First COVID-19 lockdown resulted in most respiratory viruses disappearing among hospitalised children, with the exception of rhinoviruses

Bronchiolitis: Increased severity in the post-COVID-19 era

INTRODUCTION

Acute bronchiolitis is a pressing public health concern, leading to numerous infant hospitalizations worldwide annually. The notable decrease in bronchiolitis hospitalizations during the COVID-19 pandemic sparked concerns about a potential resurgence post-pandemic. Questions also arose about the severity of post-pandemic cases compared to prepandemic ones. This study aimed to compare bronchiolitis severity before and after the COVID-19 pandemic, alongside changes in the epidemiology of bronchiolitis viral agents.

MATERIAL AND METHODS

We conducted a retrospective analysis of medical records concerning infants under 12 months hospitalized for acute bronchiolitis in our pediatric pulmonology department over a period of 5 years: 2 pre-COVID years (2018-2020), the COVID year (2020), and 2 post-COVID years (2021-2023). Clinical and laboratory data were collected using standardized forms.

RESULTS

Hospital admissions exhibited comparable rates pre- and post-COVID but witnessed a decline during the COVID period. Post-COVID, bronchiolitis severity increased, with longer hospitalization durations (p < 0.001) and increased oxygen therapy (p = 0.04), coinciding with a surge in the prevalence of RSV infections (p = 0.01). Patients testing positive for RSV were significantly younger (p = 0.005) and exhibited more severe symptoms.

DISCUSSION AND CONCLUSION

This study reveals a significant increase in bronchiolitis severity and a rise in RSV cases following the COVID pandemic. The implementation of preventive measures such as nirsevimab is crucial to alleviate the burden of respiratory illnesses in vulnerable populations. Continued vigilance and research are needed to address the evolving challenges of bronchiolitis in the post-COVID era.

Alleviation of PM2.5-associated Risk of Daily Influenza Hospitalization by COVID-19 Lockdown Measures: A Time-series Study in Northeastern Thailand

OBJECTIVES

Abrupt changes in air pollution levels associated with the coronavirus disease 2019 (COVID-19) outbreak present a unique opportunity to evaluate the effects of air pollution on influenza risk, at a time when emission sources were less active and personal hygiene practices were more rigorous.

METHODS

This time-series study examined the relationship between influenza cases (n=22 874) and air pollutant concentrations from 2018 to 2021, comparing the timeframes before and during the COVID-19 pandemic in and around Thailand's Khon Kaen province. Poisson generalized additive modeling was employed to estimate the relative risk of hospitalization for influenza associated with air pollutant levels.

RESULTS

Before the COVID-19 outbreak, both the average daily number of influenza hospitalizations and particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) concentration exceeded those later observed during the pandemic (p<0.001). In single-pollutant models, a 10 μg/m3 increase in PM2.5 before COVID-19 was significantly associated with increased influenza risk upon exposure to cumulative-day lags, specifically lags 0-5 and 0-6 (p<0.01). After adjustment for co-pollutants, PM2.5 demonstrated the strongest effects at lags 0 and 4, with elevated risk found across all cumulative-day lags (0-1, 0-2, 0-3, 0-4, 0-5, and 0-6) and significantly greater risk in the winter and summer at lag 0-5 (p<0.01). However, the PM2.5 level was not significantly associated with influenza risk during the COVID-19 outbreak.

CONCLUSIONS

Lockdown measures implemented during the COVID-19 pandemic could mitigate the risk of PM2.5-induced influenza. Effective regulatory actions in the context of COVID-19 may decrease PM2.5 emissions and improve hygiene practices, thereby reducing influenza hospitalizations.

[Increase in severe acute respiratory infections in children during the last phase of the COVID-19 pandemic]

OBJECTIVE

The COVID-19 pandemic has caused a variation in the circulation of respiratory pathogens. Our aim was to analyze the epidemiology of severe acute respiratory infections (SARI) in children during 3 years of the COVID-19 pandemic, in comparison with a previous period.

METHODS

An observational study was conducted in a tertiary hospital in Spain, which analyzed the frequency and characteristics of patients admitted for SARI in the Pediatric Intensive Care Unit (PICU) during the COVID-19 pandemic (1 March 2020 to 28 February 2023), compared to pre-pandemic period (1 March 2017 to 29 February 2020).

RESULTS

A total of 268 patients were included (59.6% males). The median age was 9.6 months (IQR 1.7 - 37). In the pre-pandemic period, there were 126 admissions with an average of 42 admissions/year. During the pandemic, there were 142 admissions, observing a significant reduction in admissions in the first year (12 admissions/year), in contrast to 82 admissions during the third year, which represented an increase of 95% compared to the average of admissions/year in pre-pandemic. In addition, in the last year there was evidence of an increase in viral coinfections in relation to pre-pandemic period (54.9% vs 39.7%; p=0.032). There were no differences in length of hospital stay or PICU stay.

CONCLUSIONS

During the last year, coinciding with low rates of hospitalization for COVID in Spain, we observed a notable increase in admissions to the PICU for SARI. Probably, the prolonged period of low exposure to pathogens due to the measures adopted during the pandemic might have caused a decrease in population immunity with a rise in severe respiratory infections.

Impact of SARS-CoV-2 Pandemic and Lockdown on the HRSV Circulation: Experience of Three Spoke Hospitals in Northern Italy

The SARS-CoV-2 Pandemic affected the global epidemiology of respiratory infections, including Human Respiratory Syncytial Virus (HRSV), thanks to state governments' implementation of mitigation strategies, like the promotion of face masks and lockdowns. However, after the Pandemic, the dramatic resurge of these diseases was reported worldwide. Our retrospective study, involving three Spoke Pediatric Departments, includes all the infants under one year of age hospitalized for HRSV bronchiolitis in a period before the Pandemic period (2017-2020), during the SARS-CoV-2 Pandemic (2020-2021), and after the Pandemic (2021-2023). The primary aim was to analyze the temporal trend of HRSV in these three periods. Then, the clinical and epidemiological characteristics were analyzed to highlight the clinical differences in the affected patients, in the severity of the infections, and in the short-term outcomes. Ultimately, we analyzed the HRSV prevalence in the global bronchiolitis hospitalization over the reported periods. Overall, we included 237 patients. Before the Pandemic, the peak was recorded in January and February, while after the Pandemic, the peak was in November and December. A higher prevalence of HRSV was demonstrated after the Pandemic compared to the period before the Pandemic; overall, no difference in severity was reported. In conclusion, an increase in HRSV cases after the Pandemic has been demonstrated with an anticipated peak, while no differences were recorded in severity.

Epidemiology of Bronchiolitis and Respiratory Syncytial Virus and Analysis of Length of Stay from 2015 to 2022: Retrospective Observational Study of Hospital Discharge Records from an Italian Southern Province before and during the COVID-19 Pandemic

BACKGROUND

Severe respiratory infections, including pneumonia or bronchiolitis, caused by RSV can range from mild upper respiratory tract infections to those leading to hospitalization and serious complications such as respiratory failure in children. High-risk groups, such as premature infants and infants with underlying medical conditions, have a higher susceptibility to severe RSV disease. We conducted a retrospective study from years 2015 to 2022 in the Local Health Authority (LHA) of Pescara that counts about 320,000 inhabitants, with the aim to evaluate the burden of RSV infection, focusing on the incidence, hospitalization, and characteristics that may prolong hospital stays.

METHODS

All hospitalizations from 2015 to 2022 were extracted from the hospital discharge record. The monthly hospitalization rates were calculated and standardized by gender and age for the population resident in the Province of Pescara on 1 January 2015.

RESULTS

During the study period, 31,837 admissions were reported among patients aged less than 6 years. Of those, 520 hospitalizations were referred for bronchiolitis. Monthly admission rates highlighted the seasonality of bronchiolitis admissions, with higher rates in the months from December to March in all study years included. The winter seasons of years 2021 and 2022 reported a surge in bronchiolitis incidence, with a rate of 4.0/1000 (95% CI 2.964-5.146) in December 2021 and 4.0 (95% CI 2.891-5.020) in December 2022.

CONCLUSIONS

Bronchiolitis represents an important cause of hospitalization among patients aged less than 6 years. The incidence was particularly increased during the winter seasons in years 2021 and 2022.

Waiting for the next winter. Outpatient pediatric visits for respiratory infections before, during, and after the COVID-19 pandemic in the city of Buenos Aires

INTRODUCTION

During the COVID-19 pandemic, pediatric visits due to acute lower respiratory infections (ALRIs) decreased, but most reports are from hospitalized patients. There is little information on this phenomenon in outpatients, who are the majority in ALRI. We evaluated the impact of the COVID-19 pandemic on ALRI-related outpatient visits in the City of Buenos Aires.

METHODS

Observational study including all outpatient visits of children under 2 years of age to the public health system of the City of Buenos Aires, between 1 January 2018 and 31 December 2022. We analyzed the total number of visits and the ALRI-related visits, and their distribution throughout the study period.

RESULTS

A total of 704,426 visits were registered, 7.38% of them due to ALRI. ALRI-related visits decreased from the implementation of a national lockdown (2020) and increased again as the restriction measures decreased, particularly the return to full school attendance (2021). In general, the proportion of ALRI-related visits was significantly higher in the cold months than in the warm ones (9.8% vs. 5.5%; odds ratio: 1.76, 95% confidence interval: 1.73-1.79; p < .001). This difference was observed before (2018 and 2019) and after the pandemic (2022), but not in 2020-2021. The peak of ALRI-related visits occurred in the cold months in pre-pandemic years (2018-2019), did not appear in 2020, reappeared delayed in 2021, and recovered seasonality in 2022.

CONCLUSION

Outpatient ALRI-related visits decreased significantly in the city of Buenos Aires during the COVID-19 pandemic and currently seem to have recovered their magnitude and seasonality.

An overview on viral interference during SARS-CoV-2 pandemic

Respiratory viruses represent the most frequent cause of mortality, morbidity and high healthcare costs for emergency visits and hospitalization in the pediatric age. Respiratory viruses can circulate simultaneously and can potentially infect the same host, determining different types of interactions, the so-called viral interference. The role of viral interference has assumed great importance since December 2019, when the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) came on the scene. The aim of this narrative review is to present our perspective regarding research in respiratory virus interference and discuss recent advances on the topic because, following SARS-CoV-2 restrictions mitigation, we are experimenting the co-circulation of respiratory viruses along with SARS-CoV-2. This scenario is raising many concerns about possible virus-virus interactions, both positive and negative, and the clinical, diagnostic and therapeutic management of these coinfections. Moreover, we cannot rule out that also climatic conditions and social behaviours are involved. Thus, this situation can lead to different population epidemic dynamics, including changes in the age of the targeted population, disease course and severity, highlighting the need for prospective epidemiologic studies and mathematical modelling able to predict the timing and magnitude of epidemics caused by SARS-CoV-2/seasonal respiratory virus interactions in order to adjust better public health interventions.

Respiratory Syncytial Virus: Willingness towards a Future Vaccine among Pregnant Women in Italy

BACKGROUND

This cross-sectional survey was designed to evaluate pregnant women's awareness regarding Respiratory Syncytial Virus (RSV) infection and willingness to receive the vaccine during pregnancy and to vaccinate their newborn against RSV.

METHODS

An anonymous survey was administered from 20 April to 30 June 2023, to pregnant women aged ≥ 18 years attending gynecology wards of randomly selected public hospitals in southern Italy. A minimum sample size of 427 participants was calculated. The survey assessed women's socio-demographic characteristics, health-related information, their source(s) of information, and attitudes regarding RSV.

RESULTS

A total of 490 women participated. Those who were married/cohabiting, with a high-school degree compared to those who had a university degree, and those who needed additional information were more concerned that the newborn could acquire the RSV infection. The perceived utility of a future RSV vaccine administered during pregnancy was higher among those who were married/cohabiting, with a university degree, those with very good perceived health status, those who received information from healthcare workers, and those who needed additional information. Only 45.9% were willing to be vaccinated during pregnancy, and this was more likely among those with a university degree, with a very good perceived health status, who had received information from healthcare workers, and who needed more information. Finally, almost two-thirds (61.1%) were willing to vaccinate their newborn, and this was more likely among women with a university degree, with a very good perceived health status, and who needed additional information.

CONCLUSIONS

An education campaign regarding RSV infection and its vaccine is needed in order to improve women's perception and to support healthcare workers in promoting it when it will be available.

Molecular Epidemiology and Genetic Diversity of Human Respiratory Syncytial Virus in Sicily during Pre- and Post-COVID-19 Surveillance Seasons

Human respiratory syncytial virus (hRSV) is an important pathogen of acute respiratory tract infection of global significance. In this study, we investigated the molecular epidemiology and the genetic variability of hRSV over seven surveillance seasons between 2015 and 2023 in Sicily, Italy. hRSV subgroups co-circulated through every season, although hRSV-B mostly prevailed. After the considerable reduction in the circulation of hRSV due to the widespread implementation of non-pharmaceutical preventive measures during the COVID-19 pandemic, hRSV rapidly re-emerged at a high intensity in 2022-2023. The G gene was sequenced for genotyping and analysis of deduced amino acids. A total of 128 hRSV-A and 179 hRSV-B G gene sequences were obtained. The phylogenetic analysis revealed that the GA2.3.5a (ON1) and GB5.0.5a (BA9) genotypes were responsible for the hRSV epidemics in Sicily.; only one strain belonged to the genotype GB5.0.4a. No differences were observed in the circulating genotypes during pre- and post-pandemic years. Amino acid sequence alignment revealed the continuous evolution of the G gene, with a combination of amino acid changes specifically appearing in 2022-2023. The predicted N-glycosylation sites were relatively conserved in ON1 and BA9 genotype strains. Our findings augment the understanding and prediction of the seasonal evolution of hRSV at the local level and its implication in the monitoring of novel variants worth considering in better design of candidate vaccines.

The prevalence of pediatric asthma hospitalizations at different stages of the COVID-19 pandemic: A systematic review and meta-analysis study protocol

BACKGROUND

Asthma is a highly prevalent chronic inflammatory lung disease and is a frequent cause of hospitalization in children. The COVID-19 pandemic has introduced several challenges that have impacted the delivery of care for vulnerable patients, including asthmatic children. Asthmatic children without immediate access to healthcare services can face severe and fatal consequences. Furthermore, various governmental restrictions and viral mutants have been introduced throughout the pandemic, affecting COVID-19 cases and hospitalization rates.

OBJECTIVES

To investigate the impact of the COVID-19 pandemic on the prevalence of asthma hospitalizations during various stages of the pandemic. We also aim to compare asthma hospital admissions during the pandemic to pre-pandemic periods.

METHODS AND ANALYSIS

The databases PubMed (MEDLINE), EMBASE, CINAHL, and the Cochrane library will be used to identify relevant articles between the start of the pandemic and the date of the search strategy. Studies will be included if they examine hospital admissions for pediatric (0 to 18 years) asthma patients, regardless of asthma severity, sex, ethnicity or race. Observational retrospective cohort, prospective cohort, and cross-sectional studies will be included. A meta-analysis will be conducted if there are ≥2 articles. Else, a narrative review will be used to report our results.

TRIAL REGISTRATION

PROSPERO registration number: CRD42022337606.

Epidemiology and molecular characteristics of respiratory syncytial virus (RSV) among italian community-dwelling adults, 2021/22 season

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infections worldwide. While historically RSV research has been focused on children, data on RSV infection in adults are limited. The goal of this study was to establish the prevalence of RSV in community-dwelling Italian adults and analyze its genetic variability during the 2021/22 winter season.

METHODS

In this cross-sectional study, a random sample of naso-/oropharyngeal specimens from symptomatic adults seeking for SARS-CoV-2 molecular testing between December 2021 and March 2022 were tested for RSV and other respiratory pathogens by means of reverse-transcription polymerase chain reaction. RSV-positive samples were further molecularly characterized by sequence analysis.

RESULTS

Of 1,213 samples tested, 1.6% (95% CI: 0.9-2.4%) were positive for RSV and subgroups A (44.4%) and B (55.6%) were identified in similar proportions. The epidemic peak occurred in December 2021, when the RSV prevalence was as high as 4.6% (95% CI: 2.2-8.3%). The prevalence of RSV detection was similar (p = 0.64) to that of influenza virus (1.9%). All RSV A and B strains belonged to the ON1 and BA genotypes, respectively. Most (72.2%) RSV-positive samples were also positive for other pathogens being SARS-CoV-2, Streptococcus pneumoniae and rhinovirus the most frequent. RSV load was significantly higher among mono-detections than co-detections.

CONCLUSION

During the 2021/22 winter season, characterized by the predominant circulation of SARS-CoV-2 and some non-pharmaceutical containment measures still in place, a substantial proportion of Italian adults tested positive for genetically diversified strains of both RSV subtypes. In view of the upcoming registration of vaccines, establishment of the National RSV surveillance system is urgently needed.

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.

UPDATE - 2022 Italian guidelines on the management of bronchiolitis in infants

Bronchiolitis is an acute respiratory illness that is the leading cause of hospitalization in young children. This document aims to update the consensus document published in 2014 to provide guidance on the current best practices for managing bronchiolitis in infants. The document addresses care in both hospitals and primary care. The diagnosis of bronchiolitis is based on the clinical history and physical examination. The mainstays of management are largely supportive, consisting of fluid management and respiratory support. Evidence suggests no benefit with the use of salbutamol, glucocorticosteroids and antibiotics with potential risk of harm. Because of the lack of effective treatment, the reduction of morbidity must rely on preventive measures. De-implementation of non-evidence-based interventions is a major goal, and educational interventions for clinicians should be carried out to promote high-value care of infants with bronchiolitis. Well-prepared implementation strategies to standardize care and improve the quality of care are needed to promote adherence to guidelines and discourage non-evidence-based attitudes. In parallel, parents' education will help reduce patient pressure and contribute to inappropriate prescriptions. Infants with pre-existing risk factors (i.e., prematurity, bronchopulmonary dysplasia, congenital heart diseases, immunodeficiency, neuromuscular diseases, cystic fibrosis, Down syndrome) present a significant risk of severe bronchiolitis and should be carefully assessed. This revised document, based on international and national scientific evidence, reinforces the current recommendations and integrates the recent advances for optimal care and prevention of acute bronchiolitis.

The Impact of the COVID-19 Pandemic on Respiratory Syncytial Virus Infection: A Narrative Review

Respiratory syncytial virus (RSV) is one of the most common respiratory viruses. It not only affects young children but also the elderly and immunocompromised patients. After the emergence of SARS-CoV-2 and the corona virus disease 2019 (COVID-19) era, a dramatic reduction in RSV activity was found, which coincided with the implementation of public health and social measures (PHSMs). However, the correlation is more complicated than we initially thought. After PHSMs were gradually lifted, a seasonality shift and a delayed RSV outbreak with greater number of infected patients were found in numerous countries, such as Israel, Australia, South Africa, New Zealand, France, United States, and Japan. Several hypotheses and possible reasons explaining the interaction between SARS-CoV-2 and RSV were mentioned. Since RSV vaccinations are still under investigation, administration of palivizumab should be considered in high-risk patients. In the post-COVID-19 era, greater attention should be paid to a further resurgence of RSV. In this narrative review, we conducted a thorough review of the current knowledge on the epidemiology of RSV during the COVID-19 era, the out-of-season outbreak of RSV, and the data on co-infection with RSV and SARS-CoV-2.

Epidemiological characteristics of respiratory viruses in hospitalized children during the COVID-19 pandemic in southwestern China

Background

Multinational studies have reported that the implementation of nonpharmaceutical interventions (NPIs) to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission coincided with the decline of other respiratory viruses, such as influenza viruses and respiratory syncytial virus.

Objective

To investigate the prevalence of common respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Respiratory specimens of children with lower respiratory tract infections (LRTIs) hospitalized at the Children's Hospital of Chongqing Medical University from January 1, 2018 to December 31, 2021 were collected. Seven common pathogens, including respiratory syncytial virus (RSV), adenovirus (ADV), influenza virus A and B (Flu A, Flu B), and parainfluenza virus types 1-3 (PIV1-3), were detected by a multiplex direct immunofluorescence assay (DFA). Demographic data and laboratory test results were analyzed.

Results

1) A total of 31,113 children with LRTIs were enrolled, including 8141 in 2018, 8681 in 2019, 6252 in 2020, and 8059 in 2021.The overall detection rates decreased in 2020 and 2021 (P < 0.001). The detection rates of RSV, ADV, Flu A, PIV-1, and PIV-3 decreased when NPIs were active from February to August 2020, with Flu A decreasing most predominantly, from 2.7% to 0.3% (P < 0.05). The detection rates of RSV and PIV-1 resurged and even surpassed the historical level of 2018-2019, while Flu A continued decreasing when NPIs were lifted (P < 0.05). 2) Seasonal patterns of Flu A completely disappeared in 2020 and 2021. The Flu B epidemic was observed until October 2021 after a long period of low detection in 2020. RSV decreased sharply after January 2020 and stayed in a nearly dormant state during the next seven months. Nevertheless, the detection rates of RSV were abnormally higher than 10% in the summer of 2021. PIV-3 decreased significantly after the COVID-19 pandemic; however, it atypically surged from August to November 2020.

Conclusion

The NPIs implemented during the COVID-19 pandemic affected the prevalence and seasonal patterns of certain viruses such as RSV, PIV-3, and influenza viruses. We recommend continuous surveillance of the epidemiological and evolutionary dynamics of multiple respiratory pathogens, especially when NPIs are no longer necessary.

Respiratory Syncytial Virus Pediatric Hospitalization in the COVID-19 Era

Respiratory syncytial virus (RSV) globally affects the population, mainly young children, potentially causing hospitalization. During the COVID-19 pandemic, non-pharmacological measures interfered with the circulation of most respiratory viruses. Then, with the discontinuation of restrictive measures, a new scenario appeared. With this scoping review, we want to globally explore whether the RSV paediatric hospitalization rate was influenced by COVID-19. This scoping review was performed according to PRISMA guidelines on PubMed using the Mesh terms "Respiratory Syncytial Viruses"[Mesh] AND "COVID-19"[Mesh] OR "SARS-CoV-2"[Mesh]. Among them, we identified studies pertaining to children and adolescents up to 18 years old hospitalized for RSV, including 18 records in the revision. With the onset of the COVID-19 pandemic, a drastic reduction in RSV hospitalization among the pediatric population in 2020-2021 season has been observed in the Northern and Southern hemispheres. After the relaxing of restrictive measures, unexpected outbreaks happened, leading to increased hospitalization and occupation of pediatric intensive care units.

An Italian Multicenter Study on the Epidemiology of Respiratory Syncytial Virus During SARS-CoV-2 Pandemic in Hospitalized Children

Since the beginning of 2020, a remarkably low incidence of respiratory virus hospitalizations has been reported worldwide. We prospectively evaluated 587 children, aged <12 years, admitted for respiratory tract infections from 1 September 2021 to 15 March 2022 in four Italian pediatric hospitals to assess the burden of respiratory viruses during the COVID-19 pandemic in Italy. At admission, a Clinical Respiratory Score was assigned and nasopharyngeal or nasal washing samples were collected and tested for respiratory viruses. Total admissions increased from the second half of October 2021 to the first half of December 2021 with a peak in early November 2021. The respiratory syncytial virus (RSV) incidence curve coincided with the total hospitalizations curve, occurred earlier than in the pre-pandemic years, and showed an opposite trend with respect to the incidence rate of SARS-CoV-2. Our results demonstrated an early peak in pediatric hospitalizations for RSV. SARS-CoV-2 may exhibit a competitive pressure on other respiratory viruses, most notably RSV.