Pediatric RSV-Associated Hospitalizations Before and During the COVID-19 Pandemic

Factors influencing acceptance of RSV immunization for newborns among pregnant individuals: A mixed-methods study

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of respiratory infections and hospitalizations in Canadian infants. Recently, Health Canada approved two novel immunizing products: a vaccine given during pregnancy and a monoclonal antibody for infants. This study assessed knowledge, attitudes, and intentions regarding RSV and its prevention among pregnant individuals.

METHODS

A mixed-methods study was conducted in Quebec from October to December 2023. Pregnant individuals were recruited through targeted Facebook advertisements. Data were collected in two phases: Phase 1 involved an online survey to assess knowledge of RSV, attitudes toward immunization, and intentions regarding both immunization products, followed by qualitative interviews in Phase 2 to explore factors impacting decision-making and preferences for RSV prevention. Survey data were analyzed using descriptive statistics; interview data were analyzed through thematic analysis.

RESULTS

Among survey participants (n = 803), 68.4 % reported some knowledge of RSV. Intention for both immunization products was high, with 88.1 % of participants willing to receive the RSV vaccine during pregnancy and 92 %, to administer monoclonal antibodies to their infants. A majority (69 %) of participants preferred vaccination during pregnancy over monoclonal antibodies. The desire to protect their infant from severe RSV complications was a key motivating factor of acceptance of new RSV immunizing products. Other key determinants included vaccine safety, efficacy, and recommendations by healthcare providers. Qualitative interviews (n = 25) highlighted safety concerns of expectant parents about these new products. The importance of clear and evidence-based recommendations by healthcare providers was also emphasized.

CONCLUSIONS

Pregnant individuals demonstrated a high level of interest in RSV immunization for infants, whether with vaccination during pregnancy or with monoclonal antibodies. Recommendations by healthcare providers and availability of information on the safety and efficacy of these new products will be key to move from intention to action.

EDP-323, a First-In-Class, Once-Daily, Oral L-Protein Inhibitor for the Treatment of RSV: Results From a Phase 1 Study in Healthy Adults

Respiratory syncytial virus (RSV) remains a significant health concern, particularly for vulnerable populations. Despite preventive strategies, there remains a need for effective antiviral treatments. EDP-323 is a first-in-class, potent oral selective non-nucleoside inhibitor of the large protein (L polymerase) of RSV under investigation for the treatment of RSV infection. This phase 1, randomized, double-blind, placebo-controlled study evaluated the safety and pharmacokinetics of EDP-323. This study included fasted single ascending dose (SAD; EDP-323 50/100/200/400/600/800 mg doses, 3:1 to placebo), fed multiple ascending dose (MAD; EDP-323200/400/600/800 mg doses, 3:1 to placebo), and food effect (EDP-323200 mg dose, 4:1 to placebo) cohorts in healthy adult participants. Key objectives were to assess the safety, tolerability, and pharmacokinetic (PK) profile of EDP-323 in plasma and urine, and to evaluate the effect of food intake on its pharmacokinetics. Among 82 randomized participants (SAD, n = 50; MAD, n = 32), EDP-323 was well tolerated up to the highest tested dose (800 mg once daily for 7 days). Adverse events (AEs) were reported in 14.6% of total participants, with the majority being mild and deemed unlikely related to the study drug. Headache was the most frequent AE (n = 3). PK analysis showed that EDP-323 was rapidly absorbed (Tmax = 3.0-5.0 h), with exposures increasing with ascending dose. The half-life of EDP-323 (t1/2 = 10.8-16.6 h) supported once-daily dosing, and no food effect was observed. EDP-323 demonstrated a favorable safety and PK profile, supporting its potential as a once-daily oral treatment for RSV.

Epidemiology of Pediatric Viral Illnesses Before, During, and After the "Tripledemic" Viral Surge

OBJECTIVES

While children represented a small percentage of those hospitalized during the COVID-19 pandemic, there was a surge of pediatric viral-related admissions in the immediate postpandemic viral season. Our study compares the epidemiology and health care utilization of children with acute respiratory infections during the 2022-2023 season to prepandemic and subsequent postpandemic seasons to see if trends persisted.

METHODS

We examined administrative data for children who presented to 2 urban pediatric emergency departments (ED) during 3 periods: 2017-2020 (prepandemic), 2022-2023 (immediate postpandemic), and 2023-2024 (subsequent postpandemic). Outcomes included hospitalization rate for viral-related indications, stepdown/intensive care unit (ICU) admission, and use of advanced respiratory support. Multivariable regression controlled for demographics and specific viruses.

RESULTS

During the study period, there were 65,313 all-cause ED encounters. Compared with prepandemic seasons, viral-related admissions doubled in 2022-2023. In addition to an increase in ED visits, the odds of viral-related admission increased by 98% [adjusted odds ratio (aOR): 1.98; 99.8% CI: 1.75-2.24], odds of stepdown/ICU admission increased by 131% (aOR: 1.31; 99.8% CI: 1.67-3.21) and odds of advanced respiratory support increased by 70% (aOR: 1.70; 99.8% CI: 1.21-2.40). In 2023-2024, the stepdown/ICU admission rate remained the same compared with 2022-2023, and the odds of advanced respiratory support increased (aOR: 1.79, 99.8% CI: 1.22-2.63). Infection with respiratory syncytial virus increased adjusted odds of more advanced care.

CONCLUSIONS

Pediatric ED visits and hospitalization rate decreased in 2023-2024 compared with the postpandemic surge, but the admission rate remained high compared with prepandemic seasons, percent admitted to stepdown/ICU persisted, and the use of advanced respiratory support continued to increase.

The Epidemiology of Respiratory Syncytial Virus and the Impact of the COVID-19 Pandemic in a Retrospective Evaluation

INTRODUCTION

Respiratory syncytial virus (RSV) is the main etiological agent in pediatric lower respiratory tract infections. The limited availability of therapeutic options for severe clinical cases associated with RSV infection makes prophylactic interventions a priority for containment. The aim of the current study was to evaluate the epidemiology of RSV in the Piedmont population and the consequences of containment measures applied during the pandemic on viral circulation in the immediate and medium-term post-pandemic phase.

METHODS

This study considered all biological samples analyzed for RSV at the City of Health and Science of Turin collected from 1 January 2016 to 31 December 2023. Evaluation of the positivity rates of samples was performed and differences between pediatric and adult population swabs (nasopharyngeal, pharyngeal, nasal aspirates) and bronchoalveolar samples were reported.

RESULTS

This study analyzed 14,085 samples and highlighted a trend in Piedmont RSV infections characterized by a higher pediatric population involvement of 82% compared to the adult population at 17%. A higher number of URT infections (95%) compared to LRT infections (4.6%) was also identified. This study shows a peak in RSV cases from November to April between 2016 and 2020. Our data show no RSV positivity during the 2020/2021 winter season, a result most likely due to the influence of containment measures implemented during the COVID-19 pandemic.

CONCLUSIONS

Our study provided an epidemiological panorama of RSV and its high prevalence in pediatrics and adults. Pediatrics had a higher prevalence, while adults presented a delayed trend of about one month compared to pediatrics. The effectiveness of infection control measures applied during the SARS-CoV-2 pandemic to limit viral infections were proved. Future studies may further investigate the impact of the SARS pandemic on RSV epidemiology considering patients at a higher risk of severe symptoms.

The severity of respiratory syncytial virus infection in children during the SARS-CoV-2/COVID-19 pandemic: A nationwide study of 11,915 cases in Germany

PURPOSE

Respiratory syncytial virus (RSV) infection is a major cause of childhood hospitalization. The COVID-19 pandemic has disrupted the usual seasonal pattern of RSV, resulting in high activity during the off-season. This study aims to evaluate the effects of the pandemic on the severity of RSV infections.

METHODS

Data from 11,915 children hospitalized due to RSV infection between 2016 and 2022 were analyzed. The hospitalized patients were categorized into two groups, from January 2016 to February 2020 (PreCoV19 group) and from March 2020 to December 2022 (CoV19 group). The hospitalization duration, intensive care unit (ICU) admissions, length of stay at ICU, mechanical ventilation requirement and duration, Elixhauser comorbidity index scores, and in-hospital mortality were analyzed.

RESULTS

Children in the PreCoV19 group had a mean age of 0.4 ± 0.7, whereas those in the CoV19 group had a mean age of 0.6 ± 1.0 years. Children during the pandemic had significantly shorter hospital stays (4.3 ± 2.6 days) compared to children of the pre-pandemic period (4.9 ± 3.3 days). Although ICU admission rates did not change, the duration of ICU stays decreased in the CoV19 group. Moreover, the in-hospital mortality did not differ between the groups. A multivariable analysis showed that younger age, regardless of the pandemic period, was associated with prolonged hospital stays, higher ICU admission rates, and an increased requirement for mechanical ventilation.

CONCLUSION

Our findings highlight significant changes of the clinical characteristics of RSV infections during the pandemic, with implications for clinical management and public health strategies.

Acceptance and preference between respiratory syncytial virus vaccination during pregnancy and infant monoclonal antibody among pregnant and postpartum persons in Canada

BACKGROUND

Vaccination during pregnancy and infant monoclonal antibodies (mAb) were recently approved to prevent respiratory syncytial virus (RSV) disease in infants. Our study aims to describe self-reported attitudes and preferences between vaccination during pregnancy and infant mAb for this indication.

METHODS

From September 2023-March 2024, we completed a web-based, cross-sectional survey within the COVERED national prospective cohort study. Individuals who became pregnant in 2023 and were ≥ 19 years of age were included. We assessed demographics and general vaccination attitudes within and outside pregnancy, as well as attitudes toward newly licensed RSV products (i.e., vaccine during pregnancy, infant mAb), that were not yet available. Univariate and multivariate analysis was completed to identify predictors of accepting RSV immunization during pregnancy.

RESULTS

A total of 723 participants completed the RSV survey module, of which 50.3 % (n = 364) were currently pregnant. Among all participants, 79 % (n = 568) would accept at least one of the RSV immunization strategies; 77 % (n = 559) would accept RSV vaccination during pregnancy and 55 % (n = 396) would accept infant mAb. Vaccination during pregnancy was preferred by 79 % (n = 567) of participants, infant mAb were preferred by 4.4 % (n = 32), and 14 % (n = 98) indicated no preference. Participants rated Tdap vaccination as the highest priority (51 %) followed by RSV (17 %), COVID-19 (14 %), hepatitis B (11 %), and influenza (7 %). Predictors of accepting RSV vaccine during pregnancy included acceptance of Tdap and COVID-19 vaccines during pregnancy (p < 0.001 and p = 0.006, respectively) and ranking RSV as a high priority among pregnancy vaccines (p = 0.006).

CONCLUSION

In this national survey, more than two thirds of participants would accept the RSV vaccine while more than half would accept mAb. If given a choice, the vast majority preferred vaccination during pregnancy over mAb. These preferences should be considered when drafting policies and could influence cost-utility analyses.

Hospital admissions for acute respiratory tract infections among infants from Nunavut and the burden of respiratory syncytial virus: a 10-year retrospective cohort study

Background

Nunavut is a northern Canadian territory where a high proportion of infants are admitted to hospital with acute respiratory tract infection (ARI). Previous studies have been limited in regional and/or short duration of coverage. This study aimed to estimate the incidence rate, microbiology and outcomes of ARI hospitalizations in Nunavut infants.

Methods

We conducted a retrospective cohort study of infants aged <1 year from Nunavut hospitalized for ARI at two regional and four tertiary pediatric hospitals in Canada, January 1, 2010, to June 30, 2020. One regional hospital was located in Nunavut; others were located across Canada. Descriptive statistics and multivariable logistic regression were performed.

Findings

We identified 1189 ARI admissions, with an incidence rate of 133.9 per 1000 infants per year (95% confidence interval (CI): 126.8, 141.3). Of these admissions, 56.0% (n = 666) were to regional hospitals alone, 72.3% (n = 860) involved hospitalization outside of Nunavut, 15.6% (n = 185) were admitted into intensive care, and 9.2% (n = 109) underwent mechanical ventilation. Among 730 admissions with a pathogen identified, 45.8% had respiratory syncytial virus (RSV; n = 334), for a yearly incidence rate of 37.8 RSV-associated hospitalizations per 1000 infants (95% CI: 33.9, 42.1). Among RSV-associated hospitalizations, 41.1% (n = 138) were infants 0-2 months of age and 32.1% (n = 108) were >6 months. Compared with non-RSV admissions, infants with RSV had higher odds of admission into intensive care, oxygen therapy, CPAP/BiPAP respiratory support and length of hospital stay over a week.

Interpretation

Understanding the high burden of ARI among Nunavut infants can inform health policy and serve as a baseline for assessing the impact of any new interventions targeting infant ARIs.

Funding

Public Health Agency of Canada and Canadian Institutes of Health Research via the Canadian Immunization Research Network (CNF 151944).

Clinical Outcomes of Respiratory Syncytial Virus Infection Among Pediatric Immunocompromised Hosts

BACKGROUND

Pediatric immunocompromised patients are at an increased risk of severe respiratory syncytial virus (RSV) infection. Here, we aimed to describe the clinical course and outcomes of RSV infection in immunocompromised children.

METHODS

This single-center study at St. Jude Children's Research Hospital involved immunocompromised children ≤21 years old with a positive RSV clinical test from 2007 to 2019. Demographic and clinical characteristics, laboratory values, treatment delays for underlying conditions, and outcomes were gathered from electronic medical records. Multivariate models identified risk factors predictive of severe RSV-lower respiratory tract infection (LRTI).

RESULTS

A total of 391 patients, predominantly children over 2 years old (median age: 5), were included in the study. Acute lymphoblastic leukemia (ALL) was the most prevalent underlying disease. Most patients (85.7%) exhibited upper respiratory tract infections, while approximately 6% progressed to LRTIs. Over half of the patients (58.8%) required hospitalization, and one-third experienced modifications or delays in their underlying disease treatment due to RSV infection. Severe RSV infections were observed in 15.9% of patients. All-cause mortality was 2.6%, with 0.7% of deaths attributed to RSV.

CONCLUSIONS

One-third of patients experienced a delay in treatment for their underlying disease due to RSV infection, a phenomenon not well understood but potentially significant. Many immunocompromised children with RSV require hospitalization, including those over 2 years old. RSV imposes a significant burden on immunocompromised children of all ages, affecting their cancer treatment plans both directly and indirectly.

Cost-effectiveness of nirsevimab and maternal RSVpreF for preventing respiratory syncytial virus disease in infants across Canada

BACKGROUND

Nirsevimab, a long-acting monoclonal antibody, and RSVpreF, a maternal vaccine, are newly approved respiratory syncytial virus (RSV) prophylactics for infants in Canada. Both have the potential to expand prevention efforts, but there is limited evidence regarding their cost-effectiveness and how it varies across the country, despite disparate hospitalisation rates and resource use among different populations.

METHODS

We developed a decision tree model to follow twelve monthly birth cohorts through their first year of life, incorporating risk differentiation based on Canadian region, prematurity, and comorbidities. The model tracked medically attended infections, including hospitalisations, intensive care unit admissions, and outpatient visits, comparing costs (in 2024 Canadian dollars) and effectiveness (in quality-adjusted life years (QALYs)) of nine different immunisation strategies compared to no intervention. The analysis was conducted from both healthcare and societal perspectives. We conducted threshold price analyses, varying the price-per-dose of each product to determine the threshold prices at which expanded coverage becomes cost-effective.

RESULTS

At base case prices, the optimal strategy varies by region, but in all cases, the optimal strategy is both cost-saving and more effective than no intervention. In southern Canada, it is optimal to immunise only palivizumab-eligible infants (those born very prematurely or with high-risk comorbidities) with nirsevimab, resulting in cost savings of $4.14 and QALY gains of 0.000022 QALY per infant compared to no intervention. In the Northwest Territories, it is best to expand protection with nirsevimab to include all preterm infants (cost savings of $28.68 and QALY gains of 0.00007 per infant). In Nunavik and Nunavut, immunising all infants under 6 months and all infants under twelve months with nirsevimab are the best strategies, respectively (cost savings of $399.61 and QALY gains of 0.000821 per infant in Nunavik, and cost savings of $1067.03 and QALY gains of 0.000884 per infant in Nunavut). Universal, country-wide immunisation with nirsevimab would require a price-per-dose of under $112 to become the most cost-effective prevention strategy.

CONCLUSIONS

The optimal strategy for preventing respiratory syncytial virus disease in Canadian infants depends on product price and regional risk level and resource use. Canadian policy should account for these factors.

One-year epidemiological patterns of respiratory pathogens across age, gender, and seasons in Chengdu during the post-COVID era

Respiratory tract infections caused by various pathogens remain a significant public health concern due to their high prevalence and potential for severe complications. This study systematically analyzed the epidemiological characteristics of six common respiratory pathogens-Chlamydia pneumoniae (CP), Mycoplasma pneumoniae (MP), Adenovirus (AdV), Influenza A virus (FluA), Influenza B virus (FluB), and Respiratory Syncytial Virus (RSV)-in patients from Sichuan Jinxin Xinan Women and Children's Hospital between April 2023 and March 2024. Throat swab samples were collected from a total of 22,717 individuals. Each sample was processed using the AUTOMOLEC 3000 analyzer and the PCR-fluorescent probe method. The results showed that 10,171 (44.8%) individuals tested positive for at least one pathogen. MP had the highest overall positive rate (21.83%), followed by FluA (17.50%) and FluB (14.84%). MP showed the highest mean monthly (average) positive rate (16.84% ± 8.41). Significant differences were found between MP and AdV, CP and RSV in average positive rate (p < 0.05). Co-infection analysis revealed frequent associations between MP and AdV, MP and CP, and FluB with MP. Seasonal analysis indicated distinct peaks: FluA and FluB in winter, RSV in spring, and MP in summer, autumn and winter. Age-stratified analysis showed higher positivity rates of RSV in children aged 0-6 years, MP and CP in the 7-17 years group. Gender-based differences were only observed in RSV positive samples. These findings provide crucial insights into the prevalence and seasonal distribution of respiratory pathogens in Chengdu, offering valuable data to inform public health strategies in the post-COVID era.

Use of the moving epidemic method to guide the launch of palivizumab immunization campaigns for respiratory syncytial virus in Québec, Canada

OBJECTIVE

The COVID-19 pandemic disrupted the seasonal transmission pattern of respiratory syncytial virus (RSV), challenging the launch of palivizumab immunization campaigns. This study explored the performance of the moving epidemic method (MEM) to guide the launch of such campaigns.

METHODS

Data were collected through a continuous RSV surveillance system (07/2013‒03/2022) in Québec, Canada. Two strategies were compared: (1) a "preestablished" approach according to which each annual campaign began on November 1 and ended upon the earliest week with an RSV positivity rate ≤ 10% after March 31; and (2) MEM, according to which each annual campaign began and ended upon meeting an epidemic threshold of RSV positivity. We estimated the proportion of RSV cases that would be covered depending on the approach used for each RSV epidemic.

RESULTS

From seasons 2013-2014 through 2019-2020, RSV cases peaked between weeks 1 and 8, and all epidemic curves overlapped with an intraclass correlation coefficient (ICC) of 0.83. From 2013-2014 through 2019-2020, the epidemic periods determined by MEM and the preestablished approach covered similar proportions of RSV cases (MEM = 91.6%, preestablished = 90.7%) and had a similar duration (MEM = 21.3 weeks, preestablished = 21.7 weeks). With MEM, the 2021-2022 epidemic period started at week 29 and ended at week 51, covering 95.7% of cases. With the preestablished approach, the epidemic period started at week 44 and ended at week 8, covering 28.3% of cases.

CONCLUSION

During normal RSV seasons, MEM is an effective alternative to the preestablished approach. However, MEM appears significantly more robust to disruptions of RSV's seasonal pattern.

The Epidemiology, Clinical, and Economic Burdens of Respiratory Syncytial Virus Infections Amongst Hospitalized Children Under 5 Years of Age in Jordan: A National Multi-Center Cross-Sectional Study

Respiratory syncytial virus (RSV) has been recognized as a highly important cause of morbidity and mortality among children and adults. A cross-sectional study at representative sites in Jordan was undertaken to provide an assessment of the epidemiology and health and economic burdens of RSV and influenza infections in Jordan amongst hospitalized children under 5 years old for the period between 15 November 2022 and 14 April 2023. This study involved 1000 patients with a mean age of 17.10 (SD: 16.57) months. Of these, half (n = 506, 50.6%) had positive results for RSV. Furthermore, 33% and 17.4% of the participants had positive results for RSV-B and RSV-A, respectively. The findings underscore the severity of RSV infections, where a significant proportion of the children experienced severe respiratory distress, which led to bronchiolitis and pneumonia. This study meticulously documented the clinical outcomes, including the need for intensive care, mechanical ventilation, and prolonged hospital stays. There was no statistically significant difference in the financial burdens between the RSV-positive and RSV-negative patients. This study revealed the urgent need for preventive measures to control the substantial burden of RSV among children under 5 years old in Jordan.

Retrospective Analysis of RSV Infection in Pediatric Patients: Epidemiology, Comorbidities, Treatment, and Costs in Dubai (2014-2023)

Background: Infections attributable to respiratory syncytial virus (RSV) are a major cause of hospitalization among young children worldwide. Despite substantial clinical and economic burden, real-world data associated with RSV infections in the United Arab Emirates (UAE) are limited. Objectives: This study aimed to assess among children (<18 years) diagnosed with RSV the epidemiology, seasonality, comorbidities, treatment patterns, length of hospital stay, healthcare resource utilization (HCRU), and costs associated with pediatric infection in Dubai, UAE. Methods: This 10-year retrospective cohort study (Jan. 1, 2014-Sept. 30, 2023) utilized Dubai Real-World Database, a private insurance claims database. Patients aged <18 years with a first-episode diagnosis claim (primary or secondary, or a hospital admission) for RSV any time during the index period (Jan. 1, 2014-June 30, 2023) were included. Outcomes were analyzed during a 3-month follow-up. Patients were stratified into 3 cohorts: Cohort 1 (<2 years), Cohort 2 (2 to <6 years), and Cohort 3 (6 to <18 years). Results: Of 28 011 patients identified, 25 729 were aged <18 years with RSV infection. An increasing trend in reported cases was observed from 2014 to 2022, with an average annual increase of 55%. Half of study patients (49.3%) belonged to Cohort 1, with a mean age of 0.6 years, while less than 2% had known risk factors and 22% of the patients in cohort 1 were hospitalized. In Cohort 1, 32.0% had upper respiratory tract infections, 39.4% had lower respiratory tract infections, and 44.4% of patients had an "other respiratory disease." The average length of hospitalization was about 4 days across all cohorts. The total hospitalization cost was highest in patients <2 years, amounting to US 9   798   174 ( m e d i a n , U S 2241.30). Conclusion: Among the RSV patients, 49.3% were <2 years of age and few had recognized risk factors. Among patients <2 years, 22% were hospitalized, with an average hospital stay of 4 days; the cost of hospitalization totaled US $9 798 174. These findings can inform healthcare stakeholders about future policy measures and the need for effective preventive strategies.

Seasons of Kawasaki Disease during the COVID-19 pandemic

The incidence of Kawasaki Disease has a peak in the winter months with a trough in late summer/early fall. Environmental/exposure factors have been associated with a time-varying incidence. These factors were altered during the COVID-19 pandemic. The study was performed through the International Kawasaki Disease Registry. Data from patients diagnosed with acute Kawasaki Disease and Multiple Inflammatory Syndrome-Children were obtained. Guideline case definitions were used to confirm site diagnosis. Enrollment was from 1/2020 to 7/2023. The number of patients was plotted over time. The patients/month were tabulated for the anticipated peak Kawasaki Disease season (December-April) and non-peak season (May-November). Data were available for 1975 patients from 11 large North American sites with verified complete data and uninterrupted site reporting. The diagnosis criteria were met for 531 Kawasaki Disease and 907 Multiple Inflammatory Syndrome-Children patients. For Multiple Inflammatory Syndrome-Children there were peaks in January of 2021 and 2022. For Kawasaki Disease, 2020 began (January-March) with a seasonal peak (peak 26, mean 21) with a subsequent fall in the number of cases/month (mean 11). After the onset of the pandemic (April 2020), there was no clear seasonal Kawasaki Disease variation (December-April mean 12 cases/month and May-November mean 10 cases/month). During the pandemic, the prevalence of Kawasaki Disease decreased and the usual seasonality was abolished. This may represent the impact of pandemic public health measures in altering environmental/exposure aetiologic factors contributing to the incidence of Kawasaki Disease.

The Impact of COVID-19 Pandemic on Respiratory Syncytial Virus Infection in Children

Background/Objective: Respiratory syncytial virus (RSV) is a major cause of bronchiolitis in infants and young children. Bronchiolitis, an acute inflammation of the lower respiratory tract, can lead to pneumonia, respiratory failure, and death. We aimed to compare the incidence and severity of RSV infection in children aged 0-60 months before and during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A retrospective chart review was conducted on patients aged 0-60 months who tested positive for RSV between May 1, 2018, and May 31, 2022, in a community hospital in Queens County, New York City, United States. Comparisons were made between seasons 2018-2019 and 2019-2020 as before, and seasons 2020-2021 and 2021-2022 as during the COVID-19 pandemic. Severity of RSV infection was assessed using the Bronchiolitis Severity Score (BSS). Data were analyzed using R software, a p value of < 0.05 was considered statistically significant. Results: The incidence of RSV infection in seasons 2018-2019 and 2019-2020 peaked from mid-October to February, whereas the first season during the COVID-19 pandemic (2020-2021) was truncated with a very low incidence of RSV infection, and season 2021-2022 peaked from September to January, with the highest incidence (37%) and lower frequency of RSV infection at any given point. Patients during the season 2021-2022 were older (H [2, 196.6] = 12.5, p < 0.001, 95% CI = [5.4, 25.6]) and had milder illness (H [2, 187.5] = 7.5, p < 0.01, 95% CI = [2.1, 19.2]). Conclusions: We observed a lower incidence of RSV infection and a lower rate of hospitalization for RSV during the COVID-19 pandemic. The second RSV season during the COVID-19 pandemic began earlier, lasted longer, and had a lower frequency. Older children with milder illnesses were affected most during this season. RSV epidemiology and disease burden were impacted by the COVID-19 pandemic and could have significant ramifications for its prevention and control strategies.

Healthcare resource utilisation and costs in infants with confirmed respiratory syncytial virus infections: a national population cohort study

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of severe respiratory infections in infants worldwide, significantly affecting their health and contributing to the global healthcare burden. We aimed to examine healthcare resource utilisation patterns and costs for infants under one year old with confirmed RSV infection across subgroups of different gestational ages and health conditions and the cost implications of RSV infections over time, thereby demonstrating the economic burden of the disease.

METHODS

This retrospective cohort study utilised nationwide claims data from the Korea Health Insurance Review and Assessment Service for infants under one year of age with confirmed RSV infection in the first year of life from January 2017 to April 2022. The infants were stratified into three subgroups based on their gestational age and health status: unhealthy preterm, healthy preterm, and full-term infants. A descriptive analysis was conducted to estimate healthcare utilization by type of resource and costs related to the treatment of RSV.

RESULTS

Out of 93,585 RSV infections identified, 31,206 patients met the inclusion criteria; these included 963 unhealthy preterm, 1,768 healthy preterm and 28,475 full-term infants. In our study, 76.3% of the infants with confirmed RSV infection required intensive care, including hospitalisation and more critical interventions such as intensive care unit (ICU) or mechanical ventilation (MV). The total average cost of RSV management was notably higher for unhealthy preterm infants ($ 6,325; 95% confidence interval (CI): $ 5,484-7,165) than for healthy preterm ($ 1,134; 95% CI: $ 1,006 - 1,261) and full-term infants ($ 606; 95% CI: 583-630). Our findings confirmed a significant epidemiological and economic burden, with infants at greater risk-shorter gestational age and poorer health conditions. Furthermore, we observed a marked increase in the total average cost of RSV management during COVID-19, reflecting the complex interplay between RSV and pandemic-related healthcare dynamics.

CONCLUSION

Our findings provide evidence for the significant economic burden of RSV infection among infants, with considerable disparities based on gestational age and health status subgroups. However, RSV prevention policies should also recognise that healthy preterm or full-term infants who receive intensive care face a significant disease burden.

Impact of COVID-19 Nonpharmaceutical Interventions on Bordetella pertussis, Human Respiratory Syncytial Virus, Influenza Virus, and Seasonal Coronavirus Antibody Levels: A Systematic Review

During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) were introduced to reduce the spread of SARS-CoV-2. This also resulted in a reduction of notifications of other acute respiratory infections and an altered seasonality when NPIs were lifted. Without circulation of pathogens, waning of antibodies is expected, which is a first indicator of decreased immunity. Here, by performing a systematic literature review, we investigated whether reduced antibody levels due to waning immunity contributed to the altered seasonality after NPIs were lifted. Thirteen articles met the inclusion criteria and reported antibody levels or seroprevalence of human respiratory syncytial virus, seasonal human coronavirus, Bordetella pertussis, and influenza virus. We show that the COVID-19 pandemic most likely led to waning of pathogen-specific antibodies, with the strongest evidence for human respiratory syncytial virus and seasonal human coronavirus and with a larger decrease in children vs adults. Waning antibodies might have resulted in out-of-season activity for these pathogens.

Cost-effectiveness of RSVpreF vaccine and nirsevimab for the prevention of respiratory syncytial virus disease in Canadian infants

BACKGROUND

Health Canada recently authorized the RSVpreF pregnancy vaccine and nirsevimab to protect infants against respiratory syncytial virus (RSV) disease.

OBJECTIVE

Assess the cost-effectiveness of RSVpreF and nirsevimab programs in preventing RSV disease in infants, compared to a palivizumab program.

METHODS

We used a static cohort model of a Canadian birth cohort during their first RSV season to estimate sequential incremental cost-effectiveness ratios (ICERs) in 2023 Canadian dollars per quality-adjusted life year (QALY) for nine strategies implemented over a one-year time period, from the health system and societal perspectives. Sensitivity and scenario analyses were conducted to explore the impact of uncertainties on the results.

RESULTS

All-infants nirsevimab programs averted more RSV-related outcomes than year-round RSVpreF programs, with the most RSV cases averted in a seasonal nirsevimab program with catch-up. Assuming list prices for these immunizing agents, all-infants nirsevimab and year-round RSVpreF programs were never cost-effective, with ICERs far exceeding commonly used cost-effectiveness thresholds. Seasonal nirsevimab with catch-up for infants born outside the RSV season was a cost-effective program if prioritized for infants at moderate/high-risk (ICER <$28,000 per QALY) or those living in settings with higher RSV burden and healthcare costs, such as remote communities where transport would be complex (ICER of $5700 per QALY). Using a $50,000 per QALY threshold, an all-infants nirsevimab program could be optimal if nirsevimab is priced at <$110-190 per dose. A year-round RSVpreF for all pregnant women and pregnant people plus nirsevimab for infants at high-risk was optimal if nirsevimab is priced at >$110-190 per dose and RSVpreF priced at <$60-125 per dose.

INTERPRETATION

Prophylactic interventions can substantially reduce RSV disease in infants, and more focused nirsevimab programs are the most cost-effective option at current product prices.

The Epidemiology of Respiratory Syncytial Virus: New Trends and Future Perspectives

RSV (respiratory syncytial virus) is a major cause of acute lower respiratory tract infection (LRTI) worldwide [...].

Pediatric Respiratory Syncytial Virus Hospitalizations, 2017-2023

Importance

Respiratory syncytial virus (RSV) transmission was disrupted worldwide following the COVID-19 pandemic, and further study is required to better understand these changes.

Objective

To compare observed and expected RSV hospital and intensive care unit (ICU) admission rates and characteristics of admitted children during the 2021-2022 and 2022-2023 seasons.

Design, Setting, and Participants

A population-based cohort study of all children aged younger than 5 years in Ontario, Canada, July 1, 2017, through March 31, 2023, was conducted.

Exposures

Individual and neighborhood-level sociodemographic and clinical characteristics were identified from administrative data, including age, palivizumab eligibility, complex medical conditions, rurality, and living in a marginalized neighborhood.

Main Outcomes and Measures

The main outcome was RSV-associated hospitalization. Secondary outcomes included ICU admissions, mechanical ventilation, extracorporeal membrane oxygenation, and in-hospital death. Poisson generalized estimating equations were used to model weekly age- and sex-specific hospitalization rates and estimate expected rates in the postpandemic era; adjusted rate ratios (RRs) and 95% CIs are reported.

Results

This cohort study included approximately 700 000 children per study year. Compared with prepandemic years (2017-2018, 2018-2019, and 2019-2020), the 2021-2022 RSV season peaked slightly earlier, but overall admission rates were comparable (289.1 vs 281.4-334.6 per 100 000, or approximately 2000 admissions). The 2022-2023 season peaked a month earlier and resulted in more than twice as many hospitalizations (770.0 per 100 000; n = 4977 admissions). The proportion of children admitted to an ICU in 2022-2023 (13.9%) was slightly higher than prepandemic (9.6%-11.4%); however, the population-based rate was triple the prepandemic levels (106.9 vs 27.6-36.6 per 100 000 children in Ontario). With the exception of palivizumab-eligible children, all sociodemographic and health status characteristics were associated with lower-than-expected RSV hospitalization rates in 2021-2022. In contrast, older age of patients was associated with higher-than-expected rates in 2022-2023 (ie, 24-59 months: RR, 1.90; 95% CI, 1.35-2.66).

Conclusions and Relevance

There were notable differences in RSV epidemiologic characteristics in Ontario following the COVID-19 pandemic. It is not yet clear whether and how long atypical RSV epidemics may persist. Clinicians and program planners should consider the potential for ongoing impacts to health care capacity and RSV immunization programs.

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.

Evolving Epidemiology of Pediatric Respiratory Syncytial Virus (RSV) Cases Around COVID-19 Pandemic: Impact and Clinical Insights, Retrospective Cohort Study

BACKGROUND

The burden of respiratory syncytial virus (RSV) in high-risk pediatric patients remains unclear. Therefore, this study aims to characterize pediatric RSV cases from January 2019 to December 2022 and assess the impact of the COVID-19 pandemic on RSV burden and RSV-related outcomes. In addition, examining factors influencing RSV-related hospitalization.

METHODS

This is a retrospective study that included pediatric patients (aged 14 and below) who presented at King Faisal Specialist Hospital and Research Centre (KFSHRC) in Riyadh, Saudi Arabia with RSV infection identified using real-time reverse-transcriptase polymerase chain reaction assays. Statistical analyses were performed using STATA.

RESULTS

A total of 885 RSV cases were reported; (56.05%) were males and (43.95%) were females with a median age of 24 months [interquartile range (IQR): 11-60]. 534 (60.34%) required hospitalization. As for RSV seasonality, there was a significant increase in RSV prevalence following the COVID-19 pandemic, escalating from 205 cases in 2019 to 425 cases in 2022. The increase in 2022 was evident in January and persisted from September to December, reaching its peak during the months of October (20.70% - 88 cases) and November (32.00% - 136 cases). About (27.12%) of RSV infected children were medically free patients. Symptomatic patients exhibited various clinical manifestations, with ventilation necessary in (13.11%) of cases. Further analysis revealed significant changes in RSV-related outcomes post-COVID-19, including a decrease in hospitalization rates, an increase in medically free patients, and a lower need for ventilation (p < 0.05). Notably, a significant proportion of RSV admissions occurred within the first 6 months of life, with (77.69%) in the age group of 0 to 5 months. In addition, previous RSV infection, prematurity, low birth weight, renal disease, congenital heart disease, endocrine/metabolic disease, neuro/neuromuscular diseases, and genetic disorders were positively associated with hospitalization (P < 0.05). Interestingly, asthma and bone marrow transplantation were negatively associated with hospitalization (P < 0.05). The mortality rate in this study is (2.37%) (21/885).

CONCLUSION

This study provides a comprehensive understanding of the demographic and clinical factors influencing RSV outcomes, highlighting the impact of the COVID-19 pandemic and shedding light on potential risk factors for RSV-related hospitalization. The highest prevalence of RSV during (September to January), aligning with global patterns and emphasizing the importance of timing in preventive strategies.

Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic

Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with the greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially in the United States (US) following the implementation of COVID-19-related non-pharmaceutical interventions but later rebounded with abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined. In this retrospective cohort study from 2009 to 2023 in Chicago, Illinois, US, we examined RSV epidemiology, clinical severity, and genetic diversity. We found that changes in RSV diagnostic platforms drove increased detections in outpatient settings post-2020 and that hospitalized adults infected with RSV-A were at higher risk of intensive care admission than those with RSV-B. While population structures of RSV-A remained unchanged, RSV-B exhibited a genetic shift into geographically distinct clusters. Mutations in the antigenic regions of the fusion protein suggest convergent evolution with potential implications for vaccine and therapeutic development.

Epidemiology of respiratory syncytial virus in a large pediatric hospital in Central Italy and development of a forecasting model to predict the seasonal peak

BACKGROUND

Respiratory Syncytial Virus (RSV) is responsible for the majority of acute lower respiratory infections in infants and can affect also older age groups. Restrictions linked to the emergence of the SARS-CoV-2 pandemic and their subsequent lifting caused a change in the dynamics of RSV circulation. It is therefore fundamental to monitor RSV seasonal trends and to be able to predict its seasonal peak to be prepared to the next RSV epidemics.

METHODS

We performed a retrospective descriptive study on laboratory-confirmed RSV infections from Bambino Gesù Children's Hospital in Rome from 1st January 2018 to 31st December 2022. Data on RSV-positive respiratory samples (n = 3,536) and RSV-confirmed hospitalizations (n = 1,895) on patients aged 0-18 years were analyzed. In addition to this, a SARIMA (Seasonal AutoRegressive Integrated Moving Average) forecasting model was developed to predict the next peak of RSV.

RESULTS

Findings show that, after the 2020 SARS-CoV-2 pandemic season, where RSV circulation was almost absent, RSV infections presented with an increased and anticipated peak compared to pre-pandemic seasons. While mostly targeting infants below 1 year of age, there was a proportional increase in RSV infections and hospitalizations in older age groups in the post-pandemic period. A forecasting model built using RSV weekly data from 2018 to 2022 predicted the RSV peaks of 2023, showing a reasonable level of accuracy (MAPE 33%). Additional analysis indicated that the peak of RSV cases is expected to be reached after 4-5 weeks from case doubling.

CONCLUSION

Our study provides epidemiological evidence on the dynamics of RSV circulation before and after the COVID-19 pandemic. Our findings highlight the potential of combining surveillance and forecasting to promote preparedness for the next RSV epidemics.

Burden of disease of respiratory syncytial virus in infants, young children and pregnant women and people

Background

Passive immunization products for infants and pregnant women and people have sparked interest in understanding Canada's respiratory syncytial virus (RSV) burden. This rapid review examines RSV burden of disease in infants, young children and pregnant women and people.

Methods

Electronic databases were searched to identify studies and systematic reviews reporting data on outpatient visits, hospitalizations, intensive care unit admissions, deaths and preterm labour associated with RSV. We also contacted Canadian respiratory virus surveillance experts for additional data.

Results

Overall, 17 studies on infants and young children and 10 studies on pregnant women and people were included, in addition to primary surveillance data from one Canadian territory (Yukon). There were higher rates of medical utilization for infants than older children. Hospitalization rates were highest in infants under six months (more than 1% annually), with 5% needing intensive care unit admission, but mortality was low. Severe outcomes often occurred in healthy full-term infants and burden was higher than influenza. Respiratory syncytial virus attack rate was 10%-13% among pregnant women and people. Only one study found a higher hospitalization rate in pregnant women and people compared to non-pregnant women and people. Limited evidence was found on intensive care unit admission, death and preterm birth for pregnant women and people.

Conclusion

While risk of severe outcomes is larger in high-risk infants and children, healthcare burden is greatest in healthy term infants. The RSV severity for pregnant women and people appears to be similar to that for non-pregnant women and people.

Altered RSV Epidemiology and Genetic Diversity Following the COVID-19 Pandemic

Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially following the implementation of non-pharmaceutical interventions to mitigate the COVID-19 pandemic but later rebounded with initially abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined. In this retrospective cohort study, we examined RSV epidemiology, clinical severity, and genetic diversity in the years surrounding the COVID-19 pandemic. We found that changes in RSV diagnostic platforms drove increased detections in outpatient settings after 2020 and that hospitalized adults with RSV-A were at higher risk of needing intensive care than those with RSV-B. While the population structure of RSV-A remained unchanged, the population structure of RSV-B shifted in geographically distinct clusters. Mutations in the antigenic regions of the fusion protein suggest convergent evolution with potential implications for vaccine and therapeutic development.