Severe bronchiolitis profiling as the first step towards prevention of asthma.

Bronchiolitis is the most common respiratory infection leading to hospitalization and constitutes a significant healthcare burden. The two main viral agents causing bronchiolitis, respiratory syncytial virus (RSV) and rhinovirus (RV), have distinct cytopathic, immune response, and clinical characteristics. Different approaches have been suggested for subtyping bronchiolitis based on viral etiology, atopic status, transcriptome profiles in blood, airway metabolome, lipidomic data, and airway microbiota. The highest risk of asthma at school age has been in a subgroup of bronchiolitis characterized by older age, high prevalence of RV infection, previous breathing problems, and/or eczema. Regarding solely viral etiology, RV-bronchiolitis in infancy has been linked to a nearly three times higher risk of developing asthma than RSV-bronchiolitis. Although treatment with betamimetics and systemic corticosteroids has been found ineffective in bronchiolitis overall, it can be beneficial for infants with severe RV bronchiolitis. Thus, there is a need to develop a more individualized therapeutic approach for bronchiolitis and follow-up strategies for infants at higher risk of asthma in the future perspective.

Worldwide research trends on bronchiolitis in pediatrics.

BACKGROUND: The COVID-19 pandemic has led to a significant increase in cases of bronchiolitis among children. As a result, there has been a corresponding increase in the number of publications on this topic. It is essential to examine the main areas of focus within the scientific literature to understand the current trends in research on pediatric bronchiolitis. This research aims to analyze the types of scientific advances related to pediatric bronchiolitis, the research trends being pursued, and the countries and research institutions leading these efforts. By understanding these aspects of bronchiolitis research, we can better understand the current state of knowledge and identify areas where further research is needed. METHODS: To conduct a bibliometric analysis of the scientific literature on pediatric bronchiolitis, all relevant publications were retrieved from the Scopus database. The Scopus API and the SW VosViewer software with optimized modularity functions were used. This analysis was intended to provide a comprehensive overview of the current state of research on this topic, including the types of scientific advances being developed, the research trends being pursued, and the countries and research institutions leading these efforts. RESULTS: A total of 3810 publications were reviewed. We observed an increasing number of publications, particularly in recent years. Of these, 73.7% were articles, 95% were written in English, and 29.4% were from the United States. The main keywords used in these publications included: human, bronchiolitis, child, preschool, preschool child, major clinical study, controlled study, pneumonia, asthma, adolescent, hospitalization, infant, and newborn. These keywords were grouped into six clusters: outpatient management, long-term consequences, etiology, intensive care management, diagnostic methods, and the main cluster, which focused on hospital treatment and clinical studies. CONCLUSIONS: The bibliometric analysis of bronchiolitis research in pediatrics reveals that there has been a significant increase in the number of publications on this topic, particularly in recent years. Most of these publications are articles written in English and published in the United States. The main keywords used in these studies relate to various aspects of bronchiolitis, including diagnosis, treatment, and long-term consequences. The results of this analysis suggest that bronchiolitis is a topic of significant interest and concern for researchers and practitioners in the field of pediatrics and that further research is needed to improve our understanding and management of this condition.

Pediatric respiratory admissions and related viral infections during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has affected the incidence of respiratory viral infections. Our aim was to assess changes in pediatric admissions due to respiratory diseases and associated respiratory viral infections. METHODS: An observational study including all respiratory admissions to the pediatric departments from January 2015 to August 2021. We compared respiratory admission percentage, respiratory viral panel results and clinical characteristics of these admissions between two study periods, January 2015 to February 2020 (pre-COVID-19 era) and March 2020 to August 2021 (COVID-19 era). RESULTS: A total of 8774 respiratory admissions were included, 7157 pre-COVID-19 era and 1617 COVID-19 era. Relative to all pediatric admissions, there was a 17% decrease in respiratory admission percentage during the COVID-19 era (p < 0.001) and a 31% and 22% decreased in the admission percentages due to bronchiolitis (p < 0.001) and pneumonia (p < 0.001), respectively. However, admission percentages for asthma, wheezing illness, complicated pneumonia, and stridor remained the same. There was a significant decrease in the detection of a respiratory viral pathogen associated with these respiratory admissions (p < 0.001). This was related to a significant decrease in the detection of respiratory syncytial virus (RSV) (37% vs. 27%, p < 0.001) and influenza (5% vs. 0.3%, p < 0.001), but not other respiratory viruses. An alteration in the circulation pattern of most respiratory viruses, was observed. CONCLUSIONS: During the COVID-19 pandemic, a decrease in the prevalence of RSV and influenza was associated with a significant decrease in admissions for bronchiolitis and pediatric pneumonia. This may allow us to estimate the significance of preventive measures for RSV and influenza on pediatric respiratory admissions.

The bronchiolitis epidemic in 2021-2022 during the SARS-CoV-2 pandemic: experience of a third level centre in Northern Italy.

BACKGROUND: The aim of this study is to compare the 2021-2022 bronchiolitis season to the four previous years (2017-2018, 2018-2019, 2019-2020, 2020-2021) to see if there was an anticipation of the peak, an overall increase of cases, and an increased need of intensive care. METHODS: A retrospective single-centre study in the San Gerardo Hospital Fondazione MBBM, Monza, Italy was performed. Emergency Departments (ED) visits of patients aged < 18 years and ≤ 12 months were analyzed: the incidence of bronchiolitis on total assessments, the urgency level at triage and the hospitalization rate were compared. Data of children admitted to the Pediatric Department due to bronchiolitis were analyzed in terms of need of intensive care, respiratory support (type and duration), length of hospital stay, main etiological agent, patient characteristics. RESULTS: During 2020-2021 (first pandemic period) an important reduction in the ED attendance for bronchiolitis was observed, while in 2021-2022 there was an increase in incidence of bronchiolitis (13% of visits in infants < 1 year) and in the rate of urgent accesses (p = 0.0002), but hospitalization rates did not differ compared to previous years. Furthermore, an anticipated peak in November 2021 was observed. In the 2021-2022 cohort of admitted children to the Pediatric Department, a statistically significative increased need of intensive care unit was detected (Odds Ratio 3.1, 95% CI 1.4-6.8 after adjustment for severity and clinical characteristics). Instead, respiratory support (type and duration) and length of hospital stay did not differ. RSV was the main etiological agent and RSV-bronchiolitis determined a more severe infection (type and duration of breathing support, intensive care need and length of hospital stay). CONCLUSIONS: During Sars-CoV-2 lockdowns (2020-2021), there was a dramatic decrease of bronchiolitis and others respiratory infections. In the following season, 2021-2022, an overall increase of cases with an anticipated peak was observed and data analysis confirmed that patients in 2021-2022 required more intensive care than children in the four previous seasons.

Impact of breastfeeding on the incidence and severity of respiratory syncytial virus bronchiolitis in infants: systematic review.

BACKGROUND AND AIMS: Breastfeeding practices have demonstrated a protective effect against severe respiratory syncytial virus (RSV) disease outcomes. RSV is the principal cause of lower respiratory tract infections in infants worldwide, and an important cause of morbidity, hospitalization, and mortality. The primary aim is to determine the impact of breastfeeding on the incidence and severity of RSV bronchiolitis in infants. Secondly, the study aims to determine if breastfeeding contributes to reduction of hospitalization rates, length of stay and oxygen use in confirmed cases. METHODS: A preliminary database search was conducted using agreed keywords and MeSH headings in MEDLINE, PubMed, Google Scholar, EMBASE, MedRχiv and Cochrane Reviews. Articles were screened based on inclusion/exclusion criteria for infants aged 0-12 months. Full text, abstract and conference articles published in English were included from 2000 to 2021. Covidence® software was used for evidence extraction using paired investigator agreement and PRISMA guidelines were followed. RESULTS: 1368 studies were screened and 217 were eligible for full text review. 188 were excluded. Twenty-nine articles were selected for data extraction: RSV-bronchiolitis (18) and viral bronchiolitis (13), with two articles discussing both. Results showed that non-breastfeeding practices are a significant risk factor for hospitalization. Exclusive breastfeeding for >4-6 months significantly lowered admission rates, length of stay and supplemental oxygen use, reducing unscheduled GP visits and emergency department presentation. DISCUSSION: Exclusive and partial breastfeeding reduce severity of RSV bronchiolitis, length of hospital stay and supplemental oxygen requirement. Breastfeeding practices should be supported and encouraged as a cost-effective method to prevent infant hospitalization and severe bronchiolitis infection.

Bronchiolitis 2021-2022 epidemic: multicentric analysis of the characteristics and treatment approach in 214 children from different areas in Italy.

Bronchiolitis causes a remarkable number of hospitalizations; its epidemiology follows that of respiratory syncytial virus (RSV), its main pathogen. The aim of this study was to evaluate the presenting features, treatment approach, and impact of medical therapy in four pediatric hospitals in Italy. Data on infants < 24 months of age hospitalized with bronchiolitis in the 2021-2022 season were collected. Between October 2021 and February 2022, 214 children were admitted. Median hospital stay was 5 days; none of the patients died. The distribution of the presenting features is largely comparable in the 33 (15.8%) RSV-negative versus the 176 (84.2%) RSV-positive children; also, no difference was observed in medical therapy provided: duration of oxygen therapy, administration of steroid, and duration of hospital stay. Systemic steroids, inhalation, or antibiotic therapy were given to 34.6%, 79.4%, and 49.1% of children respectively. Of the 214 patients with bronchiolitis, only 19 (8.8%) were admitted to ICU.   Conclusion: Our data suggest that, irrespective of treatments provided, RSV-positive and RSV-negative children had a similar clinical course. The results of our retrospective study further underline the need to improve adherence to existing guidelines on bronchiolitis treatment. What is Known: • Bronchiolitis is a common diseases with seasonal peak. The outcome is usually favorable but hospitalization and even ICU admission is not exceptional. What is New: • Children with RSV associated bronchiolitis do not have a different course and outcome. The analysis of the 2021-2022 cohort, following COVID pandemic peaking, did not show a different course and outcome. • Adherence to literature recommendation, i.e. to focus on oxygen and hydration therapy while avoiding unnecessary systemic therapy with steroid and antibiotics, should be improved.

The acute bronchiolitis rebound in children after COVID-19 restrictions: a retrospective, observational analysis.

BACKGROUND AND AIM: Bronchiolitis represents the main cause of illness and hospitalization in infants and young children. The aim of this study was to compare the Pediatric Emergency Department (PED) admissions for bronchiolitis during the post-COVID (Coronavirus disease) period to those of previous seasons and to analyze their etiology during COVID and post-COVID period. METHODS: We compared demographics, clinical and microbiological data of children admitted to PED with bronchiolitis between September 2021 and March 2022 (post-COVID period) to the previous seasons (COVID and pre-COVID period). RESULTS: During the post-COVID period the bronchiolitis season started earlier than usual, with a peak reached in November 2021; a gradual reduction was subsequently observed between December 2021 and January 2022. Our data showed a prevalence of High Priority code in children admitted to the PED with bronchiolitis during the post-COVID period (61.4%) compared the pre-COVID period (34.8%) (p=0.00). Also regarding the hospitalization of these patients, we found a major rate of hospitalization during this epidemic season (p=0.035). In addition, only 4 (1.5%) of the tested children resulted positive for SARS-CoV-2 and all of them were admitted to PED during the post-COVID period. The search for the other respiratory viruses showed during the current season a prevalence of respiratory syncytial virus (RSV) (60.2%), followed by Human Rhinovirus (30.1%). CONCLUSIONS: The post-COVID period was characterized by an early and short-term peak in acute bronchiolitis, with an increased rate of hospitalization. In addition, SARS-CoV-2 infection was rarely cause of bronchiolitis in children under 2 years old.

Hospital admissions and need for mechanical ventilation in children with respiratory syncytial virus before and during the COVID-19 pandemic: a Danish nationwide cohort study.

BACKGROUND: The incidence of respiratory syncytial virus (RSV) increased in several countries after the relaxation of COVID-19 restrictions. We aimed to investigate the age-related risk of RSV-associated hospital admissions and need for mechanical ventilation during the RSV resurgence in summer and autumn 2021 compared with the four RSV seasons preceding the COVID-19 pandemic. We also aimed to describe the clinical complications necessitating mechanical ventilation. METHODS: This population-based cohort study included patients aged 0-17 years admitted to hospital with RSV in Denmark during the RSV resurgence in summer and autumn 2021, and the four pre-COVID-19 RSV seasons (2016-17, 2017-18, 2018-19, and 2019-20). We retrieved data on RSV-associated hospital admissions from the Danish National Patient Registry and demographic and clinical details of children who received mechanical ventilation through prospective real-time data collection in 2021-22 and retrospective data collection for the 2016-17 to 2019-20 RSV seasons from all eight paediatric and neonatal intensive care units in Denmark. Risk factors for severe RSV disease were as defined as age younger than 3 months or severe comorbidities. We calculated the risk of RSV-associated hospital admissions per 100 000 population in each RSV season from week 21 to week 20 of the following year. We also calculated the risk rate of receiving mechanical ventilation per 100 000 population and 1000 RSV-associated hospital admissions during each RSV season from week 21 to week 20 of the following year. We calculated risk ratios (RRs) for hospital admission and mechanical ventilation by dividing the risk rate of hospital admission and mechanical ventilation in 2021-22 by annual mean risk rates in the four pre-COVID-19 RSV epidemics (2016-17 to 2019-20). We compared RRs using Fisher's exact test. We compared complications leading to intubation between children with and without risk factors for severe RSV disease. The study is registered at ClinicalTrials.gov, NCT05186597. FINDINGS: Among 310 423 Danish children aged younger than 5 years, the mean number of RSV-associated hospital admissions increased from 1477 (SD 226) in the 2016-17 to 2019-20 RSV seasons to 3000 in the 2021-22 RSV season (RR 2·0 [95% CI 1·9-2·1]). 54 children with RSV received mechanical ventilation in 2021-22 compared with 15-28 annually in the 2016-17 to 2019-20 RSV seasons (2·3 [1·6-3·3]). The highest increase in hospital admissions and need for mechanical ventilation occurred among children aged 24-59 months (4·1 [3·6-4·7] for hospital admission; 4·6 [1·7-12·6] for mechanical ventilation). Among children admitted to hospital, the risk of mechanical ventilation was similar in 2021-22 and the four pre-COVID-19 seasons (risk rate 14·3 per 1000 RSV-associated hospital admissions [95% CI 10·4-19·3] vs 12·9 [10·1-16·1]; RR 1·1 [95% CI 0·8-1·6]). Across all RSV seasons studied, among children younger than 3 months or those with severe comorbidities, respiratory failure due to bronchiolitis led to mechanical ventilation in 69 (79%) of 87 children. Of 46 children with no risk factors for severe RSV, 40 (87%) received mechanical ventilation due to additional complications, including neurological (n=16; 35%), cardiac (n=1; 2%), and pulmonary complications (n=23; 50%; eg, wheeze responsive to bronchodilator therapy, severe bacterial co-infections, and pneumothorax). INTERPRETATION: In Denmark, RSV disease did not seem to be more severe for the individual child during the RSV resurgence in 2021 following relaxation of COVID-19 restrictions. However, hospital admissions were higher among older children, possibly due to a postponed first RSV infection or no recent reinfection. Older children without risk factors for severe RSV disease had atypical complications that led to intubation. If new RSV-preventive interventions for healthy infants delay first RSV infection, a higher number of older children might be admitted to hospital due to atypical clinical phenotypes, rather than classical bronchiolitis. FUNDING: National Ministry of Higher Education and Science and the Innovation Fund Denmark.

How has the SARS-CoV-2 pandemic changed the epidemiology and management of acute bronchiolitis?

OBJECTIVE: SARS-COV-2 pandemic profoundly impacted acute bronchiolitis epidemiology worldwide, especially respiratory syncytial virus (RSV) diffusion and the burden of disease, with remarkable implications on the management of health resources. We aimed to study the epidemiology and clinical course of bronchiolitis in the past 5 years in our region and to assess the trends that occurred during and after the SARS-COV-2 pandemic. METHODS: We conducted an observational study including all children aged 0-2 years with bronchiolitis admitted to a tertiary children's hospital during the last 5 years. Demographic, clinical, and microbiological data were collected. Comparisons between patient subgroups were carried out. RESULTS: A total of 647 patients admitted for bronchiolitis were included (median age 78 days). Molecular diagnostic tests were performed in 617 patients (95.4%) with RSV detected in 51.5% of patients in prepandemic years and 74.5% in pandemic years. Through the study period, we observed a progressive increase in the number of children requiring respiratory support, RSV infections, and children with a history of prematurity. Conversely, this was not true for mechanical ventilation, duration of respiratory support, intensive care unit admission, and length of stay. CONCLUSIONS: Clinical course and epidemiology of bronchiolitis showed a significant change through the study years with a heavy impact during the 2021-2022 season. The increase in the number of patients requiring respiratory support, although not associated with an increase in mechanical ventilation, may be explained by the higher prevalence of RSV. The change in epidemiology highlights the importance of surveillance systems to monitor RSV circulation, to plan prophylactic strategies, and prepare healthcare systems.

Acute bronchiolitis during the COVID-19 pandemic.

INTRODUCTION: The autumn and winter bronchiolitis epidemics have virtually disappeared in the first year of the COVID-19 pandemic. Our objectives were characterised bronchiolitis during fourth quarter of 2020 and the role played by SARS-CoV-2. METHODS: Prospective multi-centre study performed in Madrid (Spain) between October and December 2020 including all children admitted with acute bronchiolitis. Clinical data were collected and multiplex PCR for respiratory viruses were performed. RESULTS: Thirty-three patients were hospitalised with bronchiolitis during the study period: 28 corresponded to rhinovirus (RV), 4 to SARS-CoV-2, and 1 had both types of infection. SAR-CoV-2 bronchiolitis were comparable to RV bronchiolitis except for a shorter hospital stay. A significant decrease in the admission rate for bronchiolitis was found and no RSV was isolated. CONCLUSION: SARS-CoV-2 infection rarely causes acute bronchiolitis and it is not associated with a severe clinical course. During COVID-19 pandemic period there was a marked decrease in bronchiolitis cases.

Retrospective observational study of the influence of the COVID-19 outbreak on infants' hospitalisation for acute bronchiolitis.

OBJECTIVES: Acute bronchiolitis is a major public health issue with high number of infants hospitalised worldwide each year. In France, hospitalisations mostly occur between October and March and peak in December. A reduction of emergency visits for bronchiolitis has been observed at onset of the COVID-19 outbreak. We aimed to assess the pandemic effects on the hospitalisations for bronchiolitis during the 2020-2021 winter (COVID-19 period) compared with three previous winters (pre-COVID-19). DESIGN: Retrospective, observational and cross-sectional study. SETTING: Tertiary university paediatric hospital in Paris (France). PARTICIPANTS: All infants aged under 12 months who were hospitalised for acute bronchiolitis during the autumn/winter seasons (1 October to 31 March) from 2017 to 2021 were included. Clinical and laboratory data were collected using standardised forms. RESULTS: During the COVID-19 period was observed, a 54.3% reduction in hospitalisations for bronchiolitis associated with a delayed peak (February instead of November-December). Clinical characteristics and hospitalisation courses were substantially similar. The differences during the COVID-19 period were: smaller proportion of infants with comorbidities (8% vs 14% p=0.02), lower need for oxygen (45% vs 55%, p=0.01), higher proportions of metapneumovirus, parainfluenzae 3, bocavirus, coronavirus NL63 and OC43 (all p≤0.01) and no influenza. The three infants positive for SARS-CoV-2 were also positive for respiratory syncytial virus, suggesting that SARS-CoV-2 alone does not cause bronchiolitis, despite previous assumptions. CONCLUSION: The dramatic reduction in infants' hospitalisations for acute bronchiolitis is an opportunity to change our future habits such as advising the population to wear masks and apply additional hygiene measures in case of respiratory tract infections. This may change the worldwide bronchiolitis burden and improve children respiratory outcomes.

Effects of COVID-19-targeted nonpharmaceutical interventions on children's respiratory admissions in China: a national multicenter time series study.

OBJECTIVES: To estimate the impact of nonpharmaceutical interventions (NPIs) targeted at the COVID-19 pandemic on the admission number of respiratory diseases, including pneumonia, acute bronchitis & bronchiolitis, and acute upper respiratory infections (AURIs) for children in China. METHODS: Continuous hospitalization records aged 0-18 years from January 1, 2016, to December 31, 2020, were collected from 26 tertiary children's hospitals. Interrupted time series analysis with a quasi-Poisson model was conducted with the start time of the COVID-19 pandemic as the interrupted timepoint and the weekly admission numbers of all-cause respiratory disease, pneumonia, acute bronchitis & bronchiolitis, and AURI as the outcome measures. Hospitalizations of childhood neoplasms were analyzed as the reference group. RESULTS: The reduction in admission numbers following NPIs was -55.0% (-57.9 to -51.9%) for all-cause respiratory diseases, -62.7% (-65.7 to -59.5%) for pneumonia, -48.1% (-53.3 to -42.3%) for bronchitis & bronchiolitis, and -24.3% (-28.6 to -19.8%) for AURI. The effect estimates of NPIs on childhood neoplasms was -29.1% (-33.6 to -24.4%). Stratification analysis showed the reduction was most drastic for children at 4-6 and 7-12 years. CONCLUSION: The admission number for respiratory diseases among children in China decreased drastically after the implementation of NPIs. NPIs with low socio-economic burdens should be suggested even outside the COVID-19 pandemic.

Increased use of high-flow nasal cannulas after the pandemic in bronchiolitis: a more severe disease or a changed physician's attitude?

After the SARS-CoV-2 pandemic, we noticed a marked increase in high-flow nasal cannula use for bronchiolitis. This study aims to report the percentage of children treated with high-flow nasal cannula (HFNC) in various seasons. The secondary outcomes were admissions for bronchiolitis, virological results, hospital burden, and NICU/PICU need. We conducted a retrospective study in four Italian hospitals, examining the medical records of all infants (< 12 months) hospitalized for bronchiolitis in the last four winter seasons (1 September-31 March 2018-2022). In the 2021-2022 winter season, 66% of admitted children received HFNC versus 23%, 38%, and 35% in the previous 3 years. A total of 876 patients were hospitalized in the study periods. In 2021-2022, 300 infants were hospitalized for bronchiolitis, 22 in 2020-2021, 259 in 2019-2020, and 295 in 2018-2019. The percentage of patients needing intensive care varied from 28.7% to 18%, 22%, and 15% in each of the four considered periods (p < 0.05). Seventy-seven percent of children received oxygen in the 2021-2022 winter; vs 50%, 63%, and 55% (p < 0.01) in the previous 3 years. NIV/CPAP was used in 23%, 9%, 16%, and 12%, respectively. In 2021-2020, 2% of patients were intubated; 0 in 2020-2021, 3% in 2019-2020, and 1% in 2018-2019. CONCLUSION: This study shows a marked increase in respiratory support and intensive care admissions this last winter. While these severity indexes were all driven by medical choices, more reliable indexes such as intubation rate and length of stay did not change. Therefore, we suggest that there is a more aggressive treatment attitude rather than a more severe disease. WHAT IS KNOWN: • COVID-19 pandemic deeply impacted bronchiolitis epidemiology, reducing hospitalizations to onetenth. In the 2021-2022 winter, bronchiolitis resurged to pre-pandemic numbers in Europe. WHAT IS NEW: • Bronchiolitis hospitalization rose much faster in the 2021-2022 winter period, peaking at a higher level. Respiratory supports and high-flow nasal cannula increased significantly compared to the pre-pandemic era.

Respiratory Syncytial Virus During the COVID-19 Pandemic Compared to Historic Levels: A Retrospective Cohort Study of a Health System.

BACKGROUND: Surveillance in 2020-2021 showed that seasonal respiratory illnesses were below levels seen during prior seasons, with the exception of interseasonal respiratory syncytial virus (RSV). METHODS: Electronic health record data of infants aged <1 year visiting the Duke University Health System from 4 October 2015 to 28 March 2020 (pre-COVID-19) and 29 March 2020 to 30 October 2021 (COVID-19) were assessed. International Classification of Diseases-Tenth Revision (ICD-10) codes for RSV (B97.4, J12.1, J20.5, J21.0) and bronchiolitis (RSV codes plus J21.8, J21.9) were used to detail encounters in the inpatient (IP), emergency department (ED), outpatient (OP), urgent care (UC), and telemedicine (TM) settings. RESULTS: Pre-COVID-19, 88% of RSV and 92% of bronchiolitis encounters were seen in ambulatory settings. During COVID-19, 94% and 93%, respectively, occurred in ambulatory settings. Pre-COVID-19, the highest RSV proportion was observed in December-January (up to 38% in ED), while the peaks during COVID-19 were seen in July-September (up to 41% in ED) across all settings. RSV laboratory testing among RSV encounters was low during pre-COVID-19 (IP, 51%; ED, 51%; OP, 41%; UC, 84%) and COVID-19 outside of UC (IP, 33%; ED, 47%; OP, 47%; UC, 87%). Full-term, otherwise healthy infants comprised most RSV encounters (pre-COVID-19, up to 57% in OP; COVID-19, up to 82% in TM). CONCLUSIONS: With the interruption of historical RSV epidemiologic trends and the emergence of interseasonal disease during COVID-19, continued monitoring of RSV is warranted across all settings as the changing RSV epidemiology could affect the distribution of health care resources and public health policy.

Bronchiolitis epidemics in France during the SARS-CoV-2 pandemic: The 2020-2021 and 2021-2022 seasons.

OBJECTIVES: We described bronchiolitis epidemics during the 2020-2021 and 2021-2022 seasons in France and their interaction with the COVID outbreak. PATIENTS AND METHODS: Data on family physician (FP) visits, emergency department (ED) visits, hospitalizations for bronchiolitis for children˂2 years, and hospital virological data were analyzed and compared with previous seasons (2015-2020). RESULTS: The 2020-2021 epidemic arrived very late, and its impact was lower than in previous seasons (2015-2020) (FP visits: -23%, ED visits: -38%, and hospitalizations: -30%). The 2021-2022 epidemic started early (week 40) and lasted for a relatively long time (13 weeks). The impact was higher than in 2015-2020 (FP visits: +13%, ED visits: +34%, hospitalizations: +28%). CONCLUSION: Findings from the 2020-2021 epidemic may be linked to the implementation of non-pharmaceutical COVID-19 prevention measures. For 2021-2022, findings may be linked to an "immunity debt" resulting from the lower impact of the previous season.

Unusual 2020 respiratory syncytial virus bronchiolitis season in Western Australia: Not explained by weather.

OBJECTIVE: To describe and explore the relationship between weather and the unusual 2020 bronchiolitis season in Western Australia during the COVID-19 pandemic. METHODS: Correlation of meteorological data and presentations of infants with bronchiolitis through the ED of Perth Children's Hospital. RESULTS: The 2020 bronchiolitis epidemic showed a reversal of the usual seasonal pattern. There were no weather events to account for this phenomenon. CONCLUSIONS: The bronchiolitis outbreak showed no relationship to local weather patterns. State-mandated COVID-19 public health measures appear as the likely rationale.