Viral Lower Respiratory Infections Research Articles

The burden of non-SARS-CoV2 viral lower respiratory tract infections in hospitalized children in Barcelona (Spain): A long-term, clinical, epidemiologic and economic study.

Viral lower respiratory tract infections (LRTI) are the leading cause of hospitalization in children. In Catalonia (Spain), information is scarce about the burden of viral LRTIs in paediatric hospitalizations. The aim of this study is to describe epidemiological, clinical, virological and economic features of paediatric hospitalizations due to viral LRTI. From October 2012 to December 2020, children aged <16 years admitted to a tertiary paediatric hospital in Catalonia (Spain) with confirmed viral LRTI were included in the study. Virus seasonality, prevalence, age and sex distribution, clinical characteristics, hospital costs and bed occupancy rates were determined. A total of 3,325 children were included (57.17% male, 9.44% with comorbidities) accounting for 4056 hospitalizations (32.47% ≤ 12 months): 53.87% with wheezing/asthma, 37.85% with bronchiolitis and 8.28% with pneumonia. The most common virus was respiratory syncytial virus (RSV) (52.59%). Influenza A was associated with pneumonia (odds ratio [OR] 7.75) and caused longer hospitalizations (7 ± 31.58 days), while RSV was associated with bronchiolitis (OR 6.62) and was the most frequent reason for admission to the paediatric intensive care unit (PICU) (11.23%) and for respiratory support (78.76%). Male sex, age ≤12 months, chronic conditions and bronchiolitis significantly increased the odds of PICU admission. From October to May, viral LRTIs accounted for 12.36% of overall hospital bed days. The total hospitalization cost during the study period was €16,603,415. Viral LRTIs are an important cause of morbidity, hospitalization and PICU admission in children. The clinical burden is associated with significant bed occupancy and health-care costs, especially during seasonal periods.

2190. Characterization of Inhaled Nitric Oxide (iNO) for the treatment of Viral Community Acquired Pneumonia (CAP)

Abstract Background Nitric Oxide (NO) has been previously demonstrated to have antimicrobial, anti-inflammatory, and vasodilator properties. Extensive work has been done in the clinical setting to explore these properties with iNO administered intermittently at high concentrations of 150-250 ppm. While viral CAP has gained major attention with the emergence of COVID-19, treatment methods remain limited and are challenging to develop. The purpose of this study is to assess iNO treatment administered to hospitalized adults with viral CAP. Methods This is a randomized, open label multi-center ongoing study. Study population includes subjects aged 18-80, hospitalized for vCAP including COVID-19. Following enrollment, subjects were randomized 1:1 to either iNO [150ppm for 40 minutes, 4 times daily, up to 7 days in addition to standard supportive treatment (SST)], or control [SST alone]. iNO was delivered by LungFitTM, an innovative NO generator under development (Beyond Air, NY, USA). Follow up period is 180 days. Study endpoints include safety and the time to reach a stable saturation of ≥93%. In addition, different other clinical parameters are collected to profile the effect of iNO in this population. Results Analyzing the Intent To Treat (ITT) population (n=35, [16 iNO and 19 control]), safety profile of iNO treatment observed so far, was found to be favorable with no treatment related Adverse Events (AEs). Faster clinical improvement was noted in the iNO treatment group, paralleling CRP improvement between baseline to end of treatment (mean 2.7 mg/dl comparing treatment group [n=8] to control group [n=7], data not final). Conclusion These data suggest that intermittent treatment with 150ppm iNO is safe and well tolerated and may contribute to faster clinical improvement in viral CAP. Different laboratory parameters may shed some light and help to characterize this observed effect, supporting the further exploration of iNO for the treatment of viral lower respiratory tract infection, including COVID-19. Preliminary findings were presented at ECCMID 2022 Disclosures Asher Tal, MD, Beyond Air Inc: Advisor/Consultant|Beyond Air Inc: Stocks/Bonds Talya Wolak, MD, talya wolak: Advisor/Consultant Dror Dicker, MD, AstraZenca: Advisor/Consultant|AstraZenca: Honoraria|Beyond Air: Grant/Research Support|Boehringer Ingelheim: Advisor/Consultant|Boehringer Ingelheim: Honoraria|Eli Lilly: Grant/Research Support|Novo Nordisk: Advisor/Consultant|Novo Nordisk: Grant/Research Support|Novo Nordisk: Honoraria.

Long-Term Pulmonary Dysfunction by Hyperoxia Exposure during Severe Viral Lower Respiratory Tract Infection in Mice.

Viral-induced lower respiratory tract infection (LRTI), mainly by respiratory syncytial virus (RSV), causes a major health burden among young children and has been associated with long-term respiratory dysfunction. Children with severe viral LRTI are frequently treated with oxygen therapy, hypothetically posing an additional risk factor for pulmonary sequelae. The main goal of this study was to determine the effect of concurrent hyperoxia exposure during the acute phase of viral LRTI on long-term pulmonary outcome. As an experimental model for severe RSV LRTI in infants, C57Bl/6J mice received an intranasal inoculation with the pneumonia virus of mice J3666 strain at post-natal day 7, and were subsequently exposed to hyperoxia (85% O2) or normoxia (21% O2) from post-natal day 10 to 17 during the acute phase of disease. Long-term outcomes, including lung function and structural development, were assessed 3 weeks post-inoculation at post-natal day 28. Compared to normoxic conditions, hyperoxia exposure in PVM-inoculated mice induced a transient growth arrest without subsequent catchup growth, as well as a long-term increase in airway resistance. This hyperoxia-induced pulmonary dysfunction was not associated with developmental changes to the airway or lung structure. These findings suggest that hyperoxia exposure during viral LRTI at young age may aggravate subsequent long-term pulmonary sequelae. Further research is needed to investigate the specific mechanisms underlying this alteration to pulmonary function.

Identifying the research, advocacy, policy and implementation needs for the prevention and management of respiratory syncytial virus lower respiratory tract infection in low- and middle-income countries.

The high burden of respiratory syncytial virus (RSV) infection in young children disproportionately occurs in low- and middle-income countries (LMICs). The PROUD (Preventing RespiratOry syncytial virUs in unDerdeveloped countries) Taskforce of 24 RSV worldwide experts assessed key needs for RSV prevention in LMICs, including vaccine and newer preventive measures. A global, survey-based study was undertaken in 2021. An online questionnaire was developed following three meetings of the Taskforce panellists wherein factors related to RSV infection, its prevention and management were identified using iterative questioning. Each factor was scored, by non-panellists interested in RSV, on a scale of zero (very-low-relevance) to 100 (very-high-relevance) within two scenarios: (1) Current and (2) Future expectations for RSV management. Ninety questionnaires were completed: 70 by respondents (71.4% physicians; 27.1% researchers/scientists) from 16 LMICs and 20 from nine high-income (HI) countries (90.0% physicians; 5.0% researchers/scientists), as a reference group. Within LMICs, RSV awareness was perceived to be low, and management was not prioritised. Of the 100 factors scored, those related to improved diagnosis particularly access to affordable point-of-care diagnostics, disease burden data generation, clinical and general education, prompt access to new interventions, and engagement with policymakers/payers were identified of paramount importance. There was a strong need for clinical education and local data generation in the lowest economies, whereas upper-middle income countries were more closely aligned with HI countries in terms of current RSV service provision. Seven key actions for improving RSV prevention and management in LMICs are proposed.

Neighborhood environmental factors linked to hospitalizations of older people for viral lower respiratory tract infections in Spain: a case-crossover study

BackgroundLower respiratory tract viral infection (LRTI) is a significant cause of morbidity-mortality in older people worldwide. We analyzed the association between short-term exposure to environmental factors (climatic factors and outdoor air pollution) and hospital admissions with a viral LRTI diagnosis in older adults.MethodsWe conducted a bidirectional case-crossover study in 6367 patients over 65 years of age with viral LRTI and residential zip code in the Spanish Minimum Basic Data Set. Spain’s State Meteorological Agency was the source of environmental data. Associations were assessed using conditional logistic regression. P-values were corrected for false discovery rate (q-values).ResultsAlmost all were hospital emergency admissions (98.13%), 18.64% were admitted to the intensive care unit (ICU), and 7.44% died. The most frequent clinical discharge diagnosis was influenza (90.25%). LRTI hospital admissions were more frequent when there were lower values of temperature and O3 and higher values of relative humidity and NO2. The regression analysis adjusted by temperatures and relative humidity showed higher concentrations at the hospital admission for NO2 [compared to the lag time of 1-week (q-value< 0.001) and 2-weeks (q-value< 0.001)] and O3 [compared to the lag time of 3-days (q-value< 0.001), 1-week (q-value< 0.001), and 2-weeks (q-value< 0.001)] were related to a higher odds of hospital admissions due to viral LRTI. Moreover, higher concentrations of PM10 at the lag time of 1-week (q-value = 0.023) and 2-weeks (q-value = 0.002), and CO at the lag time of 3-days (q-value = 0.023), 1-week (q-value< 0.001) and 2-weeks (q-value< 0.001)], compared to the day of hospitalization, were related to a higher chances of hospital admissions with viral LRTI.ConclusionUnfavorable environmental factors (low temperatures, high relative humidity, and high concentrations of NO2, O3, PM10, and CO) increased the odds of hospital admissions with viral LRTI among older people, indicating they are potentially vulnerable to these environmental factors.Graphical

A Comparative Analysis of the Occurrence of Lower Respiratory Tract Infections Caused by Respiratory Syncytial Virus among Newborns in the Years before and during Covid-19 Pandemic at a Tertiary Referral Hospital in Slovenia

Objective − In this study we aimed to compare the occurrence of lower respiratory tract infections caused by respiratory syncytial virus in the neonatal population in the years before and during the COVID-19 pandemic.Methods − Cases of newborns, hospitalized due to viral lower respiratory tract infection from 2015 to 2020, were analyzed retrospectively, and compared according to cause (respiratory syncytial virus, non-respiratory syncytial virus) and treatment requirements before (2015−2019) and after (2020) the outbreak of the COVID-19 pandemic.Results − The number of newborns with lower respiratory tract infections and newborns contracting respiratory syncytial virus declined significantly during the COVID-19 pandemic. Respiratory syncytial virus was the major causative agent before the pandemic, while after the lockdown no more cases were reported. There were no significant differences between the two periods regarding the number of patients requiring treatment with oxygen (P=0.705), non-invasive (P=0.842) and invasive ventilation (P=0.574), or in terms of median hospital stay (P=0.670) and the duration of non-invasive (P=0.350) and invasive ventilation (P=0.556), while the difference in the duration of treatment with oxygen was statistically significant (P=0.048).Conclusions − A decline was found in the number of newborns hospitalized due to respiratory syncytial virus and non-respiratory syncytial virus lower respiratory tract infections during the COVID-19. Our results strongly suggest that social distancing and other lockdown strategies were effective in slowing down the spread of respiratory syncytial virus and decreasing the need for hospitalization among newborns, but may be not equally effective for all agents causing lower respiratory tract infections.

Bronchodilator effect on regional lung function in pediatric viral lower respiratory tract infections

Objective. Viral lower respiratory tract infections (LRTI) are the leading cause for acute admission to the intensive care unit in infants and young children. Nebulized bronchodilators are often used when treating the most severe cases. The aim of this study was to investigate the bronchodilator effect on respiratory mechanics during intensive care with electrical impedance tomography (EIT) and to assess the feasibility of EIT in this context. Approach. We continuously monitored the children with chest EIT for up to 72 h in an observational study design. The treatment decisions were done by clinical assessment, as the clinicians were blinded to the EIT information during data collection. In a retrospective analysis, clinical parameters and regional expiratory time constants determined by EIT were used to assess the effects of bronchodilator administration, especially regarding airway resistance. Main results. We included six children from 11 to 27 months of age requiring intensive care due to viral LRTI and receiving bronchodilator agents. Altogether 131 bronchodilator administrations were identified during EIT monitoring. After validation of the exact timing of events and EIT data quality, 77 administrations were included in the final analysis. Fifty-five bronchodilator events occurred during invasive ventilation and 22 during high-flow nasal cannulae treatment. Only 17% of the bronchodilator administrations resulted in a relevant decrease in calculated expiratory time constants. Significance. Continuous monitoring with EIT might help to optimize the treatment of LRTI in pediatric intensive care units. In particular, EIT-based regional expiratory time constants would allow objective assessment of the effects of bronchodilators and other respiratory therapies.

All Infants Are at Risk of Developing Medically Attended Respiratory Syncytial Virus Lower Respiratory Tract Infection and Deserve Protection.

All Infants Are at Risk of Developing Medically Attended Respiratory Syncytial Virus Lower Respiratory Tract Infection and Deserve Protection.

The burden of viral lower respiratory tract infections during the neonatal period: six-year experience at a tertiary referral hospital

AimTo identify the epidemiological and clinical features of acute viral lower respiratory tract infections (LRTI) caused by respiratory syncytial virus and other respiratory viruses, and to determine the risk factors for the severe disease among neonates.MethodsWe retrospectively reviewed the records of neonates aged up to 44 postconceptional weeks who were hospitalized at a tertiary referral hospital due to confirmed viral LRTI between January 2015 and December 2020.ResultsOf 228 neonates with viral LRTI, one-third were born prematurely. A seasonal distribution of LRTIs from December to March was noticed, peaking in February. Forty-two percent of neonates were treated in the neonatal intensive care unit. One third of these presented with complications and needed mechanical ventilation. The most detected viruses were respiratory syncytial virus and rhinovirus. Prematurity was identified as a risk factor for worse clinical course and more complications, while rhinovirus infection was associated with an increased risk of apnea.ConclusionsThe burden of respiratory syncytial virus LRTI in the neonatal period is high, although other respiratory viruses can also cause a severe respiratory disease. In preterm infants, rhinovirus infection presents an important risk factor for a severe course of LRTI with complications. Infection with two respiratory viruses leads to a more severe clinical course.

Epidemiology of Lower Respiratory Tract Infections and Community-Acquired Respiratory Viruses in Patients with Bronchiolitis Obliterans Syndrome after Hematopoietic Cell Transplantation: A Retrospective Cohort Study

Bronchiolitis obliterans syndrome (BOS)-chronic graft-versus-host disease (cGVHD) affecting the lungs-is an uncommon complication of allogeneic hematopoietic cell transplant (HCT). The epidemiology and complications of lower respiratory tract infections (LRTIs) and community-acquired respiratory viruses (CARVs) in these patients are poorly understood. We aim to characterize the epidemiology of LRTIs in patients with BOS complicating HCT. We also aim to explore the association of LRTIs and CARV detection on lung function in BOS patients. Adult patients with BOS at Stanford Health Care between January 2010 and December 2019 were included in this retrospective cohort study. LRTI diagnosis was based on combined clinical, microbiologic, and radiographic criteria, using consensus criteria where available. Fifty-five patients with BOS were included. BOS was diagnosed at a median of 19.2 (IQR 12.5-24.7) months after HCT, and patients were followed for a median of 29.3 (IQR 9.9-53.2) months from BOS diagnosis. Twenty-two (40%) patients died after BOS diagnosis; 17 patients died from complications of cGVHD (including respiratory failure and infection) and 5 died from relapsed disease. Thirty-four (61.8%) patients developed at least one LRTI. Viral LRTIs were most common, occurring in 29 (52.7%) patients, primarily due to rhinovirus. Bacterial LRTIs-excluding Nocardia and non-tuberculous mycobacteria (NTM)-were the second most common, occurring in 21 (38.2%) patients, mostly due to Pseudomonas aeruginosa. Fungal LRTIs, NTM, and nocardiosis occurred in 14 (25.5%), 10 (18.2%), and 4 (7.3%) patients, respectively. Median time to development of the first LRTI after BOS diagnosis was 15.3 (4.7-44.7) months. Twenty-six (76.5%) of the 34 patients who developed LRTIs had infections due to more than one type of organism-fungi, viruses, Nocardia, NTM, and other bacteria-over the observation period. Patients with at least one LRTI had significantly lower forced expiratory volume in one second percent predicted (FEV1%) (37% vs. 53%, p = 0.0096) and diffusing capacity of carbon monoxide (DLCO) (45.5% predicted vs. 69% predicted, p = 0.0001). Patients with at least one LRTI trended toward lower overall survival (OS) (p = 0.0899) and higher non-relapse mortality (NRM) (p = 0.2707). Patients with a CARV detected or LRTI diagnosed after BOS-compared to those without any CARV detected or LRTI diagnosed-were more likely to have a sustained drop in FEV1% from baseline of at least 10% (21 [61.8%] versus 7 [33.3%]) and a sustained drop in FEV1% of at least 30% (12 [36.4%] versus 2 [9.5%]). LRTIs are common in BOS and associated with lower FEV1%, lower DLCO, and a trend toward decreased OS and higher NRM. Patients with LRTIs or CARVs (even absent lower respiratory tract involvement) were more likely to have substantial declines in FEV1% over time than those without. The array of organisms-including P. aeruginosa, mold, Nocardia, NTM, and CARVs-seen in BOS reflects the unique pathophysiology of this form of cGVHD, involving both systemic immunodeficiency and structural lung disease. These patterns of LRTIs and their outcomes can be used to guide clinical decisions and inform future research.

Overnutrition, Nasopharyngeal Pathogenic Bacteria and Proinflammatory Cytokines in Infants with Viral Lower Respiratory Tract Infections.

Background: Little is known about the interaction between the nasopharyngeal bacterial profile and the nutritional status in children. In this study, our main goal was to evaluate the associations between overnutrition and the presence of four potentially pathogenic bacteria in the nasopharynx of infants with viral lower respiratory tract infections (LRTI). In addition, we determined whether changes in the nasopharyngeal bacterial profile were associated with mucosal and serum proinflammatory cytokines and with clinical disease severity. Methods: We enrolled 116 children less than 2 years old hospitalized for viral LRTI during two consecutive respiratory seasons (May 2016 to August 2017); their nutritional status was assessed, and nasopharyngeal and blood samples were obtained. S. aureus, S. pneumoniae, H. influenzae, M. catarrhalis, and respiratory viruses were identified in nasopharyngeal samples by qPCR. Cytokine concentrations were measured in nasopharyngeal and blood samples. Disease severity was assessed by the length of hospitalization and oxygen therapy. Results: Nasopharyngeal pathogenic bacteria were identified in 96.6% of the enrolled children, and 80% of them tested positive for two or more bacteria. The presence and loads of M. catarrhalis was higher (p = 0.001 and p = 0.022, respectively) in children with overnutrition (n = 47) compared with those with normal weights (n = 69). In addition, the detection of >2 bacteria was more frequent in children with overnutrition compared to those with normal weight (p = 0.02). Multivariate regression models showed that the presence and loads of S. pneumoniae and M. catarrhalis were associated with higher concentrations of IL-6 in plasma and TNF-α in mucosal samples in children with overnutrition. Conclusions: The nasopharyngeal profile of young children with overnutrition was characterized by an over representation of pathogenic bacteria and proinflammatory cytokines.

Association between early viral lower respiratory tract infections and subsequent asthma development.

BACKGROUNDThe association between hospitalization for human respiratory syncytial virus (HRSV) bronchiolitis in early childhood and subsequent asthma is well established. The long-term prognosis for non-bronchiolitis lower respiratory tract infections (LRTI) caused by viruses different from HRSV and rhinovirus, on the other hand, has received less interest.AIMTo investigate the relationship between infant LRTI and later asthma and examine the influence of confounding factors.METHODSThe PubMed and Global Index Medicus bibliographic databases were used to search for articles published up to October 2021 for this systematic review. We included cohort studies comparing the incidence of asthma between patients with and without LRTI at ≤ 2 years regardless of the virus responsible. The meta-analysis was performed using the random effects model. Sources of heterogeneity were assessed by stratified analyses.RESULTSThis review included 15 articles (18 unique studies) that met the inclusion criteria. LRTIs at ≤ 2 years were associated with an increased risk of subsequent asthma up to 20 years [odds ratio (OR) = 5.0, 95%CI: 3.3-7.5], with doctor-diagnosed asthma (OR = 5.3, 95%CI: 3.3-8.6), current asthma (OR = 5.4, 95%CI: 2.7-10.6), and current medication for asthma (OR = 1.2, 95%CI: 0.7-3.9). Our overall estimates were not affected by publication bias (P = 0.671), but there was significant heterogeneity [I2 = 58.8% (30.6-75.5)]. Compared to studies with hospitalized controls without LRTI, those with ambulatory controls had a significantly higher strength of association between LRTIs and subsequent asthma. The strength of the association between LRTIs and later asthma varied significantly by country and age at the time of the interview. The sensitivity analyses including only studies with similar proportions of confounding factors (gender, age at LRTI development, age at interview, gestational age, birth weight, weight, height, smoking exposure, crowding, family history of atopy, and family history of asthma) between cases and controls did not alter the overall estimates.CONCLUSIONRegardless of the causative virus and confounding factors, viral LRTIs in children < 2 years are associated with an increased risk of developing a subsequent asthma. Parents and pediatricians should be informed of this risk.

The role of exhaled nitric oxide (FeNO) in the evaluation of lung parenchymal involvement in COVID-19 patients.

The inflammatory balance is an important factor in the clinical course of COVID-19 (SARS-CoV-2) infection, which has affected over 300 million people globally since its appearance in December 2019. This study aimed to evaluate the correlation between exhaled nitric oxide (FeNO) level and parenchymal involvement in COVID-19. The study included 106 patients with the delta variant of COVID-19 identified by real-time PCR as well as 40 healthy control groups between October 2021 and March 2022. The patients were analyzed in three groups: moderate COVID-19 (group 1), severe COVID-19 without macrophage activation syndrome (MAS) (group 2), and severe COVID-19 with MAS (group 3). FeNO and CT scores were significantly higher in groups 2 and 3 at admission and discharge compared to group 1 (p = 0.001 for all). In addition, CT score at admission and CT score and FeNO level at discharge were higher in group 3 than in group 2 (p = 0.001 for all). It was found that the FeNO levels were higher in Groups 2 and 3 than in the control group (p = 0.001) during the admission. FeNO and CT scores showed strong positive correlation at admission and discharge (r = 0.917, p = 0.001; r = 0.790, p = 0.001). In receiver operating characteristic curve analysis for prediction of MAS, FeNO at a cut-off of 10.5 ppb had 66% sensitivity and 71% specificity. COVID-19 causes more severe lung involvement than other viral lower respiratory tract infections, leading to the frequent use of chest CT in these patients. FeNO assessment is a practical and noninvasive method that may be useful in evaluating for parenchymal infiltration in the diagnosis and follow-up of COVID-19 patients.

Early origins of respiratory disease.

Chronic respiratory morbidity is unfortunately common in childhood, particularly in those born very prematurely or with congenital anomalies affecting pulmonary development and those with sickle cell disease. Our research group, therefore, has focused on the early origins of chronic respiratory disease. This has included assessing antenatal diagnostic techniques and potentially therapeutic interventions in infants with congenital diaphragmatic hernia. Undertaking physiological studies, we have increased the understanding of the premature baby's response to resuscitation and evaluated interventions in the delivery suite. Mechanical ventilation modes have been optimised and randomised controlled trials (RCTs) with short- and long-term outcomes undertaken. Our studies highlighted respiratory syncytial virus lower respiratory tract infections (LRTIs) and other respiratory viral LRTIs had an adverse impact on respiratory outcomes of prematurely born infants, who we demonstrated have a functional and genetic predisposition to respiratory viral LRTIs. We have described the long-term respiratory outcomes for children with sickle cell disease and importantly identified influencing factors. In conclusion, it is essential to undertake long term follow up of infants at high risk of chronic respiratory morbidity if effective preventative strategies are to be developed.

P1614: MOLECULAR EPIDEMIOLOGY OF INFLUENZA VIRUS IN PATIENTS WITH HEMATOLOGIC DISORDERS

Background: Whereas influenza virus infections usually present as self-limiting upper respiratory tract infections, they are also one of the most common causes of viral lower respiratory tract infections. Especially immunocompromised patients, such as ones suffering from malignant diseases, are at a higher risk of severe influenza virus infection, thus leading to increased morbidity and mortality. With influenza viruses possessing the ability of antigenic shift and antigenic drift, consequently altering the viral genome frequently and avoiding long-term immunity of the host, the necessity for regular data collection is clear. Aims: With this study we want to retrospectively assess influenza virus epidemiology in patients with hematological malignancies and investigate clinical and virological risk factors of severe infection to be able to apply information about improvement of hygiene and care. Methods: We included clinical data from 159 influenza positive patients from the Department of Haematology of the University Hospital Heidelberg from the seasons of 2014 to 2019 to analyse occurrence of nosocomial transmission, prolonged viral shedding and associated risk factors for severe infection. Virological data was obtained by nasopharyngeal swabs, which were collected routinely, then Sanger sequencing of the hemagglutinin gene was performed for phylogenetic and mutational analysis. Combination of clinical and virological data was assessed to evaluate specific susceptibility to influenza subtype, subgroup or amino acid mutation. Results: 42 patients (26%) developed LRTI. Associated risk factors with development of lower respiratory tract infection (LRTI) (p<0.05) were nosocomial infection (p=0.008), IgG levels lower than 6g/dl (p=0.046), bacterial (p=0.001), fungal (p<0.001) and bacterial and fungal (p=0.017) coinfection. 9 of 31 (29%) of bacterial copathogens belonged to multi-resistant strains. LRTI associated mortality rate in our study population was noticeably high with 38%. 67% of patients with consecutive testing (n=54) presented with prolonged viral shedding (median 9.5 days). Epidemiological comparison with national surveillance data mostly showed no divergence of our patient group regarding influenza type and subtype. In 115 patients, sequencing of influenza hemagglutinin gene was successful, and 13 virus isolates revealed significant substitutions: In A/H1N1 samples P137S, D187N and D222V; in A/H3N2 samples D7N, T10M, D101E, I140M, Q197K, Q197R and I214T; in B/Yamagata samples Y165H, P171Q and N202R and none in B/Victoria samples. Most of these substitutions could be assigned to an antigenic site or receptor binding site. Summary/Conclusion: While no specific susceptibility to influenza subtypes or subgroups could be observed, high LRTI associated mortality rate and occurrence of nosocomial transmission as well as multi-resistant copathogens illustrate the need for better hospital hygiene and early evaluation of disease severity. To understand detected mutations and their impact on the course of infection as well as virus evolution and vaccination efficiency, further collection of data is needed.

Incidence of Respiratory Syncytial Virus Lower Respiratory Tract Infections During the First 2 Years of Life: A Prospective Study Across Diverse Global Settings.

BackgroundThe true burden of lower respiratory tract infections (LRTIs) due to respiratory syncytial virus (RSV) remains unclear. This study aimed to provide more robust, multinational data on RSV-LRTI incidence and burden in the first 2 years of life.MethodsThis prospective, observational cohort study was conducted in Argentina, Bangladesh, Canada, Finland, Honduras, South Africa, Thailand, and United States. Children were followed for 24 months from birth. Suspected LRTIs were detected via active (through regular contacts) and passive surveillance. RSV and other viruses were detected from nasopharyngeal swabs using PCR-based methods.ResultsOf 2401 children, 206 (8.6%) had 227 episodes of RSV-LRTI. Incidence rates (IRs) of first episode of RSV-LRTI were 7.35 (95% confidence interval [CI], 5.88–9.08), 5.50 (95% CI, 4.21–7.07), and 2.87 (95% CI, 2.18–3.70) cases/100 person-years in children aged 0–5, 6–11, and 12–23 months. IRs for RSV-LRTI, severe RSV-LRTI, and RSV hospitalization tended to be higher among 0–5 month olds and in lower-income settings. RSV was detected for 40% of LRTIs in 0–2 month olds and for approximately 20% of LRTIs in older children. Other viruses were codetected in 29.2% of RSV-positive nasopharyngeal swabs.ConclusionsA substantial burden of RSV-LRTI was observed across diverse settings, impacting the youngest infants the most. Clinical Trials Registration. NCT01995175.

Use of β2-agonists for viral bronchiolitis

A 9-month-old baby presented to my rural emergency department with 2 days of cough and congestion and 1 day of breathing difficulties in the month of February. An auscultation examination of the lungs indicated there were scattered, faint wheezes and coarse sounds. Based on the baby’s age, symptomatology, and the winter season, the likely diagnosis was bronchiolitis. Are inhaled β2-agonists an appropriate treatment for this patient?The use of inhaled β2-agonists in children younger than 2 years of age with bronchiolitis is not indicated. Wheezing is most commonly part of the diagnosis of bronchiolitis, a lower respiratory viral infection in young children. Unlike with asthma, smooth muscle constriction in the lungs is not a symptom of bronchiolitis. Treatment of bronchiolitis requires supportive care, but pharmaceutical interventions such as β2-agonists, steroids, and antibiotics have not been shown to decrease length of illness, illness severity, or hospitalization rates. There may be a subgroup of infants with bronchiolitis who respond to β2-agonists treatment; however, this group has not been fully identified in the literature to date.

Myxovirus resistance protein A for discriminating between viral and bacterial lower respiratory tract infections in children – The TREND study

ObjectiveDiscriminating between viral and bacterial lower respiratory tract infection (LRTI) in children is challenging, leading to an excessive use of antibiotics. Myxovirus resistance protein A (MxA) is a promising biomarker for viral infections. The primary aim of the study was to assess differences in blood MxA levels between children with viral and bacterial LRTI. Secondary aims were to assess differences in blood MxA levels between children with viral LRTI and asymptomatic controls and to assess MxA levels in relation to different respiratory viruses. MethodsChildren with LRTI were enrolled as cases at Sachs' Children and Youth Hospital, Stockholm, Sweden. Nasopharyngeal aspirates and blood samples for analysis of viral PCR, MxA, and C-reactive protein were systematically collected from all study subjects in addition to standard laboratory/radiology assessment. Aetiology was defined according to an algorithm based on laboratory and radiological findings. Asymptomatic children with minor surgical disease were enrolled as controls. ResultsMxA levels were higher in children with viral LRTI (n = 242) as compared to both bacterial (n = 5) LRTI (p <0.01, area under the curve (AUC) 0.90, 95% CI: 0.81 to 0.99), and controls (AUC 0.92, 95% CI: 0.88 to 0.95). In the subgroup of children with pneumonia diagnosis, a cutoff of MxA 430 μg/l discriminated between viral (n = 29) and bacterial (n = 4) aetiology with 93% (95% CI: 78–99%) sensitivity and 100% (95% CI: 51–100%) specificity (AUC 0.98, 95% CI: 0.94 to 1.00). The highest MxA levels were seen in cases PCR positive for influenza (median MxA 1699 μg/l, interquartile range: 732 to 2996) and respiratory syncytial virus (median MxA 1115 μg/l, interquartile range: 679 to 2489). DiscussionMxA accurately discriminated between viral and bacterial aetiology in children with LRTI, particularly in the group of children with pneumonia diagnosis, but the number of children with bacterial LRTI was low.

Identifying distinct T cell subsets in the context of pediatric ARDS

Abstract Acute respiratory distress syndrome (ARDS) is a condition defined by sudden respiratory failure caused by severe lung injury, with disease etiology that can differ across pediatric and adult patients. While T lymphocytes have been implicated in ARDS, the role of T cell subsets in pediatric ARDS (pARDS) is not fully understood. In this study, we sought to characterize the potential role of T cells in pARDS caused by viral lower respiratory tract infection (LRTI). To do this, we performed single cell RNA-Seq on tracheal aspirate samples from three categories of mechanically ventilated pediatric patients: 1) LRTI patients with pARDS, 2) LRTI patients without pARDS, and 3) ventilated patients without underlying LRTI or pARDS. All LRTI patients were diagnosed with respiratory viral infections, 70 percent of which were respiratory syncytial virus (RSV). Within the T lymphocytes, we identified populations of CD8+ T cells, CD4+ regulatory T cells, and γδ T cells that each expressed unique gene signatures with distinct distribution across disease states. We compared these data to T cell subsets within healthy lung tissue at multiple ages, and within the periphery of healthy adults. These analyses identified age, location, and disease-specific differences within T cell subsets, highlighting the unique role of T cells in pARDS. Supported by grants from NIH (R01 AI54470, R01 AI121832)

Activation of the Carboxypeptidase U (CPU, TAFIa, CPB2) System in Patients with SARS-CoV-2 Infection Could Contribute to COVID-19 Hypofibrinolytic State and Disease Severity Prognosis.

Coronavirus disease 2019 (COVID-19) is a viral lower respiratory tract infection caused by the highly transmissible and pathogenic SARS-CoV-2 (severe acute respiratory-syndrome coronavirus-2). Besides respiratory failure, systemic thromboembolic complications are frequent in COVID-19 patients and suggested to be the result of a dysregulation of the hemostatic balance. Although several markers of coagulation and fibrinolysis have been studied extensively, little is known about the effect of SARS-CoV-2 infection on the potent antifibrinolytic enzyme carboxypeptidase U (CPU). Blood was collected longitudinally from 56 hospitalized COVID-19 patients and 32 healthy controls. Procarboxypeptidase U (proCPU) levels and total active and inactivated CPU (CPU+CPUi) antigen levels were measured. At study inclusion (shortly after hospital admission), proCPU levels were significantly lower and CPU+CPUi antigen levels significantly higher in COVID-19 patients compared to controls. Both proCPU and CPU+CPUi antigen levels showed a subsequent progressive increase in these patients. Hereafter, proCPU levels decreased and patients were, at discharge, comparable to the controls. CPU+CPUi antigen levels at discharge were still higher compared to controls. Baseline CPU+CPUi antigen levels (shortly after hospital admission) correlated with disease severity and the duration of hospitalization. In conclusion, CPU generation with concomitant proCPU consumption during early SARS-CoV-2 infection will (at least partly) contribute to the hypofibrinolytic state observed in COVID-19 patients, thus enlarging their risk for thrombosis. Moreover, given the association between CPU+CPUi antigen levels and both disease severity and duration of hospitalization, this parameter may be a potential biomarker with prognostic value in SARS-CoV-2 infection.