Bronchiolitis-associated hospitalizations among US children, 1980-1996

RSV Prevention Within Reach for Older Infants and Toddlers: The Role of Active Immunization

This review article will summarize the vaccines and monoclonal antibodies currently under evaluation for the prevention of RSV disease in older infants, toddlers and young children. We will review the rationale for passive protection during the first months of life, and the role of active immunization afterwards, either with live attenuated, protein-based or mRNA vaccines.

Epidemiology, Outcomes, and Trend Analysis of Hospitalized Infants With Respiratory Syncytial Virus (RSV) Bronchiolitis From 1997 to 2019

Background  Most children with respiratory syncytial virus (RSV) infection have a self-limiting course that can be managed with supportive care, and hospitalization is uncommon. The objectives of this study were to evaluate the epidemiology, outcomes, associated comorbidities, and temporal trends in the prevalence of infants one to 24 months of age who required hospitalization for RSV infection in the United States of America from 1997 to 2019. Methods In this retrospective cross-sectional study, we utilized the Kids' Inpatient Database (KID) to investigate the prevalence and outcomes of RSV bronchiolitis within a large cohort of discharged patients from 1997 to 2019. We included children one to 24 months of age admitted with a diagnosis of RSV bronchiolitis. Neonates were excluded from the analysis. A chi-square for linear trend was used to analyze trends in the prevalence of RSV bronchiolitis hospitalization, the presence of complex chronic conditions (CCC), congenital heart disease (CHD), the use of non-invasive and invasive mechanical ventilation (NIV and IMV), and hospital mortality. Results There were a total of 566,786 infants aged one to 24 months hospitalized with RSV infection out of a total of 9,309,597 discharges during the eight-year cohort, with a hospital prevalence of 60.9 per 1000 discharges and a hospital mortality rate of 0.09% (95% confidence interval (CI): 0.08%-0.1%). There was no trend in hospitalization rates of RSV infections per 100,000 U.S. population during the study period, with a decrease in hospital mortality trend. Children with RSV bronchiolitis were more likely to have government insurance and reside in zip codes with the lowest income quartile. There was a significant seasonal and regional variation in RSV-related hospitalizations. The presence of CCC was identified in 2.4% of the RSV group compared to 5.1% of non-RSV discharges (odds ratio (OR): 0.46, 95% CI: 0.45-0.47; p<0.001). The prevalence of RSV among all discharges has significantly increased over the study period, rising from 51.6 cases per 1000 discharges in 1997 to 180.1 cases per 1000 discharges in 2019 (p<0.001). The prevalence of CCC and CHD among RSV patients has also shown an upward trend, with CCC cases increasing from 1,411 in 1997 to 2,795 in 2019 and CHD cases rising from 1,795 to 3,622 during the same period. The use of invasive mechanical ventilation, non-invasive ventilation, and extracorporeal membrane oxygenation has consistently increased over time. Additionally, complications such as the need for cardiopulmonary resuscitation have demonstrated a similar increasing trend, although they have remained overall low. However, population-based hospitalization rates showed no significant trend. Conclusions The hospitalization rates at a population level in the United States for RSV infection in children aged one to 24 months remained steady from 1997 to 2019, while hospital mortality rates showed a declining trend. There is an increased proportion of comorbid conditions and increased resource utilization in children with RSV. These findings are important for monitoring the effectiveness of preventive strategies for severe RSV infections.

Pediatric Respiratory Syncytial Virus Hospitalizations and Respiratory Support After the COVID-19 Pandemic

Importance

After the COVID-19 pandemic, there was a surge of pediatric respiratory syncytial virus (RSV) infections, but national data on hospitalization and intensive care unit use and advanced respiratory support modalities have not been reported.

Objective

To analyze demographics, respiratory support modes, and clinical outcomes of children with RSV infections at tertiary pediatric hospitals from 2017 to 2023.

Design, Setting, and Participants

This cross-sectional study evaluated children from 48 freestanding US children's hospitals registered in the Pediatric Health Information System (PHIS) database. Patients 5 years or younger with RSV from July 1, 2017, to June 30, 2023, were included. Each season was defined from July 1 to June 30. Prepandemic RSV seasons included 2017 to 2018, 2018 to 2019, and 2019 to 2020. The postpandemic season was delineated as 2022 to 2023.

Exposure

Hospital presentation with RSV infection.

Main Outcomes and Measures

Data on emergency department presentations, hospital or intensive care unit admission and length of stay, demographics, respiratory support use, mortality, and cardiopulmonary resuscitation were analyzed. Postpandemic season data were compared with prepandemic seasonal averages.

Results

A total of 288 816 children aged 5 years or younger (median [IQR] age, 8.9 [3.3-21.5] months; 159 348 [55.2%] male) presented to 48 US children's hospitals with RSV from July 1, 2017, to June 30, 2023. Respiratory syncytial virus hospital presentations increased from 39 698 before the COVID-19 pandemic to 94 347 after the pandemic (P < .001), with 86.7% more hospitalizations than before the pandemic (50 619 vs 27 114; P < .001). In 2022 to 2023, children were older (median [IQR] age, 11.3 [4.1-26.6] months vs 6.8 [2.6-16.8] months; P < .001) and had fewer comorbidities (17.6% vs 21.8% of hospitalized patients; P < .001) than during prepandemic seasons. Advanced respiratory support use increased 70.1% in 2022 to 2023 (9094 vs 5340; P < .001), and children requiring high-flow nasal cannula (HFNC) or noninvasive ventilation (NIV) were older than during prepandemic seasons (median [IQR] age for HFNC, 6.9 [2.7-16.0] months vs 4.6 [2.0-11.7] months; for NIV, 6.0 [2.1-16.5] months vs 4.3 [1.9-11.9] months). Comorbid conditions were less frequent after the pandemic across all respiratory support modalities (HFNC, 14.9% vs 19.1%, NIV, 22.0% vs 28.5%, invasive mechanical ventilation, 30.5% vs 38.0%; P < .001).

Conclusions and Relevance

This cross-sectional study identified a postpandemic pediatric RSV surge that resulted in markedly increased hospital volumes and advanced respiratory support needs in older children with fewer comorbidities than prepandemic seasons. These clinical trends may inform novel vaccine allocation to reduce the overall burden during future RSV seasons.

Updates on respiratory syncytial virus prophylaxis: the past, present and future

PURPOSE OF REVIEW

Human respiratory syncytial virus (RSV) causes acute respiratory infection in individuals of all age groups. It is the most common pathogen identified in infants and young children with acute lower respiratory infection. Although most infants and young children experience mild, cold-like symptoms, some infants develop severe lower respiratory tract disease such as pneumonia and bronchiolitis that may result in an emergency department visit or hospitalization.

RECENT FINDINGS

In the United States, hospitalization rates have risen during the last decades, and while premature infants with chronic lung disease and congenital heart disease are at increased risk for severe presentations, the majority of hospitalizations occur in previously healthy infants. Until recently, RSV prophylaxis was only available for former preterm infants and those with certain underlying medical conditions.

SUMMARY

The need for preventive interventions against RSV is crucial. This paper will provide a review of the vaccine development, the spectrum of RSV prophylaxis, current challenges associated with the cost, insurance coverage and equitable distribution of targeted therapies.

Respiratory Support Practices for Bronchiolitis in the Pediatric Intensive Care Unit

Importance

Admissions to the pediatric intensive care unit (PICU) due to bronchiolitis are increasing. Whether this increase is associated with changes in noninvasive respiratory support practices is unknown.

Objective

To assess whether the number of PICU admissions for bronchiolitis between 2013 and 2022 was associated with changes in the use of high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), and invasive mechanical ventilation (IMV) and to identify factors associated with HFNC and NIV success and failure.

Design, Setting, and Participants

This cross-sectional study examined encounter data from the Virtual Pediatric Systems database on annual PICU admissions for bronchiolitis and ventilation practices among patients aged younger than 2 years admitted to 27 PICUs between January 1, 2013, and December 31, 2022. Use of HFNC and NIV was defined as successful if patients were weaned to less invasive support (room air or low-flow nasal cannula for HFNC; room air, low-flow nasal cannula, or HFNC for NIV).

Main Outcomes and Measures

The main outcome was the number of PICU admissions for bronchiolitis requiring the use of HFNC, NIV, or IMV. Linear regression was used to analyze the association between admission year and absolute numbers of encounters stratified by the maximum level of respiratory support required. Multivariable logistic regression was used to analyze factors associated with HFNC and NIV success and failure (defined as not meeting the criteria for success).

Results

Included in the analysis were 33 816 encounters for patients with bronchiolitis (20 186 males [59.7%]; 1910 patients [5.6%] aged ≤28 days and 31 906 patients [94.4%] aged 29 days to <2 years) treated at 27 PICUs from 2013 to 2022. A total of 7615 of 15 518 patients (49.1%) had respiratory syncytial virus infection and 1522 of 33 816 (4.5%) had preexisting cardiac disease. Admissions to the PICU increased by 350 (95% CI, 170-531) encounters annually. When data were grouped by the maximum level of respiratory support required, HFNC use increased by 242 (95% CI, 139-345) encounters per year and NIV use increased by 126 (95% CI, 64-189) encounters per year. The use of IMV did not significantly change (10 [95% CI, -11 to 31] encounters per year). In all, 22 381 patients (81.8%) were successfully weaned from HFNC to low-flow oxygen therapy or room air, 431 (1.6%) were restarted on HFNC, 3057 (11.2%) were escalated to NIV, and 1476 (5.4%) were escalated to IMV or extracorporeal membrane oxygenation (ECMO). Successful use of HFNC increased from 820 of 1027 encounters (79.8%) in 2013 to 3693 of 4399 encounters (84.0%) in 2022 (P = .002). In all, 8476 patients (81.5%) were successfully weaned from NIV, 787 (7.6%) were restarted on NIV, and 1135 (10.9%) were escalated to IMV or ECMO. Success with NIV increased from 224 of 306 encounters (73.2%) in 2013 to 1335 of 1589 encounters (84.0%) in 2022 (P < .001). In multivariable logistic regression, lower weight, higher Pediatric Risk of Mortality III score, cardiac disease, and PICU admission from outside the emergency department were associated with greater odds of HFNC and NIV failure.

Conclusions and Relevance

Findings of this cross-sectional study of patients aged younger than 2 years admitted for bronchiolitis suggest there was a 3-fold increase in PICU admissions between 2013 and 2022 associated with a 4.8-fold increase in HFNC use and a 5.8-fold increase in NIV use. Further research is needed to standardize approaches to HFNC and NIV support in bronchiolitis to reduce resource strain.

High-flow nasal cannula therapy for infants with bronchiolitis

BACKGROUND

Bronchiolitis is a common lower respiratory tract illness, usually of viral aetiology, affecting infants younger than 24 months of age and is the most common cause of hospitalisation of infants. It causes airway inflammation, mucus production and mucous plugging, resulting in airway obstruction. Effective pharmacotherapy is lacking and bronchiolitis is a major cause of morbidity and mortality. Conventional treatment consists of supportive therapy in the form of fluids, supplemental oxygen, and respiratory support. Traditionally, oxygen delivery is as a dry gas at 100% concentration via low-flow nasal prongs. However, the use of heated, humidified, high-flow nasal cannula (HFNC) therapy enables delivery of higher inspired gas flows of an air/oxygen blend, at 2 to 3 L/kg per minute up to 60 L/min in children. It can provide some level of continuous positive airway pressure (CPAP) to improve ventilation in a minimally invasive manner. This may reduce the need for invasive respiratory support, thus potentially lowering costs, with clinical advantages and fewer adverse effects.

OBJECTIVES

To assess the effects of HFNC therapy compared with conventional respiratory support in the treatment of infants with bronchiolitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, and Web of Science (from June 2013 to December 2022). In addition, we consulted ongoing trial registers and experts in the field to identify ongoing studies, checked reference lists of relevant articles, and searched for conference abstracts. Date restrictions were imposed such that we only searched for studies published after the original version of this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs that assessed the effects of HFNC (delivering oxygen or oxygen/room air blend at flow rates greater than 4 L/minute) compared to conventional treatment in infants (< 24 months) with a clinical diagnosis of bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently used a standard template to assess trials for inclusion and extract data on study characteristics, risk of bias elements, and outcomes. We contacted trial authors to request missing data. Outcome measures included the need for invasive respiratory support and time until discharge, clinical severity measures, oxygen saturation, duration of oxygen therapy, and adverse events.

MAIN RESULTS

In this update we included 15 new RCTs (2794 participants), bringing the total number of RCTs to 16 (2813 participants). Of the 16 studies, 11 compared high-flow to low-flow, and five compared high-flow to CPAP. These studies included infants less than 24 months of age as stated in our selection criteria. There were no significant differences in sex. We found that when comparing high-flow to low-flow oxygen therapy for infants with bronchiolitis there may be a reduction in the total length of hospital stay (mean difference (MD) -0.65 days, 95% confidence interval (CI) -1.23 to -0.06; P < 0.00001, I2 = 89%; 7 studies, 1951 participants; low-certainty evidence). There may also be a reduction in the duration of oxygen therapy (MD -0.59 days, 95% CI -1 to -0.18; P < 0.00001, I2 = 86%; 7 studies, 2132 participants; low-certainty evidence). We also found that there was probably an improvement in respiratory rate at one and 24 hours, and heart rate at one, four to six, and 24 hours in those receiving high-flow oxygen therapy when compared to pre-intervention baselines. There was also probably a reduced risk of treatment escalation in those receiving high-flow when compared to low-flow oxygen therapy (risk ratio (RR) 0.55, 95% CI 0.39 to 0.79; P = 0.001, I2 = 43%; 8 studies, 2215 participants; moderate-certainty evidence). We found no difference in the incidence of adverse events (RR 1.2, 95% CI 0.38 to 3.74; P = 0.76, I2 = 26%; 4 studies, 1789 participants; low-certainty evidence) between the two groups. The lack of comparable outcomes in studies comparing high-flow and CPAP, as well as the small numbers of participants, limited our ability to perform meta-analysis on this group.

AUTHORS' CONCLUSIONS

High-flow nasal cannula therapy may have some benefits over low-flow oxygen for infants with bronchiolitis in terms of a greater improvement in respiratory and heart rates, as well as a modest reduction in the length of hospital stay and duration of oxygen therapy, with a reduced incidence of treatment escalation. There does not appear to be a difference in the number of adverse events. Further studies comparing high-flow nasal cannula therapy and CPAP are required to demonstrate the efficacy of one modality over the other. A standardised clinical definition of bronchiolitis, as well as the use of a validated clinical severity score, would allow for greater and more accurate comparison between studies.

Respiratory syncytial virus subtypes in children with bronchiolitis: does it correlate with clinical severity?

BACKGROUND

In this retrospective study, we aimed to evaluate the factors associated with the severity of respiratory syncytial virus (RSV) bronchiolitis in children aged under 2 years who were admitted to the Children's Hospital of Hebei between June 2018 and January 2019.

METHODS

Sputum samples positive for RSV via multiplex PCR were subtyped using real-time PCR. Data collected included risk factors for disease severity, demographics, microbiology, and outcomes.

RESULTS

Of the 82 children with RSV bronchiolitis, 79 were treated and discharged with improvement, while 3 died. All three patients had underlying medical conditions, including complex congenital heart disease and severe combined immunodeficiency. Further, disease severity was associated with preexisting underlying disease, fever duration, and bacterial co-infection, but not with the RSV subtype.

CONCLUSIONS

Our findings suggest that an appropriate therapeutic regimen should include the detection of bacterial co-infections and the identification of underlying diseases for the effective management of severe RSV bronchiolitis.

Admissions for Bronchiolitis at Children's Hospitals Before and During the COVID-19 Pandemic

Importance

The COVID-19 pandemic has been associated with a transient decrease in bronchiolitis hospitalizations compared with prepandemic patterns, but current effects remain unknown.

Objective

To analyze changes in patterns of bronchiolitis admissions at US children's hospitals during the 2020-2023 bronchiolitis seasons compared with the 2010-2019 seasons.

Design, Setting, and Participants

This retrospective cross-sectional study used data from 41 US children's hospitals in the Pediatric Health Information System database. Bronchiolitis has winter-predominant seasonality, so hospitalizations were grouped according to bronchiolitis season (from July through June). This study included all patients aged younger than 2 years admitted with a diagnosis of bronchiolitis between July 1, 2010, and June 30, 2023. Bronchiolitis seasons from July through June between 2010-2011 and 2019-2020 were classified as the prepandemic era, and seasons between 2020-2021 and 2022-2023 were classified as the pandemic era. Data analysis was performed from July 1, 2010, through June 30, 2023.

Exposures

Admission date.

Main Outcomes and Measures

The primary outcome was number of hospitalizations for bronchiolitis by season and month. Monthly admission counts from the prepandemic era were transformed into time series and used to train seasonal ensemble forecasting models. Forecasts were compared to monthly admissions during the pandemic era.

Results

In this study, there were 400 801 bronchiolitis admissions among 349 609 patients between July 1, 2010, and June 30, 2023. The median patient age was 6 (IQR, 2-12) months; 58.7% were boys and 43.7% were White. Hospitalizations increased gradually during the prepandemic era (median, 29 309 [IQR, 26 196-34 157]), decreased 69.2% (n = 9030) in the 2020-2021 season, and increased 75.3% (n = 51 397) in the 2022-2023 season. Patients in the pandemic era were older than those in the prepandemic era (median, 7 [IQR, 3-14] vs 6 [2-12] months; P < .001). Intensive care unit (ICU) admissions increased from 32.2% (96 245 of 298 535) in the prepandemic era to 36.7% (37 516 of 102 266) in the pandemic era (P < .001). The seasonality of bronchiolitis admissions changed during the pandemic era. Admissions peaked in August 2021 (actual 5036 vs 943 [95% CI, 0-2491] forecasted) and November 2022 (actual 10 120 vs 5268 [95% CI, 3425-7419] forecasted). These findings were unchanged in sensitivity analyses excluding children with complex chronic conditions and excluding repeat admissions. In a sensitivity analysis including all viral lower respiratory tract infections in children aged younger than 5 years, there were 66 767 admissions in 2022-2023 vs 35 623 (31 301-41 002) in the prepandemic era, with the largest increase in children aged 24 to 59 months.

Conclusions and Relevance

The findings of this cross-sectional study suggest that bronchiolitis hospitalizations decreased transiently and then increased markedly during the COVID-19 pandemic era. Patients admitted during the pandemic era were older and were more likely to be admitted to an ICU. These findings suggest that bronchiolitis seasonality has not yet returned to prepandemic patterns, and US hospitals should prepare for the possibility of atypical timing again in 2023.

Gamma Irradiation-Inactivated Respiratory Syncytial Virus Vaccine Provides Protection but Exacerbates Pulmonary Inflammation by Switching from Prefusion to Postfusion F Protein

Respiratory syncytial virus (RSV) is a common respiratory pathogen that causes lower respiratory diseases among infants and elderly people. Moreover, formalin-inactivated RSV (FI-RSV) vaccine induces serious enhanced respiratory disease (ERD). Radiation has been investigated as an alternative approach for producing inactivated or live-attenuated vaccines, which enhance the antigenicity and heterogeneous protective effects of vaccines compared with conventional formalin inactivation. In this study, we developed an RSV vaccine using gamma irradiation and analyzed its efficacy against RSV vaccine-induced ERD in a mouse model. Although gamma irradiation-inactivated RSV (RI-RSV) carbonylation was lower than FI-RSV carbonylation and RI-RSV showed a significant antibody production and viral clearance, RI-RSV caused more obvious body weight loss, pulmonary eosinophil infiltration, and pulmonary mucus secretion. Further, the conversion of prefusion F (pre-F) to postfusion F (post-F) was significant for both RI-RSV and FI-RSV, while that of RI-RSV was significantly higher than that of FI-RSV. We found that the conversion from pre- to post-F during radiation was caused by radiation-induced reactive oxygen species. Although we could not propose an effective RSV vaccine manufacturing method, we found that ERD was induced by RSV vaccine by various biochemical effects that affect antigen modification during RSV vaccine manufacturing, rather than simply by the combination of formalin and alum. Therefore, these biochemical actions should be considered in future developments of RSV vaccine. IMPORTANCE Radiation inactivation for viral vaccine production has been known to elicit a better immune response than other inactivation methods due to less surface protein damage. However, we found in this study that radiation-inactivated RSV (RI-RSV) vaccine induced a level of immune response similar to that induced by formalin-inactivated RSV (FI-RSV). Although RI-RSV vaccine showed less carbonylation than FI-RSV, it induced more conformational changes from pre-F to post-F due to the gamma radiation-induced reactive oxygen species response, which may be a key factor in RI-RSV-induced ERD. Therefore, ERD induced by RSV vaccine may be due to pre-F to post-F denaturation by random protein modifications caused by external stress. Our findings provide new ideas for inactivated vaccines for RSV and other viruses and confirm the importance of pre-F in RSV vaccines.

Health service utilisation for acute respiratory infections in infants graduating from the neonatal intensive care unit: a population-based cohort study

BACKGROUND

Despite advances in neonatal intensive care, babies admitted to Neonatal Intensive Care Units (NICU) suffer from adverse outcomes. We aim to describe the longer-term respiratory infectious morbidity of infants discharged from NICU using state-wide population-based linked data in Western Australia.

STUDY DESIGN

We used probabilistically linked population-based administrative data to analyse respiratory infection morbidity in a cohort of 23,784 infants admitted to the sole tertiary NICU, born 2002-2013 with follow up to 2015. We analysed incidence rates of secondary care episodes (emergency department presentations and hospitalisations) by acute respiratory infection (ARI) diagnosis, age, gestational age and presence of chronic lung disease (CLD). Poisson regression was used to investigate the differences in rates of ARI hospital admission between gestational age groups and those with CLD, after adjusting for age at hospital admission.

RESULTS

From 177,367 child-years at risk (i.e., time that a child could experience an ARI outcome), the overall ARI hospitalisation rate for infants and children aged 0-8 years was 71.4/1000 (95% confidence interval, CI: 70.1, 72.6), with the highest rates in infants aged 0-5 months (242.9/1000). For ARI presentations to emergency departments, equivalent rates were 114/1000 (95% CI: 112.4, 115.5) and 337.6/1000, respectively. Bronchiolitis was the most common diagnosis among both types of secondary care, followed by upper respiratory tract infections. Extremely preterm infants (< 28 weeks gestation at birth) were 6.5 (95% CI: 6.0, 7.0) times more likely and those with CLD were 5.0 (95% CI: 4.7, 5.4) times more likely to be subsequently admitted for ARI than those in NICU who were not preterm or had CLD after adjusting for age at hospital admission.

CONCLUSIONS

There is an ongoing burden of ARI in children who graduate from the NICU, especially those born extremely preterm, that persists into early childhood. Early life interventions to prevent respiratory infections in these children and understanding the lifelong impact of early ARI on later lung health are urgent priorities.

Nebulised hypertonic saline solution for acute bronchiolitis in infants

BACKGROUND

Airway oedema (swelling) and mucus plugging are the principal pathological features in infants with acute viral bronchiolitis. Nebulised hypertonic saline solution (≥ 3%) may reduce these pathological changes and decrease airway obstruction. This is an update of a review first published in 2008, and updated in 2010, 2013, and 2017.

OBJECTIVES

To assess the effects of nebulised hypertonic (≥ 3%) saline solution in infants with acute bronchiolitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily, Embase, CINAHL, LILACS, and Web of Science on 13 January 2022. We also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov on 13 January 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs using nebulised hypertonic saline alone or in conjunction with bronchodilators as an active intervention and nebulised 0.9% saline or standard treatment as a comparator in children under 24 months with acute bronchiolitis. The primary outcome for inpatient trials was length of hospital stay, and the primary outcome for outpatients or emergency department (ED) trials was rate of hospitalisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and assessment of risk of bias in included studies. We conducted random-effects model meta-analyses using Review Manager 5. We used mean difference (MD), risk ratio (RR), and their 95% confidence intervals (CI) as effect size metrics.

MAIN RESULTS

We included six new trials (N = 1010) in this update, bringing the total number of included trials to 34, involving 5205 infants with acute bronchiolitis, of whom 2727 infants received hypertonic saline. Eleven trials await classification due to insufficient data for eligibility assessment. All included trials were randomised, parallel-group, controlled trials, of which 30 were double-blinded. Twelve trials were conducted in Asia, five in North America, one in South America, seven in Europe, and nine in Mediterranean and Middle East regions. The concentration of hypertonic saline was defined as 3% in all but six trials, in which 5% to 7% saline was used. Nine trials had no funding, and five trials were funded by sources from government or academic agencies. The remaining 20 trials did not provide funding sources. Hospitalised infants treated with nebulised hypertonic saline may have a shorter mean length of hospital stay compared to those treated with nebulised normal (0.9%) saline or standard care (mean difference (MD) -0.40 days, 95% confidence interval (CI) -0.69 to -0.11; 21 trials, 2479 infants; low-certainty evidence). Infants who received hypertonic saline may also have lower postinhalation clinical scores than infants who received normal saline in the first three days of treatment (day 1: MD -0.64, 95% CI -1.08 to -0.21; 10 trials (1 outpatient, 1 ED, 8 inpatient trials), 893 infants; day 2: MD -1.07, 95% CI -1.60 to -0.53; 10 trials (1 outpatient, 1 ED, 8 inpatient trials), 907 infants; day 3: MD -0.89, 95% CI -1.44 to -0.34; 10 trials (1 outpatient, 9 inpatient trials), 785 infants; low-certainty evidence). Nebulised hypertonic saline may reduce the risk of hospitalisation by 13% compared with nebulised normal saline amongst infants who were outpatients and those treated in the ED (risk ratio (RR) 0.87, 95% CI 0.78 to 0.97; 8 trials, 1760 infants; low-certainty evidence). However, hypertonic saline may not reduce the risk of readmission to hospital up to 28 days after discharge (RR 0.83, 95% CI 0.55 to 1.25; 6 trials, 1084 infants; low-certainty evidence). We are uncertain whether infants who received hypertonic saline have a lower number of days to resolution of wheezing compared to those who received normal saline (MD -1.16 days, 95% CI -1.43 to -0.89; 2 trials, 205 infants; very low-certainty evidence), cough (MD -0.87 days, 95% CI -1.31 to -0.44; 3 trials, 363 infants; very low-certainty evidence), and pulmonary moist crackles (MD -1.30 days, 95% CI -2.28 to -0.32; 2 trials, 205 infants; very low-certainty evidence). Twenty-seven trials presented safety data: 14 trials (1624 infants; 767 treated with hypertonic saline, of which 735 (96%) co-administered with bronchodilators) did not report any adverse events, and 13 trials (2792 infants; 1479 treated with hypertonic saline, of which 416 (28%) co-administered with bronchodilators and 1063 (72%) hypertonic saline alone) reported at least one adverse event such as worsening cough, agitation, bronchospasm, bradycardia, desaturation, vomiting and diarrhoea, most of which were mild and resolved spontaneously (low-certainty evidence).

AUTHORS' CONCLUSIONS

Nebulised hypertonic saline may modestly reduce length of stay amongst infants hospitalised with acute bronchiolitis and may slightly improve clinical severity score. Treatment with nebulised hypertonic saline may also reduce the risk of hospitalisation amongst outpatients and ED patients. Nebulised hypertonic saline seems to be a safe treatment in infants with bronchiolitis with only minor and spontaneously resolved adverse events, especially when administered in conjunction with a bronchodilator. The certainty of the evidence was low to very low for all outcomes, mainly due to inconsistency and risk of bias.

Variation in clinical practice guidelines for use of palivizumab in preventing severe respiratory syncytial viral (RSV) disease in high-risk infants

BACKGROUND

Uniformity and compliance with clinical practice guidelines (CPGs) for use of palivizumab in preventing severe respiratory syncytial viral infection in Australian high-risk infants remain unclear.

METHODS

An online survey was conducted across the Australian and New Zealand Neonatal Network (ANZNN) to determine clinical practices around palivizumab. A literature search was also performed to identify and compare national and international guidelines.

RESULTS

A total of 65 of 422 ANZNN members completed the survey. Respondents included 61 senior medical staff of consultants/staff specialists (78%) and four nursing staff (6%). According to the survey, infants most likely to be recommended palivizumab included preterm infants born <29 weeks gestational age (GA) (30%), children with chronic lung diseases (CLDs) born <32 weeks GA (40%), and with hemodynamically significant heart disease (35%). Many of the respondents (53%) stated that CPGs for palivizumab were developed locally. Literature search identified 20 guidelines (10 international and 10 domestic); 16 (80%) recommended palivizumab use in preterm infants, 16 (80%) recommended use in infants with CLD, 17 (85%) in congenital heart disease and 6 (30%) in bronchopulmonary dysplasia (BPD). Eight (40%) guidelines provided specific recommendations for immunocompromised infants. Canada, Western Australia, and American Academy of Paediatrics provided recommendations for Indigenous children. Frequency and dosage of palivizumab was universal across all CPGs. None of the international guidelines obtained were from low- or middle-income countries.

CONCLUSIONS

Standardization of CPGs may improve clinical decision making around use of palivizumab in high-risk infants.

Respiratory Syncytial Virus Outbreak in Infants and Young Children during COVID-19 Pandemic in Taiwan

Respiratory syncytial virus (RSV) is a major burden of disease in babies and young children, including hospitalizations and deaths. RSV is a seasonal disease that peaks when temperatures decrease in temperate zones and humidity increases in tropical regions. Existing research reveals that RSV hospitalization activity is year-round in Taiwan, which is a subtropical region with small peaks in spring and fall. The monthly distribution and COVID-19 pandemic impact were unclear. The aim of this study was to investigate Taiwan’s RSV hospitalization seasonality and the COVID-19 pandemic effects. The National Health Insurance Database and Death Registration Files from the Center for Health and Welfare Data Science Center were connected to birth data for this study. RSV hospitalization (RSVH) in infants aged 0–1 years ranged from 0.9518% (2009) to 1.7113% (2020), substantially higher than in children aged 1–5. Most years had 2 or 3 RSV epidemic seasons in 0–5-year-olds over the 13-year follow-up. RSVH incidence was low until the autumn of 2020, when a major rise occurred after September and lasted until December 2020. We detected RSVH peaks in February–May and July–August. The 2020 RSV outbreak was found at the end of 2020.

Acute Bronchitis and Bronchiolitis Infection in Children with Asthma and Allergic Rhinitis: A Retrospective Cohort Study Based on 5,027,486 Children in Taiwan

This study evaluated the risks of childhood acute bronchitis and bronchiolitis (CABs) for children with asthma or allergic rhinitis (AR). Using insurance claims data of Taiwan, we identified, from children of ≤12 years old in 2000-2016, cohorts with and without asthma (N = 192,126, each) and cohorts with and without AR (N = 1,062,903, each) matched by sex and age. By the end of 2016, the asthma cohort had the highest bronchitis incidence, AR and non-asthma cohorts followed, and the lowest in the non-AR cohort (525.1, 322.4, 236.0 and 169.9 per 1000 person-years, respectively). The Cox method estimated adjusted hazard ratios (aHRs) of bronchitis were 1.82 (95% confidence interval (CI), 1.80-1.83) for the asthma cohort and 1.68 (95% CI, 1.68-1.69) for the AR cohort, relative to the respective comparisons. The bronchiolitis incidence rates for these cohorts were 42.7, 29.5, 28.5 and 20.1 per 1000 person-years, respectively. The aHRs of bronchiolitis were 1.50 (95% CI, 1.48-1.52) for the asthma cohort and 1.46 (95% CI, 1.45-1.47) for the AR cohort relative to their comparisons. The CABs incidence rates decreased substantially with increasing age, but were relatively similar for boys and girls. In conclusion, children with asthma are more likely to develop CABs than are children with AR.

Oxygen saturation thresholds for bronchiolitis at high altitudes: a cost-effectiveness analysis

BACKGROUND

There is evidence suggesting that exaggerated reliance on pulse oximetry (SpO2) and the use of arbitrary/inadequate thresholds of SpO2 might drive unnecessary hospitalizations for viral bronchiolitis, especially among high-altitude residents. The aim of the present study was to compare the cost-effectiveness of two oxygen SpO2 thresholds for deciding whether infants with viral bronchiolitis living at high altitudes need hospital admission or can be discharged home.

METHODS

A cost-effectiveness study was performed to compare the cost and clinical outcomes of two oxygen SpO2 thresholds, adjusted or not, to an altitude above the sea level of Bogota, Colombia (2640 m), for deciding whether infants with viral bronchiolitis need hospitalization or can be discharged home. The principal outcome was avoidance of hospital admission.

RESULTS

Compared to the use of an SpO2 threshold of 90%, using an SpO2 threshold of 85% in infants with viral bronchiolitis was associated with lower overall costs (US$130.4 vs. US$194.0 average cost per patient) and a higher probability of hospitalization avoided (0.7500 vs. 0.5900), thus leading to dominance.

CONCLUSIONS

The use of an SpO2 threshold below 90% for deciding on hospitalization in infants with viral bronchiolitis living at high altitudes appears to be logical, secure, and cost-effective.

Improving Outcomes for Bronchiolitis Patients After Implementing a High-Flow Nasal Cannula Holiday and Standardizing Discharge Criteria in a PICU

OBJECTIVES

To decrease length of high-flow nasal cannula (HFNC), PICU, and hospital length of stay (LOS).

DESIGN

Quality improvement project.

SETTING

A quaternary academic PICU.

PATIENTS

Patients with bronchiolitis less than 24 months old.

INTERVENTIONS

After initial implementation of a respiratory therapist (RT)-driven HFNC protocol (Plan-Do-Study-Act [PDSA] 1) in October 2017, additional interventions included adjusting HFNC wean rate (PDSA 2) in July 2020, a HFNC holiday (PDSA 3), and standardized discharge criteria (PDSA 4) in October 2021.

MEASUREMENTS AND MAIN RESULTS

Duration of HFNC was used as the primary outcome measure. PICU LOS and hospital LOS were used as secondary outcome measures. Noninvasive ventilation use, invasive mechanical ventilation use, and 7-day PICU and hospital readmission rates were used as balancing measures. A total of 1,310 patients were included in this study. Patients in PDSA 2, PDSA 3 and 4 groups were older compared with pre-intervention and PDSA 1 (median of 9 and 10 mo compared with 8 mo; p = 0.01). HFNC duration decreased from 2.5 to 1.8 days after PDSA 1, then to 1.3 days after PDSA 2. PICU LOS decreased from 2.6 to 2.1 days after PDSA 1, 1.8 days after PDSA 2, and 1.5 days after PDSA 3 and 4. Hospital LOS decreased from 5.7 to 4.5 days after PDSA 1, 3.1 days after PDSA 2, and 2.7 days after PDSA 3 and 4. The use of noninvasive ventilation and invasive mechanical ventilation decreased throughout the study from 23.2% in the pre-intervention group, to 6.9% at the end of the project. The 7-day PICU and hospital readmission rates did not increase after implementation. The percentage of patients discharged from the PICU increased from 6.2% to 21.5%.

CONCLUSIONS

Modifications to an existing RT-driven HFNC protocol and standardization of discharge criteria led to an improvement in outcomes for patients admitted to the PICU with bronchiolitis without an increase in adverse events.

Comparison of two oxygen saturation targets to decide on hospital discharge of infants with viral bronchiolitis living at high altitudes: a cost-effectiveness analysis

OBJECTIVES

The objective of the current study was to evaluate the cost-effectiveness of two pulse oximetry (SpO2) thresholds to decide on hospital discharge when all other discharge criteria are met, in infants with viral bronchiolitis living at high altitudes.

METHODS

A decision analysis model was developed to estimate the cost-effectiveness of the use of an SpO2 threshold of 90% versus one of 85% for deciding whether infants hospitalized for viral bronchiolitis can be safely discharged to home, from a third-party payer's perspective. The main outcome was discharge to home at day 4 of the initial hospitalization. The time horizon was 28 days after discharge from hospital. We performed deterministic sensitivity analyses and probabilistic sensitivity analyses.

RESULTS

Compared to the use of an SpO2 threshold of 90%, treating infants with viral bronchiolitis with the use of an SpO2 threshold of 85% resulted in lower total costs (US$119.39 vs. US$188.357 mean cost per patient) and a greater probability of discharge to home at day 4 of the initial hospitalization (0.8400 vs. 0.7600), therefore being a dominant strategy. Sensitivity analyses were in line with base case results.

CONCLUSIONS

In Bogota, a high-altitude city, in infants admitted for viral bronchiolitis, the use of an SpO2 threshold of 85% to decide on hospital discharge when all other discharge criteria are met is dominant because it entails a greater probability of discharge to home at day 4 of the initial hospitalization and generates fewer costs than the use of an SpO2 threshold of 90%.

Lack of Association Between a Quantified Lung Ultrasound Score and Illness Severity in Pediatric Emergency Department Patients With Acute Lower Respiratory Infections

OBJECTIVES

Lung ultrasound (LUS) may help determine illness severity in children with acute lower respiratory tract infections (LRTI) but limited pediatric studies exist. Our objective was to determine the association between LUS findings and illness severity in children with LRTI.

METHODS

We conducted a prospective study of patients <20 years with LRTI. Trained investigators performed standardized LUS examinations of 12 regions. Blinded sonologists reviewed examinations for individual pathologic features and also calculated a Quantified Lung Ultrasound Score (QLUS). We defined focal severity as QLUS of ≥2 in ≥1 region, and diffuse severity as QLUS of ≥1 in ≥3 regions. The primary outcome was the Respiratory component of the Pediatric Early Warning Score (RPEWS), a 14-item scale measuring respiratory illness severity. Secondary outcomes included hospital admission, length of stay, supplemental oxygen, and antibiotic use.

RESULTS

We enrolled 85 patients with LRTIs, 46 (54%) whom were hospitalized (5.4% intensive care). Median RPEWS was 1 (interquartile range 2). Neither individual features on ultrasound nor total QLUS were associated with RPEWS, hospitalization, length of stay, or oxygen use. Mean RPEWS was similar for participants regardless of focal (1.46 versus 1.26, P = .57) or diffuse (1.47 versus 1.21, P = .47) severity findings, but those with focal or diffuse severity, or isolated consolidation, had greater antibiotic administration (P < .001).

CONCLUSIONS

In children with LRTI, neither individual features nor QLUS were associated with illness severity. Antibiotics were more likely in patients with either focal or diffuse severity or presence of consolidation on ultrasound.

Identification of biomarkers for disease severity in nasopharyngeal secretions of infants with upper or lower respiratory tract viral infections

Lower respiratory tract infections (LRTIs) produced by viruses are the most frequent cause of morbidity and mortality in children younger than 5 years of age. The immune response triggered by viral infection can induce a strong inflammation in the airways and cytokines could be considered as biomarkers for disease severity as these molecules modulate the inflammatory response that defines the outcome of patients. Aiming to predict the severity of disease during respiratory tract infections, we conducted a 1-year follow-up observational study in infants who presented upper or lower respiratory tract infections caused by seasonal respiratory viruses. At the time of enrollment, nasopharyngeal swabs (NPS) were obtained from infants to measure mRNA expression and protein levels of IL-3, IL-8, IL-33, and thymic stromal lymphopoietin. While all cytokines significantly increased their protein levels in infants with upper and lower respiratory tract infections as compared to control infants, IL-33 and IL-8 showed a significant increase in respiratory syncytial virus (RSV)-infected patients with LRTI as compared to patients with upper respiratory tract infection. We also found higher viral loads of RSV-positive samples with a greater IL-8 response at the beginning of the symptoms. Data obtained in this study suggest that both IL-8 and IL-33 could be used as biomarkers for clinical severity for infants suffering from LRTIs caused by the RSV.

Clinical and Socioeconomic Burden of Respiratory Syncytial Virus in Iceland

INTRODUCTION

Respiratory syncytial virus (RSV), a very common pathogen, causes variable disease severity. In addition to considerable clinical burden on children, their families and healthcare facilities, RSV infections in children also carry significant direct and indirect socioeconomic burden.

METHODS

We analyzed data from 5 consecutive RSV seasons (2015-2020) and used virologically confirmed RSV infections and age <5 years as case definition. Clinical information was retrieved from electronic patient records. Costs were estimated by assuming an annual 30% attack rate and a combination of direct medical costs and calculations of societal costs of lost productivity.

RESULTS

A total of 716 children younger than 5 years of age had confirmed RSV infection of which 254 needed hospitalizations, most of whom were previously healthy. The median length of admission was 3.6 days and 13 patients needed intensive care. The hospital admission incidence rate was 2.5/1000 children/year, but 9.1 for children younger than 1 years of age. The total annual cost of RSV was estimated at €4.3 million, of which 10% was direct healthcare costs.

DISCUSSION

The clinical and socioeconomic disease burden of RSV in Iceland is substantial despite slightly lower hospital admission rates than other high-income countries. The prevention of RSV in young children, either through maternal or infant vaccination, has the potential to decrease both clinical and financial impact of the annual epidemics.

Validation of Prediction Models for Pneumonia Among Children in the Emergency Department

BACKGROUND

Several prediction models have been reported to identify patients with radiographic pneumonia, but none have been validated or broadly implemented into practice. We evaluated 5 prediction models for radiographic pneumonia in children.

METHODS

We evaluated 5 previously published prediction models for radiographic pneumonia (Neuman, Oostenbrink, Lynch, Mahabee-Gittens, and Lipsett) using data from a single-center prospective study of patients 3 months to 18 years with signs of lower respiratory tract infection. Our outcome was radiographic pneumonia. We compared each model's area under the receiver operating characteristic curve (AUROC) and evaluated their diagnostic accuracy at statistically-derived cutpoints.

RESULTS

Radiographic pneumonia was identified in 253 (22.2%) of 1142 patients. When using model coefficients derived from the study dataset, AUROC ranged from 0.58 (95% confidence interval, 0.52-0.64) to 0.79 (95% confidence interval, 0.75-0.82). When using coefficients derived from original study models, 2 studies demonstrated an AUROC >0.70 (Neuman and Lipsett); this increased to 3 after deriving regression coefficients from the study cohort (Neuman, Lipsett, and Oostenbrink). Two models required historical and clinical data (Neuman and Lipsett), and the third additionally required C-reactive protein (Oostenbrink). At a statistically derived cutpoint of predicted risk from each model, sensitivity ranged from 51.2% to 70.4%, specificity 49.9% to 87.5%, positive predictive value 16.1% to 54.4%, and negative predictive value 83.9% to 90.7%.

CONCLUSIONS

Prediction models for radiographic pneumonia had varying performance. The 3 models with higher performance may facilitate clinical management by predicting the risk of radiographic pneumonia among children with lower respiratory tract infection.

Positioning for acute respiratory distress in hospitalised infants and children

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a significant cause of hospitalisation and death in young children. Positioning and mechanical ventilation have been regularly used to reduce respiratory distress and improve oxygenation in hospitalised patients. Due to the association of prone positioning (lying on the abdomen) with sudden infant death syndrome (SIDS) within the first six months, it is recommended that young infants be placed on their back (supine). However, prone positioning may be a non-invasive way of increasing oxygenation in individuals with acute respiratory distress, and offers a more significant survival advantage in those who are mechanically ventilated. There are substantial differences in respiratory mechanics between adults and infants. While the respiratory tract undergoes significant development within the first two years of life, differences in airway physiology between adults and children become less prominent by six to eight years old. However, there is a reduced risk of SIDS during artificial ventilation in hospitalised infants. Thus, an updated review focusing on positioning for infants and young children with ARDS is warranted. This is an update of a review published in 2005, 2009, and 2012.

OBJECTIVES

To compare the effects of different body positions in hospitalised infants and children with acute respiratory distress syndrome aged between four weeks and 16 years.

SEARCH METHODS

We searched CENTRAL, which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE, Embase, and CINAHL from January 2004 to July 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing two or more positions for the management of infants and children hospitalised with ARDS.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from each study. We resolved differences by consensus, or referred to a third contributor to arbitrate. We analysed bivariate outcomes using an odds ratio (OR) and 95% confidence interval (CI). We analysed continuous outcomes using a mean difference (MD) and 95% CI. We used a fixed-effect model, unless heterogeneity was significant (I² statistic > 50%), when we used a random-effects model.

MAIN RESULTS

We included six trials: four cross-over trials, and two parallel randomised trials, with 198 participants aged between 4 weeks and 16 years, all but 15 of whom were mechanically ventilated. Four trials compared prone to supine positions. One trial compared the prone position to good-lung dependent (where the person lies on the side of the healthy lung, e.g. if the right lung was healthy, they were made to lie on the right side), and independent (or non-good-lung independent, where the person lies on the opposite side to the healthy lung, e.g. if the right lung was healthy, they were made to lie on the left side) position. One trial compared good-lung independent to good-lung dependent positions. When the prone (with ventilators) and supine positions were compared, there was no information on episodes of apnoea or mortality due to respiratory events. There was no conclusive result in oxygen saturation (SaO_2; MD 0.40 mmHg, 95% CI -1.22 to 2.66; 1 trial, 30 participants; very low certainty evidence); blood gases, PCO₂ (MD 3.0 mmHg, 95% CI -1.93 to 7.93; 1 trial, 99 participants; low certainty evidence), or PO₂ (MD 2 mmHg, 95% CI -5.29 to 9.29; 1 trial, 99 participants; low certainty evidence); or lung function (PaO₂/FiO₂ ratio; MD 28.16 mmHg, 95% CI -9.92 to 66.24; 2 trials, 121 participants; very low certainty evidence). However, there was an improvement in oxygenation index (FiO₂% X M_PAW/ PaO₂) with prone positioning in both the parallel trials (MD -2.42, 95% CI -3.60 to -1.25; 2 trials, 121 participants; very low certainty evidence), and the cross-over study (MD -8.13, 95% CI -15.01 to -1.25; 1 study, 20 participants). Derived indices of respiratory mechanics, such as tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP) were reported. There was an apparent decrease in tidal volume between prone and supine groups in a parallel study (MD -0.60, 95% CI -1.05 to -0.15; 1 study, 84 participants; very low certainty evidence). When prone and supine positions were compared in a cross-over study, there were no conclusive results in respiratory compliance (MD 0.07, 95% CI -0.10 to 0.24; 1 study, 10 participants); changes in PEEP (MD -0.70 cm H₂O, 95% CI -2.72 to 1.32; 1 study, 10 participants); or resistance (MD -0.00, 95% CI -0.05 to 0.04; 1 study, 10 participants). One study reported adverse events. There were no conclusive results for potential harm between groups in extubation (OR 0.57, 95% CI 0.13 to 2.54; 1 trial, 102 participants; very low certainty evidence); obstructions of the endotracheal tube (OR 5.20, 95% CI 0.24 to 111.09; 1 trial, 102 participants; very low certainty evidence); pressure ulcers (OR 1.00, 95% CI 0.41 to 2.44; 1 trial, 102 participants; very low certainty evidence); and hypercapnia (high levels of arterial carbon dioxide; OR 3.06, 95% CI 0.12 to 76.88; 1 trial, 102 participants; very low certainty evidence). One study (50 participants) compared supine positions to good-lung dependent and independent positions. There was no conclusive evidence that PaO₂ was different between supine and good-lung dependent positioning (MD 3.44 mm Hg, 95% CI -23.12 to 30.00; 1 trial, 25 participants; very low certainty evidence). There was also no conclusive evidence for supine position and good-lung independent positioning (MD -2.78 mmHg, 95% CI -28.84, 23.28; 25 participants; very low certainty evidence); or between good-lung dependent and independent positioning (MD 6.22, 95% CI -21.25 to 33.69; 1 trial, 25 participants; very low certainty evidence). As most trials did not describe how possible biases were addressed, the potential for bias in these findings is unclear.

AUTHORS' CONCLUSIONS

Although included studies suggest that prone positioning may offer some advantage, there was little evidence to make definitive recommendations. There appears to be low certainty evidence that positioning improves oxygenation in mechanically ventilated children with ARDS. Due to the increased risk of SIDS with prone positioning and lung injury with artificial ventilation, it is recommended that hospitalised infants and children should only be placed in this position while under continuous cardiorespiratory monitoring.

Bronchiolitis hospitalizations in rural New England: clues to disease prevention

Background:

An improved understanding of the clinico-epidemiology of bronchiolitis hospitalizations, a clinical surrogate of respiratory syncytial virus (RSV) disease, is critical to inform public health strategies for mitigating the in-patient burden of bronchiolitis in early life.

Methods:

A retrospective chart review was conducted of all bronchiolitis first admissions (N = 295) to the Children’s Hospital at Dartmouth-Hitchcock, CHaD, between 1 November 2010 and 31 October 2017 using the relevant International Classification of Diseases (ICD)-9 and ICD-10 codes for this illness. Abstracted data included laboratory confirmation of RSV infection, severity of illness, duration of hospitalization, age at admission in days, weight at admission, prematurity, siblings, and relevant medical pre-existing conditions.

Results:

Admissions for bronchiolitis were strongly associated with age of the child, the calendar month of an infant’s birth, and the presence of older children in the family. Medical risk factors associated with admission included premature birth and underlying cardiopulmonary disease.

Conclusion:

The very early age of hospitalization emphasizes the high penetration of RSV in the community, by implication the limited protection afforded by maternal antibody, and the complexity of protecting infants from this infection.

Plain Language Summary

Although risks for respiratory syncytial virus (RSV)/bronchiolitis hospitalization are well described, few studies have examined, with precision, the age-related frequency and severity of RSV/bronchiolitis. We also explore the implications of RSV clinico-epidemiology for our understanding of the pathogenesis of the disease and development of optimal approaches to prevention.

Distinguishing viruses responsible for influenza-like illness

The many respiratory viruses that cause influenza-like illness (ILI) are reported and tracked as one entity, defined by the CDC as a group of symptoms that include a fever of 100 degrees Fahrenheit, a cough, and/or a sore throat. In the United States alone, ILI impacts 9-49 million people every year. While tracking ILI as a single clinical syndrome is informative in many respects, the underlying viruses differ in parameters and outbreak properties. Most existing models treat either a single respiratory virus or ILI as a whole. However, there is a need for models capable of comparing several individual viruses that cause respiratory illness, including ILI. To address this need, here we present a flexible model and simulations of epidemics for influenza, RSV, rhinovirus, seasonal coronavirus, adenovirus, and SARS/MERS, parameterized by a systematic literature review and accompanied by a global sensitivity analysis. We find that for these biological causes of ILI, their parameter values, timing, prevalence, and proportional contributions differ substantially. These results demonstrate that distinguishing the viruses that cause ILI will be an important aspect of future work on diagnostics, mitigation, modeling, and preparation for future pandemics.

Respiratory viral infections are prevalent but uncomplicated in single ventricle CHD

BACKGROUND

Patients with single ventricle CHD have significant morbidity and healthcare utilisation throughout their lifetime, including non-cardiac hospital admissions. Respiratory viral infections are the main cause of hospitalisation in children, but few data exist for single ventricle patients. We sought to identify how respiratory viral infections impact patients with single ventricle CHD and potential differences between Glenn and Fontan circulation.

METHODS

We conducted a retrospective study of patients seen from 01/01/2011-12/31/2020. We identified patients with a history of single ventricle CHD and Glenn palliation, and a normoxic control group with isolated atrial septal defect requiring surgical closure. We compared viral-related clinical presentations, admissions, and admission characteristics.

RESULTS

A total of 312 patients were included (182 single ventricle, 130 atrial septal defect). Single ventricle patients were more likely than children with isolated atrial septal defect to be admitted with a respiratory virus (odds ratio 4.15 [2.30-7.46]), but there was no difference in mechanical ventilation or hospital length of stay (p = 0.4709). Single ventricle patients with Glenn circulation were more likely than those with Fontan circulation to present and be admitted (odds ratio 3.25 [1.62-6.52]), but there was no difference in ICU admission, mechanical ventilation, or hospital length of stay (p = 0.1516).

CONCLUSIONS

Respiratory viral infections are prevalent but uncomplicated in patients with single ventricle CHD. Viral-related presentations and admissions are more prevalent during the period of Glenn circulation compared to Fontan circulation; however, rate of mechanical ventilation and hospital length of stay are similar.

Rapid typing diagnosis and clinical analysis of subtypes A and B of human respiratory syncytial virus in children

Background

Human respiratory syncytial virus (HRSV) is the leading pathogens causing acute respiratory infections (ARI) in children under five years old. We aimed to investigate the distribution of HRSV subtypes and explore the relationship between viral subtypes and clinical symptoms and disease severity.

Methods

From November 2016 to April 2017, 541 children hospitalized because of ARI were included in the study. Throat swabs were collected for analysis and all samples were tested by multiplex one-step qRT-PCR for quantitative analysis and typing of HRSV. Patients’ demographics, clinical symptoms as well as laboratory and imaging results were retrieved from medical records.

Results

HRSV was detected in 19.6% of children hospitalized due to ARI. HRSV-positive children were younger (P < 0.001), had a higher frequency of wheezing and pulmonary rales (P < 0.001; P = 0.003), and were more likely to develop bronchopneumonia (P < 0.001). Interleukin (IL) 10、CD4/CD8 (below normal range) and C-reactive protein levels between subtypes A and B groups were significantly different (P = 0.037; P = 0.029; P = 0.007), and gender differences were evident. By age-stratified analysis between subtypes A and B, we found significant differences in fever frequency and lymphocyte ratio (P = 0.008; P = 0.03) in the 6–12 months age group, while the 12. 1–36 months age group showed significant differences in fever days and count of leukocytes, platelets, levels aspartate aminotransferase, IL-6, lactate dehydrogenase and proportion CD4 positive T cells(P = 0.013; P = 0.018; P = 0.016; P = 0.037; P = 0.049; P = 0.025; P = 0.04). We also found a positive correlation between viral load and wheezing days in subtype A (P < 0.05), and a negative correlation between age, monocyte percentage and LDH concentration in subtype B (P < 0.05).

Conclusions

HRSV is the main causative virus of bronchopneumonia in infants and children. The multiplex one-step qRT-PCR not only provides a rapid and effective diagnosis of HRSV infection, but also allows its typing. There were no significant differences in the severity of HRSV infection between subtypes A and B, except significant gender-specific and age-specific differences in some clinical characteristics and laboratory results. Knowing the viral load of HRSV infection can help understanding the clinical features of different subtypes of HRSV infection.

High Flow Nasal Cannula Therapy in the Emergency Department: Main Benefits in Adults, Pediatric Population and against COVID-19: A Narrative Review

This review aims to summarize the literature’s main results about high flow nasal cannula therapy (HFNC) HFNC benefits in the Emergency Department (ED) in adults and pediatrics, including new Coronavirus Disease (COVID-19). HFNC has recently been established as the usual treatment in the ED to provide oxygen support. Its use has been generalized due to its advantages over traditional oxygen therapy devices, including decreased nasopharyngeal resistance, washing out of the nasopharyngeal dead space, generation of positive pressure, increasing alveolar recruitment, easy adaptation due to the humidification of the airways, increased fraction of inspired oxygen and improved mucociliary clearance. A wide range of pathologies has been studied to evaluate the potential benefits of HFNC; some examples are heart failure, pneumonia, chronic pulmonary obstructive disease, asthma, and bronchiolitis. The regular use of this oxygen treatment is not established yet due to the literature’s controversial results. However, several authors suggest that it could be useful in several pathologies that generate acute respiratory failure. Consequently, the COVID-19 irruption has generated the question of HFNC as a safety and effective treatment. Our results suggested that HFNC seems to be a useful tool in the ED, especially in patients affected by acute hypoxemic respiratory failure, acute heart failure, pneumonia, bronchiolitis, asthma and acute respiratory distress syndrome in patients affected by COVID-19. Its benefits in hypercapnic respiratory failure are more discussed, being only observed benefits in patients with mild-moderate disease. These results are based in clinical as well as cost-effectiveness outcomes. Future studies with largest populations are required to confirm these results as well as establish a practical guideline to use this device.

The Role of Interferons in Driving Susceptibility to Asthma Following Bronchiolitis: Controversies and Research Gaps

Bronchiolitis is the most common cause of hospitalization in infancy and is associated with a higher risk for the development of childhood asthma. However, not all children hospitalized with bronchiolitis will develop asthma. The mechanisms underlying asthma development following bronchiolitis hospitalization are complex. Immune responses to respiratory viruses may underlie both bronchiolitis severity and long-term sequela (such as asthma). Interferons (IFNs) are important components of innate immune responses to respiratory viruses and could influence both asthma development and asthma exacerbations. However, the nature of the relationship between interferon production and wheezing illnesses is controversial. For example, low peripheral blood IFN responses at birth have been linked with recurrent wheeze and asthma development. In contrast, there is evidence that severe illnesses (e.g., hospitalization for bronchiolitis) are associated with increased IFN responses during acute infection (bronchiolitis hospitalization) and a higher risk for subsequent asthma diagnosis. Furthermore, mechanistic studies suggest that bronchial epithelial cells from asthmatic children have impaired IFN responses to respiratory viruses, which may enable increased viral replication followed by exaggerated secondary IFN responses. This review aims to discuss controversies around the role of IFNs as drivers of susceptibility to asthma development following bronchiolitis hospitalization. Past evidence from both mechanistic and cohort studies are discussed. We will highlight knowledge gaps that can inform future research study design.

Detailed Evolutionary Analyses of the F Gene in the Respiratory Syncytial Virus Subgroup A

We performed evolution, phylodynamics, and reinfection-related antigenicity analyses of respiratory syncytial virus subgroup A (RSV-A) fusion (F) gene in globally collected strains (1465 strains) using authentic bioinformatics methods. The time-scaled evolutionary tree using the Bayesian Markov chain Monte Carlo method estimated that a common ancestor of the RSV-A, RSV-B, and bovine-RSV diverged at around 450 years ago, and RSV-A and RSV-B diverged around 250 years ago. Finally, the RSV-A F gene formed eight genotypes (GA1-GA7 and NA1) over the last 80 years. Phylodynamics of RSV-A F gene, including all genotype strains, increased twice in the 1990s and 2010s, while patterns of each RSV-A genotype were different. Phylogenetic distance analysis suggested that the genetic distances of the strains were relatively short (less than 0.05). No positive selection sites were estimated, while many negative selection sites were found. Moreover, the F protein 3D structure mapping and conformational epitope analysis implied that the conformational epitopes did not correspond to the neutralizing antibody binding sites of the F protein. These results suggested that the RSV-A F gene is relatively conserved, and mismatches between conformational epitopes and neutralizing antibody binding sites of the F protein are responsible for the virus reinfection.

An outbreak of RSV infections in a neonatology clinic during the RSV-season

BACKGROUND

Respiratory syncytial virus (RSV) is the predominant cause of lower respiratory tract infections (LRTI) in infancy. Preterm infants with bronchopulmonary dysplasia (BPD) are at the highest risk of severe RSV-LRTI. This is a retrospective study that analyses a nosocomial outbreak of RSV infections in the Neonatology clinic of the University Hospital of Obstetrics and Gynecology, Sofia, 2019.

METHODS

Two groups of infants without contact between them were diagnosed with RSV-infection: 14 infants were treated in the Department for healthy newborns - Group 1, and 7 preterm infants were treated in the Neonatal Intensive Care Unit (NICU) - Group 2. The detection of RSV was performed using Real-Time PCR in nasal/throat swabs.

RESULTS

Respiratory symptoms occurred 2-5 days after discharge in 14 of 148 healthy term infants born February 5 to 18, 2019; 12 babies were re-hospitalized with LRTI and recovered in a few days. RSV-PCR was positive in 6 infants, while in the others, RSV etiology was suggested, due to similar symptoms and contact between them. The first NICU patient with RSV-LRTI was one of the 26 gestational weeks (GW) twins, who had severe BPD. The other twin was always discharged home without LRTI-symptoms. In the period February 19 to March 15, 2019, 26 premature babies born at 26-34 GW, were tested for RSV (33 nasal/throat swabs). They received a first or subsequent palivizumab injection. We identified 11 positive samples in 7 of the babies. Despite the clinical recovery, the second RSV-PCR remained positive in 4 babies. Six of the 7 NICU patients had symptoms of LRTI, and two of them needed mechanical ventilation. Six babies were discharged home after stabilization, one was transferred to the Pediatric department for further treatment of BPD and later discharged too.

CONCLUSIONS

This was the most serious outbreak of RSV infections in neonates since the RSV-PCR diagnostic in Bulgaria was introduced. The course of RSV-LRTI was severe in extremely preterm patients with underlying BPD. So, routine in-hospital RSV-prophylaxis with palivizumab should be considered for infants at the highest risk.

Healthcare cost attributable to bronchiolitis: A population-based cohort study

OBJECTIVE

To determine 1-year attributable healthcare costs of bronchiolitis.

METHODS

Using a population-based matched cohort and incidence-based cost analysis approach, we identified infants <12 months old diagnosed in an emergency department (ED) or hospitalized with bronchiolitis between April 1, 2003 and March 31, 2014. We propensity-score matched infants with and without bronchiolitis on sex, age, income quintile, rurality, co-morbidities, gestational weeks, small-for-gestational-age status and pre-index healthcare cost deciles. We calculated mean attributable 1-year costs using a generalized estimating equation model and stratified costs by age, sex, income quintile, rurality, co-morbidities and prematurity.

RESULTS

We identified 58,375 infants with bronchiolitis (mean age 154±95 days, 61.3% males, 4.2% with comorbidities). Total 1-year mean bronchiolitis-attributable costs were $4,313 per patient (95%CI: $4,148-4,477), with $2,847 (95%CI: $2,712-2,982) spent on hospitalizations, $610 (95%CI: $594-627) on physician services, $562 (95%CI: $556-567)] on ED visits, $259 (95%CI: $222-297) on other healthcare costs and $35 ($27-42) on drugs. Attributable bronchiolitis costs were $2,765 (95%CI: $2735-2,794) vs $111 (95%CI: $102-121) in the initial 10 days post index date, $4,695 (95%CI: $4,589-4,800) vs $910 (95%CI: $847-973) in the initial 180 days and $1,158 (95%CI: $1,104-1213) vs $639 (95%CI: $599-679) during days 181-360. Mean 1-year bronchiolitis costs were higher in infants <3 months old [$5,536 (95%CI: $5,216-5,856)], those with co-morbidities [$17,530 (95%CI: $14,683-20,377)] and with low birthweight [$5,509 (95%CI: $4,927-6,091)].

CONCLUSIONS

Compared to no bronchiolitis, bronchiolitis incurs five-time and two-time higher healthcare costs within the initial and subsequent six-months, respectively. Most expenses occur in the initial 10 days and relate to hospitalization.

Risk Factors Associated with Mechanical Ventilation in Critical Bronchiolitis

The American Academy of Pediatrics (AAP) recommends supportive care for the management of bronchiolitis. However, patients admitted to the intensive care unit with severe (critical) bronchiolitis define a unique group with varying needs for both non-invasive and invasive respiratory support. Currently, no guidance exists to help clinicians discern who will progress to invasive mechanical support. Here, we sought to identify key clinical features that distinguish pediatric patients with critical bronchiolitis requiring invasive mechanical ventilation from those that did not. We conducted a retrospective cohort study at a tertiary pediatric medical center. Children ≤2 years old admitted to the pediatric intensive care unit (PICU) from January 2015 to December 2019 with acute bronchiolitis were studied. Patients were divided into non-invasive respiratory support (NRS) and invasive mechanical ventilation (IMV) groups; the IMV group was further subdivided depending on timing of intubation relative to PICU admission. Of the 573 qualifying patients, 133 (23%) required invasive mechanical ventilation. Median age and weight were lower in the IMV group, while incidence of prematurity and pre-existing neurologic or genetic conditions were higher compared to the NRS group. Multi-microbial pneumonias were diagnosed more commonly in the IMV group, in turn associated with higher severity of illness scores, longer PICU lengths of stay, and more antibiotic usage. Within the IMV group, those intubated earlier had a shorter duration of mechanical ventilation and PICU length of stay, associated with lower pathogen load and, in turn, shorter antibiotic duration. Taken together, our data reveal that critically ill patients with bronchiolitis who require mechanical ventilation possess high risk features, including younger age, history of prematurity, neurologic or genetic co-morbidities, and a propensity for multi-microbial infections.

Health Care-Acquired Viral Respiratory Diseases

Health care-acquired viral respiratory infections are common and cause increased patient morbidity and mortality. Although the threat of viral respiratory infection has been underscored by the coronavirus disease 2019 (COVID-19) pandemic, respiratory viruses have a significant impact in health care settings even under normal circumstances. Studies report decreased nosocomial transmission when aggressive infection control measures are implemented, with more success noted when using a multicomponent approach. Influenza vaccination of health care personnel furthers decrease rates of transmission; thus, mandatory vaccination is becoming more common. This article discusses the epidemiology, transmission, and control of health care-associated respiratory viral infections.

Evaluation of Human Respiratory Syncytial Virus and Human Parainfluenza Virus Type 3 among Hospitalized Children in Northwest of Iran

Background

Acute respiratory tract infections (ARTIs) are the leading cause of illnesses in children. Human respiratory syncytial virus (HRSV) and human parainfluenza viruses (HPIVs) are among the most common etiologic agents associated with viral respiratory tract infections in children worldwide. Nevertheless, limited information is available on the spread of infections of these two viruses in northwest Iran.

Objective

The purpose of the current study is to evaluate the frequency of RSV and HPIV-3 and clinical features among Iranian children with confirmed respiratory infections between April 2019 and March 2020.

Methods

100 nasopharyngeal swabs were collected from hospitalized patients (under 5 years old) with ARTI from Tabriz Children's Hospital. Detection of respiratory viruses was performed using the nested RT-PCR method.

Results

Respiratory syncytial virus and HPIV-3 were recognized in 18% (18/100) and 2% (2/100) of children, respectively. Ten (55.6%) of the RSV-positive samples were male, while 8 (44.4%) were female. HPIV-3 was found only among 2 male patients (100%). Most patients (61.1%) with RSV infection were less than 12 months old. Additionally, samples that were positive for HPIV-3 were less than 12 months old. RSV infections had occurred mainly during the winter season.

Conclusions

This study confirms that RSV can be one of the important respiratory pathogens in children in northwestern Iran. However, according to this study, HPIV-3 has a lower prevalence among children in this area than RSV. Therefore, implementing a routine diagnosis for respiratory pathogens can improve the management of respiratory infections in children.

A Cost Analysis of Pulse Oximetry as a Determinant in the Decision to Admit Infants With Mild to Moderate Bronchiolitis

OBJECTIVES

A previous randomized controlled trial showed that artificially elevating the pulse oximetry display resulted in fewer hospitalizations with no worse outcomes. This suggests that management decisions based mainly on pulse oximetry may unnecessarily increase health care costs. This study assessed the incremental cost of altered relative to true oximetry in infants with mild to moderate bronchiolitis.

METHODS

A cost analysis was undertaken from the health care system and societal perspectives using patient-level data from the randomized controlled trial, with a 5-day time horizon after emergency department visit. Infants aged 4 weeks to 12 months with mild to moderate bronchiolitis were randomized to pulse oximetry measurements with true or altered saturation values displayed by artificially increasing saturation 3% points above true values. Direct and indirect health care costs were measured. Sensitivity analyses were performed to assess parameter uncertainty.

RESULTS

From the health care system perspective, the average cost per patient was Can $1155 for altered oximetry and $1967 for true oximetry, with a net savings of $812. From a societal perspective, the average cost per patient was $1559 for altered oximetry and $2473 for true oximetry, with a net savings of $914. Probabilistic analyses demonstrated that altered oximetry remained the less costly study group, with an average savings of $810 (95% confidence interval, $748-$872) from the health care system perspective and $910 (95% confidence interval, $848-$973) from the societal system perspective.

CONCLUSIONS

Reliance on oximetry as a major determinant in the decision to hospitalize infants with mild to moderate bronchiolitis is associated with significantly greater costs.

Effectiveness of Targeted Interventions on Treatment of Infants With Bronchiolitis: A Randomized Clinical Trial

IMPORTANCE

In developed countries, bronchiolitis is the most common reason for infants to be admitted to the hospital, and all international bronchiolitis guidelines recommend supportive care; however, significant variation in practice continues with infants receiving non-evidence-based therapies. Deimplementation research aims to reduce the use of low-value care, and advancing science in this area is critical to delivering evidence-based care.

OBJECTIVE

To determine the effectiveness of targeted interventions vs passive dissemination of an evidence-based bronchiolitis guideline in improving treatment of infants with bronchiolitis.

DESIGN, SETTING, AND PARTICIPANTS

This international, multicenter cluster randomized clinical trial included 26 hospitals (clusters) in Australia and New Zealand providing tertiary or secondary pediatric care (13 randomized to intervention, 13 to control) during the 2017 bronchiolitis season. Data were collected on 8003 infants for the 3 bronchiolitis seasons (2014-2016) before the implementation period and 3727 infants for the implementation period (2017 bronchiolitis season, May 1-November 30). Data were analyzed from November 16, 2018, to December 9, 2020.

INTERVENTIONS

Interventions were developed using theories of behavior change to target key factors that influence bronchiolitis management. These interventions included site-based clinical leads, stakeholder meetings, a train-the-trainer workshop, targeted educational delivery, other educational and promotional materials, and audit and feedback.

MAIN OUTCOMES AND MEASURES

The primary outcome was compliance during the first 24 hours of care with no use of chest radiography, albuterol, glucocorticoids, antibiotics, and epinephrine, measured retrospectively from medical records of randomly selected infants with bronchiolitis who presented to the hospital. There were no patient-level exclusions.

RESULTS

A total of 26 hospitals were randomized without dropouts. Analysis was by intention to treat. Baseline data collected on 8003 infants for 3 bronchiolitis seasons (2014-2016) before the implementation period were similar between intervention and control hospitals. Implementation period data were collected on 3727 infants, including 2328 boys (62%) and 1399 girls (38%), with a mean (SD) age of 6.0 (3.2) months. A total of 459 (12%) were Māori (New Zealand), and 295 (8%) were Aboriginal/Torres Strait Islander (Australia). Compliance with recommendations was 85.1% (95% CI, 82.6%-89.7%) in intervention hospitals vs 73.0% (95% CI, 65.3%-78.8%) in control hospitals (adjusted risk difference, 14.1%; 95% CI, 6.5%-21.7%; P < .001).

CONCLUSIONS AND RELEVANCE

Targeted interventions led to improved treatment of infants with bronchiolitis. This study has important implications for bronchiolitis management and the development of effective interventions to deimplement low-value care.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry: ACTRN12616001567415.

Ozone inactivation of airborne influenza and lack of resistance of respiratory syncytial virus to aerosolization and sampling processes

Influenza and RSV are human viruses responsible for outbreaks in hospitals, long-term care facilities and nursing homes. The present study assessed an air treatment using ozone at two relative humidity conditions (RHs) in order to reduce the infectivity of airborne influenza. Bovine pulmonary surfactant (BPS) and synthetic tracheal mucus (STM) were used as aerosols protectants to better reflect the human aerosol composition. Residual ozone concentration inside the aerosol chamber was also measured. RSV's sensitivity resulted in testing its resistance to aerosolization and sampling processes instead of ozone exposure. The results showed that without supplement and with STM, a reduction in influenza A infectivity of four orders of magnitude was obtained with an exposure to 1.70 ± 0.19 ppm of ozone at 76% RH for 80 min. Consequently, ozone could be considered as a virucidal disinfectant for airborne influenza A. RSV did not withstand the aerosolization and sampling processes required for the use of the experimental setup. Therefore, ozone exposure could not be performed for this virus. Nonetheless, this study provides great insight for the efficacy of ozone as an air treatment for the control of nosocomial influenza A outbreaks.

Aligning Patient Safety and Stewardship: A Harm Reduction Strategy for Children

Purpose of review

Review important patient safety and stewardship concepts and use clinical examples to describe how they align to improve patient outcomes and reduce harm for children.

Recent findings

Current evidence indicates that healthcare overuse is substantial. Unnecessary care leads to avoidable adverse events, anxiety and distress, and financial toxicity. Increases in antimicrobial resistance, venous thromboembolism, radiation exposure, and healthcare costs are examples of patient harm associated with a lack of stewardship. Studies indicate that many tools can increase standardization of care, improve resource utilization, and enhance safety culture to better align safety and stewardship.

Summary

The principles of stewardship and parsimonious care can improve patient safety for children.

Respiratory syncytial virus induces β2-adrenergic receptor dysfunction in human airway smooth muscle cells

Pharmacologic agonism of the β₂-adrenergic receptor (β₂AR) induces bronchodilation by activating the enzyme adenylyl cyclase to generate cyclic adenosine monophosphate (cAMP). β₂AR agonists are generally the most effective strategy to relieve acute airway obstruction in asthmatic patients, but they are much less effective when airway obstruction in young patients is triggered by infection with respiratory syncytial virus (RSV). Here, we investigated the effects of RSV infection on the abundance and function of β₂AR in primary human airway smooth muscle cells (HASMCs) derived from pediatric lung tissue. We showed that RSV infection of HASMCs resulted in proteolytic cleavage of β₂AR mediated by the proteasome. RSV infection also resulted in β₂AR ligand-independent activation of adenylyl cyclase, leading to reduced cAMP synthesis compared to that in uninfected control cells. Last, RSV infection caused stronger airway smooth muscle cell contraction in vitro due to increased cytosolic Ca²⁺ concentrations. Thus, our results suggest that RSV infection simultaneously induces loss of functional β₂ARs and activation of multiple pathways favoring airway obstruction in young patients, with the net effect of counteracting β₂AR agonist-induced bronchodilation. These findings not only provide a potential mechanism for the reported lack of clinical efficacy of β₂AR agonists for treating virus-induced wheezing but also open the path to developing more precise therapeutic strategies.

A Retrospective Analysis of Feeding Practices and Complications in Patients with Critical Bronchiolitis on Non-Invasive Respiratory Support

Limited data exist regarding feeding pediatric patients managed on non-invasive respiratory support (NRS) modes that augment oxygenation and ventilation in the setting of acute respiratory failure. We conducted a retrospective cohort study to explore the safety of feeding patients managed on NRS with acute respiratory failure secondary to bronchiolitis. Children up to two years old with critical bronchiolitis managed on continuous positive airway pressure, bilevel positive airway pressure, or RAM cannula were included. Of the 178 eligible patients, 64 were reportedly nil per os (NPO), while 114 received enteral nutrition (EN). Overall equivalent in severity of illness, younger patients populated the EN group, while the NPO group experienced a higher incidence of intubation. Duration of stay in the pediatric intensive care unit and non-invasive respiratory support were shorter in the NPO group, though intubation eliminated the former difference. Within the EN group, ninety percent had feeds initiated within 48 h and 94% reached full feeds within 7 days of NRS initiation, with an 8% complication and <1% aspiration rate. Reported complications did not result in escalation of respiratory support. Notably, a significant improvement in heart rate and respiratory rate was noted after feeds initiation. Taken together, our study supports the practice of early enteral nutrition in patients with critical bronchiolitis requiring NRS.

Monoclonal Antibodies for Prevention of Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the leading cause of hospitalizations in infants worldwide. Palivizumab, a humanized monoclonal antibody against the RSV F protein, is the only licensed agent for prevention of severe RSV infection in high-risk infants. Palivizumab is administered intramuscularly, every month during the RSV season, usually 5 doses are required. In recent years, the resolution of the structure of the RSV F protein, with identification of potent neutralizing epitopes, and new technologies for production of monoclonal antibodies (mAbs) have facilitated the development of new alternative strategies for the prevention of RSV infections. One promising approach is a new generation of mAbs directed to new neutralizing epitopes and with prolonged half life. These enhanced mAbs are expected to provide adequate protection during the complete RSV season with a single intramuscular (IM) dose. The long-term goal of this approach is to provide passive immunization for the prevention of RSV lower respiratory tract infection to all infants (preterm and full term) in the first months of life before their initial exposure to RSV.

Predictive factors of continuous negative extrathoracic pressure management failure in children with moderate to severe respiratory syncytial virus infection

Continuous negative extrathoracic pressure (CNEP) might be beneficial for children with severe respiratory tract infections. However, there are no available data on the predictors of its failure among individuals with respiratory syncytial virus (RSV) infections. Here, we conducted a retrospective cohort study between October 1, 2015 and October 31, 2018 in hospitalized children with moderate to severe symptoms of respiratory syncytial virus (RSV) infections. We divided 45 children requiring CNEP ventilation with a non-fluctuating negative pressure of - 12 cm H2O into two groups. They were classified based on improvement or deterioration of their respiratory disorder under CNEP ventilation (responder group: n = 27, failure group: n = 18). Based on the univariate analysis, the responder and failure groups significantly differed in terms of median age, days elapsed from RSV onset to the initiation of CNEP, white blood cell count (WBC), titer of venous pCO2, body temperature at admission, and modified Wood-Downes Score (mWDS) 6 h after initiating CNEP. Based on a logistic regression analysis adjusted for age < 1 year upon admission, less than 5 days elapsed from RSV onset to the initiation of CNEP, not high value of WBC and body temperature at admission, and high values of mWDS 6 h after initiating CNEP were found to be significant independent risk factors for CNEP ventilation failure. The former two variables were associated with less failure (odds ratio was approximately 5), and the latter two variables are associated with more failure (odds ratio was approximately 8-9). Thus, CNEP could be a valid option for children with moderate to severe RSV infections, especially in those who were aged > 1 year, and specific clinical and laboratory findings.

RSV infection potentiates TRPV1-mediated calcium transport in bronchial epithelium of asthmatic children

The transient receptor potential vanilloid 1 (TRPV₁) channel is expressed in human bronchial epithelium (HBE), where it transduces Ca²⁺ in response to airborne irritants. TRPV₁ activation results in bronchoconstriction, cough, and mucus production, and may therefore contribute to the pathophysiology of obstructive airway disease. Since children with asthma face the greatest risk of developing virus-induced airway obstruction, we hypothesized that changes in TRPV₁ expression, localization, and function in the airway epithelium may play a role in bronchiolitis and asthma in childhood. We sought to measure TRPV₁ protein expression, localization, and function in HBE cells from children with versus without asthma, both at baseline and after RSV infection. We determined changes in TRPV₁ protein expression, subcellular localization, and function both at baseline and after RSV infection in primary HBE cells from normal children and children with asthma. Basal TRPV₁ protein expression was higher in HBE from children with versus without asthma and primarily localized to plasma membranes (PMs). During RSV infection, TRPV₁ protein increased more in the PM of asthmatic HBE as compared with nonasthmatic cells. TRPV₁-mediated increase in intracellular Ca²⁺ was greater in RSV-infected asthmatic cells, but this increase was attenuated when extracellular Ca²⁺ was removed. Nerve growth factor (NGF) recapitulated the effect of RSV on TRPV₁ activation in HBE cells. Our data suggest that children with asthma have intrinsically hyperreactive airways due in part to higher TRPV₁-mediated Ca²⁺ influx across epithelial membranes, and this abnormality is further exacerbated by NGF overexpression during RSV infection driving additional Ca²⁺ from intracellular stores.

Molecular epidemiology of respiratory syncytial virus in children in sub-Saharan Africa

OBJECTIVES

This study investigated the molecular epidemiology of respiratory syncytial virus (RSV) among febrile children with acute respiratory tract infection in Ghana, Gabon, Tanzania and Burkina Faso between 2014 and 2017 as well as the evolution and diversification of RSV strains from other sub-Saharan countries.

METHODS

Pharyngeal swabs were collected at four study sites (Agogo, Ghana: n = 490; Lambaréné, Gabon: n = 182; Mbeya, Tanzania: n = 293; Nouna, Burkina Faso: n = 115) and analysed for RSV and other respiratory viruses using rtPCR. For RSV-positive samples, sequence analysis of the second hypervariable region of the G gene was performed. A dataset of RSV strains from sub-Saharan Africa (2011-2017) currently available in GenBank was compiled. Phylogenetic analysis was conducted to identify the diversity of circulating RSV genotypes.

RESULTS

In total, 46 samples were tested RSV positive (Ghana n = 31 (6.3%), Gabon n = 4 (2.2%), Tanzania n = 9 (3.1%) and Burkina Faso n = 2 (1.7%)). The most common RSV co-infection was with rhinovirus. All RSV A strains clustered with genotype ON1 strains with a 72-nucleotide duplication and all RSV B strains belonged to genotype BAIX. Phylogenetic analysis of amino acid sequences from sub-Saharan Africa revealed the diversification into 11 different ON1 and 22 different BAIX lineages and differentiation of ON1 and BAIX strains into potential new sub-genotypes, provisionally named ON1-NGR, BAIX-KEN1, BAIX-KEN2 and BAIX-KEN3.

CONCLUSION

The study contributes to an improved understanding of the molecular epidemiology of RSV infection in sub-Saharan Africa. It provides the first phylogenetic data for RSV from Tanzania, Gabon and Burkina Faso and combines it with RSV strains from all other sub-Saharan countries currently available in GenBank.

Drug Resistance Assessment Following Administration of Respiratory Syncytial Virus (RSV) Fusion Inhibitor Presatovir to Participants Experimentally Infected With RSV

BACKGROUND

Presatovir is an oral respiratory syncytial virus (RSV) fusion inhibitor targeting RSV F protein. In a double-blind, placebo-controlled study in healthy adults experimentally infected with RSV (Memphis-37b), presatovir significantly reduced viral load and clinical disease severity in a dose-dependent manner.

METHODS

Viral RNA from nasal wash samples was amplified and the F gene sequenced to monitor presatovir resistance. Effects of identified amino acid substitutions on in vitro susceptibility to presatovir, viral fitness, and clinical outcome were assessed.

RESULTS

Twenty-eight treatment-emergent F substitutions were identified. Of these, 26 were tested in vitro; 2 were not due to lack of recombinant virus recovery. Ten substitutions did not affect presatovir susceptibility, and 16 substitutions reduced RSV susceptibility to presatovir (2.9- to 410-fold). No substitutions altered RSV susceptibility to palivizumab or ribavirin. Frequency of phenotypically resistant substitutions was higher with regimens containing lower presatovir dose and shorter treatment duration. Participants with phenotypic presatovir resistance had significantly higher nasal viral load area under the curve relative to those without, but substitutions did not significantly affect peak viral load or clinical manifestations of RSV disease.

CONCLUSIONS

Emergence of presatovir-resistant RSV occurred during therapy but did not significantly affect clinical efficacy in participants with experimental RSV infection.