Duration of rhinovirus shedding in the upper respiratory tract in the first year of life

Prevalence of Serious Bacterial Infection in Young Infants with Hypothermia with Positive Respiratory Pathogen Testing

Objectives

We sought to compare the prevalence of serious bacterial infections (SBI; urinary tract infection, bacteremia, and/or meningitis) and invasive bacterial infections (IBI; bacteremia and/or meningitis) among infants with hypothermia with positive vs negative respiratory pathogen testing.

Study design

We conducted a multicenter retrospective cohort study of infants ≤90 days presenting to an emergency department or directly admitted to a hospital from September 1, 2016, to May 5, 2021, with reported or documented hypothermia (≤36°C). Positive respiratory pathogen testing included positive single or multiplex nucleic acid amplification testing. The primary outcome was prevalence of SBI, defined as positive blood, urine, and/or cerebrospinal fluid culture and antibiotic treatment course; the prevalence of SBI and IBI was compared between infants with positive vs negative respiratory pathogen tests using the χ2 test.

Results

Respiratory pathogen testing was obtained in 40.6% (446/1098) of infants with hypothermia; of those, 24.9% (111/446) had a positive respiratory pathogen result. Infants with a positive respiratory pathogen result were more often older, ill-appearing at presentation, and evaluated during fall/winter months. The prevalence of SBI in our cohort was 7.4%, and the prevalence of IBI was 4.5%. There were no associations between respiratory pathogen test result and SBI or IBI.

Conclusions

Most young infants with hypothermia evaluated did not have respiratory pathogen testing performed. The diagnosis of SBI or IBI was not associated with a positive respiratory pathogen test. Further research is needed to understand the utility of respiratory pathogen testing in risk stratification for infants with hypothermia.

Factors Associated With Prolonged Respiratory Virus Detection From Polymerase Chain Reaction of Nasal Specimens Collected Longitudinally in Healthy Children in a US Birth Cohort

BACKGROUND

Respiratory viral shedding is incompletely characterized by existing studies due to the lack of longitudinal nasal sampling and limited inclusion of healthy/asymptomatic children. We describe characteristics associated with prolonged virus detection by polymerase chain reaction (PCR) in a community-based birth cohort.

METHODS

Children were followed from birth to 2 years of age in the PREVAIL cohort. Weekly nasal swabs were collected and tested using the Luminex Respiratory Pathogen Panel. Weekly text surveys were administered to ascertain the presence of acute respiratory illnesses defined as fever and/or cough. Maternal reports and medical chart abstractions identified healthcare utilization. Prolonged virus detection was defined as a persistently positive test lasting ≥4 weeks. Factors associated with prolonged virus detection were assessed using mixed effects multivariable logistic regression.

RESULTS

From a sub-cohort of 101 children with ≥70% weekly swabs collected, a total of 1489 viral infections were detected. Prolonged virus detection was found in 23.4% of viral infections overall, 39% of bocavirus infections, 33% of rhinovirus/enterovirus infections, 14% of respiratory syncytial virus (RSV) A infections, and 7% of RSV B infections. No prolonged detection was found for influenza virus A or B, coronavirus 229E or HKU1, and parainfluenza virus 2 or 4 infections. First-lifetime infection with each virus, and co-detection of another respiratory virus were significantly associated with prolonged detection, while symptom status, child sex, and child age were not.

CONCLUSIONS

Prolonged virus detection was observed in 1 in 4 viral infections in this cohort of healthy children and varied by pathogen, occurring most often for bocavirus and rhinovirus/enterovirus. Evaluating the immunological basis of how viral co-detections and recurrent viral infections impact duration of virus detection by PCR is needed to better understand the dynamics of prolonged viral shedding.

Asymptomatic viruses detectable in saliva in the first year of life: a narrative review

Viral infections are common in children. Many can be asymptomatic or have delayed health consequences. In view of increasing availability of point-of-care viral detection technologies, with possible application in newborn screening, this review aimed to (1) identify potentially asymptomatic viruses detectable in infants under one year old, via saliva/nasopharyngeal swab, and (2) describe associations between viruses and long-term health conditions. We systematically searched Embase(Ovid), Medline(Ovid) and PubMed, then further searched the literature in a tiered approach. From the 143 articles included, 28 potentially asymptomatic viruses were identified. Our second search revealed associations with a range of delayed health conditions, with most related to the severity of initial symptoms. Many respiratory viruses were linked with development of recurrent wheeze or asthma. Of note, some potentially asymptomatic viruses are linked with later non-communicable diseases: adenovirus serotype 36 and obesity, Enterovirus-A71 associated Hand, Foot, Mouth Disease and Attention-Deficit Hyperactivity Disorder, Ebstein Barr Virus (EBV) and malignancy, EBV and multiple sclerosis, HHV-6 and epilepsy, HBoV-1 and lung fibrosis and Norovirus and functional gastrointestinal disorders. Our review identified many potentially asymptomatic viruses, detectable in early life with potential delayed health consequences, that could be important to screen for in the future using rapid point-of-care viral detection methods. IMPACT: Novel point-of-care viral detection technologies enable rapid detection of viruses, both old and emerging. In view of increasing capability to screen for viruses, this is the first review to explore which potentially asymptomatic viruses, that are detectable using saliva and/or nasopharyngeal swabs in infants less than one year of age, are associated with delayed adverse health conditions. Further research into detecting such viruses in early life and their delayed health outcomes may pave new ways to prevent non-communicable diseases in the future.

Burden of Respiratory Viruses in Children Less Than 2 Years Old in a Community-based Longitudinal US Birth Cohort

BACKGROUND

Respiratory viral infections are a major cause of morbidity and hospitalization in young children. Nevertheless, the population burden of respiratory viral infections, especially asymptomatic cases, is not known due to the lack of prospective community-based cohort studies with intensive monitoring.

METHODS

To address this gap, we enacted the PREVAIL cohort, a Centers for Disease Control and Prevention-sponsored birth cohort in Cincinnati, Ohio, where children were followed from 0 to 2 years of age. Weekly text surveys were administered to record acute respiratory illnesses (ARIs), which were defined as the presence of cough or fever (≥38°C). Weekly midturbinate nasal swabs were collected and tested using the Luminex Respiratory Pathogen Panel, which detected 16 viral pathogens. Viral infection was defined as ≥1 positive tests from the same virus or viral subtype ≤30 days of a previous positive test. Maternal report and medical chart abstractions identified healthcare utilization.

RESULTS

From 4/2017 to 7/2020, 245 mother-infant pairs were recruited and followed. From the 13 781 nasal swabs tested, a total of 2211 viral infections were detected, of which 821 (37%) were symptomatic. Children experienced 9.4 respiratory viral infections/child-year; half were rhinovirus/enterovirus. Viral ARI incidence was 3.3 episodes/child-year. Emergency department visits or hospitalization occurred with only 15% of respiratory syncytial virus infections, 10% of influenza infections, and only 4% of all viral infections. Regardless of pathogen, most infections were asymptomatic or mild.

CONCLUSIONS

Respiratory viral infections are common in children 0-2 years. Most viral infections are asymptomatic or non-medically attended, underscoring the importance of community-based cohort studies.

Viral infection in chronic otitis media with effusion in children

Background

The role of respiratory viruses in chronic otitis media with effusion (COME) in children is not clearly defined. In our study we aimed to investigate the detection of respiratory viruses in middle ear effusions (MEE) as well as the association with local bacteria, respiratory viruses in the nasopharynx and cellular immune response of children with COME.

Methods

This 2017-2019 cross-sectional study included 69 children aged 2-6 undergoing myringotomy for COME. MEE and nasopharyngeal swabs were analyzed via PCR and CT-values for the genome and loads of typical respiratory viruses. Immune cell populations and exhaustion markers in MEE related to respiratory virus detection were studied via FACS. Clinical data including the BMI was correlated.

Results

Respiratory viruses were detected in MEE of 44 children (64%). Rhinovirus (43%), Parainfluenzavirus (26%) and Bocavirus (10%) were detected most frequently. Average Ct values were 33.6 and 33.5 in MEE and nasopharynx, respectively. Higher detection rates correlated with elevated BMI. Monocytes were elevated in MEE (9.5 ± 7.3%/blood leucocytes). Exhaustion markers were elevated on CD4+ and CD8+ T cells and monocytes in MEE.

Conclusion

Respiratory viruses are associated with pediatric COME. Elevated BMI was associated with increased rates of virus associated COME. Changes in cell proportions of innate immunity and expression of exhaustion markers may be related to chronic viral infection.

Persistence of RNA Viruses in the Respiratory Tract: An Overview

Respiratory RNA viruses are a major cause of acute lower respiratory tract infections and contribute substantially to hospitalization among infants, elderly, and immunocompromised. Complete viral clearance from acute infections is not always achieved, leading to persistence. Certain chronic respiratory diseases like asthma and chronic obstructive pulmonary disease have been associated with persistent infection by human respiratory syncytial virus and human rhinovirus, but it is still not clear whether RNA viruses really establish long-term infections as it has been recognized for DNA viruses as human bocavirus and adenoviruses. Herein, we summarize evidence of RNA virus persistence in the human respiratory tract, as well as in some animal models, to highlight how long-term infections might be related to development and/or maintenance of chronic respiratory symptoms.

Trends in Risk Factors and Symptoms Associated With SARS-CoV-2 and Rhinovirus Test Positivity in King County, Washington, June 2020 to July 2022

IMPORTANCE

Few US studies have reexamined risk factors for SARS-CoV-2 positivity in the context of widespread vaccination and new variants or considered risk factors for cocirculating endemic viruses, such as rhinovirus.

OBJECTIVES

To evaluate how risk factors and symptoms associated with SARS-CoV-2 test positivity changed over the course of the pandemic and to compare these with the risk factors associated with rhinovirus test positivity.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study used a test-negative design with multivariable logistic regression to assess associations between SARS-CoV-2 and rhinovirus test positivity and self-reported demographic and symptom variables over a 25-month period. The study was conducted among symptomatic individuals of all ages enrolled in a cross-sectional community surveillance study in King County, Washington, from June 2020 to July 2022.

EXPOSURES

Self-reported data for 15 demographic and health behavior variables and 16 symptoms.

MAIN OUTCOMES AND MEASURES

Reverse transcription-polymerase chain reaction-confirmed SARS-CoV-2 or rhinovirus infection.

RESULTS

Analyses included data from 23 498 individuals. The median (IQR) age of participants was 34.33 (22.42-45.08) years, 13 878 (59.06%) were female, 4018 (17.10%) identified as Asian, 654 (2.78%) identified as Black, and 2193 (9.33%) identified as Hispanic. Close contact with an individual with SARS-CoV-2 (adjusted odds ratio [aOR], 3.89; 95% CI, 3.34-4.57) and loss of smell or taste (aOR, 3.49; 95% CI, 2.77-4.41) were the variables most associated with SARS-CoV-2 test positivity, but both attenuated during the Omicron period. Contact with a vaccinated individual with SARS-CoV-2 (aOR, 2.03; 95% CI, 1.56-2.79) was associated with lower odds of testing positive than contact with an unvaccinated individual with SARS-CoV-2 (aOR, 4.04; 95% CI, 2.39-7.23). Sore throat was associated with Omicron infection (aOR, 2.27; 95% CI, 1.68-3.20) but not Delta infection. Vaccine effectiveness for participants fully vaccinated with a booster dose was 93% (95% CI, 73%-100%) for Delta, but not significant for Omicron. Variables associated with rhinovirus test positivity included being younger than 12 years (aOR, 3.92; 95% CI, 3.42-4.51) and experiencing a runny or stuffy nose (aOR, 4.58; 95% CI, 4.07-5.21). Black race, residing in south King County, and households with 5 or more people were significantly associated with both SARS-CoV-2 and rhinovirus test positivity.

CONCLUSIONS AND RELEVANCE

In this case-control study of 23 498 symptomatic individuals, estimated risk factors and symptoms associated with SARS-CoV-2 infection changed over time. There was a shift in reported symptoms between the Delta and Omicron variants as well as reductions in the protection provided by vaccines. Racial and sociodemographic disparities persisted in the third year of SARS-CoV-2 circulation and were also present in rhinovirus infection. Trends in testing behavior and availability may influence these results.

Rhinovirus as the main co-circulating virus during the COVID-19 pandemic in children

OBJECTIVE

Changes in the epidemiology of respiratory infections during the restrictions imposed as a response to the coronavirus disease 2019 (COVID-19) pandemic have been reported elsewhere. The present study's aim was to describe the prevalence of a large array of respiratory pathogens in symptomatic children and adolescents during the pandemic in Southern Brazil.

METHODS

Hospitalized and outpatients aged 2 months to 18 years with signs and symptoms of acute COVID-19 were prospectively enrolled in the study from May to November 2020 in two hospitals in a large metropolitan area in a Brazilian city. All participants performed a real-time PCR panel assessing 20 respiratory pathogens (three bacteria and 17 viruses).

RESULTS

436 participants were included, with 45 of these hospitalized. Rhinovirus was the most prevalent pathogen (216/436) followed by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, 97/436), with a coinfection of these two viruses occurring in 31/436 participants. The remaining pathogens were found in 24 symptomatic participants (adenovirus, n = 6; Chlamydophila pneumoniae, n = 1; coronavirus NL63, n = 2; human enterovirus, n = 7; human metapneumovirus, n = 2; Mycoplasma pneumoniae, n = 6). Hospitalization was more common among infants (p = 0.004) and those with pathogens other than SARS-CoV-2 (p = 0.001).

CONCLUSION

During the period of social distancing in response to COVID-19, the prevalence of most respiratory pathogens was unusually low. Rhinovirus remained as the main virus co-circulating with SARS-CoV-2. COVID-19 in symptomatic children was less associated with hospitalization than with other respiratory infections in children and adolescents.

Human Rhinoviruses in Pediatric Patients in a Tertiary Care Hospital in Germany: Molecular Epidemiology and Clinical Significance

Rhinoviruses (RVs) constitute a substantial public health burden. To evaluate their abundance and genetic diversity in pediatric patients, RV RNA in respiratory samples was assessed using real-time RT-PCR and partial nucleic acid sequencing of viral genomes. Additionally, clinical data were retrieved from patient charts to determine the clinical significance of pediatric RV infections. In total, the respiratory specimens of 776 patients (<18 years), collected from 2013 to 2017, were analyzed. Infections occurred throughout the entire year, with peaks occurring in fall and winter, and showed remarkably high intra- and interseasonal diversity for RV genotypes. RV species were detected in the following frequencies: 49.1% RV-A, 5.9% RV-B, and 43.6% RV-C. RV-C was found to be more frequently associated with asthma (p = 0.04) and bronchiolitis (p < 0.001), while RV-A was more frequently associated with fever (p = 0.001) and pneumonia (p = 0.002). Additionally, 35.3% of the patients had co-infections with other pathogens, which were associated with a longer hospital stay (p < 0.001), need for ventilation (p < 0.001), and pneumonia (p < 0.001). Taken together, this study shows pronounced RV genetic diversity in pediatric patients and indicates differences in RV-associated pathologies, as well as an important role for co-infections.

Decline in Pneumococcal Disease in Young Children During the Coronavirus Disease 2019 (COVID-19) Pandemic in Israel Associated With Suppression of Seasonal Respiratory Viruses, Despite Persistent Pneumococcal Carriage: A Prospective Cohort Study

BACKGROUND

The incidence of invasive pneumococcal disease (IPD) declined during the COVID-19 pandemic. Previous studies hypothesized that this was due to reduced pneumococcal transmission resulting from nonpharmaceutical interventions. We used multiple ongoing cohort surveillance projects in children <5 years to test this hypothesis.

METHODS

The first SARS-CoV-2 cases were detected in February 2020, resulting in a full lockdown, followed by several partial restrictions. Data from ongoing surveillance projects captured the incidence dynamics of community-acquired alveolar pneumonia (CAAP), nonalveolar lower respiratory infections necessitating chest X-rays (NA-LRIs), nasopharyngeal pneumococcal carriage in nonrespiratory visits, nasopharyngeal respiratory virus detection (by polymerase chain reaction), and nationwide IPD. Monthly rates (January 2020 through February 2021 vs mean monthly rates 2016-2019 [expected rates]) adjusted for age and ethnicity were compared.

RESULTS

CAAP and bacteremic pneumococcal pneumonia were strongly reduced (incidence rate ratios [IRRs]: .07 and .19, respectively); NA-LRIs and nonpneumonia IPD were also reduced by a lesser magnitude (IRRs: .46 and .42, respectively). In contrast, pneumococcal carriage prevalence was only slightly reduced, and density of colonization and pneumococcal serotype distributions were similar to previous years. The decline in pneumococcus-associated disease was temporally associated with a full suppression of respiratory syncytial virus, influenza viruses, and human metapneumovirus, often implicated as co-pathogens with pneumococcus. In contrast, adenovirus, rhinovirus, and parainfluenza activities were within or above expected levels.

CONCLUSIONS

Reductions in pneumococcal and pneumococcus-associated diseases occurring during the COVID-19 pandemic in Israel were not predominantly related to reduced pneumococcal carriage and density but were strongly associated with the disappearance of specific respiratory viruses.

Human Rhinoviruses in Adult Patients in a Tertiary Care Hospital in Germany: Molecular Epidemiology and Clinical Significance

Rhinoviruses (RVs) constitute a substantial public health burden. To evaluate their abundance and genetic diversity in adult patients, RV RNA in respiratory samples was assessed using real-time RT-PCR and the partial nucleic acid sequencing of viral genomes. Additionally, clinical data were retrieved from patient charts to determine the clinical significance of adult RV infections. In total, the respiratory specimens of 284 adult patients (18-90 years), collected from 2013 to 2017, were analyzed. Infections occurred throughout the entire year, with peaks occurring in fall and winter, and showed a remarkably high intra- and interseasonal diversity of RV genotypes. RV species were detected in the following ratios: 60.9% RV-A 173, 12.7% RV-B, and 26.4% RV-C. No correlations between RV species and underlying comorbidities such as asthma (p = 0.167), COPD (p = 0.312) or immunosuppression (p = 0.824) were found. However, 21.1% of the patients had co-infections with other pathogens, which were associated with a longer hospital stay (p = 0.024), LRTI (p < 0.001), and pneumonia (p = 0.01). Taken together, this study shows a pronounced genetic diversity of RV in adults and underlines the important role of co-infections. No correlation of specific RV species with a particular clinical presentation could be deduced.

Epidemiology of the Rhinovirus (RV) in African and Southeast Asian Children: A Case-Control Pneumonia Etiology Study

Rhinovirus (RV) is commonly detected in asymptomatic children; hence, its pathogenicity during childhood pneumonia remains controversial. We evaluated RV epidemiology in HIV-uninfected children hospitalized with clinical pneumonia and among community controls. PERCH was a case-control study that enrolled children (1–59 months) hospitalized with severe and very severe pneumonia per World Health Organization clinical criteria and age-frequency-matched community controls in seven countries. Nasopharyngeal/oropharyngeal swabs were collected for all participants, combined, and tested for RV and 18 other respiratory viruses using the Fast Track multiplex real-time PCR assay. RV detection was more common among cases (24%) than controls (21%) (aOR = 1.5, 95%CI:1.3–1.6). This association was driven by the children aged 12–59 months, where 28% of cases vs. 18% of controls were RV-positive (aOR = 2.1, 95%CI:1.8–2.5). Wheezing was 1.8-fold (aOR 95%CI:1.4–2.2) more prevalent among pneumonia cases who were RV-positive vs. RV-negative. Of the RV-positive cases, 13% had a higher probability (>75%) that RV was the cause of their pneumonia based on the PERCH integrated etiology analysis; 99% of these cases occurred in children over 12 months in Bangladesh. RV was commonly identified in both cases and controls and was significantly associated with severe pneumonia status among children over 12 months of age, particularly those in Bangladesh. RV-positive pneumonia was associated with wheezing.

Remodeling of bronchial epithelium caused by asthmatic inflammation affects its response to rhinovirus infection

Human rhinoviruses (HRV) are frequent cause of asthma exacerbations, however the influence of airway inflammation on the severity of viral infection is poorly understood. Here, we investigated how cytokine-induced remodeling of airway epithelium modulates antiviral response. We analyzed gene expression response in in vitro differentiated bronchial epithelium exposed to cytokines and next infected with HRV16. IL-13-induced mucous cell metaplasia (MCM) was associated with impaired ciliogenesis and induction of antiviral genes, resulting in lower susceptibility to HRV. Epithelial-mesenchymal transition caused by TGF-β was associated with increased virus replication and boosted innate response. Moreover, HRV infection per se caused transient upregulation of MCM markers and growth factors, followed by low-level virus replication and shedding. Our data suggest that the outcome of HRV infection depends on the type of lower airway inflammation and the extent of epithelial damage. Type-2 inflammation (eosinophilic asthma) may induce antiviral state of epithelium and decrease virus sensitivity, while growth factor exposure during epithelial repair may facilitate virus replication and inflammatory response. Additionally, responses to HRV were similar in cells obtained from asthma patients and control subjects, which implicates that antiviral mechanisms are not intrinsically impaired in asthma, but may develop in the presence of uncontrolled airway inflammation.

Fever without source as the first manifestation of SARS-CoV-2 infection in infants less than 90 days old

Fever without source (FWS) in infants is a frequent cause of consultation at the emergency department, and the emergence of SARS-CoV-2 could affect the approach to those infants. The aim of this study is to define the clinical characteristics and rates of bacterial coinfections of infants < 90 days with FWS as the first manifestation of SARS-CoV-2 infection. This is a cross-sectional study of infants under 90 days of age with FWS and positive SARS-CoV2 PCR in nasopharyngeal swab/aspirate, attended at the emergency departments of 49 Spanish hospitals (EPICO-AEP cohort) from March 1 to June 26, 2020. Three hundred and thirty-three children with COVID-19 were included in EPICO-AEP. A total of 67/336 (20%) were infants less than 90 days old, and 27/67(40%) presented with FWS. Blood cultures were performed in 24/27(89%) and were negative in all but one (4%) who presented a Streptococcus mitis bacteremia. Urine culture was performed in 26/27(97%) children and was negative in all, except in two (7%) patients. Lumbar puncture was performed in 6/27(22%) cases, with no growth of bacteria. Two children had bacterial coinfections: 1 had UTI and bacteremia, and 1 had UTI. C-reactive was protein over 20 mg/L in two children (one with bacterial coinfection), and procalcitonin was normal in all. One child was admitted to the pediatric intensive care unit because of apnea episodes. No patients died.Conclusion: FWS was frequent in infants under 90 days of age with SARS-CoV-2 infection. Standardized markers to rule out bacterial infections remain useful in this population, and the outcome is generally good. What is Known: • Fever without source (FWS) in infants is a common cause of consultation at the emergency department, and young infants have a higher risk of serious bacterial infections (SBI). • The emergence of the new coronavirus SARS-CoV-2 could affect the approach to young infants with FWS in the emergency department. management of those children is a challenge because information about bacterial coinfection and prognosis is scarce. What is New: • SARS-CoV-2 infection should be ruled out in young infants (< 90 days of age) with FWS in areas with community transmission. • Bacterial coinfection rarely coexists in those infants. • Inflammatory markers were not increased in children without bacterial coinfection. • Outcome is good in most patients.

Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack

Exacerbations are a main characteristic of asthma. In childhood, the risk is increasing with severity. Exacerbations are a strong phenotypic marker, particularly of severe and therapy-resistant asthma. These early-life events may influence the evolution and be involved in lung function decline. In children, asthma attacks are facilitated by exposure to allergens and pollutants, but are mainly triggered by microbial agents. Multiple studies have assessed immune responses to viruses, and to a lesser extend bacteria, during asthma exacerbation. Research has identified impairment of innate immune responses in children, related to altered pathogen recognition, interferon release, or anti-viral response. Influence of this host-microbiota dialog on the adaptive immune response may be crucial, leading to the development of biased T helper (Th)2 inflammation. These dynamic interactions may impact the presentations of asthma attacks, and have long-term consequences. The aim of this review is to synthesize studies exploring immune mechanisms impairment against viruses and bacteria promoting asthma attacks in children. The potential influence of the nature of infectious agents and/or preexisting microbiota on the development of exacerbation is also addressed. We then discuss our understanding of how these diverse host-microbiota interactions in children may account for the heterogeneity of endotypes and clinical presentations. Finally, improving the knowledge of the pathophysiological processes induced by infections has led to offer new opportunities for the development of preventive or curative therapeutics for acute asthma. A better definition of asthma endotypes associated with precision medicine might lead to substantial progress in the management of severe childhood asthma.

Frequency of asymptomatic and symptomatic respiratory virus detection in pediatric hematopoietic cell transplant patients

Respiratory viral infections are common and can cause significant morbidity and mortality in pediatric patients undergoing hematopoietic cell transplantation (HCT). The prevalence of disease has been primarily identified from retrospective studies using standard-of-care specimens. The incidence of both asymptomatic respiratory viral detection and symptomatic respiratory viral detection in this high-risk population is not well described. We performed longitudinal, active, prospective surveillance in pediatric HCT patients. Subjects underwent weekly midturbinate swabs (MTSs) for the detection of 18 respiratory viruses and subtypes peri-HCT and 100 days post-HCT. Clinical data were obtained from the medical record. From September 2015 to February 2017, 24 children underwent 29 HCT, and 284 MTSs were collected. Forty-two (15%) specimens were virus-positive from 10 (42%) subjects. Specimens from children undergoing allogeneic HCT were more likely to have a virus detected (17% vs 8%, P = .04) compared with specimens from children undergoing autologous HCT. Sixteen (38%) detections were not associated with symptoms. Almost half (8/17) of the unique viral infections occurred during the HCT hospitalization after a negative specimen, suggesting nosocomial acquisition, and preceded detection from a clinical specimen. Rhinovirus, the most common virus detected, was the only virus detected in 33 (81%) virus-positive specimens; only 11 (33%) rhinovirus detections were asymptomatic. Asymptomatic detection of coronavirus and bocavirus occurred. Asymptomatic respiratory virus detection occurred in more than one-third of the children undergoing HCT. The acquisition of respiratory viruses during HCT hospitalization suggests nosocomial acquisition. Early detection of respiratory viruses during asymptomatic periods could have infection prevention and treatment implications.

Molecular Epidemiology of Human Rhinovirus From 1-Year Surveillance Within a School Setting in Rural Coastal Kenya

Background

Human rhinovirus (HRV) is the most common cause of the common cold but may also lead to more severe respiratory illness in vulnerable populations. The epidemiology and genetic diversity of HRV within a school setting have not been previously described. The objective of this study was to characterize HRV molecular epidemiology in a primary school in a rural location of Kenya.

Methods

Between May 2017 and April 2018, over 3 school terms, we collected 1859 nasopharyngeal swabs (NPS) from pupils and teachers with symptoms of acute respiratory infection in a public primary school in Kilifi County, coastal Kenya. The samples were tested for HRV using real-time reverse transcription polymerase chain reaction. HRV-positive samples were sequenced in the VP4/VP2 coding region for species and genotype classification.

Results

A total of 307 NPS (16.4%) from 164 individuals were HRV positive, and 253 (82.4%) were successfully sequenced. The proportion of HRV in the lower primary classes was higher (19.8%) than upper primary classes (12.2%; P < .001). HRV-A was the most common species (134/253; 53.0%), followed by HRV-C (73/253; 28.9%) and HRV-B (46/253; 18.2%). Phylogenetic analysis identified 47 HRV genotypes. The most common genotypes were A2 and B70. Numerous (up to 22 in 1 school term) genotypes circulated simultaneously, there was no individual re-infection with the same genotype, and no genotype was detected in all 3 school terms.

Conclusions

HRV was frequently detected among school-going children with mild acute respiratory illness symptoms, particularly in the younger age groups (<5-year-olds). Multiple HRV introductions were observed that were characterized by considerable genotype diversity.

Increased Respiratory Viral Detection and Symptom Burden Among Patients with Primary Antibody Deficiency: Results from the BIPAD Study

BACKGROUND

Patients with primary antibody deficiency (PAD) are at increased risk of respiratory tract infections, but our understanding of their nature and consequences remains limited.

OBJECTIVE

To define the symptomatic and microbial burden of upper airway infection in adults with PAD relative to age-matched controls.

METHODS

Prospective 12-month observational study consisting of a daily upper and lower airway symptom score alongside fortnightly nasal swab with molecular detection of 19 pathogen targets.

RESULTS

A total of 44 patients and 42 controls (including 34 household pairs) were recruited, providing more than 22,500 days of symptom scores and 1,496 nasal swabs. Swab and questionnaire compliance exceeded 70%. At enrollment, 64% of patients received prophylactic antibiotics, with a 34% prevalence of bronchiectasis. On average, patients with PAD experienced symptomatic respiratory exacerbations every 6 days compared with 6 weeks for controls, associated with significant impairment of respiratory-specific quality-of-life scores. Viral detections were associated with worsening of symptom scores from a participant's baseline. Patients with PAD had increased odds ratio (OR) for pathogen detection, particularly viral (OR, 2.73; 95% CI, 2.09-3.57), specifically human rhinovirus (OR, 3.60; 95% CI, 2.53-5.13) and parainfluenza (OR, 3.06; 95% CI, 1.25-7.50). Haemophilus influenzae and Streptococcus pneumoniae were also more frequent in PAD. Young child exposure, IgM deficiency, and presence of bronchiectasis were independent risk factors for viral detection. Prophylactic antibiotic use was associated with a lower risk of bacterial detection by PCR.

CONCLUSIONS

Patients with PAD have a significant respiratory symptom burden associated with increased viral infection frequency despite immunoglobulin replacement and prophylactic antibiotic use. This highlights a clear need for future therapeutic trials in the population with PAD, and informs future study design.

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.

Association of Cough Status With Bacterial Infections in Febrile Infants

OBJECTIVES

To examine the association between cough status and bacterial infections (BIs) to more accurately stratify risk and predict BIs in febrile infants.

METHODS

A retrospective cohort study was performed by identifying all infants ≤60 days old with temperature ≥38°C at an urban pediatric emergency department from 2014 to 2016. The Rochester Risk model was used to stratify risk. Cough status (with or without) was the main covariate of interest. The primary outcome was a BI, including urinary tract infection, bacteremia, or meningitis. Analyses consisted of descriptive statistics, simple and multiple regression to compare the odds of BI on the basis of cough status, as well as χ² statistics to compare the BI rates among high-risk infants with and without cough.

RESULTS

Of 508 febrile infants ≤60 days old, 46 (9.1%) had a BI, 13 of which were either bacteremia or meningitis. There were no BIs among low-risk infants with a cough. The odds of BI increased progressively, peaking at 14.6 (95% confidence interval: 4.3-49.7) for high-risk infants without a cough. The adjusted odds of BI among infants with cough was 0.47 (95% confidence interval: 0.22-0.99).

CONCLUSIONS

In our findings, an inverse relationship is demonstrated between presence of cough and odds of BI, suggesting that cough status may be a useful marker of viral infections in febrile infants. Considering that detecting cough status is noninvasive, inexpensive, and immediately available, it represents an attractive value-based risk factor to enhance current BI prediction models.

Association between multiple respiratory viral infections and pediatric intensive care unit admission among infants with bronchiolitis

Background

It is unclear whether multiple respiratory viral infections are associated with more severe bronchiolitis requiring pediatric intensive care unit (PICU) admission. We aimed to identify the association between multiple respiratory viral infections and PICU admission among infants with bronchiolitis.

Methods

We performed a 1:1 case-control study enrolling previously healthy full-term infants (≤12 months) with bronchiolitis admitted to the PICU as cases and those to the general pediatric ward as controls from 2015 to 2017. Multiplex polymerase chain reaction (PCR) was used for detection of the respiratory viruses. We summarized the characteristics of infants admitted to the PICU and the general pediatric unit. Multivariable logistic regression analysis was used to fit the association between multiple respiratory viral infections (≥2 strains) and PICU admission.

Results

A total of 135 infants admitted to the PICU were compared with 135 randomly selected control infants admitted to the general pediatric unit. The PICU patients were younger (median: 2.2 months, interquartile range: 1.3–4.2) than the general ward patients (median: 3.2 months, interquartile range: 1.6–6.4). Respiratory syncytial virus (74.1%), rhinovirus (28.9%), and coronavirus (5.9%) were the most common viruses for bronchiolitis requiring PICU admission. Patients with bronchiolitis admitted to the PICU tended to have multiple viral infections compared with patients on the general ward (23.0% vs. 10.4%, P < 0.001). In the multivariable logistic regression analysis, bronchiolitis with multiple viral infections was associated with higher odds of PICU admission (adjusted odds ratio: 2.56, 95% confidence interval: 1.17–5.57, P = 0.02).

Conclusion

Infants with multiviral bronchiolitis have higher odds of PICU admission compared with those with a single or nondetectable viral infection.

Multiplex Platforms for the Identification of Respiratory Pathogens: Are They Useful in Pediatric Clinical Practice?

Respiratory tract infections (RTIs) are extremely common especially in the first year of life. Knowledge of the etiology of a RTI is essential to facilitate the appropriate management and the implementation of the most effective control measures. This perspective explains why laboratory methods that can identify pathogens in respiratory secretions have been developed over the course of many years. High-complexity multiplex panel assays that can simultaneously detect up to 20 viruses and up to four bacteria within a few hours have been marketed. However, are these platforms actually useful in pediatric clinical practice? In this manuscript, we showed that these platforms appear to be particularly important for epidemiological studies and clinical research. On the contrary, their routine use in pediatric clinical practice remains debatable. They can be used only in the hospital as they require specific equipment and laboratory technicians with considerable knowledge, training, and experience. Moreover, despite more sensitive and specific than other tests routinely used for respiratory pathogen identification, they do not offer significantly advantage for detection of the true etiology of a respiratory disease. Furthermore, knowledge of which virus is the cause of a respiratory disease is not useful from a therapeutic point of view unless influenza virus or respiratory syncytial virus are the infecting agents as effective drugs are available only for these pathogens. On the other hand, multiplex platforms can be justified in the presence of severe clinical manifestations, and in immunocompromised patients for whom specific treatment option can be available, particularly when they can be used simultaneously with platforms that allow identification of antimicrobial resistance to commonly used drugs. It is highly likely that these platforms, particularly those with high sensitivity and specificity and with low turnaround time, will become essential when new drugs effective and safe against most of the respiratory viruses will be available. Further studies on how to differentiate carriers from patients with true disease, as well as studies on the implications of coinfections and identification of antimicrobial resistance, are warranted.

Introducing a New Algorithm for Classification of Etiology in Studies on Pediatric Pneumonia: Protocol for the Trial of Respiratory Infections in Children for Enhanced Diagnostics Study

Background

There is a need to better distinguish viral infections from antibiotic-requiring bacterial infections in children presenting with clinical community-acquired pneumonia (CAP) to assist health care workers in decision making and to improve the rational use of antibiotics.

Objective

The overall aim of the Trial of Respiratory infections in children for ENhanced Diagnostics (TREND) study is to improve the differential diagnosis of bacterial and viral etiologies in children aged below 5 years with clinical CAP, by evaluating myxovirus resistance protein A (MxA) as a biomarker for viral CAP and by evaluating an existing (multianalyte point-of-care antigen detection test system [mariPOC respi] ArcDia International Oy Ltd.) and a potential future point-of-care test for respiratory pathogens.

Methods

Children aged 1 to 59 months with clinical CAP as well as healthy, hospital-based, asymptomatic controls will be included at a pediatric emergency hospital in Stockholm, Sweden. Blood (analyzed for MxA and C-reactive protein) and nasopharyngeal samples (analyzed with real-time polymerase chain reaction as the gold standard and antigen-based mariPOC respi test as well as saved for future analyses of a novel recombinase polymerase amplification–based point-of-care test for respiratory pathogens) will be collected. A newly developed algorithm for the classification of CAP etiology will be used as the reference standard.

Results

A pilot study was performed from June to August 2017. The enrollment of study subjects started in November 2017. Results are expected by the end of 2019.

Conclusions

The findings from the TREND study can be an important step to improve the management of children with clinical CAP.

International Registered Report Identifier (IRRID)

DERR1-10.2196/12705

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.

Approach to Neonates and Young Infants with Fever without a Source Who Are at Risk for Severe Bacterial Infection

INTRODUCTION

Among neonates and infants <3 months of age with fever without a source (FWS), 5% to 15% of cases are patients with fever caused by a serious bacterial infection (SBI). To favour the differentiation between low- and high-risk infants, several algorithms based on analytical and clinical parameters have been developed. The aim of this review is to describe the management of young infants with FWS and to discuss the impact of recent knowledge regarding FWS management on clinical practice.

MATERIALS AND METHODS

PubMed was used to search for all of the studies published over the last 35 years using the keywords: "fever without source" or "fever of unknown origin" or "meningitis" or "sepsis" or "urinary tract infection" and "neonate" or "newborn" or "infant <90 days of life" or "infant <3 months".

RESULTS AND DISCUSSION

The selection of neonates and young infants who are <3 months old with FWS who are at risk for SBI remains a problem without a definitive solution. The old Rochester criteria remain effective for identifying young infants between 29 and 60 days old who do not have severe bacterial infections (SBIs). However, the addition of laboratory tests such as C-reactive protein (CRP) and procalcitonin (PCT) can significantly improve the identification of children with SBI. The approach in evaluating neonates is significantly more complicated, as their risk of SBIs, including bacteremia and meningitis, remains relevant and none of the suggested approaches can reduce the risk of dramatic mistakes. In both groups, the best antibiotic must be carefully selected considering the clinical findings, the laboratory data, the changing epidemiology, and increasing antibiotic resistance of the most common infectious bacteria.

Transmission of rhinovirus in the Utah BIG-LoVE families: Consequences of age and household structure

BACKGROUND

Common cold viruses create significant health and financial burdens, and understanding key loci of transmission would help focus control strategies. This study (1) examines factors that influence when individuals transition from a negative to positive test (acquisition) or a positive to negative test (loss) of rhinovirus (HRV) and other respiratory tract viruses in 26 households followed weekly for one year, (2) investigates evidence for intrahousehold and interhousehold transmission and the characteristics of individuals implicated in transmission, and (3) builds data-based simulation models to identify factors that most strongly affect patterns of prevalence.

METHODS

We detected HRV, coronavirus, paramyxovirus, influenza and bocavirus with the FilmArray polymerase chain reaction (PCR) platform (BioFire Diagnostics, LLC). We used logistic regression to find covariates affecting acquisition or loss of HRV including demographic characteristics of individuals, their household, their current infection status, and prevalence within their household and across the population. We apply generalized linear mixed models to test robustness of results.

RESULTS

Acquisition of HRV was less probable in older individuals and those infected with a coronavirus, and higher with a higher proportion of other household members infected. Loss of HRV is reduced with a higher proportion of other household members infected. Within households, only children and symptomatic individuals show evidence for transmission, while between households only a higher number of infected older children (ages 5-19) increases the probability of acquisition. Coronaviruses, paramyxoviruses and bocavirus also show evidence of intrahousehold transmission. Simulations show that age-dependent susceptibility and transmission have the largest effects on mean HRV prevalence.

CONCLUSIONS

Children are most likely to acquire and most likely to transmit HRV both within and between households, with infectiousness concentrated in symptomatic children. Simulations predict that the spread of HRV and other respiratory tract viruses can be reduced but not eliminated by practices within the home.

Pathogen Clearance and New Respiratory Tract Infections Among Febrile Children in Zanzibar Investigated With Multitargeting Real-Time Polymerase Chain Reaction on Paired Nasopharyngeal Swab Samples

BACKGROUND

New molecular methods have revealed frequent and often polymicrobial respiratory infections in children in low-income settings. It is not known whether presence of multiple pathogens is due to prolonged infections or to frequent exposure. The aim of this study was to analyze short-term pathogen clearance from nasopharynx and the rate of new respiratory tract infections in febrile preschool children.

METHODS

Children (n = 207) with uncomplicated acute febrile illness 2-59 months of age presenting to a health center in Zanzibar, Tanzania, April-July 2011, were included. Paired nasopharyngeal swab samples, collected at enrolment and after 14 days, were analyzed by multiple real-time polymerase chain reaction for Adenovirus, bocavirus, Bordetella pertussis, Chlamydophila pneumoniae, Coronaviruses, Enterovirus, influenza A and B virus, metapneumovirus, measles virus, Mycoplasma pneumoniae, parainfluenza virus, Parechovirus, respiratory syncytial virus and Rhinovirus. An age-matched and geographically matched healthy control group (n = 166) underwent nasopharyngeal sampling on 1 occasion.

RESULTS

At baseline, 157/207 (76%) patients had at least 1 pathogen detected, in total 199 infections. At follow-up (day 14), 162/199 (81%) of these infections were not detected, including >95% of the previously detected infections with Enterovirus, influenza A virus, influenza B virus, metapneumovirus or parainfluenza virus. Still 115 (56%) children were positive for at least 1 pathogen at follow-up, of which 95/115 (83%) were not found at baseline. Detection of influenza B on day 14 was significantly associated with fever during follow-up.

CONCLUSION

The results suggest that children with acute febrile illness in Zanzibar rapidly clear respiratory tract infections but frequently acquire new infections within 14 days.

Review on Clinical and Molecular Epidemiology of Human Rhinovirus-Associated Lower Respiratory Tract Infections in African and Southeast Asian Children

BACKGROUND

The detection of human rhinoviruses (HRV) is highly prevalent in children with pneumonia, bronchiolitis, acute asthma and croup; however, there is also evidence that HRV is common in asymptomatic individuals. The majority of studies on the role of different HRV serotypes during acute respiratory tract infections episodes have limited sample size to fully characterize the epidemiology of HRV infection, including those from low-middle income countries, where the burden of childhood respiratory disease is greatest.

METHODS

We systematically reviewed HRV clinical and molecular epidemiology in low- and middle-income countries in Africa and Southeast Asia before November 2015.

RESULTS

We identified 31 studies, which included data from 13 African and 6 Southeast Asian countries, emphasizing the gaps in knowledge surrounding HRV infections. HRV was one of the most prevalent respiratory viruses detected during childhood respiratory disease (13%-59%); however, many studies could not determine the attributable role of HRV in the pathogenesis of acute respiratory infections due to high prevalence of detection among asymptomatic individuals (6%-50%). A meta-analysis showed no significant difference in the prevalence of HRV identification between children of different age groups; or between children with severe disease compared with asymptomatic children.

CONCLUSIONS

These data highlight the need for large-scale surveillance projects to determine the attributable etiologic role of HRV in respiratory disease.

Transmission of respiratory and gastrointestinal infections in German households with children attending child care

Transmission of acute respiratory infections (ARI) and acute gastroenteritis (AGE) often occurs in households. The aim of this study was to assess which proportion of ARI and AGE is introduced and transmitted by children in German households with children attending child care. We recruited families with children aged 0-6 years in Braunschweig (Germany), for a 4 months prospective cohort study in the winter period 2014/2015. Every household member was included in a health diary and used nasal swabs for pathogen identification in case of ARI. We defined a transmission if two persons had overlapping periods with symptoms and used additional definitions for sensitivity analyses. In total, 77 households participated with 282 persons. We observed 277 transmission events for ARI and 23 for AGE. In most cases, the first infected person in a household was a child (ARI: 63%, AGE: 53%), and the risk of within-household transmission was two times higher when the index case was a child. In 26 ARI-transmission events, pathogens were detected for both cases; hereof in 35% (95% confidence interval (17-56%)) the pathogens were different. Thus, symptomatic infections in household members, apparently linked in time, were in 2/3 associated with the same pathogens.

Detection of Respiratory Viruses from ARTI Patients by xTAG RVP Fast v2 Assay and Conventional Methods

Introduction

Acute respiratory tract infections (ARTIs) are a major cause of morbidity and mortality in paediatric patients. Therefore, early detection of the viral aetiologies of ARTIs is essential for patient management and infection control. In this study, we evaluated the performance of a new multiplex polymerase chain reaction (PCR) assay (xTAG Respiratory Viral Panel [RVP] Fast v2) in the detection of respiratory viruses by comparing it with that of viral culture and direct immunofluorescence (IF) staining.

Methods

Nasopharyngeal swab and aspirate samples were collected prospectively from 199 patients who presented with ARTIs at the University Malaya Medical Centre (UMMC) in Kuala Lumpur, Malaysia during a 10-month period. The PCR assay was conducted in parallel with conventional culture and direct IF staining methods.

Results

The positive rate of the xTAG RVP Fast v2 assay (78.4%) in detecting respiratory viruses was higher than that of the viral isolation (7.5%) and direct IF (23.1%) methods. Using the xTAG RVP Fast v2 assay, human enterovirus/human rhinovirus (HEV/HRV) was the most frequently detected (46.2%). The xTAG RVP Fast v2 assay revealed mixed infection caused by two or three respiratory viruses in 40 specimens, and these were undetected by the viral isolation and direct IF methods.

Conclusion

The xTAG RVP Fast v2 assay was superior to conventional methods in the identification of common respiratory viruses, with higher sensitivity and shorter turnaround times for laboratory results.

Rhinovirus in Febrile Infants and Risk of Bacterial Infection

BACKGROUND

Febrile infants with viral respiratory infections have a reduced risk of bacterial infection compared with virus-negative infants. The risk of concomitant bacterial infection in febrile infants positive for human rhinovirus (HRV) by polymerase chain reaction (PCR) is unknown.

METHODS

Infants 1-90 days old managed using the care process model for well-appearing febrile infants and with respiratory viral testing by PCR (RVPCR) in the emergency department or inpatient setting of 22 hospitals in the Intermountain Healthcare system from 2007-2016 were identified. Relative risk (RR) of bacterial infection was calculated for infants with HRV, non-HRV viruses, or no virus detected.

RESULTS

Of 10 964 febrile infants identified, 4037 (37%) had RVPCR. Of these, 2212 (55%) were positive for a respiratory virus; 1392 (35%) for HRV alone. Bacterial infection was identified in 9.5%. Febrile infants with HRV detected were more likely to have bacterial infection than those with non-HRV viruses (7.8% vs 3.7%; P < .001; RR 2.12 [95% CI 1.43-3.15]). Risk of urinary tract infection was not significantly different for HRV-positive infants at any age, nor was risk of invasive bacterial infection (IBI; bacteremia and/or meningitis) meaningfully different for infants 1-28 day olds. Infants 29-90 days old with HRV had a decreased likelihood of IBI (RR 0.52 [95% CI 0.34-0.80]).

CONCLUSIONS

HRV is common in febrile infants. Detection did not alter risk of concomitant urinary tract infection at any age or risk of IBI in infants 1-28 days old. HRV detection may be relevant in considering risk of IBI for infants 29-90 days of age.

Nosocomial Transmission and Genetic Diversity of Rhinovirus in a Neonatal Intensive Care Unit

Rhinoviruses were detected as sole pathogens in 6 preterm infants who developed severe respiratory infections while hospitalized in a neonatal intensive care unit. We confirmed 2 nosocomial rhinovirus transmission episodes and describe the genetic diversity of rhinovirus strains that circulated simultaneously during a winter season.

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.

Viral Etiology and the Impact of Codetection in Young Children Presenting With Influenza-Like Illness

BACKGROUND

Children with acute respiratory tract infection (ARTI) frequently exhibit virus-virus codetection, yet the clinical significance of ARTI remains contentious. Using data from a prospective cohort of children with influenza-like illness, we examined the virology of ARTI and determined the clinical impact of virus-virus codetection.

METHODS

Children aged 6 to 59 months who presented to a tertiary pediatric hospital between influenza seasons 2008 and 2012 with fever and acute respiratory symptoms were enrolled, and nasal samples were collected. Respiratory viruses were identified by culture and polymerase chain reaction. We compared demographics, presenting symptoms, and clinical outcomes of children with a single-virus infection and those in whom 2 or more viruses were detected (virus-virus codetection). We used logistic regression models and estimated marginal means to calculate the adjusted odds ratios and probabilities of symptom presentation, prescription of antibiotics, and hospitalization.

RESULTS

Of 2356 children, a virus was detected in 1630 (69.2%) of them; rhinovirus (40.8%), influenza (29.5%), and respiratory syncytial virus (26.4%) were detected most commonly. Two or more viruses were detected in 25% of these children. After we adjusted for demographic factors, children with virus-virus codetection had greater odds of presenting with cough (adjusted odds ratio [aOR], 1.9; 95% confidence interval [CI], 1.2-3.1) and rhinorrhea (aOR, 1.8; 95% CI, 1.1-2.9) than those with a single-virus infection, although both symptoms were common. Children with influenza and respiratory syncytial virus combined had the highest probability of hospitalization (55%; 95% CI, 35%-73%), which was significantly greater than for those with influenza infection alone (22%; 95% CI, 16%-29%).

CONCLUSIONS

Overall, virus-virus codetection has limited impact on clinical severity among children with influenza-like illness. However, infection with specific pathogen pairs might be associated with more severe outcomes. Routine diagnostics to identify specific viruses should be restricted to common pathogens.

Clinical and Virus Surveillance After the First Wheezing Episode: Special Reference to Rhinovirus A and C Species

BACKGROUND

Susceptibility to rhinovirus (RV)-induced early wheezing episode has been recognized as an important risk factor for asthma, but the data on different RV species are limited. Our aim was to investigate the risk for recurrences in first-time wheezing children with special focus on RV species.

METHODS

First-time wheezing children (88 inpatients and 23 outpatients) were prospectively followed at 2-week, 2-month and 12-month time-points, and at first recurrence within 12 months. The respiratory virus etiology was analyzed using polymerase chain reaction. RV-positive samples were sequenced. The primary outcomes were time to a new physician-confirmed wheezing episode, time to a new RV-induced wheezing episode and time to the initiation of regular controller medication for asthma symptoms.

RESULTS

The median age of the children was 12 months (standard deviation, 6.0), 67% were males and 23% were sensitized. RV dominated in symptomatic and asymptomatic infections. Different RV strains were observed in 97% (67/69) of consecutive samples during follow-up. First-time wheezing children with RV-C and RV-A had an increased risk for a new physician-confirmed wheezing episode and a new RV-associated wheezing episode than non-RV group (all P < 0.05). Also, the risk for the initiation of regular controller medication was increased in RV-A and RV-C groups when compared with non-RV group (both P < 0.05).

CONCLUSIONS

RV causes reinfections with different strains in small children after the first wheezing episode. Both RV-A and RV-C affected children have an increased risk for recurrence, especially RV associated, and initiation of regular controller medication than those with other viruses.

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.

Panel 4: Report of the Microbiology Panel

Objective To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources PubMed database of the National Library of Medicine. Review Methods Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.

Within host RNA virus persistence: mechanisms and consequences

In a prototypical response to an acute viral infection it would be expected that the adaptive immune response would eliminate all virally infected cells within a few weeks of infection. However many (non-retrovirus) RNA viruses can establish 'within host' persistent infections that occasionally lead to chronic or reactivated disease. Despite the importance of 'within host' persistent RNA virus infections, much has still to be learnt about the molecular mechanisms by which RNA viruses establish persistent infections, why innate and adaptive immune responses fail to rapidly clear these infections, and the epidemiological and potential disease consequences of such infections.

Facing the ongoing challenge of the febrile young infant

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

In Vivo Persistence of Human Rhinoviruses in Immunosuppressed Patients

Several species of the genus Enterovirus cause persistent infections in humans. Human rhinovirus (HRV) infections are generally self-limiting but occasionally persistent infections have been described. This study aimed to identify persistent HRV infections and investigate the clinical and virologic characteristics of patients with persistent infections. From January 2012 to March 2015, 3714 respiratory specimens from 2608 patients were tested for respiratory viruses by using a multiplex reverse transcription–polymerase chain reaction. A retrospective study was performed. Patients with at least two specimens positive for HRV/enterovirus taken 45 days or longer apart were identified and the HRV/enteroviruses were typed. Patients with persistent infection were compared to patients with reinfection and patients with cleared infection. Phylogenetic analysis of the viral protein(VP)4/VP2 region was performed. 18 patients with persistent HRV/enterovirus infection were identified. Minimum median duration of persistence was 92 days (range 50–455 days). All but one patients with persistence were immunosuppressed. Immunosuppression and hematologic disorders were more frequent in patients with persistence (n = 18) than in patients with reinfection (n = 33) and with cleared infection (n = 25) (p = 0.003 and p = 0.001, respectively). In conclusion, this retrospective study identified HRV persistence in vivo which occurred mainly in immunosuppressed patients.

Epidemiologic Analysis of Respiratory Viral Infections Mainly in Hospitalized Children and Adults in a Midwest University Medical Center After the Implementation of a 14-Virus Multiplex Nucleic Acid Amplification Test

OBJECTIVES

To investigate the etiology of viral respiratory tract infections mainly in hospitalized children and adults over a 12-month consecutive period after implementation of a 14-virus multiplex nucleic acid amplification test.

METHODS

From January 2014 to January 2015, a total of 2,237 respiratory samples were analyzed with the US Food and Drug Administration-cleared eSensor Respiratory Viral Panel (GenMark Diagnostics, Carlsbad, CA).

RESULTS

Of the 2,237 specimens tested, 788 specimens were positive for at least one virus, giving a positivity rate of 35.2%, and because of viral codetection, a total of 862 viral targets were identified. The age groups with the highest positivity rates were the 0- to 1-year (73.5%) and 2- to 6-year (78.4%) age groups. The overall viral codetection rate was 9.1%. Human rhinovirus (HRV) was the most prevalent respiratory virus found in children and adults. The peak of HRV seen in September 2014 represented a combination of HRV and enterovirus D68, 2014 epidemic respiratory infections.

CONCLUSION

The ability to detect a wider range of respiratory viruses gave us a better understanding of the etiology of respiratory infections in our population, particularly for HRV and enhanced our ability to detect viral coinfection.

Respiratory Viruses in Neonates: A Prospective, Community-based Birth Cohort Study

A community-based birth cohort study collected weekly nasal swabs and recorded daily symptoms from 157 full-term infants. An average of 0.25 (95% confidence interval: 0.18, 0.34) respiratory virus infections per neonatal period were detected. Human rhinoviruses of diverse subtypes dominated; almost 50% were asymptomatic and continued rhinovirus detections may signify new genotypes. Respiratory viruses are common and often unrecognized in healthy neonates.

[Respiratory viral infections in a cohort of children during the first year of life and their role in the development of wheezing]

Introducción

Las infecciones respiratorias virales que requieren hospitalización parecen conferir riesgo de desarrollar sibilancias recurrentes, pero existen pocos datos publicados en poblaciones no seleccionadas por tener factores de riesgo. Nuestro objetivo principal fue analizar si las infecciones respiratorias virales sintomáticas y asintomáticas, de diferente gravedad, durante el primer año de vida en una cohorte de recién nacidos, suponen un mayor riesgo de sibilancias recurrentes.

Pacientes y métodos

Se incluyeron 302 recién nacidos. Se recogió aspirado nasofaríngeo a los niños cuando presentaron una infección respiratoria y de forma periódica en los controles de salud (2, 4, 6 y 12 meses). Se estudiaron 16 virus respiratorios mediante reacción en cadena de polimerasa (PCR).

Resultados

Se analizaron 1.293 muestras (1.005 controles de salud y 288 infecciones respiratorias). El 30,8% de las muestras tomadas en los controles de salud fueron positivas, frente a un 77,8% en las infecciones respiratorias, p < 0,001 (OR: 3, IC 95%: 2,4-3,8). Un total de 239 (79%) lactantes tuvieron al menos una detección viral positiva durante el primer año de vida. El virus más frecuentemente identificado (71%) fue el rinovirus (RV). En 27 lactantes (11%) se detectaron sibilancias recurrentes durante su primer año de vida (2,9 DE: 1,2 episodios). El 58,3% de los lactantes cuya primera infección respiratoria requirió hospitalización desarrollaron sibilancias de repetición, frente al 8,6% de los niños cuya primera infección fue leve o asintomática, p < 0,001 (OR: 2,18; lC 95%: 1,05-4,5).

Conclusiones

En nuestra serie, las infecciones respiratorias virales graves en los primeros meses de vida supusieron un factor de riesgo para desarrollar sibilancias recurrentes. No ocurrió lo mismo con las infecciones respiratorias leves.

Maternal vitamin D supplementation during pregnancy and lactation to prevent acute respiratory infections in infancy in Dhaka, Bangladesh (MDARI trial): protocol for a prospective cohort study nested within a randomized controlled trial

Background

Early infancy is a high-risk period for severe acute respiratory infection (ARI), particularly in low-income countries with resource-limited health systems. Lower respiratory tract infection (LRTI) is commonly preceded by upper respiratory infection (URTI), and often caused by respiratory syncytial virus (RSV), influenza and other common community-acquired viral pathogens. Vitamin D status is a candidate modifiable early-life determinant of the host antiviral immune response and thus may influence the risk of ARI-associated morbidity in high-risk populations.

Methods/Design

In the Maternal Vitamin D for Infant Growth (MDIG) study in Dhaka, Bangladesh (NCT01924013), 1300 pregnant women are randomized to one of five groups: placebo, 4200 IU/week, 16,800 IU/week, or 28,000 IU/week from 2^nd trimester to delivery plus placebo from 0–6 months postpartum; or, 28,000 IU/week prenatal and until 6-months postpartum. In the Maternal Vitamin D for ARI in Infancy (MDARI) sub-study nested within the MDIG trial, trained personnel conduct weekly postnatal home visits to inquire about ARI symptoms and conduct a standardized clinical assessment. Supplementary home visits between surveillance visits are conducted when caregivers make phone notifications of new infant symptoms. Mid-turbinate nasal swab samples are obtained from infants who meet standardized clinical ARI criteria. Specimens are tested by polymerase chain reaction (PCR) for 8 viruses (influenza A/B, parainfluenza 1/2/3, RSV, adenovirus, and human metapneumovirus), and nasal carriage density of Streptococcus pneumoniae. The primary outcome is the incidence rate of microbiologically-positive viral ARI, using incidence rate ratios to estimate between-group differences. We hypothesize that among infants 0–6 months of age, the incidence of microbiologically-confirmed viral ARI will be significantly lower in infants whose mothers received high-dose prenatal/postpartum vitamin D supplements versus placebo. Secondary outcomes include incidence of ARI associated with specific pathogens (influenza A or B, RSV), clinical ARI, and density of pneumococcal carriage.

Discussion

If shown to reduce the risk of viral ARI in infancy, integration of maternal prenatal/postpartum vitamin D supplementation into antenatal care programs in South Asia may be a feasible primary preventive strategy to reduce the burden of ARI-associated morbidity and mortality in young infants.

Trial registration

NCT02388516, registered March 9, 2015.

Rhinovirus Infections and Associated Respiratory Morbidity in Infants: A Prospective Cohort Study

BACKGROUND

Risk factors promoting rhinovirus (RV) infections are inadequately described in healthy populations, especially infants.

OBJECTIVES

To determine the frequency of symptomatic and asymptomatic RV infections and identify possible risk factors from host and environment among otherwise healthy infants.

METHODS

In a prospective birth cohort, respiratory health was assessed in 41 term-born infants by weekly telephonic interviews during the first year of life, and weekly nasal swabs were collected to determine RV prevalence. In a multilevel logistic regression model, associations between prevalence and respiratory symptoms during RV infections and host/environmental factors were determined.

RESULTS

Twenty-seven percent of nasal swabs in 41 infants tested positive for RVs. Risk factors for RV prevalence were autumn months [odds ratio (OR) = 1.71, P = 0.01, 95% confidence interval (CI): 1.13-2.61], outdoor temperatures between 5 and 10°C (OR = 2.33, P = 0.001, 95% CI: 1.41-3.86), older siblings (OR = 2.60, P = 0.001, 95% CI: 1.50-4.51) and childcare attendance (OR = 1.53, P = 0.07, 95% CI: 0.96-2.44). Fifty-one percent of RV-positive samples were asymptomatic. Respiratory symptoms during RV infections were less likely during the first 3 months of life (OR = 0.34, P = 0.003, 95% CI: 0.17-0.69) and in infants with atopic mothers (OR = 0.44, P = 0.008, 95% CI: 0.24-0.80). Increased tidal volume (OR = 1.67, P = 0.03, 95% CI: 1.04-2.68) and outdoor temperatures between 2 and 5°C (OR = 2.79, P = 0.02, 95% CI: 1.17-6.61) were associated with more symptoms.

CONCLUSIONS

RVs are highly prevalent during the first year of life, and most infections are asymptomatic. Frequency of RV infections is associated with environmental factors, while respiratory symptoms during RV infections are linked to host determinants like infant age, maternal atopy or premorbid lung function.

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.

Frequent Respiratory Viral Infections in Children with Febrile Neutropenia - A Prospective Follow-Up Study

OBJECTIVE

Febrile neutropenia is common in children undergoing chemotherapy for the treatment of malignancies. In the majority of cases, the cause of the fever is unknown. Although respiratory viruses are commonly associated with this condition, the etiologic significance of this finding remains unclear and is therefore the subject of this study.

STUDY DESIGN

Nasopharyngeal aspirates were collected during 87 episodes of febrile neutropenia in children age 0-18 years, being treated at a children's oncology unit between January 2013 and June 2014. Real-time polymerase chain reaction was used to determine the presence of 16 respiratory viruses. Follow-up samples were collected from children who tested positive for one or more respiratory viruses. Rhinoviruses were genotyped by VP4/VP2 sequencing. Fisher's exact test and Mann-Whitney U test were used for group comparisons.

RESULTS

At least one respiratory virus was detected in samples from 39 of 87 episodes of febrile neutropenia (45%), with rhinoviruses the most frequently detected. Follow-up samples were collected after a median of 28 days (range, 9-74 days) in 32 of the 39 virus-positive episodes. The respiratory viral infection had resolved in 25 episodes (78%). The same virus was detected at follow-up in one coronavirus and six rhinovirus episodes. Genotyping revealed a different rhinovirus species in two of the six rhinovirus infections.

CONCLUSION

The frequency of respiratory viral infections in this group of patients suggests an etiologic role in febrile neutropenia. However, these findings must be confirmed in larger patient cohorts.