with greater post-operative HLOS, CICU LOS, intubation time, respiratory complications, or use of oxygen at discharge compared to negative testing. The questionnaire poorly predicted positive molecular testing. Routine screening for respiratory viruses in asymptomatic infants may not be an effective strategy to predict infants at risk of post-operative complications.

PCR Detection of Respiratory Pathogens in Asymptomatic and Symptomatic Adults

The frequency of viral respiratory pathogens in asymptomatic subjects is poorly defined. The aim of this study was to explore the prevalence of respiratory pathogens in the upper airways of asymptomatic adults, compared with a reference population of symptomatic patients sampled in the same centers during the same period. Nasopharyngeal (NP) swab samples were prospectively collected from adults with and without ongoing symptoms of respiratory tract infection (RTI) during 12 consecutive months, in primary care centers and hospital emergency departments, and analyzed for respiratory pathogens by a PCR panel detecting 16 viruses and four bacteria. Altogether, 444 asymptomatic and 75 symptomatic subjects completed sampling and follow-up (FU) at day 7. In the asymptomatic subjects, the detection rate of viruses was low (4.3%), and the most common virus detected was rhinovirus (3.2%). Streptococcus pneumoniae was found in 5.6% of the asymptomatic subjects and Haemophilus influenzae in 1.4%. The only factor independently associated with low viral detection rate in asymptomatic subjects was age ≥65 years (P = 0.04). An increased detection rate of bacteria was seen in asymptomatic subjects who were currently smoking (P < 0.01) and who had any chronic condition (P < 0.01). We conclude that detection of respiratory viruses in asymptomatic adults is uncommon, suggesting that a positive PCR result from a symptomatic patient likely is relevant for ongoing respiratory symptoms. Age influences the likelihood of virus detection among asymptomatic adults, and smoking and comorbidities may increase the prevalence of bacterial pathogens in the upper airways.

Impact of community respiratory viral infections in urban children with asthma

Background

Upper respiratory tract viral infections cause asthma exacerbations in children. However, the impact of natural colds on children with asthma in the community, particularly in the high-risk urban environment, is less well defined.

Objective

We hypothesized that children with high-symptom upper respiratory viral infections have reduced airway function and greater respiratory tract inflammation than children with virus-positive low-symptom illnesses or virus-negative upper respiratory tract symptoms.

Methods

We studied 53 children with asthma from Detroit, Michigan, during scheduled surveillance periods and self-reported respiratory illnesses for 1 year. Symptom score, spirometry, fraction of exhaled nitric oxide (FeNO), and nasal aspirate biomarkers, and viral nucleic acid and rhinovirus (RV) copy number were assessed.

Results

Of 658 aspirates collected, 22.9% of surveillance samples and 33.7% of respiratory illnesses were virus-positive. Compared with the virus-negative asymptomatic condition, children with severe colds (symptom score ≥5) showed reduced forced expiratory flow at 25% to 75% of the pulmonary volume (FEF_25%-75%), higher nasal messenger RNA expression of C-X-C motif chemokine ligand (CXCL)-10 and melanoma differentiation-associated protein 5, and higher protein abundance of CXCL8, CXCL10 and C-C motif chemokine ligands (CCL)-2, CCL4, CCL20, and CCL24. Children with mild (symptom score, 1-4) and asymptomatic infections showed normal airway function and fewer biomarker elevations. Virus-negative cold-like illnesses demonstrated increased FeNO, minimal biomarker elevation, and normal airflow. The RV copy number was associated with nasal chemokine levels but not symptom score.

Conclusion

Urban children with asthma with high-symptom respiratory viral infections have reduced FEF_25%-75% and more elevations of nasal biomarkers than children with mild or symptomatic infections, or virus-negative illnesses.

Asymptomatic Shedding of Respiratory Virus among an Ambulatory Population across Seasons

Most observation of human respiratory virus carriage is derived from medical surveillance; however, the infections documented by this surveillance represent only a symptomatic fraction of the total infected population. As the role of asymptomatic infection in respiratory virus transmission is still largely unknown and rates of asymptomatic shedding are not well constrained, it is important to obtain more-precise estimates through alternative sampling methods. We actively recruited participants from among visitors to a New York City tourist attraction. Nasopharyngeal swabs, demographics, and survey information on symptoms, medical history, and recent travel were obtained from 2,685 adults over two seasonal arms. We used multiplex PCR to test swab specimens for a selection of common respiratory viruses. A total of 6.2% of samples (168 individuals) tested positive for at least one virus, with 5.6% testing positive in the summer arm and 7.0% testing positive in the winter arm. Of these, 85 (50.6%) were positive for human rhinovirus (HRV), 65 (38.7%) for coronavirus (CoV), and 18 (10.2%) for other viruses (including adenovirus, human metapneumovirus, influenza virus, and parainfluenza virus). Depending on the definition of symptomatic infection, 65% to 97% of infections were classified as asymptomatic. The best-fit model for prediction of positivity across all viruses included a symptom severity score, Hispanic ethnicity data, and age category, though there were slight differences across the seasonal arms. Though having symptoms is predictive of virus positivity, there are high levels of asymptomatic respiratory virus shedding among the members of an ambulatory population in New York City.IMPORTANCE Respiratory viruses are common in human populations, causing significant levels of morbidity. Understanding the distribution of these viruses is critical for designing control methods. However, most data available are from medical records and thus predominantly represent symptomatic infections. Estimates for asymptomatic prevalence are sparse and span a broad range. In this study, we aimed to measure more precisely the proportion of infections that are asymptomatic in a general, ambulatory adult population. We recruited participants from a New York City tourist attraction and administered nasal swabs, testing them for adenovirus, coronavirus, human metapneumovirus, rhinovirus, influenza virus, respiratory syncytial virus, and parainfluenza virus. At recruitment, participants completed surveys on demographics and symptomology. Analysis of these data indicated that over 6% of participants tested positive for shedding of respiratory virus. While participants who tested positive were more likely to report symptoms than those who did not, over half of participants who tested positive were asymptomatic.

Asthma exacerbations in a subtropical area and the role of respiratory viruses: a cross-sectional study

BACKGROUND

Multiple factors are involved in asthma exacerbations, including environmental exposure and viral infections. We aimed to assess the association between severe asthma exacerbations, acute respiratory viral infections and other potential risk factors.

METHODS

Asthmatic children aged 4-14 years were enrolled for a period of 12 months and divided into two groups: those with exacerbated asthma (group 1) and non-exacerbated asthma (group 2). Clinical data were obtained and nasopharyngeal samples were collected through nasopharyngeal aspirate or swab and analysed via indirect fluorescent immunoassays to detect influenza A and B viruses, parainfluenza 1-3, adenovirus and respiratory syncytial virus. Rhinovirus was detected via molecular assays. Potential risk factors for asthma exacerbation were identified in univariate and multivariate analyses.

RESULTS

In 153 children (group 1: 92; group 2: 61), median age 7 and 8 years, respectively, the rate of virus detection was 87.7%. There was no difference between groups regarding the frequency of virus detection (p = 0.68); however, group 1 showed a lower frequency (19.2%) of inhaled corticosteroid use (91.4%, p < 0.01) and evidence of inadequate disease control. In the multivariate analysis, the occurrence of three or more visits to the emergency room in the past 12 months (IRR = 1.40; p = 0.04) and nonadherence to inhaled corticosteroid (IRR = 4.87; p < 0.01) were the only factors associated with exacerbation.

CONCLUSION

Our results suggest an association between asthma exacerbations, poor disease control and nonadherence to asthma medication, suggesting that viruses may not be the only culprits for asthma exacerbations in this population.

PreDicta chip-based high resolution diagnosis of rhinovirus-induced wheeze

Rhinovirus (RV) infections are major triggers of acute exacerbations of severe respiratory diseases such as pre-school wheeze, asthma and chronic obstructive pulmonary disease (COPD). The occurrence of numerous RV types is a major challenge for the identification of the culprit virus types and for the improvement of virus type-specific treatment strategies. Here, we develop a chip containing 130 different micro-arrayed RV proteins and peptides and demonstrate in a cohort of 120 pre-school children, most of whom had been hospitalized due to acute wheeze, that it is possible to determine the culprit RV species with a minute blood sample by serology. Importantly, we identify RV-A and RV-C species as giving rise to most severe respiratory symptoms. Thus, we have generated a chip for the serological identification of RV-induced respiratory illness which should be useful for the rational development of preventive and therapeutic strategies targeting the most important RV types.

Defining lower airway bacterial infection in children with chronic endobronchial disorders

BACKGROUND

Differentiating lower airway bacterial infection from possible upper airway contamination in children with endobronchial disorders undergoing bronchoalveolar lavage (BAL) is important for guiding management. A diagnostic bacterial load threshold based on inflammatory markers has been determined to differentiate infection from upper airway contamination in infants with cystic fibrosis, but not for children with protracted bacterial bronchitis (PBB), chronic suppurative lung disease (CSLD), or bronchiectasis.

METHODS

BAL samples from children undergoing bronchoscopy underwent quantitative bacterial culture, cytologic examination, and respiratory virus testing; a subset also had interleukin-8 examined. Geometric means (GMs) of total cell counts (TCCs) and neutrophil counts were plotted by respiratory pathogen bacterial load. Logistic regression determined associations between age, sex, Indigenous status, antibiotic exposure, virus detection and bacterial load, and elevated TCCs (>400 × 10³ cells/mL) and airway neutrophilia (neutrophils >15% BAL leukocytes).

RESULTS

From 2007 to 2016, 655 children with PBB, CSLD, or bronchiectasis were enrolled. In univariate analyses, Indigenous status and bacterial load ≥10⁵ colony-forming units (CFU)/mL were positively associated with high TCCs. Viruses and bacterial load ≥10⁴ CFU/mL were positively associated with neutrophilia; negative associations were seen for Indigenous status and macrolides. In children who had not received macrolide antibiotics, bacterial load was positively associated in multivariable analyses with high TCCs at ≥10⁴ CFU/mL and with neutrophilia at ≥10⁵ CFU/mL; GMs of TCCs and neutrophil counts were significantly elevated at 10⁴ and 10⁵ CFU/mL compared to negative cultures.

CONCLUSIONS

Our findings support a BAL threshold ≥10⁴ CFU/mL to define lower airway infection in children with chronic endobronchial disorders.

Reduction in Rate of Nosocomial Respiratory Virus Infections in a Children's Hospital Associated With Enhanced Isolation Precautions

OBJECTIVE To determine whether the use of enhanced isolation precautions (droplet and contact precautions) for inpatients with respiratory tract viral infections is associated with a reduction in rate of nosocomial viral respiratory infections. DESIGN Quasi-experimental study with the rate of nosocomial respiratory virus infection as the primary dependent variable and rate of nosocomial Clostridium difficile infection as a nonequivalent dependent variable comparator. SETTING Cohen Children's Medical Center of NY, a tertiary-care children's hospital attached to a large general hospital. INTERVENTION During years 1 and 2 (July 2012 through June 2014), the Centers for Disease Control and Prevention/Healthcare Infection Control Practices Advisory Committee's recommended isolation precautions for inpatients with selected respiratory virus infections were in effect. Enhanced isolation precautions were in effect during years 3 and 4 (July, 2014 through June, 2016), except for influenza, for which enhanced precautions were in effect during year 4 only. RESULTS During the period of enhanced isolation precautions, the rate of nosocomial respiratory virus infections with any of 4 virus categories decreased 39% from 0.827 per 1,000 hospital days prior to enhanced precautions to 0.508 per 1,000 hospital days (P<.0013). Excluding rhinovirus/enterovirus infections, the rates decreased 58% from 0.317 per 1,000 hospital days to 0.134 per 1,000 hospital days during enhanced precautions (P<.0014). During these periods, no significant change was detected in the rate of nosocomial C. difficile infection. CONCLUSIONS Enhanced isolation precautions for inpatients with respiratory virus infections were associated with a reduction in the rate of nosocomial respiratory virus infections. Infect Control Hosp Epidemiol 2018;39:152-156.

Temporal Association Between Rhinovirus Activity and Kingella kingae Osteoarticular Infections

OBJECTIVE

To determine whether the seasonal distribution of Kingella kingae osteoarticular infections is similar to that of common respiratory viruses.

STUDY DESIGN

Between October 2009 and September 2016, we extracted the results of K kingae-specific real-time polymerase chain reaction analyses performed for bone or joint specimens in patients from 2 pediatric tertiary care centers in Paris. We used data of respiratory virus detection from the Réseau National des Laboratoires network with coordination with the National Influenza Center of France. The Spearman rank correlation was used to assess a correlation between weekly distributions, with P < .05 denoting a significant correlation.

RESULTS

During the 7-year study period, 322 children were diagnosed with K kingae osteoarticular infection, and 317 testing episodes were K kingae-negative. We observed high activity for both K kingae osteoarticular infection and human rhinovirus (HRV) during the fall (98 [30.4%] and 2401 [39.1%] cases, respectively) and low activity during summer (59 [18.3%] and 681 [11.1%] cases, respectively). Weekly distributions of K kingae osteoarticular infection and rhinovirus activity were significantly correlated (r = 0.30; P = .03). In contrast, no significant correlation was found between the weekly distribution of K kingae osteoarticular infection and other respiratory viruses (r = -0.17, P = .34 compared with respiratory syncytial virus; r = -0.13, P = .34 compared with influenza virus; and r = -0.22, P = .11 compared with metapneumovirus).

CONCLUSION

A significant temporal association was observed between HRV circulation and K kingae osteoarticular infection, strengthening the hypothesis of a role of viral infections in the pathophysiology of K kingae invasive infection.

Respiratory Tract Viral Infections and Coinfections Identified by Anyplex™ II RV16 Detection Kit in Pediatric Patients at a Riyadh Tertiary Care Hospital

Respiratory infections are caused by an array of viruses, and limited information is available about viral coexistence, comparative symptoms, and the burden of illness. This retrospective cohort study aimed to determine the etiological agents responsible for respiratory tract infections by Anyplex II RV16 detection kit (RV16, Seegene), involving 2266 pediatric patients with respiratory infections admitted to the Department of Pediatrics at King Abdul-Aziz Medical City, Ministry of National Guard, Riyadh, from July 2014 to June 2015. The most frequent respiratory infections were recorded in the 1 to 5 year age group (44.7%). Rhinovirus (32.5%), Adenovirus (16.9%), and Respiratory syncytial virus (RSV) B (10.4%) were most common. In single viral infections, Rhinovirus (41.2%), Metapneumovirus (15.3%), and Bocavirus (13.7%) were most frequent. In multiple viral infections, Rhinovirus (36.7%), Adenovirus (35.2%), Bocavirus (11.2), RSV B (7.8%), and RSV A (6.7%) were most frequent. No significant difference was observed in clinical presentations; however, rhinorrhea and hypodynamia were significantly associated with viral respiratory infections. Most respiratory viral pathogens peaked during December, January, March, and April. Rhinovirus, Adenovirus, and Bocavirus circulations were detected throughout the year. Winter peaks were recorded for Rhinovirus, RSV B, Adenovirus, and RSV A, whereas the Metapneumovirus, and the Bocavirus peaked in March and April. These findings enhance understanding of viral etiology and distribution to improve respiratory infection management and treatment.

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam

Background: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam.Methods: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.   Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents.Conclusions: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription.

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam

BACKGROUND

Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam.

METHODS

Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.    Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents.

CONCLUSIONS

The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription.

Prevalence of respiratory viruses among adults, by season, age, respiratory tract region and type of medical unit in Paris, France, from 2011 to 2016

BACKGROUND

Multiplex PCR tests have improved our understanding of respiratory viruses' epidemiology by allowing their wide range detection. We describe here the burden of these viruses in hospital settings over a five-year period.

METHODS

All respiratory samples from adult patients (>20 years old) tested by multiplex-PCR at the request of physicians, from May 1 2011 to April 30 2016, were included retrospectively. Viral findings are reported by season, patient age group, respiratory tract region (upper or lower) and type of clinical unit (intensive care unit, pneumology unit, lung transplantation unit and other medical units).

RESULTS

In total, 7196 samples (4958 patients) were included; 29.2% tested positive, with viral co-infections detected in 1.6% of samples. Overall, two viral groups accounted for 60.2% of all viruses identified: picornaviruses (rhinovirus or enterovirus, 34.3%) and influenza (26.6%). Influenza viruses constituted the group most frequently identified in winter (34.4%), in the upper respiratory tract (32%) and in patients over the age of 70 years (36.4%). Picornavirus was the second most frequently identified viral group in these populations and in all other groups, including lower respiratory tract infections (41.3%) or patients in intensive care units (37.6%).

CONCLUSION

This study, the largest to date in Europe, provides a broad picture of the distribution of viruses over seasons, age groups, types of clinical unit and respiratory tract regions in the hospital setting. It highlights the burden associated with the neglected picornavirus group. These data have important implications for the future development of vaccines and antiviral drugs.

An update on pediatric bronchiectasis

INTRODUCTION

The prevalence and awareness of bronchiectasis not related to cystic fibrosis (CF) is increasing and it is now recognized as a major cause of respiratory morbidity, mortality and healthcare utilization worldwide. The need to elucidate the early origins of bronchiectasis is increasingly appreciated and has been identified as an important research priority. Current treatments for pediatric bronchiectasis are limited to antimicrobials, airway clearance techniques and vaccination. Several new drugs targeting airway inflammation are currently in development. Areas covered: Current management of pediatric bronchiectasis, including discussion on therapeutics, non-pharmacological interventions and preventative and surveillance strategies are covered in this review. We describe selected adult and pediatric data on bronchiectasis treatments and briefly discuss emerging therapeutics in the field. Expert commentary: Despite the burden of disease, the number of studies evaluating potential treatments for bronchiectasis in children is extremely low and substantially disproportionate to that for CF. Research into the interactions between early life respiratory tract infections and the developing immune system in children is likely to reveal risk factors for bronchiectasis development and inform future preventative and therapeutic strategies. Tailoring interventions to childhood bronchiectasis is imperative to halt the disease in its origins and improve adult outcomes.

Dual RNA-seq reveals viral infections in asthmatic children without respiratory illness which are associated with changes in the airway transcriptome

Background

Respiratory illness caused by viral infection is associated with the development and exacerbation of childhood asthma. Little is known about the effects of respiratory viral infections in the absence of illness. Using quantitative PCR (qPCR) for common respiratory viruses and for two genes known to be highly upregulated in viral infections (CCL8/CXCL11), we screened 92 asthmatic and 69 healthy children without illness for respiratory virus infections.

Results

We found 21 viral qPCR-positive and 2 suspected virus-infected subjects with high expression of CCL8/CXCL11. We applied a dual RNA-seq workflow to these subjects, together with 25 viral qPCR-negative subjects, to compare qPCR with sequencing-based virus detection and to generate the airway transcriptome for analysis. RNA-seq virus detection achieved 86% sensitivity when compared to qPCR-based screening. We detected additional respiratory viruses in the two CCL8/CXCL11-high subjects and in two of the qPCR-negative subjects. Viral read counts varied widely and were used to stratify subjects into Virus-High and Virus-Low groups. Examination of the host airway transcriptome found that the Virus-High group was characterized by immune cell airway infiltration, downregulation of cilia genes, and dampening of type 2 inflammation. Even the Virus-Low group was differentiated from the No-Virus group by 100 genes, some involved in eIF2 signaling.

Conclusions

Respiratory virus infection without illness is not innocuous but may determine the airway function of these subjects by driving immune cell airway infiltration, cellular remodeling, and alteration of asthmogenic gene expression.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-016-1140-8) contains supplementary material, which is available to authorized users.

Respiratory and Enteric Virus Detection in Children

The majority of children with febrile seizures have viral infections and viruses were detected in 22% to 63% of children in published studies. Using molecular methods, viruses were also detected in asymptomatic persons. A prospective study was conducted to detect respiratory and enteric viruses in 192 children with febrile seizures and compare the detection rates to those found in 156 healthy age-matched controls. A respiratory or enteric virus was detected in 72.9% of children with febrile seizures and in 51.4% of healthy controls. The viruses most strongly associated with febrile seizures were influenza, respiratory syncytial virus, parainfluenza, human coronavirus, and rotavirus. Compared to healthy controls, the age-adjusted odds ratios for nasopharynx virus positivity in febrile seizure patients were 79.4, 2.8, 7.2, and 4.9 for influenza virus, parainfluenza virus, respiratory syncytial virus, and human coronavirus, respectively, and 22.0 for rotavirus in stool. The detected virus did not influence clinical features of febrile seizure.

Child pneumonia - focus on the Western Pacific Region

Worldwide, pneumonia is the leading cause of death in infants and young children (aged <5 years). We provide an overview of the global pneumonia disease burden, as well as the aetiology and management practices in different parts of the world, with a specific focus on the WHO Western Pacific Region. In 2011, the Western Pacific region had an estimated 0.11 pneumonia episodes per child-year with 61,900 pneumonia-related deaths in children less than 5 years of age. The majority (>75%) of pneumonia deaths occurred in six countries; Cambodia, China, Laos, Papua New Guinea, the Philippines and Viet Nam. Historically Streptococcus pneumoniae and Haemophilus influenzae were the commonest causes of severe pneumonia and pneumonia-related deaths in young children, but this is changing with the introduction of highly effective conjugate vaccines and socio-economic development. The relative contribution of viruses and atypical bacteria appear to be increasing and traditional case management approaches may require revision to accommodate increased uptake of conjugated vaccines in the Western Pacific region. Careful consideration should be given to risk reduction strategies, enhanced vaccination coverage, improved management of hypoxaemia and antibiotic stewardship.

Viral etiology of severe acute respiratory infections in hospitalized children in Cameroon, 2011-2013

BACKGROUND

Severe acute respiratory illness (SARI) is recognized as an important cause of morbidity, mortality, and hospitalization among children in developing countries. Little is known, however, in tropical countries like Cameroon about the cause and seasonality of respiratory infections, especially in hospitalized settings.

OBJECTIVES

Our study investigates the viral etiology and seasonality of SARI in hospitalized children in Yaounde, Cameroon.

METHODS

Prospective clinic surveillance was conducted to identify hospitalized children aged ≤15 years presenting with respiratory symptoms ≤5-day duration. Demographic and clinical data, and respiratory specimens were collected. Nasopharyngeal samples were tested for 17 respiratory viruses using a multiplex polymerase chain reaction. The viral distribution and demographic data were statistically analyzed.

RESULTS

From September 2011 through September 2013, 347 children aged ≤15 years were enrolled. At least one virus was identified in each of 65·4% children, of which 29·5% were coinfections; 27·3% were positive for human adenovirus (hAdV), 13·2% for human respiratory syncytial virus (hRSV), 11·5% for rhinovirus/enterovirus (RV/EV), 10·6% for human bocavirus (hBoV), 9·8% for influenza virus (Inf), 6·6% for human parainfluenza virus (hPIV), 5·7% for human coronavirus (hCoV), and 2·3% for human metapneumovirus (hMPV). While hRSV showed seasonal patterns, hAdV and RV/EV were detected throughout the year and no evident temporal patterns were observed for the remaining viruses.

CONCLUSION

Respiratory viruses were associated with a high burden of hospitalizations among children in Cameroon. Nevertheless, additional studies evaluating asymptomatic Cameroonian children will be important in understanding the relationship between viral carriage and disease.

Rhinovirus Detection in Symptomatic and Asymptomatic Children: Value of Host Transcriptome Analysis

RATIONALE

Rhinoviruses (RVs) are a major cause of symptomatic respiratory tract infection in all age groups. However, RVs can frequently be detected in asymptomatic individuals.

OBJECTIVES

To evaluate the ability of host transcriptional profiling to differentiate between symptomatic RV infection and incidental detection in children.

METHODS

Previously healthy children younger than 2 years old (n = 151) were enrolled at four study sites and classified into four clinical groups: RV- healthy control subjects (n = 37), RV+ asymptomatic subjects (n = 14), RV+ outpatients (n = 30), and RV+ inpatients (n = 70). Host responses were analyzed using whole-blood RNA transcriptional profiles.

MEASUREMENTS AND MAIN RESULTS

RV infection induced a robust transcriptional signature, which was validated in three independent cohorts and by quantitative real-time polymerase chain reaction with high prediction accuracy. The immune profile of symptomatic RV infection was characterized by overexpression of innate immunity and underexpression of adaptive immunity genes, whereas negligible changes were observed in asymptomatic RV+ subjects. Unsupervised hierarchical clustering identified two main clusters of subjects. The first included 93% of healthy control subjects and 100% of asymptomatic RV+ subjects, and the second comprised 98% of RV+ inpatients and 88% of RV+ outpatients. Genomic scores of healthy control subjects and asymptomatic RV+ children were similar and significantly lower than those of RV+ inpatients and outpatients (P < 0.0001).

CONCLUSIONS

Symptomatic RV infection induced a robust and reproducible transcriptional signature, whereas identification of RV in asymptomatic children was not associated with significant systemic transcriptional immune responses. Transcriptional profiling represents a useful tool to discriminate between active infection and incidental virus detection.

Risk factors for adverse outcomes of Indigenous infants hospitalized with bronchiolitis

BACKGROUND

Hospitalized bronchiolitis imposes a significant burden among infants, particularly among Indigenous children. Traditional or known risk factors for severe disease are well described, but there are limited data on risks for prolonged hospitalization and persistent symptoms. Our aims were to determine factors (clinical and microbiological) associated with (i) prolonged length of stay (LOS); (ii) persistent respiratory symptoms at 3 weeks; (iii) bronchiectasis up to ∼24 months post-hospitalisation; and (iv) risk of respiratory readmissions within 6 months.

METHODS

Indigenous infants hospitalized with bronchiolitis were enrolled at Royal Darwin Hospital between 2008 and 2013. Standardized forms were used to record clinical data. A nasopharyngeal swab was collected at enrolment to identify respiratory viruses and bacteria.

RESULTS

The median age of 232 infants was 5 months (interquartile range 3-9); 65% male. On multivariate regression, our 12 point severity score (including accessory muscle use) was the only factor associated with prolonged LOS but the effect was modest (+3.0 hr per point, 95%CI: 0.7, 5.1, P = 0.01). Presence of cough at 3 weeks increased the odds of bronchiectasis (OR 3.0, 95%CI: 1.1, 7.0, P = 0.03). Factors associated with respiratory readmissions were: previous respiratory hospitalization (OR 2.3, 95%CI: 1.0, 5.4, P = 0.05) and household smoke (OR 2.6, 95%CI: 1.0, 6.3, P = 0.04).

CONCLUSION

Increased severity score is associated with prolonged LOS in Indigenous children hospitalized with bronchiolitis. As persistent symptoms at 3 weeks post-hospitalization are associated with future diagnosis of bronchiectasis, optimising clinical care beyond hospitalization is needed to improve long-term respiratory outcomes for infants at risk of respiratory disease. Pediatr Pulmonol. 2016;51:613-623. © 2015 Wiley Periodicals, Inc.

Does Viral Co-Infection Influence the Severity of Acute Respiratory Infection in Children?

Background

Multiple viruses are often detected in children with respiratory infection but the significance of co-infection in pathogenesis, severity and outcome is unclear.

Objectives

To correlate the presence of viral co-infection with clinical phenotype in children admitted with acute respiratory infections (ARI).

Methods

We collected detailed clinical information on severity for children admitted with ARI as part of a Spanish prospective multicenter study (GENDRES network) between 2011–2013. A nested polymerase chain reaction (PCR) approach was used to detect respiratory viruses in respiratory secretions. Findings were compared to an independent cohort collected in the UK.

Results

204 children were recruited in the main cohort and 97 in the replication cohort. The number of detected viruses did not correlate with any markers of severity. However, bacterial superinfection was associated with increased severity (OR: 4.356; P-value = 0.005), PICU admission (OR: 3.342; P-value = 0.006), higher clinical score (1.988; P-value = 0.002) respiratory support requirement (OR: 7.484; P-value < 0.001) and longer hospital length of stay (OR: 1.468; P-value < 0.001). In addition, pneumococcal vaccination was found to be a protective factor in terms of degree of respiratory distress (OR: 2.917; P-value = 0.035), PICU admission (OR: 0.301; P-value = 0.011), lower clinical score (-1.499; P-value = 0.021) respiratory support requirement (OR: 0.324; P-value = 0.016) and oxygen necessity (OR: 0.328; P-value = 0.001). All these findings were replicated in the UK cohort.

Conclusion

The presence of more than one virus in hospitalized children with ARI is very frequent but it does not seem to have a major clinical impact in terms of severity. However bacterial superinfection increases the severity of the disease course. On the contrary, pneumococcal vaccination plays a protective role.

Clinical Features, Virus Identification, and Sinusitis as a Complication of Upper Respiratory Tract Illness in Children Ages 4-7 Years

OBJECTIVE

To determine the rate of sinusitis complicating upper respiratory tract illnesses (URIs) in children. We prospectively identified the clinical, virologic, and epidemiologic characteristics of URIs in a population of 4- to 7-year-old children followed for 1 year.

STUDY DESIGN

This was an observational cohort study in 2 primary care pediatric practices in Madison, Wisconsin. Nasal samples were obtained during 4 asymptomatic surveillance visits and during symptomatic URIs. A polymerase chain reaction-based assay for 9 respiratory viruses was performed on nasal samples. A diagnosis of sinusitis was based on published criteria.

RESULTS

Two hundred thirty-six children ages 48-96 months were enrolled. A total of 327 URIs were characterized. The mean number of URIs per child was 1.3 (range 0-9) per year. Viruses were detected in 81% of URIs; rhinovirus (RV) was most common. Seventy-two percent of URIs were resolved clinically by the 10th day. RV-A and RV-C were detected more frequently at URI visits; RV-B was detected at the same rate for both asymptomatic surveillance visits and URI visits. Sinusitis was diagnosed in 8.8% of symptomatic URIs. Viruses were detected frequently (33%) in samples from asymptomatic children.

CONCLUSIONS

Sinusitis occurred in 8.8% of symptomatic URIs in our study. The virus most frequently detected with URIs in children was RV; RV-A and RV-C detection but not RV-B detection were associated with illness. Viruses, especially RV, are detected frequently in asymptomatic children. Most URIs have improved or resolved by the 10th day after onset. Children experienced a mean of 1.3 URIs per year, which was lower than expected.

Protracted bacterial bronchitis: The last decade and the road ahead

Cough is the single most common reason for primary care physician visits and, when chronic, a frequent indication for specialist referrals. In children, a chronic cough (>4 weeks) is associated with increased morbidity and reduced quality of life. One common cause of childhood chronic cough is protracted bacterial bronchitis (PBB), especially in children aged <6 years. PBB is characterized by a chronic wet or productive cough without signs of an alternative cause and responds to 2 weeks of appropriate antibiotics, such as amoxicillin-clavulanate. Most children with PBB are unable to expectorate sputum. If bronchoscopy and bronchoalveolar lavage are performed, evidence of bronchitis and purulent endobronchial secretions are seen. Bronchoalveolar lavage specimens typically reveal marked neutrophil infiltration and culture large numbers of respiratory bacterial pathogens, especially Haemophilus influenzae. Although regarded as having a good prognosis, recurrences are common and if these are frequent or do not respond to antibiotic treatments of up to 4-weeks duration, the child should be investigated for other causes of chronic wet cough, such as bronchiectasis. The contribution of airway malacia and pathobiologic mechanisms of PBB remain uncertain and, other than reduced alveolar phagocytosis, evidence of systemic, or local immune deficiency is lacking. Instead, pulmonary defenses show activated innate immunity and increased gene expression of the interleukin-1β signalling pathway. Whether these changes in local inflammatory responses are cause or effect remains to be determined. It is likely that PBB and bronchiectasis are at the opposite ends of the same disease spectrum, so children with chronic wet cough require close monitoring.

Systematic review and meta-analysis of respiratory viral coinfections in children

Respiratory infections are a common cause of paediatric morbidity. Clinical outcomes in children hospitalized with single respiratory virus infection are compared with those with two or more viral-viral coinfection. Studies were restricted to those reporting on children aged less than 5 years (PROSPERO CRD#42014009133). Published data to calculate risk ratios (RR) comparing children with single viral infections to coinfection using a random effects model were used. Similar analyses by pathogen pairs and by excluding children with comorbidities were performed. Of 4443 articles reviewed, 19 were included. Overall, no differences in the risk of fever, admission to an intensive care unit (ICU), oxygen use, mechanical ventilation and abnormal radiographs between children with single infection and those with coinfection were found. When analysing only children without comorbidities, the risk of fever (RR = 1.16 to RR = 1.24, 95% confidence intervals (CI) = 1.00-1.55) and ICU admission (RR = 1.08 to RR = 1.31, 95% CI = 0.93-1.83) increased but remained non-significant. Point estimates suggested an increased risk of ICU admission in those coinfected with either respiratory syncytial virus or human metapneumovirus compared with those with single infection but was non-significant. Our findings suggest that coinfection is not associated with increased clinical severity, but further investigations by pathogen pairs are warranted.

Respiratory Infections

The majority of respiratory tract infections (RTIs) are community acquired and are the single most common cause of physician office visits and among the most common causes of hospitalizations. The morbidity and mortality associated with RTIs are significant and the financial and social burden high due to lost time at work and school. The scope of clinical symptoms can significantly overlap among the respiratory pathogens, and the severity of disease can vary depending on patient age, underlying disease, and immune status, thereby leading to inaccurate presumptions about disease etiology. The rapid and accurate diagnosis of the causative agent of RTIs improves patient care, reduces morbidity and mortality, promotes effective hospital bed utilization and antibiotic stewardship, and reduces length of stay. This chapter focuses on the clinical utility, advantages, and disadvantages of viral and bacterial tests cleared by the Food and Drug Administration (FDA), and new promising technologies for the detection of bacterial agents of pneumonia currently in development or in US FDA clinical trials are briefly reviewed.

Upper airway viruses and bacteria detection in clinical pneumonia in a population with high nasal colonisation do not relate to clinical signs

Indigenous Australian children have high (up to 90%) rates of nasopharyngeal microbial colonisation and of hospitalisation for pneumonia. In Indigenous children hospitalised with pneumonia in Central Australia, we describe the nasopharyngeal detection of viruses and bacteria and assessed whether their presence related to signs of pneumonia (tachypnoea and/or chest in-drawing) on hospital admission and during subsequent days. Nasopharyngeal swabs (NPS) and data were prospectively collected from 145 children (median age = 23.5 months, interquartile range [IQR] 8.7–50) hospitalised with pneumonia at Alice Springs Hospital, Australia, between April 2001 and July 2002. The cohort was enrolled in a randomised controlled study using zinc and/or vitamin A supplementation. NPS were taken within 24 hours of hospitalisation and kept frozen at-80°C until analysed in 2014. Polymerase chain reaction (PCR) was used to detect Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Chlamydophila pneumoniae, Mycoplasma pneumoniae, and 16 respiratory viruses. Uni- and multi-variate analyses were used to examine the relationships. One or more organisms were present in 137 (94.5%) NPS; 133 (91.7%) detected ≥ 1 bacterium, 34 (37.2%) for ≥ 1 virus and 50 (34.5%) were positive for both viruses and bacteria. C. pneumoniae (n = 3) and M. pneumoniae (n = 2) were rare. In multi-variate analyses, age < 12 months (odds ratio [OR] 6.6 [95% confidence interval {CI} 1.7–25.4]) and fever (OR 4.1 [95% CI 1.7–10.4]) were associated with tachypnoea and chest in-drawing. However the presence of bacteria and/or virus type was not associated with tachypnoea and/or chest in-drawing on admission or during recovery. In children with high nasopharyngeal microbial colonisation rates, the utility of NPS in determining the diagnosis of clinical pneumonia or duration of tachypnoea or in-drawing is likely limited. Larger cohort and case-control studies are required to confirm our findings.

Severe Acute Respiratory Illness Deaths in Sub-Saharan Africa and the Role of Influenza: A Case Series From 8 Countries

BACKGROUND

Data on causes of death due to respiratory illness in Africa are limited.

METHODS

From January to April 2013, 28 African countries were invited to participate in a review of severe acute respiratory illness (SARI)-associated deaths identified from influenza surveillance during 2009-2012.

RESULTS

Twenty-three countries (82%) responded, 11 (48%) collect mortality data, and 8 provided data. Data were collected from 37 714 SARI cases, and 3091 (8.2%; range by country, 5.1%-25.9%) tested positive for influenza virus. There were 1073 deaths (2.8%; range by country, 0.1%-5.3%) reported, among which influenza virus was detected in 57 (5.3%). Case-fatality proportion (CFP) was higher among countries with systematic death reporting than among those with sporadic reporting. The influenza-associated CFP was 1.8% (57 of 3091), compared with 2.9% (1016 of 34 623) for influenza virus-negative cases (P < .001). Among 834 deaths (77.7%) tested for other respiratory pathogens, rhinovirus (107 [12.8%]), adenovirus (64 [6.0%]), respiratory syncytial virus (60 [5.6%]), and Streptococcus pneumoniae (57 [5.3%]) were most commonly identified. Among 1073 deaths, 402 (37.5%) involved people aged 0-4 years, 462 (43.1%) involved people aged 5-49 years, and 209 (19.5%) involved people aged ≥50 years.

CONCLUSIONS

Few African countries systematically collect data on outcomes of people hospitalized with respiratory illness. Stronger surveillance for deaths due to respiratory illness may identify risk groups for targeted vaccine use and other prevention strategies.

The respiratory health of urban indigenous children aged less than 5 years: study protocol for a prospective cohort study

BACKGROUND

Despite the burden of acute respiratory illnesses (ARI) among Aboriginal and Torres Strait Islander children being a substantial cause of childhood morbidity and associated costs to families, communities and the health system, data on disease burden in urban children are lacking. Consequently evidence-based decision-making, data management guidelines, health resourcing for primary health care services and prevention strategies are lacking. This study aims to comprehensively describe the epidemiology, impact and outcomes of ARI in urban Aboriginal and Torres Strait Islander children (hereafter referred to as Indigenous) in the greater Brisbane area.

METHODS/DESIGN

An ongoing prospective cohort study of Indigenous children aged less than five years registered with a primary health care service in Northern Brisbane, Queensland, Australia. Children are recruited at time of presentation to the service for any reason. Demographic, epidemiological, risk factor, microbiological, economic and clinical data are collected at enrolment. Enrolled children are followed for 12 months during which time ARI events, changes in child characteristics over time and monthly nasal swabs are collected. Children who develop an ARI with cough as a symptom during the study period are more intensely followed-up for 28 (±3) days including weekly nasal swabs and parent completed cough diary cards. Children with persistent cough at day 28 post-ARI are reviewed by a paediatrician.

DISCUSSION

Our study will be one of the first to comprehensively evaluate the natural history, epidemiology, aetiology, economic impact and outcomes of ARIs in this population. The results will inform studies for the development of evidence-based guidelines to improve the early detection, prevention and management of chronic cough and setting of priorities in children during and after ARI.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry Registration Number: 12614001214628 . Registered 18 November 2014.

Viral coinfection in acute respiratory infection in Mexican children treated by the emergency service: A cross-sectional study

Background

Acute respiratory infections (ARIs) cause illness. Children under five years of age are highly vulnerable to these infections. Viral coinfection or multiple viral infection is a variable that can have a significant impact on the evolution of these diseases.

Methods

This cross-sectional study was carried out in Mexican children (under five years of age) who had an ARI and who were treated by an emergency service in a hospital in Guadalajara, Jalisco, Mexico. The viral etiology, as well as the presence of multiple viral infections, was determined. A structured questionnaire was used to obtain demographic and clinical information. Odds ratio (OR) was calculated, and univariate and multivariate analyses using logistic regression were performed.

Results

In the study population, metapneumovirus (hMPV) was the most frequent virus (22%), followed by adenovirus (hAD) (16%), respiratory syncytial virus (RSV) (14%), rhinovirus (hRV) (12%), bocavirus (hBoV) (9%), influenza virus (IF) (7%), and parainfluenza (PIF) (4%). The frequency of viral coinfections was 31.62%, and multiple logistic regression analysis revealed that hMPV, RSV, PIF, and hBoV were independently associated with multiple viral infection. No difference was found in the clinical manifestation of children with simple and multiple infections. Simple hMPV infection was associated with patients who presented with severe ARI. Using a multivariate analysis, we found that overcrowding is associated with coinfection when the viral etiology was hRV (OR = 2.56, 95% confidence interval (CI) 1.07 to 6.13), IF (OR = 2.56, 95% CI 1.07 to 6.13), PIF (OR = 2.96, 95% CI 1.15 to 7.65), hAD (OR = 2.56, 95% CI 1.07 to 6.13), and hBoV (OR = 2.9, 95% CI 1.14 to 7.34).

Conclusions

Viral coinfections are frequent in children requiring treatment by an emergency service. However, the severity of ARI is similar to that of children with a simple infection. The hMPV is common and may confer a significant disease burden in the Mexican population. Finally, overcrowding is a housing characteristic that favors the development of coinfections.

Electronic supplementary material

The online version of this article (doi:10.1186/s13052-015-0133-7) contains supplementary material, which is available to authorized users.